Allan J Hamilton

Interests

Teaching

Neurosurgery, clinical medical simulation, simulation assessment and systems integration, artificial tissues, glioma angiogenesis, tumor genomic alterations, stereotaxic, stereotactic neurosurgery, stereotactic radiosurgery, 3D computerized navigation, medical humanities, electrical & computerized engineering, biomedical engineering and design

Research

gliomas, glioma radiobiology, glioma chemotherapy, glioma mutagenesis, stereotactic radiosurgery, medical simulation, computerized assessment of surgical skills, artificial tissues

Courses

Scholarly Contributions

Books

• Hamilton, A. J. (2023). The New Encyclopedia of Downhill Skiing: The Definitive Guide* to Everything About Alpine Skiing from Novice to Expert Skier . Salt Lake City: Snows of Yesteryear Publishing.
• Hamilton, A. J. (2016). Lead With Your Heart. North Adams, MA: Storey Publishing. doi:September 1, 2016
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  Award-winning author and celebrated neurosurgeon Allan J. Hamilton combines his understanding of the human brain with nearly 30 years’ experience training horses to offer wisdom on such universal themes as leadership, motivation, ambition, and humility. The results are showcased in more than 100 thoughtful essays that treat working with horses as a metaphor for personal, professional, and spiritual growth. Whether you’re searching for greater spiritual depth or simply want to better understand your four-legged partner, this wise and important collection has something for you.Review“Allan Hamilton is a real brain surgeon with true horse sense. If you want to be a better leader, teacher, parent — a more conscious human being, rather than a human doing — this is a book to keep close.”— Stephen Kiesling, editor-in-chief, Spirituality & Health“Dr. Hamilton blends horse sense with common sense and adds lessons on trust, respect, and compassion, which we can take from the round pen, to the saddle, to the office, and to our living rooms.”— Molly Sweeney, vice president of the Horses & Humans Research Foundation“Lead with Your Heart takes you deep into learning the art of horsemanship and helps you enter the sensory-based world of the horse.”— Temple Grandin, author of Humane Livestock Handling and Animals in Translation“What a gem of a book! Allan Hamilton offers jewels to enrich our relationships with horse, family, colleagues, and self. This is the sort of book to keep close to refer to as life’s inevitable chaotic waves threaten.”— Barbara K. Rector, CEIP-ED, co-founder of Equine Facilitated Mental Health Association"Recent research tells us that horses are much smarter than we once believed. Allan J. Hamilton provides an excellent foundation for how to achieve a deeper and more rewarding partnership with them.”— Wendy Williams, author of The Horse: The Epic History of Our Noble Companion“Dr. Allan Hamilton’s unfailing respect for the dignity and wisdom of horses provides an excellent blueprint for all who love our equine companions.”— Elizabeth Letts, New York Times best-selling author of The Eighty-Dollar Champion and The Perfect Horse"Hamilton transfers life lessons learned from his history with horses to be applicable to anyone wishing to live a more mindful life. Both the writing and paintings invite quiet reflection on the ways we live, act, and interact with each other, horses, and the world."— Carmela Caruso, Bookseller at Novels & Novelties Bookstore Read moreFrom the Back CoverThe Wisdom of HorsesWorking with horses can be a transformative experience. Their soft eyes, wild spirit, and shy honesty offer a glimpse of how entirely different the horse's mind is from our own. Allan J. Hamilton, a neurosurgeon and a pioneer in equine-assisted therapy, distills in 112 short essays what horses have taught him about forgiveness, true leadership, courage, and love.
• Hamilton, A. J. (2019). Protecting the Female Brain for Life. New York: Workman Publishing.
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  A book of hope, Younger Next Year for Women shows you how to become functionally younger for the next five to ten years, and continue to live thereafter with newfound vitality. Learn how the Younger Next Year plan of following “Harry’s Rules”—a program of exercise, diet, and maintaining emotional connections—will not only help you turn back your physical biological clock, but will improve memory, cognition, mood, and more. In two new chapters, prominent neurologist Allan Hamilton explains how the program directly affects your brain—all the way down to the cellular level—while Chris Crowley, in his inimitable voice, gives the personal side of the story. In other words, how to live brilliantly for the three decades or more after menopause. The results will be amazing.
• Hamilton, A. J. (2019). Younger Next Year: Live Strong, Fit, and Sexy--Until You're 80 and Beyond. New York: Workman Publishing.
• Hamilton, A. J. (2011). Zen Mind, Zen Horse. North Adams, MA: Storey Publisher. doi:September 1, 2011
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  Editorial ReviewsReview"These deceptively simple techniques embody a powerful set of spiritual techniques." Andrew Weil, MD, Author, Eight Weeks to Optimum Health"Zen Mind, Zen Horse is both practical and profound, offering sound advice for tapping the wisdom of horses as natural mindfulness teachers." Linda Kohanov, Author, The Tao of Equus"Hamilton has given humans a way to achieve our highest good by allowing horses to be our guides. This beautiful testament to the power and magic of equine energy captures the soul of a horse perfectly." Susan Richards, Author, Chosen By a Horse"Combining brain science, horse sense, and fine storytelling, this spiritual handbook points toward a special and completely real form of enlightenment." Stephen Kiesling, Editor-in-Chief, Spirituality and Health MagazineZen Mind, Zen Horse is far more than a book about how to care for a horse, though it stands out as one of the best on the subject. Rather, Hamilton has given humans a way to achieve our highest good by allowing horses to be our guides. This beautiful testament to the power and magic of equine energy captures the soul of a horse perfectly. Susan Richards, Author, Chosen By a HorseFrom the Back CoverHorse training presents unique opportunities to explore powerful spiritual truths. The exercises in Zen Mind, Zen Horse offer everyone who works with horses -- novice or expert -- a new understanding of how humans train and interact with horses and why these two species, one a master predator and the other the ultimate prey animal, have such a deep, natural connection. Horses have evolved to understand and respond to the flow of vital energy -- chi -- around them, using it in their body language to communicate with members of their herd, to express dominance, and to sense danger from nearby predators. Being quietly present and receptive to your horse's energy opens the potential of your emotional, intuitive right brain. These simple, safe groundwork techniques reveal a pathway to awakening your deep sensitivity, calm leadership, intuition, and mindfulness.
• Hamilton, A. J. (2008). The Scalpel and the Soul. New York: Penguin/Tarcher.
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  From Publishers WeeklyHamilton has led a remarkable life as a neurosurgeon. There are moments in this spiritual memoir when readers will wish he were their personal guide for the scariest of surgeries. In many ways, this is a story about real doctors as Hamilton understands them—people with exemplary bedside manners who not only make life-and-death decisions for the most vulnerable of the sick, but who have the vision (sometimes literally) to sit and listen as long as it takes, to take patients' hands, dealing with their questions and fears with the utmost gentleness and an eye toward the transcendent and supernatural. Readers will be moved by stories of former patients like Thomas, a child burn victim with such a gift of spirit that he could manage joy despite his tragic condition, and Donald, a brave man determined to live life to the fullest despite a vicious brain tumor. Hamilton's voice soars when he reflects directly on his experience as a brain surgeon, the bulk of which occurs (unfortunately) in the book's second half. In light of these high points, Hamilton's occasionally stumbling and awkward prose when straying from his patients' sides can seem jarring. (Mar. 13) Copyright © Reed Business Information, a division of Reed Elsevier Inc. All rights reserved. --This text refers to an out of print or unavailable edition of this title.Review"Funny, irreverent, earthy, big-hearted, honest, real."-Family Circle online "Books of the Month" Review"Allan Hamilton is a natural storyteller. His real-life experiences remind us that patients and surgeons can share in a spiritual transformation during the course of battling disease." -Linda Klein, R.N., producer of Grey's Anatomy and Nip/Tuck"His observations and insights push the limits of current scientific knowledge as he attempts to bring some rational thought to the unexplainable."-Richard Carmona, M.D., MPH, FACS, 17th Surgeon General of the United States"A moving account of what can happen when a doctor opens his heart and his eyes to life's spiritual lessons and to the mystery that thrives amidst the terror and trauma of life-threatening illness."-Bernie Siegel, M.D., author of Help Me to Heal and Prescriptions for Living

Chapters

• Hamilton, A. J. (2017). Chapter 10: Systems Design, Modeling, and Simulation in Medicine. In Advances in Design and Engineering in Medical Simulation(pp 209-234).
• Rhoton, A. L., & Hamilton, A. J. (2005). Chiari Malformation and Syringomyelia. In 7. Rhoton A, Hamilton AJ, Tabor C: "Chiari Malformation and Syringomyelia”. In Benzel EC (Ed): Spine Surgery: Techniques, Complication Avoidance & Management, New York: Churchill Livingstone, Inc., Vol 2, p 793-812, 1999.(pp 793-812). Elsevier. doi:10.1016/B978-0-443-06616-0.50089-4
• McCormick, W., Steinmetz, M., Hamilton, A., Crownover, R., Kalfas, I., & Benzel, E. (1999).

  1.     Takacs I, Hamilton AJ: "Extracranial Stereotactic Radiosurgery: Applications for the Spine and Beyond”.  In Kondziolka D (ed) Neurosurgery Clinics of North America 10(2): 257-270, 1999. In Neurosurgery Clinics of North America. doi:10.1016/B978-0-443-06616-0.50139-5

Journals/Publications

• Hamilton, A. J. (2024). Hamilton A (July 02, 2024) The Future of Artificial Intelligence in Surgery. Cureus 16(7): e63699. doi:10.7759/cureus.63699. Cureus, 16(7), 30. doi:doi:10.7759/cureus.63699
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  Until recently, innovations in surgery were largely represented by extensions or augmentations of the surgeon’s perception. This includes advancements such as the operating microscope, tumor fluorescence, intraoperative ultrasound, and minimally invasive surgical instrumentation. However, introducing artificial intelligence (AI) into the surgical disciplines represents a transformational event. Not only does AI contribute substantively to enhancing a surgeon’s perception with such methodologies as three-dimensional anatomic overlays with augmented reality, AI-improved visualization for tumor resection, and AI-formatted endoscopic and robotic surgery guidance. What truly makes AI so different is that it also provides ways to augment the surgeon’s cognition. By analyzing enormous databases, AI can offer new insights that can transform the operative environment in several ways. It can enable preoperative risk assessment and allow a better selection of candidates for procedures such as organ transplantation. AI can also increase the efficiency and throughput of operating rooms and staff and coordinate the utilization of critical resources such as intensive care unit beds and ventilators. Furthermore, AI is revolutionizing intraoperative guidance, improving the detection of cancers, permitting endovascular navigation, and ensuring the reduction in collateral damage to adjacent tissues during surgery (e.g., identification of parathyroid glands during thyroidectomy). AI is also transforming how we evaluate and assess surgical proficiency and trainees in postgraduate programs. It offers the potential for multiple, serial evaluations, using various scoring systems while remaining free from the biases that can plague human supervisors. The future of AI-driven surgery holds promising trends, including the globalization of surgical education, the miniaturization of instrumentation, and the increasing success of autonomous surgical robots. These advancements raise the prospect of deploying fully autonomous surgical robots in the near future into challenging environments such as the battlefield, disaster areas, and even extraplanetary exploration. In light of these transformative developments, it is clear that the future of surgery will belong to those who can most readily embrace and harness the power of AI.
• Hamilton, A. J. (2024). Artificial Intelligence and Healthcare Simulation: The Shifting Landscape of Medical Education. Cureus, 16(5), 1-18 125 references. doi:doi:10.7759/cureus.59747
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  18 pages 125 referncesAbstractThe impact of artificial intelligence (AI) will be felt not only in the arena of patient care and deliverable therapies but will also be uniquely disruptive in medical education and healthcare simulation (HCS), in particular. As HCS is intertwined with computer technology, it offers opportunities for rapid scalability with AI and, therefore, will be the most practical place to test new AI applications. This will ensure the acquisition of AI literacy for graduates from the country’s various healthcare professional schools. Artificial intelligence has proven to be a useful adjunct in developing interprofessional education and team and leadership skills assessments. Outcome-driven medical simulation has been extensively used to train students in image- centric disciplines such as radiology, ultrasound, echocardiography, and pathology. Allowing students and trainees in healthcare to first apply diagnostic decision support systems (DDSS) under simulated conditions leads to improved diagnostic accuracy, enhanced communication with patients, safer triage decisions, and improved outcomes from rapid response teams. However, the issue of bias, hallucinations, and the uncertainty of emergent properties may undermine the faith of healthcare professionals as they see AI systems deployed in the clinical setting and participating in diagnostic judgments. Also, the demands of ensuring AI literacy in our healthcare professional curricula will place burdens on simulation assets and faculty to adapt to a rapidly changing technological landscape. Nevertheless, the introduction of AI will place increased emphasis on virtual reality platforms, thereby improving the availability of self-directed learning and making it available 24/7, along with uniquely personalized evaluations and customized coaching. Yet, caution must be exercised concerning AI, especially as society’s earlier, delayed, and muted responses to the inherent dangers of social media raise serious questions about whether the American government and its citizenry can anticipate the security and privacy guardrails that need to be in place to protect our healthcare practitioners, medical students, and patients.
• Hamilton, A. J. (2024).  Optimizing Individual Wound Closure Practice Using Augmented Reality: A Randomized Controlled Study. Cureus 16(4): e59296. doi:10.7759/cureus.59296. Cureus, 16(4), 7 pages 23 references. doi:doi:10.7759/cureus.59296
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  AbstractBackgroundSuturing requires repeated practice with guidance to prevent skill deterioration; however, guidance is often limited by expert availability. There is evidence that augmented reality (AR) may assist procedural skill acquisition among learners. This study examines the use of an AR suture guidance application to assist the independent practice of suturing.MethodologyA novel suture guidance application was designed for the Microsoft HoloLens. The guidance system included a calibration system and holograms that projected over a suture pad in a stepwise manner. To assess the application, 30 medical students were recruited and randomly assigned to two groups. The control group (n = 16) was given 30 minutes of independent suture practice, while the experimental group (n = 14) utilized the suture guidance application. Both groups completed a pre- and post-test wound closure assessment. After the post-test, the control group trialed the suture guidance application. All participants completed a feedback survey on the application. Statistical analysis was completed using Stata (StataCorp., College Station, TX, USA) with paired Student’s t-tests and Welch’s t-tests with a significance of 95%.ResultsBoth groups demonstrated a significant improvement in total time and time per stitch during the post-test. Additionally, comparing pre- and post-test assessments in the experimental group revealed a significant improvement in the total number of stitches (p = 0.007), the ratio of bisecting stitches (p = 0.02), and the symmetry of stitch bite (p = 0.03). The feedback survey supported the application for guiding suture placement and spacing. Participants identified limitations in the hologram stability and neck positioning.ConclusionsThis study suggests the potential to use AR to facilitate the independent practice of wound closure within simulation environments.
• Ghlandian, A., Hamilton, A., Hua, H., Katz, J., Lee, S., Nabhani, J., Nguyen, M., & Samakar, K. (2022).

