David Teh Chung Tzou

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• Tzou, D. T., Taguchi, K., Chi, T., & Stoller, M. L. (2017). Animal Models to Study Urolithiasis. In Animal Models for the Study of Human Disease, 2nd Edition(pp 419-443). Elsevier. doi:10.1016/b978-0-12-809468-6.00017-6
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  Abstract The etiology of stone disease remains unknown. Clinically, urologists have relied on 24-h urine collections to help direct medical therapy in hopes of reducing stone recurrence. Despite these efforts, little progress has been made in preventing stone disease. As such, there is an urgent need to develop reliable animal models to study the pathogenesis of stone formation and to assess novel interventions. A variety of vertebrate and invertebrate models have been used to help understand stone pathogenesis. Genetic knockout and exogenous induction models are described. Surrogates for an endpoint of stone formation have been urinary crystals on histologic examination and/or urinalyses. Other models are able to actually develop true stones. It is only through these animal models that real breakthroughs in the management of urinary stone disease will become a reality.

Journals/Publications

• Ghazi, A., Shepard, L., Li, O., Im, C., Schuler, N., Saba, P., Ballon-Landa, E., Bechis, S. K., Hsi, R. S., Kavoussi, N., Wiener, S., Tzou, D. T., Sur, R. L., Chang, H. C., Tailly, T., Ahn, J., Bayne, D., & Chi, T. (2024). A Modern Education Theory Approach to Development of a Benchtop Simulation Model for Ultrasound-Guided Percutaneous Nephrolithotomy. Journal of Endourology.
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  To develop and validate a high-fidelity, nonbiohazardous simulator model for the ultrasound-guided percutaneous nephrolithotomy procedure. We employed a systematic framework based on Delphi consensus and modern education theory to design a simulation model. Twelve expert surgeons provided input through a hierarchal task analysis and identified procedural tasks, anatomical landmarks, and potential errors. These were translated into engineering deliverables by a team of biomedical engineers and surgical educators. A prototype was developed using three-dimensional printing and hydrogel molding, followed by expert validation through recorded simulations and subsequent multicenter trails with 48 participants. A hydrogel prototype with realistic anatomical features was created using results from the Delphi process. It received positive feedback in areas such as anatomy, procedural fidelity, and education effectiveness, with overall high satisfaction ratings. Validation studies showed a significant difference in performance between novices and experts. Residents demonstrated significant skill improvement and retention after repeated simulations. The developed simulator provides a realistic, effective training tool for urologic education, addressing the need for safer and more accessible surgical training modalities.
• Panthier, F., Kwok, J. L., Tzou, D. T., Monga, M., Traxer, O., & Keller, E. X. (2024). What is the definition of stone dust and how does it compare with clinically insignificant residual fragments? A comprehensive review. World Journal of Urology, 42(1), 292.
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  During endoscopic stone surgery, Holmium:YAG (Ho:YAG) and Thulium Fiber Laser (TFL) technologies allow to pulverize urinary stones into fine particles, ie DUST. Yet, currently there is no consensus on the exact definition of DUST. This review aimed to define stone DUST and Clinically Insignificant Residual Fragments (CIRF).
• Tzou, D. T. (2024). Letter: Radiating for Two: Quantifying Radiation Exposure to Pregnant Urologists During Percutaneous Nephrolithotomy. The Journal of Urology, 101097JU0000000000004325.
• Shepard, L., Schuler, N., Saxton, A., Saba, P., Cook, A., Holler, T., Stern, K., Tzou, D. T., Chang, H. R., Ahn, J., Tailly, T., Chi, T., & Ghazi, A. (2023). V02-07 DEVELOPMENT AND VALIDATION OF A BENCHTOP SIMULATOR FOR ULTRASOUND GUIDED PERCUTANEOUS NEPHROLITHOTOMY TRAINING USING 3D PRINTING AND HYDROGEL MOLDING. Journal of Urology. doi:10.1097/ju.0000000000003232.07
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  You have accessJournal of UrologyCME1 Apr 2023V02-07 DEVELOPMENT AND VALIDATION OF A BENCHTOP SIMULATOR FOR ULTRASOUND GUIDED PERCUTANEOUS NEPHROLITHOTOMY TRAINING USING 3D PRINTING AND HYDROGEL MOLDING Lauren Shepard, Nathan Schuler, Aaron Saxton, Patrick Saba, Andrew Cook, Tyler Holler, Karen Stern, David Tzou, Helena Chang, Justin Ahn, Thomas Tailly, Thomas Chi, and Ahmed Ghazi Lauren ShepardLauren Shepard More articles by this author , Nathan SchulerNathan Schuler More articles by this author , Aaron SaxtonAaron Saxton More articles by this author , Patrick SabaPatrick Saba More articles by this author , Andrew CookAndrew Cook More articles by this author , Tyler HollerTyler Holler More articles by this author , Karen SternKaren Stern More articles by this author , David TzouDavid Tzou More articles by this author , Helena ChangHelena Chang More articles by this author , Justin AhnJustin Ahn More articles by this author , Thomas TaillyThomas Tailly More articles by this author , Thomas ChiThomas Chi More articles by this author , and Ahmed GhaziAhmed Ghazi More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003232.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Ultrasound-guided percutaneous nephrolithotomy (US-PCNL) is an effective and safe approach for management of large renal stones, yet adoption has been limited. The vast majority of US-PCNL are performed in the prone position vs supine position (80% vs 20%); however, there is a need for a safe, realistic procedural training platform for both approaches. We have previously demonstrated the ability of similar hydrogel simulations to improve operative outcomes during fluoroscopic PCNL training. Our objective was the development of a benchtop, non-biohazardous US-PCNL simulator using 3D printing and hydrogel molding and its validation using educational theory. METHODS: Consensus among 12 experts was reached regarding the essential aspects of an ideal US-PCNL model and an associated evaluation checklist using a Delphi consensus methodology. Segmentation software was used to generate a 3D model from an approved patient computed tomography (CT) scan, including kidney, pelvicalyceal system, stone, spine and ribs, abdominal wall, and iliac crest. Post-processing generated 3D printed casts into which hydrogel formulations replicating various anatomical and tissue mechanical properties of the structures were created according to the consensus statement. A prototype was fabricated for expert approval, after which 20 experts and 28 novices performed US-PCNL with performance assessed using the developed checklist. RESULTS: The simulator fulfilled all criteria established in the consensus statement, including external and ultrasound appearance mimicking in vivo appearance, a watertight pelvicalyceal system containing a functional stone that is distensible with retrograde instillation, and realistic tactile feedback during puncture. Experts agreed the simulator provides a safe training alternative (100%), bridges gaps between classroom and clinic (95.7%), and allows trainee performance evaluation (100%) in a risk free environment that can be modified for variable anatomy (88.9%). Highly significant differences were found between expert and novices using the checklist developed (93.4% vs 42.3%, p
• Shepard, L., Schuler, N., Saxton, A., Saba, P., Cook, A., Holler, T., Tzou, D. T., Stern, K., Chang, H. R., Ahn, J., Tailly, T., Chi, T., & Ghazi, A. (2023). Use of 3D printing and hydrogel molding to develop a model for ultrasound-guided percutaneous nephrolithotomy (PCNL) training and education. Urology Video Journal. doi:10.1016/j.urolvj.2023.100216
• Tzou, D. T., Tailly, T. O., & Stern, K. L. (2023). Ultrasound-Guided PCNL - Why Are We Still Performing Exclusively Fluoroscopic Access?. Current urology reports, 24(7), 335-343.
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  While urologists are traditionally taught to perform percutaneous nephrolithotomy (PCNL) utilizing exclusively fluoroscopy, ultrasound has emerged as a safe alternative. This article showcases the major reasons why ultrasound-guided access should be considered the first-line approach for performing access for PCNL.