  Surgeon Assessment of a Novel Multi-Resolution Foveated Laparoscope

  . Surgical Innovation, 29(6), 769-780. doi:10.1177/15533506221081100
• Katz, J., Hua, H., Lee, S., Nguyen, M., & Hamilton, A. (2022). A dual-view multi-resolution laparoscope for safer and more efficient minimally invasive surgeryKatz, Jeremy, Hong Hua, Sangyoon Lee, Mike Nguyen, and Allan Hamilton. "A dual-view multi-resolution laparoscope for safer and more efficient minimally invasive surgery." Scientific Reports 12, no. 1 (2022): 18444.. Katz, Jeremy, Hong Hua, Sangyoon Lee, Mike Nguyen, and Allan Hamilton. "A dual-view multi-resolution laparoscope for safer and more efficient minimally invasive surgery." Scientific Reports 12, no. 1 (2022): 18444., 12(1). doi:10.1038/s41598-022-23021-2
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  Minimally invasive surgery (MIS) is limited in safety and efficiency by the hand-held nature and narrow fields of view of traditional laparoscopes. A multi-resolution foveated laparoscope (MRFL) was invented to address these concerns. The MRFL is a stationary dual-view imaging device with optical panning and zooming capabilities. It is designed to simultaneously capture and display a zoomed view and supplemental wide view of the surgical field. Optical zooming and panning capabilities facilitate repositioning of the zoomed view without physically moving the system. Additional MRFL features designed to improve safety and efficiency include its snub-nosed endoscope, tool-tip auto tracking, programmable focus profiles, unique selectable display modalities, foot pedal controls, and independently controlled surgeon and assistant displays. An MRFL prototype was constructed to demonstrate and test these features. Testing of the prototype validates its design architecture and confirms the functionality of its features. The current MRFL prototype functions adequately as a proof of concept, but the system features and performance require further improvement to be practical for clinical use.
• Hamilton, A. J. (2021). Neural Changes Following Equine-assisted Therapy for PTSD: A Longitudinal Multimodal Brain Imaging Study. Human Brain Mapping.
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  Zhu X, Suarez-Jimenez B, Zilcha-Mano S, Lazarov A, Arnon S, Lowell A Bergman M, Matthew R, Hamilton A, Hamilton J, Turner JB, Markowitz M, Fisher PW, and Neria Y: Neural Changes Following Equine-assisted Therapy for PTSD: A Longitudinal Multimodal Brain Imaging Study, submitted Nov 6, 2020 to Human Brain Mapping.
• Nguyen, M., Lee, S., Hua, H., & Hamilton, A. J. (2021). Further Comparison of 4 Display Modes for a Multi-Resolution Foveated Laparoscope.. Surgical innovation, 28(1), 85-93. doi:10.1177/1553350620957799
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  Background. To overcome field of view and ergonomic limitations of standard laparoscopes, we are developing a multi-resolution foveated laparoscope (MRFL), which can simultaneously obtain both wide- and zoomed-in-view images. To facilitate the effectiveness of our MRFL, we have been investigating various ways of organizing and visualizing dual-view multi-resolution images acquired by the MRFL. In our prior study, we implemented and compared 6 display modes for the MRFL, assuming a typical clinical environment where a standard (but limited) resolution monitor is available. To take full advantage of our MRFL, displays having sufficient screen resolutions might be advantageous. The present study aims to further understand the effects of view configurations through displays with a standard high-definition (HD) resolution and a 4K resolution. In this study, we compare 3 display modes for limited-resolution displays against a new mode for sufficient-resolution displays. Methods. Twenty subjects performed 3 evaluation trials of a touching task with each display mode in an emulated MRFL environment. Various objective measurements including task completion time and the number of collisions, and subjective preference were recorded. Results. The new mode showed a better task completion time than the other modes, while it maintained a low number of collisions similar to the others. Moreover, the majority of participants selected the new mode as their most preferred one. Conclusions. With a sufficient display resolution, the co-registration between the unblocked and unwarped wide context view and the high-resolution zoomed-in view offered by the new mode was highly effective on both task performance and user preference.
• Rozenblit, J. W., Hong, M., & Hamilton, A. J. (2021). Simulation-based surgical training systems in laparoscopic surgery: a current review. Virtual Reality, 25(2), 491-510. doi:10.1007/s10055-020-00469-z
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  Simulation-based training has been widely used in medical education. More specifically, various systems for minimally invasive surgery training have been proposed in the past two decades. The aim of this article is to review and summarize the existing simulation-based training systems for laparoscopic surgery in terms of their technical realizations. Forty-three training systems were found and analyzed. These training systems generally consist of training tasks, a visualization interface, and an instrument interface. Three different approaches—physical, virtual, and augmented reality—to implement visualization interfaces are discussed first. Then, haptic feedback, performance evaluation, and guidance methods are summarized. Portable devices to enable at-home training and instrument tracking technologies to support visualization, evaluation, and guidance are also presented. Based on survey of the relevant literature, we propose several recommendations to design the next-generation training systems in laparoscopic surgery. Novel guidance and assessment schemes with augmented reality visualization are recommended to design an intelligent surgical training simulator. This intelligent simulator enhances the training procedure and ultimately improves the patient safety.
• Zhu, X., Suarez‐Jimenez, B., Zilcha‐Mano, S., Lazarov, A., Arnon, S., Lowell, A. L., Bergman, M., Ryba, M., Hamilton, A. J., Hamilton, J. F., Turner, J. B., Markowitz, J. C., Fisher, P. W., & Neria, Y. (2021). Neural changes following equine‐assisted therapy for posttraumatic stress disorder: A longitudinal multimodal imaging study. Human Brain Mapping, 42(6), 1930-1939. doi:10.1002/hbm.25360
• Arnon, S., Farber, D. G., Fisher, P. W., Hamilton, J. F., Hamilton, A., Hilburn, A., Jacob-McVey, J., Lowell, A., Malajian, B. E., Markowitz, J. C., Neria, Y., Pickover, A., & Turner, J. B. (2020). Equine-Assisted Therapy for Veterans with PTSD: Manual Development and Preliminary Findings. Military Medicine, 185(5-6), e557-e564. doi:10.1093/milmed/usz444
• Hamilton, A. J. (2020). Equine-Assisted Therapy for Veterans with PTSD: Manual Development and Preliminary Findings. Military Medicine, 5/6, 1-8.
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  Equine-Assisted Therapy for Veterans with PTSD: Manual Development and Preliminary Findings.Arnon S, Fisher PW, Pickover A, Lowell A, Turner JB, Hilburn A, Jacob-McVey J, Malajian BE, Farber DG, Hamilton JF, Hamilton A, Markowitz JC, Neria Y.Mil Med. 2020 Feb 8. pii: usz444. doi: 10.1093/milmed/usz444. [Epub ahead of print]PMID: 32034416AbstractINTRODUCTION:Equine-assisted therapy (EAT) for post-traumatic stress disorder (PTSD) has attracted great interest despite lacking empirical support, a manual, and a standardized protocol. Our team of experts in EAT and PTSD developed an eight-session group EAT treatment protocol for PTSD (EAT-PTSD) and administered it to two pilot groups of military veterans to assess initial effects.MATERIALS AND METHODS:We describe the development of the treatment manual, which was used with two pilot groups of veterans. Protocol safety, feasibility, and acceptability were assessed by reported adverse events, treatment completion rates, and self-rated patient satisfaction. Preliminary data on PTSD, depressive, and anxiety symptoms and quality of life were collected pretreatment, midpoint, post-treatment, and at 3-month follow up.RESULTS:No adverse events were recorded. All patients completed treatment, reporting high satisfaction. Preliminary data showed decreases in clinician-assessed PTSD and depressive symptoms from pre to post-treatment and follow-up (medium to large effect sizes, d = .54-1.8), with similar trends across self-report measures (d = 0.72-1.6). In our pilot sample, treatment response and remission varied; all patients showed some benefit post-treatment, but gains did not persist at follow-up.CONCLUSIONS:This article presents the first standardized EAT protocol. Highly preliminary results suggest our new manualized group EAT-PTSD appears safe, well-regarded, and well-attended, yielding short-term benefits in symptomatology and quality of life if unclear length of effect. Future research should test this alternative treatment for PTSD more rigorously.Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2019. This work is written by (a) US Government employee(s) and is in the public domain in the US.PMID: 32034416 DOI: 10.1093/milmed/usz444
• Hamilton, A. J., Lee, S., Hua, H., & Nguyen, M. (2020). Further Comparison of 4 Display Modes for a Multi-Resolution Foveated Laparoscope. Surgical Innovation. doi:https://doi.org/10.1177/1553350620957799
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  AbstractBackground. To overcome field of view and ergonomic limitations of standard laparoscopes, we are developing a multi-resolution foveated laparoscope (MRFL), which can simultaneously obtain both wide- and zoomed-in-view images. To facilitate the effectiveness of our MRFL, we have been investigating various ways of organizing and visualizing dual-view multi-resolution images acquired by the MRFL. In our prior study, we implemented and compared 6 display modes for the MRFL, assuming a typical clinical environment where a standard (but limited) resolution monitor is available. To take full advantage of our MRFL, displays having sufficient screen resolutions might be advantageous. The present study aims to further understand the effects of view configurations through displays with a standard high-definition (HD) resolution and a 4K resolution. In this study, we compare 3 display modes for limited-resolution displays against a new mode for sufficient-resolution displays. Methods. Twenty subjects performed 3 evaluation trials of a touching task with each display mode in an emulated MRFL environment. Various objective measurements including task completion time and the number of collisions, and subjective preference were recorded. Results. The new mode showed a better task completion time than the other modes, while it maintained a low number of collisions similar to the others. Moreover, the majority of participants selected the new mode as their most preferred one. Conclusions. With a sufficient display resolution, the co-registration between the unblocked and unwarped wide context view and the high-resolution zoomed-in view offered by the new mode was highly effective on both task performance and user preference.Keywords laparoscope, display interface, dual views, multi-resolution visualization, focus plus context, overview plus detail
• Tzou, D. T., Phung, M. C., Lovett*, M. K., Lovett, M., Lee, B. R., Hamilton, A. J., & Biffar, D. E. (2020). MP47-11 DEVELOPMENT OF A LOW-COST, HIGH-FIDELITY SIMULATOR FOR ULTRASOUND-GUIDED PERCUTANEOUS NEPHROLITHOTOMY (PCNL) TRAINING. The Journal of Urology, 203, e688. doi:10.1097/ju.0000000000000902.011
• Hamilton, A. J. (2019). Single shot state detection in simulation-based laparoscopy training.. Proceedings 2019 Spring Simulation Conference (SpringSim), 2019.. doi:Doi: 10.23919/SpringSim.2019.8732863
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  Peng, Kuo Shiuan, Minsik Hong, Jerzy Rozenblit, and Allan J. Hamilton. "Single shot state detection in simulation-based laparoscopy training." In 2019 Spring Simulation Conference (SpringSim), 2019. Doi: 10.23919/SpringSim.2019.8732863
• Lee, S., Hua, H., Nguyen, M., & Hamilton, A. J. (2019). Comparison of six display modes for a multi-resolution foveated laparoscope. Surgical endoscopy, 33(1), 341-351.
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  To overcome the field of view and ergonomic limitations of standard laparoscopes, we are developing a multi-resolution foveated laparoscope that can simultaneously obtain both wide- and zoomed-in-view images through a single scope. To facilitate the effective access to the dual views of images with different resolution and field coverage acquired by our laparoscope, six different display modes have been developed. Each of the six display modes has inherent advantages and disadvantages. This study compares the six display modes through a human-subject experiment, which was conducted with an emulated laparoscope using a 4K camera.
• Hamilton, A. J. (2018). Comparison of Six Display Modes for a Multi-Resolution Foveated Laparscope. J. of Society of Laparoendoscopic Surgeons, TBA(TBA), 20.
• Hamilton, A. J. (2018). Evaluation of an Innovative Bleeding Cricothyroidotomy Model. Cereus, 10(9). doi:doi:10.7759/cureus.3327
• Hughes, K. E., Biffar, D., Ahanonu, E. O., Cahir, T. M., Hamilton, A., & Sakles, J. C. (2018). Evaluation of an Innovative Bleeding Cricothyrotomy Model. Cureus, 10(9), e3327.
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  Objectives Emergency medicine (EM) residents are required to perform a cricothyrotomy during training as per the Accreditation Council for Graduate Medical Education (ACGME) guidelines. Cricothyrotomy is a rare procedure, comprising 0.45% of emergency department airway management procedures. Procedural competence in utilizing a realistic trainer is of utmost importance. We have developed a cricothyrotomy trainer using a fused deposition modeling (FDM) three-dimensional (3D) printer and innovative bleeding tissue to enhance fidelity. We aim to evaluate the trainer's realism. Methods Implementation occurred during a difficult airway educational lab for EM residents in April 2018. Participants completed anonymous written surveys after performing a cricothyrotomy on the trainer. The survey evaluated the realism of the trainer and compared it to other available models by utilizing five-point visual analog scales (VAS). The participants rated their comfort level in performing the procedure pre- and post-educational lab on a five-point VAS. Demographic data included postgraduate year, prior clinical cricothyrotomy experience as a primary operator versus as an assistant, and previous trainer experience. The survey included open-response suggestions for trainer improvement.  Results Forty-three EM residents completed the survey (82.7%, 43/52). The mean realism rating of the trainer was 3.81 (95% CI = 3.54-4.1). The participants reported previous training on cadaver (62.8%, 27/43), porcine (46.5%, 20/43), and manikin (67.4%, 29/43) models prior to using this trainer. The bleeding cricothyrotomy trainer was rated higher than other models (4.45, 95% CI = 4.28-4.63). Participants noted improved comfort with performing the cricothyrotomy after the educational lab (average improvement of 1.23±0.75). Participants specifically commented on the realism of the bleeding and skin texture; however, they also recommended a reduction in the size of the cricothyroid membrane space.  Conclusion The innovative bleeding cricothyrotomy trainer has greater fidelity and reported superiority when compared to other commonly used nonbleeding models. This trainer provides a more advanced platform to teach an infrequent yet critical procedural skill to emergency medicine residents.
• Hughes, K., Biffar, D., Ahanonu, E., Cahir, T., Hamilton, A. J., & Sakles, J. C. (2018). Evaluation of an Innovative Bleeding Cricothyrotomy Model. Cureus, 10(9), e3327. doi:10.7759/cureus.3327
• Hong, M., Rozenblit, J. W., Rozenblit, J. W., Hamilton, A. J., & Hamilton, A. J. (2017). A simulation-based assessment system for computer assisted surgical trainer. Proceedings of the 2017 Spring Simulation Conference on Modeling and Simulation in Medicine (SpringSim-MSM), pp. 834-844, 2017, Virginia Beach, VA, 834-844.
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  An assessment system is presented to provide objective assessment results for laparoscopic surgery skills training. Six innovative evaluation metrics are introduced in the design of the proposed system. Like a video game, the system suggests achievable goals that are used to define evaluation metrics for a trainee who is performing a particular training task. To implement the proposed system, a design method of the hierarchical fuzzy system is used. The simulation results and the prototype illustrate the feasibility of the proposed evaluation approach.
• Grisham, L. M., Vickers, V., Biffar, D. E., Prescher, H., Battaglia, N. J., Jarred, J. E., Reid, S. A., & Hamilton, A. J. (2016). Feasibility of Air Transport Simulation Training: A Case Series. Air Medical Journal, 35(5), 308-13.
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  Limited clinical site availability and an increased need for clinical training experiences often make it difficult for prehospital health care providers to complete new and annual training requirements. Medical simulation provides an alternative learning environment that provides trainees the opportunity to acquire and perfect new clinical skills without compromising patient care. The following is a detailed description of an air medical transport simulation of a neonate with hypoxic ischemic encephalopathy requiring transport to a higher level of care. Patient parameters were altered during flight to simulate potential complications unique to air medical transport. Use of this training strategy is particularly beneficial for low-volume, high-risk patients, and these lessons can be applied across all age patient groups, making the experience broadly applicable.
• Ng, V., Prescher, H., Barbosa, A., Biffar, D., & Hamilton, A. J. (2016). Development of An Ultrasound Pericardiocentesis Model for Simulation Training. Simulation in Healthcare, 11(6), 489.
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  AbstractApproximately 7.25 hours spent on project for 2016
• Amini, R., Kartchner, J. Z., Stolz, L. A., Biffar, D., Hamilton, A. J., & Adhikari, S. (2015). A Novel and Inexpensive Ballistic Gelatin Phantom for Ultrasound Training. World Journal of Emergency Medicine, 6(3), 225-8.
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  Ultrasonography use is increasing in emergency departments, and ultrasound education is now recommended in resident training. Ultrasound phantoms are used in many institutions for training purposes. The purpose of this study is to describe an inexpensive and simple method to create ultrasound-imaging models for the purpose of education and practice using clear ballistic gel.
• Hamilton, A. J., Prescher, H., Biffar, D. E., & Poston, R. S. (2015). Simulation trainer for practicing emergent open thoracotomy procedures. The Journal of Surgical Research, 197(1), 78-84.
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  An emergent open thoracotomy (OT) is a high-risk, low-frequency procedure uniquely suited for simulation training. We developed a cost-effective Cardiothoracic (CT) Surgery trainer and assessed its potential for improving technical and interprofessional skills during an emergent simulated OT.
• Prescher, H., Grover, E., Mosier, J., Stolz, U., Biffar, D. E., Hamilton, A. J., & Sakles, J. C. (2015). Telepresent Intubation Supervision Is as Effective as In-Person Supervision of Procedurally Naive Operators. Telemedicine and e-Health, 21(3), 170-175. doi:10.1089/tmj.2014.0090
• Prescher, H., Grover, E., Mosier, J., Stolz, U., Biffar, D. E., Hamilton, A. J., & Sakles, J. C. (2015). Telepresent intubation supervision is as effective as in-person supervision of procedurally naive operators. Telemedicine journal and e-health : the official journal of the American Telemedicine Association, 21(3), 170-5.
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  Telepresence is emerging in clinical and educational settings as a potential modality to provide expert guidance during remote airway management. This study aimed to compare the effectiveness of telepresent versus in-person supervision of tracheal intubation.
• Prescher, H., Biffar, D. E., Galvani, C. A., Rozenblit, J. W., & Hamilton, A. J. (2014). Evaluation of a Navigation Grid to Increase the Efficacy of Instrument Movement During Laparoscopic Surgery. Journal of Laparoendoscopic & Advanced Surgical Techniques, 24(9), 656-659. doi:10.1089/lap.2014.0016
• Prescher, H., Biffar, D. E., Galvani, C. A., Rozenblit, J. W., & Hamilton, A. J. (2014). Evaluation of a navigation grid to increase the efficacy of instrument movement during laparoscopic surgery. Journal of laparoendoscopic & advanced surgical techniques. Part A, 24(9), 656-9.
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  The objective of this study was to determine whether or not a navigation grid (NG) with a coordinate system overlaid on a laparoscopic display might allow attending surgeons to more easily and precisely direct their assistants' instruments to specific sites in a simulated laparoscopic field.
• Thompson, J. L., Grisham, L. M., Scott, J., Mogan, C., Prescher, H., Biffar, D., Jarred, J., Meyer, R. J., & Hamilton, A. J. (2014). Construction of a reusable, high-fidelity model to enhance extracorporeal membrane oxygenation training through simulation. Advances in neonatal care : official journal of the National Association of Neonatal Nurses, 14(2), 103-9.
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  Initiation of extracorporeal membrane oxygenation (ECMO) is stressful, especially for inexperienced extracorporeal life support providers. The main objective of this study was to create a novel, reusable mannequin for high-fidelity simulation of ECMO initiation. We modified a Laerdal neonatal mannequin (SimNewB; Stavanger, Norway) so that it could be used to simulate an ECMO initiation. A simulation of a neonatal patient suffering from meconium aspiration was performed in the pediatric intensive care unit, and participants included new extracorporeal life support specialists in addition to the composition of the clinical ECMO team. A total of 17 individuals participated in the neonatal ECMO initiation simulation. Questionnaire results showed that 88% of participants felt better prepared to assist in an ECMO initiation after the simulation. All participants (100%) agreed that the modified mannequin and the environment were realistic and that this simulation helps teamwork and communication in future initiations of ECMO. Simulation can be used for the prevention, identification, and reduction of anxiety-related crisis situations that novice providers may infrequently encounter during routine clinical use of mechanical circulatory support. Use of a reusable, high-fidelity mannequin may be beneficial for effective team training of complex pediatric ECMO-related procedures.