• Tzou, D. T., Tailly, T., & Stern, K. (2023). Ultrasound-Guided PCNL — Why Are We Still Performing Exclusively Fluoroscopic Access?. Current Urology Reports, 24(7), 335-343. doi:10.1007/s11934-023-01163-8
• Anwar, F., Chi, T., Harris, D., Tzou, D. T., Vedantam, G., & Wong, A. C. (2022). PD32-10 KIDNEY STONE ENDOTOXIN CONCENTRATION CORRELATES WITH POST-OPERATIVE SEPSIS FOLLOWING PERCUTANEOUS NEPHROLITHOTOMY. The Journal of Urology, 207(S5). doi:10.1097/ju.0000000000002583.10
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  You have accessJournal of UrologyCME1 May 2022PD32-10 KIDNEY STONE ENDOTOXIN CONCENTRATION CORRELATES WITH POST-OPERATIVE SEPSIS FOLLOWING PERCUTANEOUS NEPHROLITHOTOMY David T. Tzou, Farhan Anwar, Ava C. Wong, David T. Harris, Thomas Chi, and Gayatri Vedantam David T. TzouDavid T. Tzou More articles by this author , Farhan AnwarFarhan Anwar More articles by this author , Ava C. WongAva C. Wong More articles by this author , David T. HarrisDavid T. Harris More articles by this author , Thomas ChiThomas Chi More articles by this author , and Gayatri VedantamGayatri Vedantam More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002583.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Patients with infected kidney stones are at risk for post-operative sepsis following surgical removal of their calculi. Of all the surgical approaches, percutaneous nephrolithotomy (PCNL) remains associated with the highest risk for experiencing post-operative SIRS (severe inflammatory response syndrome). Accurate prediction of patients at risk for SIRS after surgery would be of clinical value. While previous studies have demonstrated infected kidney stones contain variable levels of endotoxin concentrations, these were limited in their rigor and ability to correlate stone immunobiology with important clinical outcomes. The aim of this study was to quantitate endotoxin levels amongst PCNL patients who experienced and did not experience SIRS. METHODS: Between October 2020 and June 2021, urine & stone specimens from consecutive stone patients were prospectively collected as part of the Registry for Stones of the Kidneys and Ureter (ReSKU) at the University of Arizona. Clinical data including stone analyses and post-operative outcomes have been tracked. Equal weights of stones were uniformly broken using an easy-to-replicate ‘beat-beating’ homogenization approach, allowing for consistent measurement of stone endotoxin using a Pierce™ LAL Chromogenic Endotoxin Quantification Kit (ThermoFisher, Waltham, MA). Endotoxin levels from stones removed during PCNL were compared between patients who experienced and did not experience SIRS. Independent T-test was used to determine statistical significance. RESULTS: Endotoxin levels amongst 4 patients with infection calculi who experienced SIRS were compared to 16 patients who did not experience SIRS – 8 of which had infection calculi and 8 had non-infection calculi (Figure 1). In the SIRS group, the mean Endotoxin concentration was 1.084 endotoxin units (EU)/ml compared to 0.476 EU/ml in the non-SIRS group (p
• Raskolnikov, D., Tzou, D. T., Ahn, J. S., Bechis, S. K., Chi, T. L., Sorensen, M. D., Stoller, M. L., & Harper, J. D. (2022). Multi-Institutional Variation in Performance of Low-Dose Computed Tomography for the Evaluation of Suspected Nephrolithiasis. Journal of Endourology, 36(10), 1377-1381.
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  Guidelines from the American Urological Association (AUA) and American College of Radiology (ACR) recommend that patients with suspected nephrolithiasis undergo low-dose CT of the kidney, ureter, and bladder (LD CT KUB) as opposed to higher dose conventional imaging. We hypothesized that even at institutions with established LD protocols, higher dose imaging is common. We identified four academic medical centers where LD CT KUB protocols were implemented to yield an effective dose (EDose) consistent with national guidelines. Fifty consecutive adult patients who underwent CT KUB specifically for the evaluation of nephrolithiasis were retrospectively reviewed at each site. Patient age, sex, body mass index (BMI), imaging location, and EDose (millisieverts [mSv]) were recorded. Two hundred patients with a mean age of 54 years were identified. Forty-six patients (23%) underwent CT KUB with an EDose 4 mSv, accounting for 10% to 48% of each institution's cohort. One hundred sixteen patients had a BMI
• Tzou, D. T., Stern, K. L., Duty, B. D., Hsi, R. S., Canvasser, N. E., De, S., Wong, A. C., Royal, C. R., Sloss, M. L., Ziemba, J. B., Harper, J. D., Bechis, S. K., Zampini, A. M., Borofsky, M. S., Bell, J. R., Friedlander, J. I., Leavitt, D. A., Nevo, A., Patel, N. D., , Patel, R. M., et al. (2022). Heterogeneity in stone culture protocols and endourologist practice patterns: a multi-institutional survey. Urolithiasis, 51(1), 15.
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  Kidney stone cultures can be beneficial in identifying bacteria not detected in urine, yet how stone cultures are performed among endourologists, under what conditions, and by what laboratory methods remain largely unknown. Stone cultures are not addressed by current clinical guidelines. A comprehensive REDCap electronic survey sought responses from directed (n = 20) and listserv elicited (n = 108) endourologists specializing in kidney stone disease. Questions included which clinical scenarios prompt a stone culture order, how results influence post-operative antibiotics, and what microbiology lab protocols exist at each institution with respect to processing and resulting stone cultures. Logistic regression statistical analysis determined what factors were associated with performing stone cultures. Of 128 unique responses, 11% identified as female and the mean years of practicing was 16 (range 1-46). A specific 'stone culture' order was available to only 50% (64/128) of those surveyed, while 32% (41/128) reported culturing stone by placing a urine culture order. The duration of antibiotics given for a positive stone culture varied, with 4-7 days (46%) and 8-14 days (21%) the most reported. More years in practice was associated with fewer stone cultures ordered, while higher annual volume of percutaneous nephrolithotomy was associated with ordering more stone cultures (p 
• Bergersen, A. M., Khan, I., Wong, A. C., Chipollini, J. J., Weiss, B. D., & Tzou, D. T. (2021). Online Kidney Stone Educational Materials Do Not Meet Recommended Readability Standards. Urology practice, 8(2), 246-252.
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  The prevalence of kidney stones is rising and there is an increasing demand for reliable, easy to understand information for patients. To evaluate the readability of common Internet-based resources for kidney stones, we examined whether the most popular online educational materials may be contributing to decreased health literacy for this chronic condition.
• Bergersen, A. M., Khan, I., Wong, A. C., Chipollini, J. J., Weiss, B. D., & Tzou, D. T. (2021). Reply by Authors. Urology practice, 8(2), 252.
• Tzou, D. T., Weiss, B. D., Chipollini, J. J., Bergersen, A. M., Khan, I., & Wong, A. C. (2021). Reply by Authors. Urology Practice, 8(2), 252-252. doi:10.1097/upj.0000000000000183.04
• Bergersen, A., Bergersen, A., Khan, I., Khan, I., Chipollini, J., Chipollini, J., Weiss, B. D., Weiss, B. D., Tzou, D. T., & Tzou, D. T. (2020). MP12-08 DECREASED READABILITY OF ONLINE KIDNEY STONE EDUCATIONAL MATERIALS. The Journal of Urology, 203(S4).