• Prescher, H., Hamilton, A. J., & Biffar, D. E. (2013). Board 533 - Technology Innovations Abstract Developing a Novel Drain Loop Skin Abscess Model for Training Intern ED Students (Submission #1439). Simulation in healthcare : journal of the Society for Simulation in Healthcare, 8(6), 625. doi:10.1097/01.sih.0000441731.33923.bd
• Prescher, H., Tomasa, L., Berg, M., Mathesen, Y., Theodorou, A., Hamilton, A. J., Grisham, L. M., & Biffar, D. E. (2013). Board 234 - Program Innovations Abstract A Seven Year Collaboration Between Three Colleges to Learn Interprofessional Skills During a CPR Team Behavior Simulation (Submission #1037). Simulation in healthcare : journal of the Society for Simulation in Healthcare, 8(6), 482-483. doi:10.1097/01.sih.0000441499.17369.22
• Stolz, U., Hamilton, A. J., Stolz, U., Sakles, J. C., Prescher, H., Mosier, J., Hamilton, A. J., Grover, E., & Biffar, D. E. (2013). Board 342 - Research Abstract Telepresent Intubation Instruction Is As Effective As In-Person When Instructing Naive Intubators (Submission #185). Simulation in healthcare : journal of the Society for Simulation in Healthcare, 8(6), 540. doi:10.1097/01.sih.0000441594.67094.e7
• Feng, C., Rozenblit, J. W., & Hamilton, A. J. (2010). A computerized assessment to compare the impact of standard, stereoscopic, and high-definition laparoscopic monitor displays on surgical technique. Surgical Endoscopy, 24(11), 2743-8.
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  Surgeons performing laparoscopic surgery have strong biases regarding the quality and nature of the laparoscopic video monitor display. In a comparative study, we used a unique computerized sensing and analysis system to evaluate the various types of monitors employed in laparoscopic surgery.
• Salkini, M. W., & Hamilton, A. J. (2010). The Effect of Age on Acquiring Laparoscopic Skills. Journal of Endourology, 24(3), 377-379. doi:10.1089/end.2009.0155
• Salkini, M. W., & Hamilton, A. J. (2010). The effect of age on acquiring laparoscopic skills. Journal of Endourology, 24(3), 377-9.
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  Laparoscopic surgery is well known as having a long and variable learning curve. In fact, successive generations of surgeons were able to reduce their operative time and plateau their learning curves. This raises the question as to how early in medical education we can integrate laparoscopic skills. In this study, we are trying to demonstrate the effect of age on acquiring new laparoscopic skills.
• Krupinski, E. A., Patel, B., Berger, W., Hamilton, A. J., Knapp, A. E., Becker, G. J., & Gatenby, R. A. (2009). Assessing radiology resident preparedness to manage IV contrast media reactions using simulation technology. Studies in health technology and informatics, 142, 139-41.
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  Investigate whether radiology residents make correct diagnosis of contrast media reactions and evaluate their treatment of reaction using simulation technology. Residents were presented with a test scenario of patient given IV contrast having anaphylactic reaction. A computer-run mechanical mannequin that simulates, with mathematical, pharmacokinetic, pharmacodynamic and cardiovascular algorithms, was used. Sessions were evaluated with respect to whether residents performed key actions to treat anaphylaxis. Times were recorded. All residents recognized the contrast reaction and initiated basic actions. As the scenario progressed and patient deteriorated, all recognized need to intubate, but intubation performance varied significantly. Radiology residents generally not prepared to deal with IV contrast reactions. Simulation technology to practice key actions would improve their preparedness.
• Chiocca, E. A., Smith, K. M., McKinney, B., Palmer, C. A., Rosenfeld, S., Lillehei, K., Hamilton, A., DeMasters, B. K., Judy, K., & Kirn, D. (2008). A phase I trial of Ad.hIFN-beta gene therapy for glioma. Journal of the American Society of Gene Therapy, 16(3), 618-26.
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  Interferon-beta (IFN-beta) is a pleiotropic cytokine with antitumoral activity. In an effort to improve the therapeutic index of IFN-beta by providing local, sustained delivery of IFN-beta to gliomas, the safety and biological activity of a human IFN-beta (hIFN-beta)-expressing adenovirus vector (Ad.hIFN-beta) was evaluated in patients with malignant glioma by stereotactic injection, followed 4-8 days later by surgical removal of tumor with additional injections of Ad.hIFN-beta into the tumor bed. Eleven patients received Ad.hIFN-beta in cohorts of 2 x 10(10), 6 x 10(10), or 2 x 10(11) vector particles (vp). The most common adverse events were considered by the investigator as being unrelated to treatment. One patient, who was enrolled in the cohort with the highest dose levels, experienced dose-limiting, treatment-related Grade 4 confusion following the post-operative injection. Ad.hIFN-beta DNA was detected within the tumor, blood, and nasal swabs in a dose-dependent fashion and hIFN-beta protein was detectable within the tumor. At the highest doses tested, a reproducible increase in tumor cell apoptosis in post-treatment versus pre-treatment biopsies with associated tumor necrosis was observed. Direct Ad.hIFN-beta injection into the tumor and the surrounding normal brain areas after surgical removal was feasible and associated with apoptosis induction.
• Maresh, C. M., Kraemer, W. J., Judelson, D. A., Vanheest, J. L., Kulikowich, J. M., Goetz, K. L., Cymerman, A., Hamilton, A. J., & Trad, L. A. (2004). Effects of high altitude and water deprivation on arginine vasopressin release in men.. American journal of physiology. Endocrinology and metabolism, 286(1), E20-4. doi:10.1152/ajpendo.00332.2003
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  High-altitude exposure changes the distribution of body water and electrolytes. Arginine vasopressin (AVP) may influence these alterations. The purpose of this study was to examine the effect of a 24-h water deprivation trial (WDT) on AVP release after differing altitude exposures. Seven healthy males (age 22 +/- 1 yr, height 176 +/- 2 cm, mass 75.3 +/- 1.8 kg) completed three WDTs: at sea level (SL), after acute altitude exposure (2 days) to 4,300 m (AA), and after prolonged altitude exposure (20 days) to 4,300 m (PA). Body mass, standing and supine blood pressures, plasma osmolality (Posm), and plasma AVP (PAVP) were measured at 0, 12, 16, and 24 h of each WDT. Urine volume was measured at each void throughout testing. Baseline Posm increased from SL to altitude (SL 291.7 +/- 0.8 mosmol/kgH2O, AA 299.6 +/- 2.2 mosmol/kgH2O, PA 302.3 +/- 1.5 mosmol/kgH2O, P < 0.05); however, baseline PAVP measurements were similar. Despite similar Posm values, the maximal PAVP response during the WDT (at 16 h) was greater at altitude than at SL (SL 1.7 +/- 0.5 pg/ml, AA 6.4 +/- 0.7 pg/ml, PA 8.7 +/- 0.9 pg/ml, P < 0.05). In conclusion, hypoxia appeared to alter AVP regulation by raising the osmotic threshold and increasing AVP responsiveness above that threshold.
• Geerts, W., & Hamilton, A. (2003). Randomized, pilot study of intermittent pneumatic compression devices plus dalteparin versus intermittent pneumatic compression devices plus heparin for prevention of venous thromboembolism in patients undergoing craniotomy: Commentary. 55. Frim DM, Barker FG, Poletti CE, Hamilton AJ (1992): Post-operative Low-Dose Heparin Decreases Thromboembolic Complications in Neurosurgical Patients; Neurosurgery, 30, 830-833., 59(5). doi:10.1016/S0090-3019(03)00127-7
• Judelson, D. A., Maresh, C. M., Kraemer, W. J., Trad, L., Goetz, K. L., Cymerman, A., & Hamilton, A. J. (2003). THE EFFECTS OF HIGH ALTITUDE AND WATER DEPRIVATION ON ARGININE VASOPRESSIN RELEASE IN MAN. Medicine and Science in Sports and Exercise, 35(Supplement 1), S356. doi:10.1097/00005768-200305001-01975
• Takacs, I., & Hamilton, A. J. (2003). Stereotaxis: Concepts, methods, and extracranial applications. Techniques in Neurosurgery, 8(1), 11-26. doi:10.1097/00127927-200308010-00004
• Zabramski, J. M., Whiting, D., Darouiche, R. O., Horner, T. G., Olson, J., Robertson, C., & Hamilton, A. J. (2003). Efficacy of antimicrobial-impregnated external ventricular drain catheters: a prospective, randomized, controlled trial. Journal of Neurosurgery, 98(4), 725-30.
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  Catheter-related infection of the cerebrospinal fluid (CSF) pathways is a potentially life-threatening complication of external ventricular drainage. A major source of infection is bacterial contamination along the external ventricular drain (EVD) catheter track. The authors examined the efficacy of EVD catheters impregnated with minocycline and rifampin in preventing these catheter-related infections.
• Reyna, V. F., & Hamilton, A. J. (2001). The importance of memory in informed consent for surgical risk.. Medical decision making : an international journal of the Society for Medical Decision Making, 21(2), 152-5. doi:10.1177/0272989x0102100209
• Takacs, I., Sherman, S. J., Bell, R. S., Gottfried, O. N., Way, D., Martin, J., & Hamilton, A. J. (2001). 719 Deep Brain Stimulation for Movement Disorders: Lead Placement without Microelectrode Recording. Neurosurgery, 49(2), 512-512. doi:10.1097/00006123-200108000-00083
• Takacs, I., Whiting, D., Darouiche, R. O., Horner, T. G., Hamilton, A. J., Zabramski, J. M., & Olson, J. J. (2001). 739 Minocycline- and Rifampin-impregnated Catheters and Ventriculitis: A Study of 252 Patients. Neurosurgery, 49(2), 518-518. doi:10.1097/00006123-200108000-00103
• Hamilton, A. J., Abdelaziz, O. S., Zheng, L. G., Zervas, N. T., Yu, C., Yeh, D. J., Yamamoto, M., Xu, D. S., Williamson, P. D., Williams, J. A., Wheatley, M., Way, D., Vighetto, A., Vega, J. L., Ulbert, I., Tulley, M., Truwit, C. L., Thompson, T. P., Thadani, V. M., , Tate, D. J., et al. (1999). Contents Vol. 73, 1999. Stereotactic and Functional Neurosurgery, 73(1-4), 159-160. doi:10.1159/000029780
• Hamilton, A. J., Abdelaziz, O. S., Zheng, L. G., Zervas, N. T., Yu, C., Yeh, D. J., Yamamoto, M., Xu, D. S., Williamson, P. D., Williams, J. A., Wheatley, M., Way, D., Vighetto, A., Vega, J. L., Ulbert, I., Tulley, M., Truwit, C. L., Thompson, T. P., Thadani, V. M., , Tate, D. J., et al. (1999). Subject Index Vol. 73, 1999. Stereotactic and Functional Neurosurgery, 73(1-4), 157-158. doi:10.1159/000029779
• Hamilton, A. J., Takacs, I., Stea, B., Sapareto, S., Lulu, B., Johnson, P., Hamilton, A. J., & Fosmire, H. (1999). Frame based stereotactic spinal radiosurgery: experience from the first 19 patients treated. Stereotactic and functional neurosurgery, 73(1-4), 69. doi:10.1159/000029755
• Takacs, I., Hamilton, A. J., J, H. A., & I, T. (1999). Extracranial stereotactic radiosurgery: applications for the spine and beyond.. Neurosurgery Clinics of North America, 10(2), 257-270. doi:10.1016/s1042-3680(18)30192-x
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  The role stereotactic radiosurgery has in the management of malformations of the spine is examined in this article. Specific problems in the application of stereotactic radiosurgery to the spine are discussed and the three techniques for spinal stereotaxis, bone screw fixation, contour mold fixation, and frameless stereotaxis, are reviewed.
• Takacs, I., Kishan, A., Deogaonkar, M., Way, D., Ogden, J., Martin, J., & Hamilton, A. J. (1999). Respiration induced target drift in spinal stereotactic radiosurgery: evaluation of skeletal fixation in a porcine model. Stereotactic and functional neurosurgery, 73(1-4), 70. doi:10.1159/000029756
• Fritsch, M. J., Leber, M. J., Gossett, L., Lulu, B. A., & Hamilton, A. J. (1998). Stereotactic biopsy of intracranial brain lesions. High diagnostic yield without increased complications: 65 consecutive biopsies with early postoperative CT scans.. Stereotactic and functional neurosurgery, 71(1), 36-42. doi:10.1159/000029645
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  Diagnostic yield and complication rate were analyzed for a series of 65 consecutive stereotactic biopsies of intra-axial brain lesions. The diagnostic yield was 98.5 +/- 1.5% and the complication rate was 1.5%. A median number of 14 biopsies (range 1-48) were taken per lesion. The biopsy sites followed a clockwise pattern, going from the superficial margin to the center and the deep margin of the lesion with respect to the inner table of the skull. A side window cannula biopsy needle was used. All patients underwent immediate postoperative CT scans within 4 h of biopsy to rule out intracranial complications. All patients were discharged within 24 h after biopsy, unless medical reasons unrelated to the biopsy required further hospitalization. We attribute the high diagnostic yield in our series to the high number of systematically taken biopsies per lesion. The higher number of biopsies did not lead to an increase in complications. From our experience, it appears safe to discharge patients the same day or within 24 h after a stereotactic biopsy if the postoperative CT shows no complication. Stereotactic biopsy could often safely be performed on an outpatient basis.
• Hamilton, A. J. (1998). On “Radiosurgery for Tumors in the Body: Clinical Experience Using a New Method” (Blomgren et al., This Issue). Journal of Radiosurgery, 1(1), 75-75. doi:10.1023/b:jora.0000010881.89315.0b
• Hamilton, A. J., Orozco, J. A., Narotam, P. K., & Bowersock, T. L. (1997). Efficacy of vancomycin/tri-iododecyclemethyl ammonium chloride-coated ventriculostomy catheters in reducing infection.. Neurosurgery, 40(5), 1043-9. doi:10.1097/00006123-199705000-00031
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  The biotoxicity of tri-iododecyclemethyl ammonium chloride (TDMAC)-coated catheters in the brain was tested, as was the efficacy of the vancomycin-bonded, TDMAC-coated catheters to inhibit staphylococcal growth in vitro and to delay the onset of clinical manifestations of catheter-related staphylococcal ventriculitis in rabbit experimental model..The brain toxicity of the TDMAC-coated catheters was tested in New Zealand White rabbits. The efficacy of the vancomycin-bonded, TDMAC-coated catheters in the inhibition of staphylococcal growth was tested in agar seeded with Staphylococcus aureus and Staphylococcus epidermidis strains. Sections of vancomycin-bonded, TDMAC-coated catheters were placed in saline solution for testing of drug release over time. Stereotactic placement of ventriculostomy catheters was performed in two groups of New Zealand White rabbits. In the experimental group, vancomycin-bonded, TDMAC-coated catheters were used. In the control group, TDMAC-coated catheters were used. Staphylococcal colonies were inoculated at the exit site of the catheters. Culture of the catheter tips was performed at the time of death of the animals..No toxic reactions were seen at the implantation sites or in surrounding brain. Significant inhibition of growth of both S. aureus and S. epidermidis was noted with the vancomycin-bonded catheters (P = 0.01). Vancomycin continued to be released from catheters for the full 6 days of the study. The median interval to development of clinical manifestations of ventriculitis among the experimental group of rabbits was 53 days; among the control group, the interval was 27 days (P < 0.001)..Vancomycin-bonded, TDMAC-coated ventriculostomy catheters bind and release the drug at levels exceeding the minimum inhibitory concentration for S. aureus and S. epidermidis for at least 6 days and can significantly delay the onset of infectious ventriculitis in a rabbit model.
• Hamilton, A. J., Stea, B., Hill, D., Hamilton, A. J., & Gannett, D. E. (1997). Paclitaxel as a radiosensitizer combined with fractionated stereotactic radiotherapy in the treatment of recurrent medulloblastoma.. American journal of clinical oncology, 20(3), 233-6. doi:10.1097/00000421-199706000-00004
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  This report describes the treatment of a 39-year-old man with recurrent medulloblastoma previously treated with extensive chemotherapy and radiation therapy. A novel treatment technique combining paclitaxel (275 mg IV bolus) and fractionated stereotactic radiotherapy (30 Gy in six fractions over 3 weeks) was given to palliate the patient's significant neurologic symptoms. The patient experienced a significant improvement both radiographically and in the quality of his life at follow-up 5 months after completion of treatment. No toxicity has been observed. The treatment of medulloblastoma with paclitaxel and fractionated stereotactic radiotherapy, either alone or in combination, merits further investigation.
• Hamilton, A. J., Woo, C., Stea, B., Lulu, B., Hamilton, A. J., & Cassady, J. R. (1997). The use of stereotactic radiosurgical boost in the treatment of medulloblastomas.. International journal of radiation oncology, biology, physics, 37(4), 761-4. doi:10.1016/s0360-3016(97)00022-9
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  Starting in 1992, we began using a stereotactic radiosurgical (SRS) boost for the treatment of medulloblastomas. Four patients ranging in age from 7 to 42 years old have since been treated and are the subject of this retrospective study..All patients were initially treated with a maximally debulking surgery and external beam radiotherapy, which were then followed by a stereotactic radiosurgical boost using a modified 6 MeV linear accelerator. Radiosurgical boost doses ranged from 4.50 to 10.0 Gy. Target volumes ranged from 1.1 to 8.1 cc. The procedure was well tolerated with minimal acute toxicities..All four patients are alive without evidence of recurrence (at 8 to 35 months). Acute nausea and vomiting was elicited during the radiosurgical procedure in the first patient treated. We have since begun premedicating patients with antiemetics or treating under general anesthesia. Late complications consisted of panhypopituitarism in one patient, which was thought to be attributable to the previous course of whole-brain radiotherapy. We have not observed any incidence of radionecrosis in this small cohort of patients..Our preliminary results with the use of radiosurgery for medulloblastomas are optimistic, and we would like to suggest the inclusion of a radiosurgery boost in future clinical trials for treatment of this disease.
• Hamilton, A. J., Lulu, B. A., Fosmire, H., Gossett, L., & Gosset, L. (1996). LINAC-based spinal stereotactic radiosurgery.. Stereotactic and functional neurosurgery, 66(1-3), 1-9. doi:10.1159/000099658
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  The authors' report on the use of a prototype spinal stereotactic radiosurgery frame which was employed for the treatment of 9 patients who presented with recurrent neoplastic involvement of the spinal column. All patients had failed standard therapy consisting of surgery, external fractionated radiation therapy, and/or chemotherapy. Eight of the lesions represented metastatic tumors in the vertebral column, one of the lesions was a primary osteosarcoma involving multiple vertebral bodies. The lesions were found at multiple levels, from the cervical through the sacral region. Six out of the 9 patients presented with epidural compression: 4 of the 9 patients with evidence of myelopathy: 2 of the 9 patients with radicular symptoms secondary to compression from the tumor, and 1 patient was free of any compressive symptoms. All patients had pain requiring narcotics. Patients were treated with a median radiosurgical dose of 800 cGy (range 800-1.000) with a median of 1 isocenter (range 1-7 isocenters) and median normalization of 80% to the isodose contour (range 80-160). Median dose delivered to the already prior irradiated spinal cord was 179 cGy (range 52-320 cGy) with a median spinal cord dose of 34 (range 4-68). To date, there have been three minor complications: one radiation-induced esophagitis which was treated medically: one wound infection, and 1 patient requiring an additional 24 h of hospitalization stay. There have been no major complications. To date, 5 of the 9 patients have died, all from causes unrelated to the spinal radiosurgery. Three out of the 9 patients have been followed for more than 1 year. In all 3, there was radiographic regression of the tumor and epidural compression. In 2 patients, there was histologic confirmation of absence of tumor in the treated site: in 1 patient. no tumor was found at postmortem. 12 months after treatment, when the patient died of unrelated causes. Although the number of patients followed is limited, the phase I study clearly shows the technical feasibility of spinal radiosurgery for the control of metastatic involvement of the vertebral column even in the face of epidural compression.
• Hamilton, A. J., Weinand, M. E., Sioutos, P. J., Narotam, P. K., & Hamilton, A. J. (1996). Unusual early recurrence of a cerebellar pilocytic astrocytoma following complete surgical resection. Case report and review of the literature.. Journal of neuro-oncology, 30(1), 47-54. doi:10.1007/bf00177442
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  Pilocytic cerebellar astrocytomas are usually benign tumors with generally an excellent prognosis following complete surgical resection. The goal of surgery is total resection to minimize the risk of recurrence. In this case report, a 5-year old boy who had undergone total resection of a posterior fossa pilocytic cerebellar astrocytoma (as documented by a contrast-enhanced computed tomography (CT) scan within 24 hours following surgery), developed a massive recurrence of the tumor within four months. Both the initial histology and the sections examined after the second resection revealed features typical for a pilocytic astrocytoma with no suspicion of malignancy. This case is unusual in that it is contrary to other reports suggesting that CT-documented complete surgical resection of pilocytic astrocytomas is without recurrence, and suggests the need for vigilant radiographic and clinical follow-up of these patients even if apparent complete resection of the tumor has been achieved.
• Hamilton, A. J., Weinand, M. E., Sioutos, P. J., Orosco, J., Nees, J., Hamilton, A. J., & Carter, L. P. (1996). Intraoperative measurement of peritumoral regional cortical cerebral blood flow.. Oncology reports, 3(3), 593-6. doi:10.3892/or.3.3.593
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  Peritumoral regional cortical blood flow (rCoBF) was studied intraoperatively using thermal diffusion flowmetry. Histology included glioblastomas (n=5), anaplastic astrocytoma (n=1), pilocytic astrocytomas (n=2), metastatic melanoma (n=1), and trigeminal schwannoma (n=1). Pre-resection rCoBF values were low in all but two tumors where perfusion was in the low normal range. Post-resection rCoBF values were either low or normalized. Seizure activity was documented in a pilocytic astrocytoma with a significant rCoBF increase during resection. Our findings indicate that hypoperfusion in the cortex adjacent to malignant brain tumors is the result of primary metabolic failure and tumor pressure ischemia.