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  You have accessJournal of UrologyGeneral & Epidemiological Trends & Socioeconomics: Practice Patterns, Quality of Life and Shared Decision Making II (MP12)1 Apr 2020MP12-08 DECREASED READABILITY OF ONLINE KIDNEY STONE EDUCATIONAL MATERIALS Andrew Bergersen*, Ismail Khan, Juan Chipollini, Barry Weiss, and David Tzou Andrew Bergersen*Andrew Bergersen* More articles by this author , Ismail KhanIsmail Khan More articles by this author , Juan ChipolliniJuan Chipollini More articles by this author , Barry WeissBarry Weiss More articles by this author , and David TzouDavid Tzou More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000832.08AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Limited health literacy has been associated with worse health outcomes across multiple medical conditions, yet how this relates to patients with kidney stones has yet to be evaluated. The Agency for Healthcare Research and Quality’s Health Literacy Toolkit and the American Medical Association’s health literacy manual for clinicians recommend a 5th-to-6th grade reading level for written health materials. Specific to kidney stone disease, patient understanding of both appropriate treatment options and prevention strategies remain crucial to limiting future stone recurrences. This study aimed to evaluate readability of the most common internet-based resources and determine if the information provided was written at an appropriate reading level to facilitate understanding. METHODS: Websites for readability analysis were chosen based on a Google.com search using the search term “kidney stones”. The top ten websites on April 20, 2019 were chosen for analysis. The presence or absence of a Health on the Net (HON) certification was recorded to assess the quality of the websites utilized. Readability was determined using six readability assessment tools: Flesch reading ease, FORCAST, Fry, Gunning Fog, Raygor Estimate, and Simple Measure of Gobbledygook (SMOG). Each website was then analyzed separately focusing specifically on the treatment and prevention sections of kidney stones. RESULTS: Of the 10 websites analyzed, 8 had HON certifications. Grade level calculations ranged from 7-13.9. All ten websites were found to have readability levels above the 6th grade reading level, with these websites generally consisting of longer words and sentences (Figure 1). With respect to treatment and prevention sections, 6/10 and 5/10 websites had readability levels above a 10th grade level, respectively. CONCLUSIONS: The readability of the most common internet-based resources for patients with kidney stones is too complex for the general population, as all are written above the recommended 5th-6th grade reading levels. Websites pertaining to kidney stones need to be simplified to facilitate patient understanding, especially with respect to the treatment and prevention of kidney stones. Source of Funding: None © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e147-e147 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Andrew Bergersen* More articles by this author Ismail Khan More articles by this author Juan Chipollini More articles by this author Barry Weiss More articles by this author David Tzou More articles by this author Expand All Advertisement PDF downloadLoading ...
• Lovett, M., Phung, M., Biffar, D., Hamilton, A. J., Lee, B. R., & Tzou, D. T. (2020). MP47-11 DEVELOPMENT OF A LOW-COST, HIGH-FIDELITY SIMULATOR FOR ULTRASOUND-GUIDED PERCUTANEOUS NEPHROLITHOTOMY (PCNL) TRAINING. The Journal of Urology, 203(S4). doi:10.1097/ju.0000000000000902.011
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  You have accessJournal of UrologySurgical Technology & Simulation: Training & Skills Assessment II (MP47)1 Apr 2020MP47-11 DEVELOPMENT OF A LOW-COST, HIGH-FIDELITY SIMULATOR FOR ULTRASOUND-GUIDED PERCUTANEOUS NEPHROLITHOTOMY (PCNL) TRAINING Marissa K. Lovett*, Michael C. Phung, David E. Biffar, Allan J. Hamilton, Benjamin R. Lee, and David T. Tzou Marissa K. Lovett*Marissa K. Lovett* More articles by this author , Michael C. PhungMichael C. Phung More articles by this author , David E. BiffarDavid E. Biffar More articles by this author , Allan J. HamiltonAllan J. Hamilton More articles by this author , Benjamin R. LeeBenjamin R. Lee More articles by this author , and David T. TzouDavid T. Tzou More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000902.011AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Ultrasound-guided percutaneous nephrolithotomy (US-PCNL) has emerged as an attractive alternative to traditional fluoroscopic PCNL. With only a limited number of training programs teaching US-PCNL, there remains a need for tools to assist with teaching this technique. Currently, most simulation PCNL models are expensive and focus on mimicking fluoroscopic guided access, with few models tailored to practicing the skills specific to US-PCNL. This study aimed to report the cost and fidelity of a novel US-PCNL simulator and assess its ability to change procedural confidence in urologic trainees. METHODS: The time, materials, and cost to creation of this model were recorded over 5 iterative versions. Using a 5-point visual analog scale (1 – Least Realistic; 5 – Most Realistic), model fidelity was assessed by: University of Arizona urology residents (n=9), and international attending urologists experienced in US-PCNL (n=8) at the AUA 2019 conference. Procedural confidence among the 9 residents was assessed before and after simulation training with the model – (5-point Likert scale; 1 – Not Comfortable, 5 – Very Comfortable). Confidence data was analyzed using a paired, two-tailed Student’s t-test. RESULTS: The model (Figure 1) costs ∼$50 USD and takes ∼1.5 hours to create. Mean overall model fidelity was 4.2 + 0.8, with high fidelity appreciated amongst specific model features including: visualization of needle (4.4 + 1.1) and fluid return (4.4 + 0.9); echogenicity of cortex (4.2 + 0.7), stones (4.2 + 0.8), and target calyces (4.1 + 0.8). After training with the model, urology resident procedural confidence increased significantly across all operational tasks, including: ultrasound probe positioning (p
• Lwin, A. A., Zeng, J., Evans, P., Phung, M. C., Hynes, K. A., Price, E. T., Twiss, C. O., Tzou, D. T., & Funk, J. T. (2020). Holmium Laser Enucleation of the Prostate Is Safe and Feasible as a Same Day Surgery. Urology, 138, 119-124.
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  To assess the safety, feasibility and treatment outcomes of holmium laser enucleation of the prostate (HoLEP) as a same day surgery (SDS).
• Raskolnikov, D., Tzou, D. T., Ahn, J., Bechis, S. K., Metzler, I., Thomas, L., Sorensen, M. D., Stoller, M. L., & Harper, J. D. (2020). PD35-11 MULTI-INSTITUTIONAL VARIATION IN PERFORMANCE OF LOW DOSE COMPUTERIZED TOMOGRAPHY FOR THE EVALUATION OF SUSPECTED NEPHROLITHIASIS. The Journal of Urology, 203(Supplement 4). doi:10.1097/ju.0000000000000906.011
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  INTRODUCTION AND OBJECTIVE: American Urological Association (AUA) guidelines recommend low dose (
• Taguchi, K., Chen, L., Usawachintachit, M., Hamamoto, S., Kang, M., Sugino, T., Unno, R., Tzou, D. T., Sherer, B. A., Okada, A., Yasui, T., Ho, S. P., Stoller, M. L., & Chi, T. (2020). Fatty acid-binding protein 4 downregulation drives calcification in the development of kidney stone disease. Kidney international, 97(5), 1042-1056.
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  Nephrolithiasis is a significant source of morbidity, and its incidence has increased significantly over the last decades. This rise has been attributed to concurrent increasing rates of obesity, associated with a 3-time risk of developing NL. To date, the mechanism by which obesity is linked to stone formation has not been elucidated. We aimed to utilize a transcriptomics approach to discover the missing link between these two epidemic diseases. We investigated gene expression profiling of nephrolithiasis patients by two RNA-sequencing approaches: comparison between renal papilla tissue with and without the presence of calcified Randall's plaques (RP), and comparison between the papilla, medulla, and cortex regions from within a single recurrent stone forming kidney. Results were overlaid between differently expressed genes found in the patient cohort and in the severely lithogenic kidney to identify common genes. Overlay of these two RNA-sequencing datasets demonstrated there is impairment of lipid metabolism in renal papilla tissue containing RP linked to downregulation of fatty acid binding protein (FABP) 4. Immunohistochemistry of human kidney specimens and microarray analysis of renal tissue from a nephrolithiasis mouse model confirmed that FABP4 downregulation is associated with renal stone formation. In a FABP4 knockout mouse model, FABP4 deficiency resulted in development of both renal and urinary crystals. Our study revealed that FABP4 plays an important, previously unrecognized role in kidney stone formation, providing a feasible mechanism to explain the link between nephrolithiasis and metabolic syndrome.
• Tzou, D. T., Metzler, I., Tsai, C., Goodman, J., Bayne, D., & Chi, T. (2020). Ultrasound-guided Morcellation During Difficult Holmium Laser Enucleation of the Prostate. Urology, 14(3), E104-E110.