• Tveraa, K., Hirschberg, H., Carol, M., Grant, W. H., Pavord, D., Eddy, P., Targovnik, H. S., Butler, B., Woo, S., Figura, J., Onufrey, V., Grossman, R. G., Selkar, R., Tronnier, V. M., Knauth, M., Bonsanto, M. M., Hassfeld, S., Albert, F. K., Kunze, S., , Hardy, T. L., et al. (1996). Subject Index Vol. 66, 1996. Stereotactic and Functional Neurosurgery, 66(4), 159-160. doi:10.1159/000099684
• Gerner, E. W., Hamilton, A. J., Woolridge, D. P., Stea, B., Hamilton, A. J., Gerner, E. W., & Gannett, D. E. (1995). 123 Hypusine as a potential prognostic marker in glial derived brain tumors. International Journal of Radiation Oncology Biology Physics, 32, 202. doi:10.1016/0360-3016(95)97786-z
• Hamilton, A. J. (1995). The endoscopic stylet: technical notes.. Neurosurgery, 36(2), 435-6. doi:10.1227/00006123-199502000-00034
• Hamilton, A. J., & Lulu, B. A. (1995). A prototype device for linear accelerator-based extracranial radiosurgery.. Acta neurochirurgica. Supplement, 63, 40-3. doi:10.1007/978-3-7091-9399-0_9
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  A prototype frame for accurate stereotactic localization and linear accelerator (LINAC)-based treatment of extracranial targets was developed. The ECRSF is designed to employ either spinal or skeletal osseous fixation to immobilize the area of interest and then encircle the targeted region with a traditional orthogonal, three-axis system. A series of experiments (n = 5) with semi-radiolucent calibration targets (n = 15) and computed tomography (CT) scanning using the EC showed that a mean localization error of 0.98 +/- 0.22 mm was obtainable in the last two and most accurate series of experiments with these targets (n = 8). Using the LINAC to irradiate these same targets demonstrated an overall radiation treatment accuracy ranging from 1.4 to 2.0 mm. This discrepancy between localization error and overall radiation treatment error can be explained by a lack of isocentricity of the LINAC treatment which is typically less than 1 mm and can be as low as 0.5 mm. These data demonstrate that extracranial stereotactic radiosurgery is now technically feasible and that the accuracy of such treatment would be acceptable for clinical treatment.
• Hamilton, A. J., Stea, B., Lulu, B. A., Hamilton, A. J., Fosmire, H., & Cassady, J. R. (1995). Preliminary clinical experience with linear accelerator-based spinal stereotactic radiosurgery.. Neurosurgery, 36(2), 311-9. doi:10.1227/00006123-199502000-00010
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  A prototype device called an extracranial stereotactic radiosurgery frame was used to deliver stereotactic radiosurgery, with a modified linear accelerator, to metastatic neoplasms in the cervical, thoracic, and lumbar regions in five patients. In all patients, the neoplasms had failed to respond to spinal cord tolerance doses delivered by standard external fractionated radiation therapy to a median dose of 45 Gy (range, 33-65 Gy/11-30 fractions). The tumors were treated with single-fraction stereotactic radiosurgery with the spinal stereotactic frame for immobilization, localization, and treatment. The median number of isocenters was one (range, one to five) with a median single fraction dose of 10 Gy (range, 8-10 Gy) with median normalization to 80% isodose contour (range, 80-160%). There has been a single complication of esophagitis to date from radiosurgery of a tumor involving the C6-T1 segments; the esophagitis resolved with medical therapy. Median follow-up in this group of patients has been 6 months (range, 1-12 mo). To date, there has been no radiographic or clinical progression of the treated tumor in any patient. Two patients have died from systemic metastatic disease. In the three surviving patients, there has been computed tomographic- or magnetic resonance-documented regression of the treated tumor with a decrease of thecal sac compression with a median follow-up of 6 months (range, 3-14 mo). These five patients represent the first clinical application of stereotactic radiosurgery in the spine. The results suggest that extracranial radiosurgery may be suitable for the treatment of paraspinal neoplasms after external fractionated radiation therapy, even in the face of spinal cord compression.
• Hamilton, A. J., Stea, B., Lulu, B., Hamilton, A. J., Cheng, C. W., & Cassady, J. R. (1995). The use of gold foil wrapping for radiation protection of the spinal cord for recurrent tumor therapy.. International journal of radiation oncology, biology, physics, 32(2), 507-11. doi:10.1016/0360-3016(94)00502-c
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  The development of a technique to provide sufficient radiation protection to previously irradiated spinal cord in such a manner that interstitial brachytherapy can be conducted after resection of a recurrent tumor and decompression of the cord..A technique was developed that uses multiple layers of gold foil that are applied around the thecal sac and nerve root sleeves to produce an enveloping radiation shield after resection of recurrent tumor. Once the layers of gold foil are in place, interstitial I125 seeds are permanently placed in the bed of the tumor resection to prevent any recurrence from microcellular disease. The technique is described and its application in the case of a 28-year-old with a third recurrence of chondrosarcoma after external fractionated radiation therapy at the second to the fourth thoracic segments is reviewed..This technique has been used in this first patient. An additional tumor dose of 120.0 Gy was delivered to the tumor bed while the spinal cord was calculated to receive only 1% of the dose over the life span of the implant. To date, this dose of radiation has prevented tumor recurrence for more than 18 months of follow-up..This technique of multiple layers of gold foil shielding over the spinal cord and nerve roots has the potential to be a useful tool for the shielding of a previously irradiated spinal cord in the setting of resection of recurrent tumor. It may also have a wider application to a number of other radiosensitive tumors where interstitial brachytherapy may be useful to provide additional treatment after external fractionated radiation therapy.
• Hamilton, A. J., Verdi, C., Stea, B., Lulu, B., Hamilton, A. J., Gannett, D. E., & Adair, T. (1995). Stereotactic radiosurgery as an adjunct to surgery and external beam radiotherapy in the treatment of patients with malignant gliomas.. International journal of radiation oncology, biology, physics, 33(2), 461-8. doi:10.1016/0360-3016(95)00087-f
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  To evaluate the efficacy and toxicity of a stereotactic radiosurgery boost as part of the primary management of a minimally selected population of patients with malignant gliomas..Between June, 1991 and January, 1994 a stereotactic radiosurgery boost was given to 30 patients after completion of fractionated external beam radiotherapy. The study population consisted of 22 males and 8 females, with a range in age at treatment from 5 to 74 years (median: 54 years). Tumor volume ranged from 2.1 to 115.5 cubic centimeters (cc) (median: 24 cc). Histology included 17 with glioblastoma multiforme, 10 with anaplastic astrocytoma, 1 with a mixed anaplastic astrocytoma-oligodendroglioma, and 2 with a gliosarcoma. A complete resection was performed in 9 (30%) patients, while 18 (60%) underwent a subtotal resection, and 3 (10%) received a biopsy only. Fractionated radiation dose ranged from 44 to 62 Gy, with a median of 59.4 Gy. Prescribed stereotactic radiosurgery dose ranged from 0.5 to 18 Gy (median: 10 Gy), and the volume receiving the prescription dose ranged from 2.1 to 158.7 cc (median: 46 cc). The volume of tumor receiving the prescription dose ranged from 70-100% (median: 100%). One to four (median: 2) isocenters were used, and collimator size ranged from 12.5 to 50 mm (median size: 32.5 mm). The median minimum stereotactic radiosurgery dose was 70% of the prescription dose and the median maximum dose was 200% of the prescription dose..With a minimum follow-up of 1 year from radiosurgery, 7 (23%) of the patients are still living and 22 (73%) have died of progressive disease. One patient died of a myocardial infarction 5 months after stereotactic radiosurgery. Follow-up for living patients ranged from 12 to 45 months, with a median of 30 months. The 1- and 2-year disease-specific survival from the date of diagnosis is 57 [95% confidence interval (CI) 39 to 74%] and 25% (95% CI 9 to 41%), respectively (median survival: 13.9 months). No significant acute or late toxicity has been observed..Stereotactic radiosurgery provides a safe and feasible technique for dose escalation in the primary management of unselected malignant gliomas. Longer follow-up and a randomized prospective trial is required to more thoroughly evaluate the role of radiosurgery in the primary management of malignant gliomas.
• Hamilton, A. J., Williams, F. C., Weinand, M. E., Sioutos, P. J., Orozco, J. A., Hamilton, A. J., & Carter, L. P. (1995). Continuous regional cerebral cortical blood flow monitoring in head-injured patients.. Neurosurgery, 36(5), 943-9; discussion 949-50. doi:10.1227/00006123-199505000-00009
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  Continuous regional cerebral cortical blood flow (rCoBF) was monitored with thermal diffusion flowmetry in 56 severely head-injured patients. Adequate, reliable data were accumulated from 37 patients (21 acute subdural hematomas, 10 cerebral contusions, 4 epidural hematomas, and 2 intracerebral hematomas). The thermal sensor was placed at the time of either craniotomy or burr hole placement. In 15 patients, monitoring was initiated within 8 hours of injury. One-third of the comatose patients monitored within 8 hours had rCoBF measurements of 18 ml per 100 g per minute or less, consistent with previous reports of significant ischemia in the early postinjury period. Initial rCoBF measurements were similar in the patients with Glasgow Coma Scale scores of 3 to 7 and in those with scores of 8 or greater. In patients with poor outcomes, rCoBF measurements did not change significantly from initial measurements; however, in those patients who had better outcomes, final rCoBF measurements were higher than initial rCoBF measurements. The patients who had better outcomes experienced normalization of rCoBF during the period of monitoring, and patients with poor outcomes had markedly reduced final rCoBF. These changes were statistically significant. When management was based strictly upon the intracranial pressure, examples of inappropriate treatment were found. For example, hyperemia and increased intracranial pressure treated with mannitol caused further rCoBF increase, and elevated intracranial pressure with low cerebral blood flow treated with hyperventilation increased the severity of ischemia. In 3 (5%) of 56 patients, wound infections developed. Continuous rCoBF monitoring in head-injured patients offers new therapeutic and prognostic insights into their management.
• Bowersock, T. L., Woodyard, L., Hamilton, A. J., & Deford, J. A. (1994). Inhibition of Staphylococci by vancomycin absorbed on triidodecylmethyl ammonium chloride-coated intravenous catheter. Journal of Controlled Release, 31(3), 237-243. doi:10.1016/0168-3659(94)90005-1
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  Catheter-related infections are a serious problem in hospitalized patients. Triidodecylmethyl ammonium chloride (TDMAC)-treated catheters were absorbed with the antibiotic vancomycin and evaluated for bactericidal activity against Staphylococcus aureus and Staphylococcus epidermidis over time. Bactericidal activity occurred in a biphasic pattern with peak activity from 0–72 h and activity detectable for up to 6 days. Incubation of the TDMAC-coated catheters in serum did not reduce the bactericidal activity of vancomycin bound to the catheter for Staphylococci. These results document that TDMAC-coated catheters could be used to absorb vancomycin thereby expanding the range of antibiotics available for binding to surfactant-treated catheters. The use of vancomycin would be helpful in preventing catheter infections by highly antibiotic-resistant organisms such as the Staphylococci, especially in sites such as the brain where effective concentration of other parenterally administered antibiotics is difficult to attain.
• Hamilton, A. J., Stea, B., Shetter, A. G., Rossman, K., Kittelson, J., Hamilton, A. J., & Cassady, J. R. (1994). Interstitial irradiation versus interstitial thermoradiotherapy for supratentorial malignant gliomas: a comparative survival analysis.. International journal of radiation oncology, biology, physics, 30(3), 591-600. doi:10.1016/0360-3016(92)90945-e
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  To compare the survival of two groups of patients with supratentorial malignant gliomas who were treated on two sequential protocols with either interstitial thermoradiotherapy or with interstitial irradiation without hyperthermia..Between 1988-1992, patients with anaplastic astrocytoma or glioblastoma multiforme were treated at the University of Arizona on a Phase I/II protocol of interstitial thermoradiotherapy with ferro-magnetic seeds. The treatment protocol consisted of debulking surgery, a course of external beam radiotherapy and hyperthermia given immediately before and after brachytherapy. The survival of patients so treated was compared with that of a similar group of patients treated with interstitial brachytherapy alone at the Barrows Neurological Institute between 1982-1990..Twenty-five patients with primary tumors treated at the time of initial presentation with thermoradiotherapy were compared with a control group of 37 patients treated with interstitial brachytherapy alone. All primary patients were followed for a minimum of 34 months post implant. Multivariate analysis based on proportional hazards models showed that hyperthermia (p = 0.027), patient age (p < or = 0.00001) and histology (anaplastic astrocytoma vs. glioblastoma multiforme, p = 0.0017) were the only factors significantly associated with survival in this data set. From the fitted model, the hazard of dying when treated with hyperthermia was .53 times (95% confidence intervals 0.29-0.94) than that of the control group. In addition, we treated a small group of patients with recurrent tumors (13 with brachytherapy alone, and eight with thermoradiotherapy) and found no survival difference (p = 0.62)..Within the constraints of the selection factors and the different treatment parameters used in these studies, we conclude that an interstitial thermoradiotherapy boost confers a statistically significant survival benefit to patients with primary high grade gliomas when compared to interstitial brachytherapy alone.
• Hamilton, A. J., Stea, B., Shetter, A. G., Rossman, K., Lulu, B., Kittelson, J., Hamilton, A. J., & Cassady, J. R. (1994). A comparison of survival between radiosurgery and stereotactic implants for malignant astrocytomas.. Acta neurochirurgica. Supplement, 62, 47-54. doi:10.1007/978-3-7091-9371-6_10
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  The purpose of this paper is to compare the survival of three groups of patients with high grade supratentorial gliomas who were treated on three sequential protocols with surgical resection, external beam fractionated radiotherapy and a boost to the residual contrasting enhancing mass by either interstitial brachytherapy (IB, n = 33), by interstitial thermoradiotherapy (IT, n = 25) or by stereotactic radiosurgery (SRS, n = 19). The primary aim of this study was to evaluate the role of different boosting techniques in the initial management of primary brain tumors. External beam radiotherapy doses were escalated from one study to the next so that the median doses given to the IB, the IT, and the SRS groups were 41.4 Gy, 48.4 Gy, and 59.4 Gy, respectively. The median dose of interstitial irradiation or stereotactic radiosurgery, were 40 Gy, 32.2 Gy and 10 Gy, respectively, for the same groups. Follow-up was such that all living patients had been followed for a minimum of 30, 27, 4 months in the IB, IT, and SRS groups, respectively; hence, twelve-month survival was 52% (95% CI: 34%-69%), 80% (95% CI: 64%-96%), and 51% (95% CI: 24%-78%) in the same respective groups. Using a multivariate Cox proportional hazards model, treatment with IT conferred a survival advantage over IB (p = 0.029). Furthermore, survival of patients treated with SRS did not significantly differ from that of patients treated with an implant with or without hyperthermia.(ABSTRACT TRUNCATED AT 250 WORDS)
• Frim, D. M., Barker, F. G., Poletti, C. E., & Hamilton, A. J. (1993). Postoperative Low-Dose Heparin Decreases Thromboembolic Complications in Neurosurgical Patients. Survey of Anesthesiology, 37(2), 89. doi:10.1097/00132586-199304000-00033
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  Thromboembolic complications are a major cause of postoperative morbidity and mortality in the neurosurgical patient. Prophylaxis with lower extremity pneumatic compression boots (PCBs) reduces the incidence of lower extremity deep vein thrombosis (DVT) but has not been shown to affect the incidence of pulmonary embolism (PE). Prophylaxis with low-dose heparin has consistently reduced the incidence of both DVT and PE in studies on general surgical patients but has not been adopted for use in neurosurgery primarily for fear of causing catastrophic hemorrhage. We report on a series of 138 consecutive adult patients who underwent major neurosurgical procedures on a general neurosurgical service at our institution. Patients were treated with intraoperative PCBs and, starting on the morning of the first postoperative day, with a regimen of 5000 U of heparin administered subcutaneously twice daily. This treatment was continued until patients were fully ambulatory. PCBs were discontinued 24 hours after the first administration of heparin. None of the heparin-treated patients suffered postoperative hemorrhage. We compared this series with a control group of 473 adult patients who had previously undergone major neurosurgical procedures on the same neurosurgical service. These patients had been treated with intraoperative and postoperative PCBs alone. The control group had a 3.2% incidence of thromboembolic complications (15 of 473; eight DVT, seven PE). Prophylaxis with PCBs plus heparin significantly (P = 0.020) reduced the incidence of thromboembolic complications: no PCBs/heparin-treated patient exhibited clinical evidence of PE or DVT (0%, 0/138). We conclude that a combination of intraoperative PCBs and postoperative low-dose heparin is a safe and effective method by which to reduce thromboembolic complications in the neurosurgical patient.
• Frim, D. M., Barker, F. G., Poletti, C. E., & Hamilton, A. J. (1992). Postoperative low-dose heparin decreases thromboembolic complications in neurosurgical patients.. Neurosurgery, 30(6), 830-833. doi:10.1227/00006123-199206000-00002
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  Thromboembolic complications are a major cause of postoperative morbidity and mortality in the neurosurgical patient. Prophylaxis with lower extremity pneumatic compression boots (PCBs) reduces the incidence of lower extremity deep vein thrombosis (DVT) but has not been shown to affect the incidence of pulmonary embolism (PE). Prophylaxis with low-dose heparin has consistently reduced the incidence of both DVT and PE in studies on general surgical patients but has not been adopted for use in neurosurgery primarily for fear of causing catastrophic hemorrhage. We report on a series of 138 consecutive adult patients who underwent major neurosurgical procedures on a general neurosurgical service at our institution. Patients were treated with intraoperative PCBs and, starting on the morning of the first postoperative day, with a regimen of 5000 U of heparin administered subcutaneously twice daily. This treatment was continued until patients were fully ambulatory. PCBs were discontinued 24 hours after the first administration of heparin. None of the heparin-treated patients suffered postoperative hemorrhage. We compared this series with a control group of 473 adult patients who had previously undergone major neurosurgical procedures on the same neurosurgical service. These patients had been treated with intraoperative and postoperative PCBs alone. The control group had a 3.2% incidence of thromboembolic complications (15 of 473; eight DVT, seven PE). Prophylaxis with PCBs plus heparin significantly (P = 0.020) reduced the incidence of thromboembolic complications: no PCBs/heparin-treated patient exhibited clinical evidence of PE or DVT (0%, 0/138). We conclude that a combination of intraoperative PCBs and postoperative low-dose heparin is a safe and effective method by which to reduce thromboembolic complications in the neurosurgical patient.
• Hamilton, A. J., Stea, B., Shetter, A. G., Shapiro, W. R., Rossman, K., Obbens, E., Lulu, B., Kittelson, J., Hamilton, A. J., Guthkelch, N., Cetas, T. C., & Cassady, J. R. (1992). Treatment of malignant gliomas with interstitial irradiation and hyperthermia.. International journal of radiation oncology, biology, physics, 24(4), 657-67. doi:10.1016/0360-3016(92)90711-p
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  A Phase I study of interstitial thermoradiotherapy for high-grade supratentorial gliomas has been completed. The objective of this trial was to test the feasibility and toxicity of hyperthermia induced by ferromagnetic implants in the treatment of intracranial tumors. The patient population consisted of 16 males and 12 females, with a median age of 44 years and a median Karnofsky score of 90. Nine patients had anaplastic astrocytoma while 19 had glioblastoma multiforme. Twenty two patients were treated at the time of their initial diagnosis with a course of external beam radiotherapy (median dose 48.4 Gy) followed by an interstitial implant with Ir-192 (median dose 32.7 Gy). Six patients with recurrent tumors received only an interstitial implant (median dose 40 Gy). Median implant volume for all patients was 55.8 cc and median number of treatment catheters implanted per tumor was eighteen. A 60-minute hyperthermia treatment was given through these catheters just before and right after completion of brachytherapy. Time-averaged temperatures of all treatments were computed for sensors located within the core of (> 5 mm from edge of implant), and at the periphery of the implant (outer 5 mm). The percentage of sensors achieving an average temperature > 42 degrees C was 61% and 35%, respectively. Hyperthermia was generally well tolerated; however, there have been 11 minor toxicities, which resolved with conservative management, and one episode of massive edema resulting in the death of a patient. In addition, there were three major complications associated with the surgical implantation of the catheters. Preliminary survival analysis shows that 16 of the 28 patients have died, with a median survival of 20.6 months from diagnosis. We conclude that interstitial hyperthermia of brain tumors with ferromagnetic implants is feasible and carries significant but acceptable morbidity given the extremely poor prognosis of this patient population.
• Yoshino, M., Meakem, T., Hamilton, A., & Carter, L. (1992). Intraspinal enterogenous cyst [13]