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  Objective To demonstrate how bladder ultrasound can be useful in completing morcellation during difficult Holmium Laser Enucleation of the Prostate (HoLEP). As HoLEP has emerged as a standard of care for the treatment of benign prostatic hyperplasia, multiple studies have reported the potentially catastrophic complication of bladder injury during morcellation. This video aims to assist any urologist performing HoLEP by providing step-by-step instruction for using ultrasound to complete morcellation safely. Methods Enucleation is performed using a 26-French continuous flow scope, off-set laser bridge with a laser stabilization catheter, and a 550 µm holmium laser fiber. Once the median and lateral lobes have been enucleated, the outer sheath is removed and the nephroscope is inserted to facilitate morcellation. Under dual inflow irrigation, the Piranha morcellator (Richard Wolf, Knittlingen, Germany) is introduced and set to the manufacturer's recommended settings of 1500 rpm. A 3.5-MHz convex abdominal ultrasound transducer (Hitachi Prosound Alpha 7; Hitachi Aloka Medical America, Wallingford, CT) under B-mode is used to visualize the bladder, predominantly in the sagittal orientation. Morcellation proceeds under simultaneous ultrasound and direct cystoscopic guidance. Results The distended bladder is visualized concurrently with the ultrasound and via the nephroscope as the Piranha engages the adenoma and begins morcellation. Once the adenoma is engaged, the operator then drops their hands to place the morcellator in the center of the bladder. Ultrasound provides real-time feedback as to the location of the morcellator in relation to the adenoma and bladder. Conclusion This video highlights the use of intraoperative bladder ultrasound as a visual aid to assist during the morcellation portion of HoLEP. This proof of concept demonstrates that ultrasound can be an additional tool to utilize during difficult cases when cystoscopic visualization during morcellation is limited.
• Ahmad, T. R., Tzou, D. T., Usawachintachit, M., Reliford-Titus, S., Wu, C., Goodman, J., Antonelli, J. A., Viprakasit, D. P., Averch, T. D., Sivalingam, S., Chew, B. H., Bird, V. G., Pais, V. M., Streeper, N. M., Sur, R. L., Nakada, S. Y., Penniston, K. L., & Chi, T. (2019). Low Income and Nonwhite Race are Strongly Associated with Worse Quality of Life in Patients with Nephrolithiasis. The Journal of urology, 202(1), 119-124.
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  Kidney stones are a source of significant morbidity which have been shown to negatively impact health related quality of life. We sought to understand the association between health related quality of life, socioeconomic status and race among patients with kidney stones.
• Armas-Phan, M., Tzou, D. T., Bayne, D. B., Wiener, S. V., Stoller, M. L., & Chi, T. (2019). Ultrasound guidance can be used safely for renal tract dilatation during percutaneous nephrolithotomy. BJU international.
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  To compare clinical outcomes in patients who underwent percutaneous nephrolithotomy (PCNL) with renal tract dilatation performed under fluoroscopic guidance vs renal tract dilatation with ultrasound guidance.
• Bayne, D. B., Usawachintachit, M., Armas-Phan, M., Tzou, D. T., Wiener, S., Brown, T. T., Stoller, M., & Chi, T. L. (2019). Influence of Socioeconomic Factors on Stone Burden at Presentation to Tertiary Referral Center: Data From the Registry for Stones of the Kidney and Ureter. Urology, 131, 57-63.
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  To determine social factors associated with advanced stone disease (defined as unilateral stone burden >2 cm) at time of presentation to a regional stone referral center. Little is known about social determinants of urolithiasis. We hypothesize that socioeconomic factors impact kidney stone severity at intake to referral centers.