  1.     Meakem TJ, Yoshino MT, Hamilton AJ, Carter LP (1992): MRI and CT Demonstration of an Anterior Cervical Enterogenous Cyst: a Case Report;  Am. J. Radiology, 159, 904.. 56. Meakem TJ, Yoshino MT, Hamilton AJ, Carter LP (1992): MRI and CT Demonstration of an Anterior Cervical Enterogenous Cyst: a Case Report; Am. J. Radiology, 159, 904., 159(4). doi:10.2214/ajr.159.4.1529870

• Louis, D. N., Hamilton, A. J., Sobel, R. A., & Ojemann, R. G. (1991). Pseudopsammomatous meningioma with elevated serum carcinoembryonic antigen: a true secretory meningioma. Case report.. Journal of neurosurgery, 74(1), 129-32. doi:10.3171/jns.1991.74.1.0129
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  A sphenoid-wing meningioma in a 60-year-old woman was accompanied by elevated serum carcinoembryonic antigen (CEA) levels, which returned to normal after removal of the tumor. Light microscopic examination revealed a secretory meningioma containing numerous pseudopsammoma bodies and a prominent vascular pattern. Immunohistochemical analysis showed the tumor cells and pseudopsammoma bodies to be CEA-positive. This case illustrates the possibility that secretory meningioma may be associated with clinically detectable secretion of CEA. The report also documents the rare occurrence of elevated serum CEA in a primary benign intracranial tumor.
• Stea, B., Kittelson, J., Lulu, B., Rossman, K., Obbens, E., Johnson, P., Cassady, J. R., Guthkelch, N., Shetter, A. G., Shapiro, W. R., Hamilton, A. J., & Cetas, T. C. (1991). Hyperthermia of high-grade gliomas with ferromagnetic implants. International Journal of Radiation Oncology Biology Physics, 21, 120. doi:10.1016/0360-3016(91)90443-8
• Bender, P., McCullough, R., Huang, S., Wagner, P., Cymerman, A., Hamilton, A., & Reeves, J. (1989). Increased exercise Sa(O2) independent of ventilatory acclimatization at 4,300 m

  1.     Bender PR, McCullough RE, McCullough RG, Huang SY, Wagner PD, Cymerman A, Hamilton AJ, Reeves JT (1989): Increased Exercise SaO2 Independent of Ventilatory Acclimatization at 4300m.  J. Appl. Physiol., 66, 2733-2738.. 61. Bender PR, McCullough RE, McCullough RG, Huang SY, Wagner PD, Cymerman A, Hamilton AJ, Reeves JT (1989): Increased Exercise SaO2 Independent of Ventilatory Acclimatization at 4300m. J. Appl. Physiol., 66, 2733-2738., 66(6). doi:10.1152/jappl.1989.66.6.2733

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  Arterial O2 saturation (Sa(O2)) decreases in hypoxia in the transition from rest to moderate exercise, but it is unknown whether over several weeks at high altitude Sa(O2) in submaximal exercise follows the same time course and pattern as that of ventilatory acclimatization in resting subjects. Ventilatory acclimatization is essentially complete after ~1 wk at 4,300 m, such that improvement in submaximal exercise Sa(O2) would then require other mechanisms. On days 2, 8, and 22 on Pikes Peak (4,300 m), 6 male subjects performed prolonged steady-state cycle exercise at 79% maximal O2 uptake [V̇(O(2 max))]. Resting Sa(O2) rose from day 1 (78.4 ± 1.6%) to day 8 (87.5 ± 1.4%) and then did not increase further by day 20 (86.4 ± 0.6%). During exercise, Sa(O2) values (mean of 5-, 15-, and 30-min measurements) were 72.7% (day 2), 78.6% (day 8), and 82.3% (day 22), meaning that all of the increase in resting Sa(O2) occurred from day 1 to day 8, but exercise Sa(O2) increased from day 2 to day 8 (5.9%) and then increased further from day 8 to day 22 (3.7%). On day 22, the exercise Sa(O2) was higher than on day 8 despite an unchanged ventilation and O2 consumption. The increased exercise Sa(O2) was accompanied by decreased CO2 production. The mechanisms responsible for the increased exercise Sa(O2) require further investigation.
• Bender, P. R., Groves, B. M., Mccullough, R. E., Mccullough, R. G., Huang, S. Y., Hamilton, A. J., Wagner, P. D., Cymerman, A., & Reeves, J. T. (1988). Oxygen transport to exercising leg in chronic hypoxia.. Journal of applied physiology (Bethesda, Md. : 1985), 65(6), 2592-7. doi:10.1152/jappl.1988.65.6.2592
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  Residence at high altitude could be accompanied by adaptations that alter the mechanisms of O2 delivery to exercising muscle. Seven sea level resident males, aged 22 +/- 1 yr, performed moderate to near-maximal steady-state cycle exercise at sea level in normoxia [inspired PO2 (PIO2) 150 Torr] and acute hypobaric hypoxia (barometric pressure, 445 Torr; PIO2, 83 Torr), and after 18 days' residence on Pikes Peak (4,300 m) while breathing ambient air (PIO2, 86 Torr) and air similar to that at sea level (35% O2, PIO2, 144 Torr). In both hypoxia and normoxia, after acclimatization the femoral arterial-iliac venous O2 content difference, hemoglobin concentration, and arterial O2 content, were higher than before acclimatization, but the venous PO2 (PVO2) was unchanged. Thermodilution leg blood flow was lower but calculated arterial O2 delivery and leg VO2 similar in hypoxia after vs. before acclimatization. Mean arterial pressure (MAP) and total peripheral resistance in hypoxia were greater after, than before, acclimatization. We concluded that acclimatization did not increase O2 delivery but rather maintained delivery via increased arterial oxygenation and decreased leg blood flow. The maintenance of PVO2 and the higher MAP after acclimatization suggested matching of O2 delivery to tissue O2 demands, with vasoconstriction possibly contributing to the decreased flow.
• Hamilton, A. (1987). High altitude cerebral edema1.     Hamilton AJ, Cymerman A, Black PM (1986): High Altitude Cerebral Edema.  Neurosurgery, 19, 841-849.

   . 63. Hamilton AJ, Cymerman A, Black PM (1986): High Altitude Cerebral Edema. Neurosurgery, 19, 841-849., 20(5). doi:10.1227/00006123-198705000-00034

• Hamilton, A. J., Black, P. M., Carr, D. B., & Madsen, J. R. (1986). Neuropeptide investigations with an ovine surgical model.. Neurosurgery, 18(6), 748-55. doi:10.1227/00006123-198606000-00012
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  An ovine surgical model for peptide investigations is presented. Techniques for exteriorization of the carotid artery, catheterization of the sagittal sinus, hypophysectomy via a transnasopharyngeal approach, and ventricular and cisternal cannulation in the sheep are employed within the model. Several experimental applications in neurosurgical research are presented.
• Hamilton, A. J., Carr, D. B., Larovere, J. M., & Black, P. M. (1986). Endotoxic shock elicits greater endorphin secretion than hemorrhage.. Circulatory shock, 19(1), 47-54.
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  Opiopeptides may contribute to the pathophysiology of both endotoxic and hemorrhagic shock. To determine if endorphin secretion is similar in both types of shock, we divided 25 sheep into three groups: a saline control group (n = 10), an endotoxin-treated group (n = 9), and a hemorrhage group (n = 6). Each sheep had baseline determinations of mean arterial pressure (MAP) and plasma levels of beta-endorphin-like immunoreactivity (iB-EP). Experimental animals either received endotoxin (450 ng/kg intravenous) or underwent withdrawal of blood volume sufficient to diminish MAP by approximately one-third of baseline values. MAP and iB-EP levels were determined every 15 minutes thereafter for 5 hours. Individual data were averaged within each group and then compared between groups using analysis of variance. Both the endotoxin- and hemorrhage-treated groups showed a significant fall in MAP, which was significantly lower in the hemorrhage group than the endotoxin group. Endotoxin-treated animals displayed a mean peak iB-EP level 1,550% above baseline as compared to a mean peak iB-EP level of only 201% above baseline in the hemorrhage-treated group, despite a significantly greater degree of hypotension in the latter group; this difference in peak iB-EP response was significant. Mean peak iB-EP levels coincided with mean trough MAP values in the endotoxin-treated group while the mean peak iB-EP lagged the onset of mean trough MAP in the hemorrhage group. These results demonstrate that iB-EP secretory patterns differ in endotoxic versus hemorrhagic shock and suggest that distinct mechanisms of opiopeptide secretion accompany the two shock states.
• Hamilton, A. J., Cymmerman, A., & Black, P. M. (1986). High altitude cerebral edema.. Neurosurgery, 19(5), 841-9. doi:10.1227/00006123-198611000-00024
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  Acute mountain sickness (AMS) is usually a benign and self-limited illness that befalls previously healthy individuals who ascend rapidly to high altitude without sufficient acclimatization. In its more severe forms, AMS can progress to a life-threatening condition in which pulmonary or cerebral edema can occur singly or in concert. High altitude cerebral edema (HACE) is a little-known clinical entity that manifests itself by a perplexing array of both generalized and localized neurological symptoms and signs. Furthermore, the development of HACE in climbers offers a unique experimental situation in which to examine the effects of hypoxia on the central nervous system. The epidemiology and clinical picture of HACE are reviewed. In addition, the pathology and predominant pathophysiological mechanisms postulated to explain HACE are examined, and the present recommendations for the prevention and treatment of this dangerous and unusual form of brain swelling are discussed.
• Carr, D. B., Jones, K. J., Bergland, R. M., Kasting, N. W., Fisher, J. E., Martin, J. B., & Hamilton, A. J. (1985). Causal links between plasma and CSF endorphin levels in stress: vector-ARMA analysis.. Peptides, 6 Suppl 1, 5-10. doi:10.1016/0196-9781(85)90004-x
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  To explore causal links between vital sign responses and immunoreactive beta-endorphin ("i-BE") rises in blood and CSF during ovine endotoxin stress, we analyzed concurrent i-BE levels in these two compartments by a "vector-ARMA" (= autoregressive moving average) method. This technique--widely used for modeling in other applications--has not to our knowledge been employed to study dynamic relationships of neuropeptides. Log-transformed i-BE levels were first "filtered" by repeated observations ANOVA to confirm significance of rises in both compartments. Next, vector-ARMA methodology was applied to derive an optimal causal model of vital sign changes and i-BE entry into plasma vs. CSF pools. The model indicated that reflux of i-BE from blood into CSF contributed to increases in CSF levels of this hormone. This novel application to neuroendocrinology of this approach illustrates its utility in evaluating changes in one or more neuropeptide levels in multiple compartments to indicate potentially causal relationships.
• Hamilton, A. J., Black, P. M., & Carr, D. B. (1985). Contrasting actions of naloxone in experimental spinal cord trauma and cerebral ischemia: a review.. Neurosurgery, 17(5), 845-9. doi:10.1227/00006123-198511000-00023
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  Endorphins have been implicated in the pathophysiology of both spinal cord injury and cerebral ischemia. This review examines the nature of the experimental evidence to support this hypothesis. Present studies suggest that naloxone administration improves neurological function and outcome in the setting of the spinal cord trauma by centrally inhibiting an opiate receptor-mediated diminution of spinal cord flow. In the setting of spinal shock, naloxone administration is associated with improvement in vital sign and cardiovascular parameters as measured by mean arterial pressure, cardiac output, body temperature, and ventilation. Experiments using a variety of animal stroke models similarly support the notion that naloxone improves neurological function in the setting of cerebral ischemia by a stereospecific opiate receptor-mediated effect, but this improvement does not seem to be accompanied by augmentation of blood flow to affected areas of the brain or by any improvement in vital signs or cardiovascular parameters as seen in spinal cord trauma. A variety of mechanisms are discussed to explain these observations. The therapeutic implications of administering opiate agonists and antagonists in the setting of neurological deficits are outlined for the neurosurgeon.
• Friedman, E., & Hamilton, A. (1983). Polytetrafluoroethylene grafts in the peripheral venous circulation of rabbits

  1.     Friedman EW, Hamilton AJ (1983): Polytetrafluoroethylene Grafts in Peripheral Venous Circulation of Rabbits.  Amer. J. Surg., 146, 355-359.. 68. Friedman EW, Hamilton AJ (1983): Polytetrafluoroethylene Grafts in Peripheral Venous Circulation of Rabbits. Amer. J. Surg., 146, 355-359., 146(3). doi:10.1016/0002-9610(83)90415-4

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  We demonstrated by venography that the patency of 3 mm PTFE grafts in the jugular veins of rabbits could be maintained by pretreating the animals with either an anticoagulant (warfarin sodium) or an antiplatelet agent (aspirin, dipyridamole, or both). Examination of the lining of the grafts up to 4 months after grafting by scanning electron microscopy or light microscopy showed that endothelial cells extended across the anastomosis for a short distance and that a neointima lined the remainder of the graft. This lining could hypertrophy to the point of almost occluding the graft unless the drugs were continued. © 1983.
• Carr, D. B., Bergland, R., Martin, J. B., Rosenblatt, M., Kasting, N. W., Hamilton, A. J., Blume, H. W., & Arnold, M. A. (1982). Endotoxin-stimulated opioid peptide secretion: two secretory pools and feedback control in vivo.. Science (New York, N.Y.), 217(4562), 845-8. doi:10.1126/science.6285473
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  Small doses of endotoxin evoked a dramatic biphasic response of opioid peptide secretion into blood in sheep. The first phase began within minutes and coincided with a brief hypertensive response to endotoxin well before the appearance of fever or hypotension. The ratio of beta-endorphin to beta-lipotropin fell abruptly at the onset of the second phase of release, suggesting early depletion of a pool rich in beta-endorphin and subsequent emergence of a pool rich in unprocessed precursor. The concentration of cerebrospinal fluid opioids increased tenfold during the second phase. Naloxone administration augmented endotoxin-induced opioid secretion in both early and late phases, suggesting a short-loop feedback regulation of stress-induced endorphin secretion.
• Bergland, R., Monica, P., Paterson, R., Hamilton, A. J., & Blume, H. W. (1980). Adrenocorticotropic hormone may be transported directly from the pituitary to the brain.. Science (New York, N.Y.), 210(4469), 541-3. doi:10.1126/science.6252607
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  Experiments were designed to test the hypothesis that pituitary hormones may be delivered directly to the brain. Concentrations of adrenocorticotropic hormone (ACTH) in the plasma were determined in blood samles obtained simultaneously from the carotid artery, the sagittal sinus, and the jugular vein of three awake sheep. Seizures were induced electrically to stimulate ACTH secretion, and at precise intervals thereafter several simultaneous comparisons were made in each animal. In many of the post-seizure comparisons, the ACTH plasma concentrations within the sagital sinus exceeded those within the carotid artery as well as those within the jugular vein, indicating that this hormone was released from the pituitary and carried directly through capillary beds of brain to the venous blood within the sagittal sinus. The experiment was repeated in one hypophysectomized sheep and, in this animal, ACTH concentration in the plasma was reduced, but that in the sagittal sinus still was elevated after the seizure, an indication that some ACTH (or ACTH-like material) was released from the brain itself.
• Jalife, J., Hamilton, A. J., & Moe, G. K. (1980). Desensitization of the cholinergic receptor at the sinoatrial cell of the kitten.. The American journal of physiology, 238(4), H439-48. doi:10.1152/ajpheart.1980.238.4.h439
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  The hyperpolarizing effects of long periods of vagal stimulation were studied in kitten sinoatrial node-vagus nerve preparations. Verapamil (2.2 x 10(-6) M) was used to arrest spontaneous pacemaker activity, thus permitting uninterrupted observation of the time course of cholinergically mediated hyperpolarizations. With progressively longer vagal trains the hyperpolarization was not maintained but decreased, rapidly at first, and then more gradually despite continuous vagal stimulation. Similar decay of the cholinergic effect was also observed during continuous iontophoretic application of acetylcholine (ACh) or carbamylcholine (CCh). The results show that, for the most part, the decay of the hyperpolarizing response cannot be due to "fatigue" of nerve terminals, to a gradual reduction in the driving force for K+, or to hydrolysis of ACh by cholinesterase. These experiments demonstrate the development of desensitization of the cholinergic receptor at the sinoatrial cell membrane. The data fit the "cyclic reaction" model proposed by Katz and Thelsleff (J. Physiol. London 138:63-80, 1957) for the neuromuscular junction.
• Jalife, J., Hamilton, A. J., Lamanna, V. R., & Moe, G. K. (1980). Effects of current flow on pacemaker activity of the isolated kitten sinoatrial node.. The American journal of physiology, 238(3), H307-16. doi:10.1152/ajpheart.1980.238.3.h307
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  The dynamic behavior of the cardiac pacemaker in response to single or to periodically repeated perturbations was studied using kitten sinoatrial (SA) nodal strips mounted in a sucrose gap. Sustained stepwise applications of current across the gap produce lasting variations in pacemaker cycle length that depend on current magnitude and polarity, but not on the phase of the pacemaker period at the time of the input. Brief current pulses, whether hyperpolarizing or depolarizing, may abbreviate or prolong the immediately affected cycle depending on their timing. These changes result in phase shifts of the subsequent discharges, but they do not alter the pacemaker period permanently. The phasic effects of brief current pulses can be described by a phase response curve (PRC), which is a plot of the phase shift as a function of the position of the stimulus in the pacemaker cycle. PRCs were constructed for inputs of different polarity and several strengths and durations. The behavior of the sinus nodal pacemaker when interacting with period perturbing inputs, such as vagal stimulation or electrotonic depolarization, can be predicted on the basis of the phase response curve.

Proceedings Publications

• Collins, C., Lovett, M., Holder, K., Holcomb, M., Yonsetto, P., Weinstein, R. S., Hamilton, A. J., & Biffar, D. E. (2019). The Use of Remote and Traditional Faciliation to Evaluate Telesimulation to Support Interprofessional Education and Processing in Healthcare Simulation Training. In 2019 Spring Simulation Conference (SpringSim).
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  This pilot study appraised traditional versus remote facilitation via telesimulation for an established interprofessional training at two geographically separate sites. Participant feedback was captured via 5- point Likert scale surveys. Results demonstrate learners supported the use of remote facilitation: to meet the interprofessional learning objectives, as an adequate replacement for live facilitation and to implement simulation education in low-resource or low-facilitator areas. Improvements were suggested for audio connectivity between participants. In conclusion, the program evaluation suggests that telesimulation, with remote and traditional facilitation, is an effective strategy to provide interprofessional simulation education. Improvements identified are to standardize the set-up of audio/visual technology and tailor participant orientation to encourage meaningful dialogue between sites.
• Lovett, M., Kanda, J., Weinstein, R. S., Rozenblit, J. W., Hamilton, A. J., & Biffar, D. E. (2019). When Hollywood Inspires Medicine: New Concepts in the Design and Architecture of Medical Simulation Facilities to Support Inter-Professional Healthcare Education and Training. In 2019 Spring Simulation Conference (SpringSim).
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  The changing landscape of healthcare education, delivery, and technology is placing new demands for significant inter-disciplinary and inter-professional training in medical simulation. New architectural concepts and building designs must ensure that large-scale healthcare simulation facilities offer customized training opportunities for nursing, medicine, public health, and pharmacy while allowing for maximal flexibility and adaptation across nearly fifty different user groups and stake holders. A novel concept of a larger, configurable “stage” design, more akin to a Hollywood production studio, with in-patient and out-patient suites seen as temporary or “standing” sets was created. The stage, called a “Sim Deck,” can be easily dismantled while providing ample square footage for mass casualty scenarios. The facility required significant technological support to provide remote simulation training via existing and future telemedical technologies as well as remaining nimble enough to incorporate technologies in augmented and virtual reality, artificial intelligence, and large-scale learner management systems.
• Lovett, M., Lee, S., Hua, H., Nguyen, M., Katz, J. I., Hamilton, A. J., & Biffar, D. E. (2019). Evaluation of Learning Curve and Peripheral Awareness Using a Novel Multiresolution Foveated Laparoscope. In 2019 Spring Simulation Conference (SpringSim).
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  Laparoscopic surgery relies on effective visualization of areas of interest and surrounding tissue. The limited field of view of traditional laparoscopes increases the risk of peripheral tissue injury. To address this limitation, a multiresolution foveated laparoscope (MRFL) was designed to enhance peripheral awareness while maintaining focus on the area of interest. Peripheral awareness and learner effect were evaluated with novices (n=13) and experts (n=8). These subjects completed a modified Fundamentals of Laparoscopy Surgery task using a traditional laparoscope, MRFL with autotracking (AT), and MRFL without autotracking (NoAT). Subjects using the traditional laparoscope performed better than MRFL AT and MRFL NoAT in task completion time and collision number. The learner effect was steeper with use of MRFL. In multiple tested parameters, MRFL NoAT performed as well as the traditional laparoscope while providing the added benefits of enhanced field of view and multiple viewing perspectives. These findings warrant further development of MRFL.
• Peng, K. S., Hong, M., Hamilton, A. J., & Rozenblit, J. W. (2019). Single Shot State Detection in Simulation-Based Laparoscopy Training. In 2019 Spring Simulation Conference (SpringSim).
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  A Single Shot State Detection (SSSD) method is proposed to support a laparoscopic surgery skills training system – Computer-Assisted Surgical Trainer (CAST). CAST actively assists a trainee with visual, audio, or force guidance during different surgical practice tasks. In each task, the guidance is provided according to the target object state, which is one of the key components of CAST. We propose SSSD using deep neural networks to detect object states in a single image. We first model semantic objects to recognize objects’ state given a training task and then apply a deep learning algorithm, single shot detector (SSD), to detect the semantic objects. The contribution of this research is to present a unified object state model collaborating with a deep learning object detector, which can be applied to the surgical training simulator, as well as other visual sensing and automation systems.
• Hamilton, A. J., Rozenblit, J. W., & Fong, M. (2017, April). A Simulation-Based Assessment System for Computer-Assisted Surgical Training. In Spring 2017 Simulation Conference on Modeling and Simulation in Medicine, pages 834-844.
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  M. Hong, J.W. Rozenblit and A. HamiltonProc. of the 2017 Spring Simulation Conference, Modeling and Simulation in Medicine (SpringSim-MSM 2017), pp. 834-844, April 23-26, Virginia Beach, VA
• Hamilton, A. J. (2019, April). WHEN HOLLYWOOD INSPIRES MEDICINE: NEW CONCEPTS IN THE DESIGN AND ARCHITECTURE OF MEDICAL SIMULATION FACILITIES TO SUPPORT MULTI-DISCIPLINARY AND INTER-PROFESSIONAL HEALTHCARE EDUCATION AND TRAINING. In Annual Conference on Medical Modeling and Engineering Practices, TBA, TBA.
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  ABSTACTThe changing landscape of healthcare education, delivery, and technology is placing new demands for significant inter-disciplinary and inter-professional training in medical simulation. New architectural concepts and building designs must ensure that large-scale healthcare simulation facilities offer customized training opportunities for nursing, medicine, pharmacy and public health, while allowing for maximal flexibility and adaptation across nearly fifty different user groups and stake holders. A novel concept of a larger, configurable “stage” design, more akin to a Hollywood production studio, with in-patient and out-patient suites operationalized as temporary or “standing” sets was created as the centerpiece of a new, futuristic, 220,000 square foot health science education building. The stage, called a “sim deck,” can be easily dismantled or reconfigured while providing ample square footage for mass casualty scenarios. The facility required significant technological support to provide remote simulation training via existing and future telemedical technologies as well as remaining nimble enough to incorporate technologies in augmented and virtual reality, artificial intelligence, and large-scale learner management systems. Keywords: architecture, building design, healthcare, informational technologies, interdisciplinary, interprofessional, medical simulation, tele-simulation
• Hamilton, A. J., Rozenblit, J. W., Prescher, H., Hamilton, A. J., Galvani, C. A., & Biffar, D. E. (2014, Summer). Surgical navigation pointer facilitates identification of targets in a simulated environment. In Proceedings of the 2014 Summer Simulation Conference, Modeling and Simulation in Medicine, pages 246-252, Pasadena, CA July 2014., 46.
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  Introduction: The objective of this study was to determine whether or not a navigation pointer (NP) integrated into a laparoscopic camera and projected onto a surgical display might allow instructors to more easily and precisely direct assistants' instruments to specific sites in a simulated laparoscopic field.Methods: Two hundred forty pins served as targets in a standard laparoscopic box trainer. An instructor guided 24 subjects to locate 5 randomly selected targets each, with verbal instructions alone, or with verbal instructions supplemented by either a navigation grid (NG) or the localizing NP. Each subject performed 15 trials alternating between use of the NP, NG and no navigation tool. The primary outcome measure was the time to target identification.Results: The mean time to identify each selected target was significantly shorter with the NP (4.53 ± 2.87 seconds) than with the NG (8.59 ± 4.35 seconds, P
• Meinke, L., Hamilton, A. J., Prescher, H., Meinke, L., Jarred, J. E., Hamilton, A. J., Brooks, A. J., & Biffar, D. E. (2014). Video-guided versus direct laryngoscopy: considerations for using simulation to teach inexperienced medical students. In Proceedings of the 2014 Summer Simulation Conference, Modeling and Simulation in Medicine, pages 211-220, Pasadena, CA July 2014., 46.
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  The goal of this study was to determine whether video laryngoscopy (VL) provides any advantage over direct laryngoscopy (DL) in first-attempt intubations. This was a controlled, randomized study of 120 medical students. Students were randomly assigned to either of 2 intubation groups, which used (1) DL (n=64) or (2) VL (n=56) with the Karl Storz C-MAC® video laryngoscope. Each student attempted 1 endotracheal intubation on a Laerdal® Airway Management Trainer. The primary outcome measure was the time for successful endotracheal intubation. Secondary outcome measures included the incidence of esophageal intubation (EI), excess application of pressure on the maxillary incisor teeth (EMP), and first-time success rate. Mean time for endotracheal intubation was significantly faster in the VL group than in the DL group (101 ± 83 seconds vs. 180 ± 102.5 seconds; P
• Napalkova, L., Rozenblit, J. W., Hwang, G., Hamilton, A. J., & Suantak, L. (2014). An optimal motion planning method for computer-assisted surgical training. In Applied Soft Computing, 24, 889-899.
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  Graphical abstractDisplay Omitted HighlightsAn optimal motion planning method for computer-assisted surgical training is developed and validated in the paper.The method generates shortest, collision-free trajectories for laparoscopic instrument movements in the rigid block world used for hand-eye coordination tasks.Optimal trajectories are displayed on a monitor to provide continuous visual guidance for optimal navigation of instruments. This paper focuses on the development and validation of an optimal motion planning method for computer-assisted surgical training. The context of this work is the development of new-generation systems that combine artificial intelligence and computer vision techniques in order to adjust the learning process to specific needs of a trainee, while preventing a trainee from the memorization of particular task settings. The problem described in the paper is the generation of shortest, collision-free trajectories for laparoscopic instrument movements in the rigid block world used for hand-eye coordination tasks. Optimal trajectories are displayed on a monitor to provide continuous visual guidance for optimal navigation of instruments. The key result of the work is a framework for the transition from surgical training systems in which users are dependent on predefined task settings and lack guidance for optimal navigation of laparoscopic instruments, to the so called intelligent systems that can potentially deliver the utmost flexibility to the learning process. A preliminary empirical evaluation of the developed optimal motion planning method has demonstrated the increase of total scores measured by total time taken to complete the task, and the instrument movement economy ratio. Experimentation with different task settings and the technical enhancement of the visual guidance are subjects of future research.
• Prescher, H., Rozenblit, J. W., Hamilton, A. J., & Biffar, D. E. (2014). The comparison of high definition versus stereoscopic display on standardized fundamental laparoscopic skill procedures. In Proceedings of the 2014 Summer Simulation Conference, Modeling and Simulation in Medicine, pages 211-220, Pasadena, CA July 2014., 46.
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  The objective of this study was to determine whether or not a standard definition stereoscopic, 3D display could improve trainees' performance on a standard Fundamentals of Laparoscopy (FLS) task. Thirty-two procedurally naive volunteers were recruited for the study. Subjects were randomized to begin the trials on either the 3D or 2D display and performed 10 trials on a peg transfer task (SAGES). Subjects alternated between 3D and 2D displays for each trial. Time to completion of task, and the number of dropped objects were recorded for each trial, and a subjective evaluation of the subjects' preference in display monitor was collected. Mean time for peg transfer was significantly faster with the 3D monitor than the 2D monitor (114.22 s. versus 133.05 s.; SE: 3.82; P
• Prescher, H., Rozenblit, J. W., Hamilton, A. J., & Biffar, D. E. (2014, Spring). The comparison of high definition versus stereoscopic display on standardized fundamental laparoscopic skill procedures. In 21. H. Prescher, D. Biffar, J. Rozenblit and A. Hamilton (2014): The Comparison of High Definition versus Stereoscopic display on Standardized Fundamental Laparoscopic Skill Procedures, Proceedings of the 2014 Summer Simulation Conference, Modeling and Simulation in Medicine, pp. 346-351, Pasadena, CA July 2014., 46, 346-351.
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  The objective of this study was to determine whether or not a standard definition stereoscopic, 3D display could improve trainees' performance on a standard Fundamentals of Laparoscopy (FLS) task. Thirty-two procedurally naive volunteers were recruited for the study. Subjects were randomized to begin the trials on either the 3D or 2D display and performed 10 trials on a peg transfer task (SAGES). Subjects alternated between 3D and 2D displays for each trial. Time to completion of task, and the number of dropped objects were recorded for each trial, and a subjective evaluation of the subjects' preference in display monitor was collected. Mean time for peg transfer was significantly faster with the 3D monitor than the 2D monitor (114.22 s. versus 133.05 s.; SE: 3.82; P
• Prescher, H., Rozenblit, J. W., Hamilton, A. J., & Biffar, D. E. (2014, Spring). The comparison of high definition versus stereoscopic display on standardized fundamental laparoscopic skill procedures. In 21. H. Prescher, D. Biffar, J. Rozenblit and A. Hamilton (2014): The Comparison of High Definition versus Stereoscopic display on Standardized Fundamental Laparoscopic Skill Procedures, Proceedings of the 2014 Summer Simulation Conference, Modeling and Simulation in Medicine, pp. 346-351, Pasadena, CA July 2014., 46.
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  The objective of this study was to determine whether or not a standard definition stereoscopic, 3D display could improve trainees' performance on a standard Fundamentals of Laparoscopy (FLS) task. Thirty-two procedurally naive volunteers were recruited for the study. Subjects were randomized to begin the trials on either the 3D or 2D display and performed 10 trials on a peg transfer task (SAGES). Subjects alternated between 3D and 2D displays for each trial. Time to completion of task, and the number of dropped objects were recorded for each trial, and a subjective evaluation of the subjects' preference in display monitor was collected. Mean time for peg transfer was significantly faster with the 3D monitor than the 2D monitor (114.22 s. versus 133.05 s.; SE: 3.82; P
• Prescher, H., Rozenblit, J. W., Hamilton, A. J., Biffar, D. E., Prescher, H., Rozenblit, J. W., Hamilton, A. J., Biffar, D. E., Prescher, H., Rozenblit, J. W., Hamilton, A. J., & Biffar, D. E. (2014, Spring). The comparison of high definition versus stereoscopic display on standardized fundamental laparoscopic skill procedures. In 21. H. Prescher, D. Biffar, J. Rozenblit and A. Hamilton (2014): The Comparison of High Definition versus Stereoscopic display on Standardized Fundamental Laparoscopic Skill Procedures, Proceedings of the 2014 Summer Simulation Conference, Modeling and Simulation in Medicine,, 46, 346-351.
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  The objective of this study was to determine whether or not a standard definition stereoscopic, 3D display could improve trainees' performance on a standard Fundamentals of Laparoscopy (FLS) task. Thirty-two procedurally naive volunteers were recruited for the study. Subjects were randomized to begin the trials on either the 3D or 2D display and performed 10 trials on a peg transfer task (SAGES). Subjects alternated between 3D and 2D displays for each trial. Time to completion of task, and the number of dropped objects were recorded for each trial, and a subjective evaluation of the subjects' preference in display monitor was collected. Mean time for peg transfer was significantly faster with the 3D monitor than the 2D monitor (114.22 s. versus 133.05 s.; SE: 3.82; P
• Prescher, H., Rozenblit, J. W., Hamilton, A. J., Biffar, D. E., Prescher, H., Rozenblit, J. W., Hamilton, A. J., Biffar, D. E., Prescher, H., Rozenblit, J. W., Hamilton, A. J., & Biffar, D. E. (2014, summer). The comparison of high definition versus stereoscopic display on standardized fundamental laparoscopic skill procedures. In 21. H. Prescher, D. Biffar, J. Rozenblit and A. Hamilton (2014): The Comparison of High Definition versus Stereoscopic display on Standardized Fundamental Laparoscopic Skill Procedures, Proceedings of the 2014 Summer Simulation Conference, Modeling and Simulation in Medicine, pp. 346-351, Pasadena, CA July 2014., 46.
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  The objective of this study was to determine whether or not a standard definition stereoscopic, 3D display could improve trainees' performance on a standard Fundamentals of Laparoscopy (FLS) task. Thirty-two procedurally naive volunteers were recruited for the study. Subjects were randomized to begin the trials on either the 3D or 2D display and performed 10 trials on a peg transfer task (SAGES). Subjects alternated between 3D and 2D displays for each trial. Time to completion of task, and the number of dropped objects were recorded for each trial, and a subjective evaluation of the subjects' preference in display monitor was collected. Mean time for peg transfer was significantly faster with the 3D monitor than the 2D monitor (114.22 s. versus 133.05 s.; SE: 3.82; P
• Prescher, H., Rozenblit, J. W., Hamilton, A. J., Biffar, D. E., Prescher, H., Rozenblit, J. W., Hamilton, A. J., Biffar, D. E., Prescher, H., Rozenblit, J. W., Hamilton, A. J., Biffar, D. E., Prescher, H., Rozenblit, J. W., Hamilton, A. J., Biffar, D. E., Prescher, H., Rozenblit, J. W., Hamilton, A. J., & Biffar, D. E. (2014, Summer). The comparison of high definition versus stereoscopic display on standardized fundamental laparoscopic skill procedures. In 21. H. Prescher, D. Biffar, J. Rozenblit and A. Hamilton (2014): The Comparison of High Definition versus Stereoscopic display on Standardized Fundamental Laparoscopic Skill Procedures, Proceedings of the 2014 Summer Simulation Conference, Modeling and Simulation in Medicine, pp. 346-351, Pasadena, CA July 2014., 46.
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  The objective of this study was to determine whether or not a standard definition stereoscopic, 3D display could improve trainees' performance on a standard Fundamentals of Laparoscopy (FLS) task. Thirty-two procedurally naive volunteers were recruited for the study. Subjects were randomized to begin the trials on either the 3D or 2D display and performed 10 trials on a peg transfer task (SAGES). Subjects alternated between 3D and 2D displays for each trial. Time to completion of task, and the number of dropped objects were recorded for each trial, and a subjective evaluation of the subjects' preference in display monitor was collected. Mean time for peg transfer was significantly faster with the 3D monitor than the 2D monitor (114.22 s. versus 133.05 s.; SE: 3.82; P
• Rozenblit, J. W., Feng, C., Riojas, M., Napalkova, L., Hamilton, A. J., Hong, M., Berthet-rayne, P., Czapiewski, P., Hwang, G., Nikodem, J., Shankaran, A., & Rao, A. (2014, Spring). The computer assisted surgical trainer: design, models, and implementation. In Proceedings of the 2014 Summer Simulation Conference, Modeling and Simulation in Medicine, pages 211-220, Pasadena, CA July 2014., 46, 211-220.
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  This paper describes a system developed to assist in model-based training of minimally invasive, laparoscopic procedures. The key factor motivating the development of the device called CAST (Computer-Assisted Surgical Trainer) is the need to improve the state-of-the-art in teaching laparoscopy, and ultimately achieve better surgical outcomes. CAST's design concept and architecture is presented with its major elements that facilitate guided (both haptic and visual) execution of tasks, performance assessment, and comparative analysis of results. Both software and hardware models and implementations are given. The system, while currently intended for off-line, laboratory use, has an excellent potential for real-time assistive functions in the operating room.
• Valenzuela, M. L., Rozenblit, J. W., & Hamilton, A. J. (2014, Spring). A predictive analytics toolbox for medical applications. In Proceedings of the 2014 Summer Simulation Conference, Modeling and Simulation in Medicine,, 46, 180-187.
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  Ever more frequently business enterprises are benefiting from the collection and analysis of large data. This paper reports on a work in progress of adapting intelligence, predictive analytics tools for analysis of medical data. While large data has been used in medical research, only recently has this become a trend for hospital management. A suite of tools originally developed for military intelligence analysts are repurposed for hospital management. The original design concepts is reviewed, its medical applications and challenges are described along with an illustrative example.
• Riojas, M., Feng, C., Rozenblit, J. W., & Hamilton, A. J. (2011). Knowledge elicitation for performance assessment in a computerized surgical training system. In Applied Soft Computing, 11, 3697-3708.
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  Effective training is the key to minimizing the dangers of minimally invasive surgery (MIS). At present, the assessment of laparoscopic skills relies on the expertise of senior surgeons. The judgment is typically based on and expressed in ordinal variables that can take values such as low, medium, high or other comparable terms. This limited assessment, along with the lack of expert surgeons' metacognitive awareness of how the judgment process takes place, results in imprecise rules for the evaluation of laparoscopic surgical skills. In this work, we present the knowledge elicitation process to model the performance metrics and the rules involved in the assessment of minimally invasive surgical skills. We have implemented a scoring system for the evaluation of laparoscopic skills based on five performance metrics capable of distinguishing between four proficiency levels while providing a quantitative score. Our assessment model is based on fuzzy logic, so that it is easier to mimic the judgment that is already performed by experienced surgeons. The presented framework was empirically validated using the performance data of 38 subjects belonging to five groups: non-medical students, medical students with no previous laparoscopic training, medical students with some training, residents, and expert surgeons.
• Feng, C., Rozenblit, J. W., Hamilton, A. J., & Wytyczak-partyka, A. (2009). Defining Spatial Regions in Computer-Assisted Laparoscopic Surgical Training. In 2009 16th Annual IEEE International Conference and Workshop on the Engineering of Computer Based Systems, 176-183.
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  To provide appropriate guidance in minimally invasive surgical training (and potentially an additional safety measure in the operating room), we propose a model called a "No-Fly Zone" based on the situational awareness enhancing system. By defining the configuration space of the instrument, a collision free region is defined. If an intrusion occurs into the no-fly region space, the system provides audio, visual, and haptic feedback to reinforce an appropriate maneuver. The proposed method is intended to refine surgical skills and to improve the patient safety. Usability experiment will be performed to test the system.
• Feng, C., Rozenblit, J. W., & Hamilton, A. J. (2008). Fuzzy Logic-Based Performance Assessment in the Virtual, Assistive Surgical Trainer (VAST). In 15th Annual IEEE International Conference and Workshop on the Engineering of Computer Based Systems (ecbs 2008), 203-209.
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  The Virtual Assistive Surgical Trainer (VAST) is an approach developed to train surgeons in minimally invasive procedures. It uses surgical instruments augmented with micro-sensors, and knowledge-based inference techniques to provide objective, data-driven feedback and performance assessment for complex exercises. The assessment is typically based on the expertise of senior surgeons and, thus, a single objective standard is difficult to define. To formulate such a standard, and to provide an accurate scoring method, a fuzzy logic method is proposed in this paper. This makes it easier to mimic tasks that are already successfully performed by human experts. A multi-level fuzzy inference engine and new performance metrics are implemented. Experimental results demonstrate the feasibility of this method and the efficacy of the new performance metrics.
• Feng, C., Rozenblit, J. W., & Hamilton, A. J. (2007). A Hybrid View in a Laparoscopic Surgery Training System. In 14th Annual IEEE International Conference and Workshops on the Engineering of Computer-Based Systems (ECBS'07), 339-348.
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  In this paper, a hybrid view application is proposed - a subsystem of a computerized laparoscopic surgery training system. To minimize the potential hazards of laparoscopic surgery, an assistive training system is being developed. A digital camera and magnetic position sensors are used to detect laparoscopic instruments in the system. The hybrid view is a component of this system which overlays the positions of organs and objects with the path history of the instruments. This method could help confirm erroneous movements made by surgeons and provide more useful information than separate sensors. This may minimize the cognitive overload on the surgeons. Initial experimental results are presented to show the feasibility of the proposed method
• Haniffa, H., Peng, J., Salkini, M., Rozenblit, J. W., & Hamilton, A. J. (2007). Motion Planning System for Minimally Invasive Surgery. In 14th Annual IEEE International Conference and Workshops on the Engineering of Computer-Based Systems (ECBS'07), 609-610.
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  Minimally invasive procedures are highly effective when performed by well trained surgeons. However, with the subjective nature of surgical training and performance assessment, it is difficult to determine when a trainee surgeon has attained a satisfactory level of competency. We propose a computer-based training and performance assessment system where we apply configuration space based techniques to determine optimal paths for the maneuver of surgical instruments to perform predefined tasks
• Gottfried, O., Way, D., & Hamilton, A. (1999, FEB 4, 1999). Flow cytometric detection of p53 protein expression in archival (frozen) pediatric neural tumors. In 25th Annual Lende Neurosurgical Symposium, Salt Lake City, UT, Feb 4, 1999.
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  Purpose: This study defines how frozen, non-fixed pediatric neural tumors can be utilized to rapidly quantify p53 status (mere presence is indicative of abnormal nonfunctioning p53) using immunochemically labeled detection and flow cytometry (FCM). Patients identified as having detectable p53 profiles become targets for eventual gene delivery therapy. Methods: Nine pediatric tumors of varied pathology were identified from previously snap-frozen material. These tissues were mechanically disaggregated, immunochemically labeled in a three step fluorescent (FITC) technique with monoclonal antibodies specific for human p53 protein and analyzed by flow cytometry for the absence or presence of p53 protein. Results: In our mixed pediatric neural tumors, three of nine stained positive for p53 or 33% of the samples would be potential candidates for gene therapy. Conclusions: These results are consistent with previously reported data from fixed sections of immunostained samples. However our use of frozen tumors and biopsy sized samples offers a more rapid, convenient and reliable determination of p53 protein status. The procedural improvement of accuracy is attributable 10 FCM, which eliminates the subjective variability inherent in the more conventional histologic and cytologic techniques. As such, this procedure allows for quick, precise and controlled p53 analysis on frozen biopsy-sized samples.

Presentations

• Hamilton, A. J. (2019, April). “Evaluation of Learning Curve and Peripheral Awareness Using a Novel Multiresolution Foveated Laparoscope,”. Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference. Tucson, AZ, Sabino Ballroom, Student Union, University of Arizona Main Campus, April 30, 2019: Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference.
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  2. Invited Presentation: “Evaluation of Learning Curve and Peripheral Awareness Using a Novel Multiresolution Foveated Laparoscope,” (Ca-authors: Marissa Lovett, Jeremy Katz, Sangyoon Lee, David Biffar, Mike Nguyen and Allan Hamilton); Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference, Tucson, AZ, Sabino Ballroom, Student Union, University of Arizona Main Campus, April 30, 2019
• Hamilton, A. J. (2019, April). “Intellectual Properties: The Neuroscience of Innovation,”. Howarth Annual Conference,. Parker House Palm Springs, Palm Springs, CA April 26, 2019.: Howarth Annual Conference,.
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  7. Invited Guest Speaker: “Intellectual Properties: The Neuroscience of Innovation,” Howarth Annual Conference, Parker House Palm Springs, Palm Springs, CA April 26, 2019.
• Hamilton, A. J. (2019, April). “Single Shot State Detection in Simulation-based Laparoscopy Training,”. Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference,. Tucson, AZ, Sabino Ballroom, Student Union, University of Arizona Main Campus, April 30, 2019: Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference,.
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  1. Invited Presentation, “Single Shot State Detection in Simulation-based Laparoscopy Training,” (Co-authors: Kuo Shiuan Peng, Minsik Hong, Jerzy Rozenblit and Allan Hamilton); Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference, Tucson, AZ, Sabino Ballroom, Student Union, University of Arizona Main Campus, April 30, 2019
• Hamilton, A. J. (2019, April). “The Use of the Horse in Post-Traumatic Stress Disorder (PTSD).. Grand Rounds, Sierra Tucson. Sierra Tucson, Tucson, AZ: Sierra Tucson.
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  8. Invited Guest Speaker: “The Use of the Horse in Post-Traumatic Stress Disorder (PTSD).” Sierra Tucson, Oro Valley, AZ April 12, 2019.
• Hamilton, A. J. (2019, May). Challenges in Healthcare Simulation – Clinical and Research Perspectives. Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference. Sabino Ballroom, Student Union, University of Arizona Main Campus, May 1, 2019.: Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference.
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  6. Invited Panelist, Challenges in Healthcare Simulation – Clinical and Research Perspectives, Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference, Tucson, AZ, Sabino Ballroom, Student Union, University of Arizona Main Campus, May 1, 2019.
• Hamilton, A. J. (2019, May). “The Use of Remote and Traditional Facilitation to Evaluate Telesimulation to Support Inter-professional Education and Processing in Healthcare Simulation Training,”. Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference,. Sabino Ballroom, Student Union, University of Arizona Main Campus, May 1, 2019.: Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference,.
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  “The Use of Remote and Traditional Facilitation to Evaluate Telesimulation to Support Inter-professional Education and Processing in Healthcare Simulation Training,” (Co-authors; Coy Collins, Marissa Lovett, David Biffar, Karen Holder, Mike Holcomb, Peter Yonsetto, Ronald Weinstein and Allan Hamilton); Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference, Tucson, AZ, Sabino Ballroom, Student Union, University of Arizona Main Campus, May 1, 2019.
• Hamilton, A. J. (2019, May). “When Hollywood Inspires Medicine: New Concepts in the Design and Architecture of Medical Simulation Facilities to Support Inter-Professional Healthcare Education and Training,”. Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference. Sabino Ballroom, Student Union, University of Arizona Main Campus, May 1, 2019.: Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference.
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  4. Invited Presentation, “When Hollywood Inspires Medicine: New Concepts in the Design and Architecture of Medical Simulation Facilities to Support Inter-Professional Healthcare Education and Training,” (Co-authors: Allan Hamilton, Marissa Lovett, Jonathan Kanda, David Biffar and Ronald Weinstein); Annual Meeting of International Modeling and Simulation in Medicine (MSM) Conference, Tucson, AZ, Sabino Ballroom, Student Union, University of Arizona Main Campus, May 1, 2019.
• Lovett, M., Phung, M., Biffar, D. E., Lee, B. R., Hamilton, A. J., & Tzou, D. T. (2019, Nov./Fall). Development of a Low-Cost, High-Fidelity Simulator for Ultrasound- Guided Percutaneous Nephrolithotomy (PCNL) Training.. 95th Annual Western Section American Urological Association Annual Conference. Monterey, CA: Western Section American Urological Association.
• Cahir, T., Ahanonu, E., Biffar, D., Hamilton, A. J., Hughes, K., & Sakles, J. C. (2018, May). Evaluation of an Innovative Bleeding Cricothyrotomy Model. American College of Emergency Medicine Research Forum. San Diego, CA: American College of Emergency Medicine.
• Ng, V., Prescher, H., Barbosa, A., Biffar, D., & Hamilton, A. J. (2017, January). Development of An Ultrasound Pericardiocentesis Model for Simulation Training. International Meeting of Simulation in Healthcare. Orlando, FL: Society for Simulation in Healthcare.
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  Abstract
• Lovett, M., Reid, S., Prescher, H., Biffar, D. B., Fiorello, A. B., & Hamilton, A. J. (2016, January). Development and Testing of a Thoracostomy Assessment Tool Through Self, Peer, and Expert Evaluation in a Simulation Environment. International Meeting for Simulation in Healthcare. San Diego, CA: Society for Simulation in Healthcare.

Poster Presentations

• Hamilton, A. J., Biffar, D., Barbosa, A., Prescher, H., & Ng, V. (2017, January). Development of An Ultrasound Pericardiocentesis Model for Simulation Training. International Meeting of Simulation in Healthcare. Orlando, FL: Society for Simulation in Healthcare.
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  Abstract
• Ng, V., Prescher, H., Reid, S., Biffar, D. E., & Hamilton, A. J. (2016, January). A Comparison Of Porcine And Synthetic Models For Lateral Canthotomy And Cantholysis. International Meeting on Simulation in Healthcare. San Diego, CA: Society for Simulation in Healthcare.
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  Approximately 16.5 hours spent on project for 2015Approximately 4 hours spent on project for 2016

Reviews

• Hamilton, A. J., & Friedman, H. (2001. Friedman H, Hamilton AJ: Management of Patients Receiving Chemotherapeutic Implants for the Treatment of Malignant Gliomas, CME Monograph, Postgraduate Inst. For Medicine, Englewood, CO, Sept 2001.(p. 45). Englewood, CO.
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  Friedman H, Hamilton AJ Management of Patients Receiving Chemotherapeutic Implants for the Treatment of Malignant Gliomas, CME Monograph, Postgraduate Inst. For Medicine, Englewood, CO, Sept 2001.

Creative Productions

• Hamilton, A. J. (2000. Medical Simulations in the Diagnosis and Management of Intracranial Neoplasms. Darien, CT: InterMed Interactive Medical Communications. Darien, CT: InterMed Interactive Medical Communications.
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  Hamilton AJ: Medical Simulations in the Diagnosis and Management of Intracranial Neoplasms, Darien, CT: InterMed Interactive Medical Communications, July 1, 2000.

Others

• Hamilton, A. J. (2020, March). These Simple National Instructions Would Help US Overcome COVID-19. Arizona Daily Star, March 31, 2020 Op-Ed Piece. http://arizonadailystar.az.newsmemory.com/?publink=2a1d9bd0e
• Mosier, J. M., & Sakles, J. C. (2018, August). Management of the Physiologically Difficult Airway in the Emergency Department. Anesthesiology News.
• Hamilton, A. J. (1999, October). Intracavitary Chemotherapy: A New Role for the Neurosurgeon. New York, NY: HealthCare, Inc., 1999..
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  Hamilton AJ: Intracavitary Chemotherapy: A New Role for the Neurosurgeon, New York, NY: HealthCare, Inc., 1999.
• Hamilton, A. J., Rupert, J., & Wilson, A. L. (1999, October). Management of the Brain Tumor Patient. Oxford Institute, 1999..