• Bayne, D., Bayne, D., Chi, T., Chi, T., Stoller, M. L., Stoller, M. L., Tzou, D. T., Tzou, D. T., Wiener, S., & Wiener, S. (2019). PD63-02 IMPACT OF THE AFFORDABLE CARE ACT ON PAYER DISTRIBUTION FOR UROLOGIC STONE SURGERY IN THE STATE OF CALIFORNIA. The Journal of Urology, 201(Supplement 4). doi:10.1097/01.ju.0000557371.05885.82
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  You have accessJournal of UrologyGeneral & Epidemiological Trends & Socioeconomics: Practice Patterns, Quality of Life and Shared Decision Making IV (PD63)1 Apr 2019PD63-02 IMPACT OF THE AFFORDABLE CARE ACT ON PAYER DISTRIBUTION FOR UROLOGIC STONE SURGERY IN THE STATE OF CALIFORNIA Scott Wiener*, David Bayne, David Tzou, Thomas Chi, and Marshall Stoller Scott Wiener*Scott Wiener* More articles by this author , David BayneDavid Bayne More articles by this author , David TzouDavid Tzou More articles by this author , Thomas ChiThomas Chi More articles by this author , and Marshall StollerMarshall Stoller More articles by this author View All Author Informationhttps://doi.org/10.1097/01.JU.0000557371.05885.82AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVES: In March 2010 the Affordable Care Act (ACA) was signed into law, yet health insurance markets did not become fully operational until January 2014. We hypothesized that enactment of this legislation would alter the payer distribution for kidney stone patients undergoing ureteroscopy (URS), shockwave lithotripsy (SWL), and percutaneous nephrolithotomy (PCNL) in California (CA). METHODS: We utilized CA's Office of Statewide Health Planning and Development (OSHPD) public inpatient and ambulatory surgical databases from 2011-2016 to examine URS, SWL, and PCNL operations for nephrolithiasis. Data was obtained on an aggregate level and split into two eras: 2011-2013 (pre-implementation) and 2014-2016 (post-implementation). The proportion of patients/procedures was compared for payer type by Chi square test for independence before and after the ACA. ArcMap 10.5 Software (ERSI, Redlands, CA) was used to create the choropleth map of CA labor market regions. RESULTS: A total of 86,437 procedures were performed from 2011-2013, while 95,866 were performed from 2014-2016. After 2014, the number of operations performed on Medicaid patients increased by 88% (from 8,878 to 16,717, p < .01, Figure), while operations on the uninsured dropped by 67% (from 2,887 to 1,676, p < .01, Figure) with a ratio of 6.5:1 in favor of increased Medicaid operations. When examined by CA region, wide variability was noted with a range of -4% to +214% for the change in procedures on Medicaid patients (Figure). Counts for privately insured and Medicare patients increased without abrupt change after 2014. CONCLUSIONS: The ACA drastically altered the payer mix for patients undergoing surgery for urinary stone disease, however not all geographic regions experienced the same degree of change. The ACA also may have improved access to stone surgery given that the increase in Medicaid patients was 6.5 times larger than the decrease in uninsured patients. It remains to be seen if the observed variation by geography is due to patient or system related factors. Source of Funding: None San Francisco, CATuscon, AZSan Francisco, CA© 2019 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 201Issue Supplement 4April 2019Page: e1112-e1113 Advertisement Copyright & Permissions© 2019 by American Urological Association Education and Research, Inc.MetricsAuthor Information Scott Wiener* More articles by this author David Bayne More articles by this author David Tzou More articles by this author Thomas Chi More articles by this author Marshall Stoller More articles by this author Expand All Advertisement PDF downloadLoading ...
• Beiko, D., Razvi, H., Bhojani, N., Bjazevic, J., Bayne, D. B., Tzou, D. T., Stoller, M. L., & Chi, T. (2019). Techniques ‒ Ultrasound-guided percutaneous nephrolithotomy: How we do it. Canadian Urological Association journal = Journal de l'Association des urologues du Canada.
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  Ultrasonography has emerged as an alternative to fluoroscopy for image-guided guided PCNL (F-PCNL), ultrasound-guided PCNL (US-PCNL) is easier to learn and reduces radiation exposure to patients and providers. Despite these advantages, uptake of ultrasound-guided PCNL (US-PCNL) in Canada has been almost nonexistent, largely because it is not incorporated into urologists' training. In this article, we seek to familiarize Canadian urologists with this approach by describing our step-by-step technique for US-PCNL. Additionally, we provide keys to successful implementation of percutaneous nephrolithotomy (PCNL) in many countries. Compared to fluoroscopy-this technique.
• Chen, L., Chi, T., Hamamoto, S., Ho, S. P., Kang, M., Sherer, B. A., Stoller, M. L., Taguchi, K., Tzou, D. T., Unno, R., Usawachintachit, M., & Yasui, T. (2019). PD38-03 FATTY ACID BINDING PROTEIN 4 IS AN ESSENTIAL MOLECULE FOR THE DEVELOPMENT OF KIDNEY STONES: A NEW UNDERSTANDING OF WHY OBESITY AND NEPHROLITHIASIS GO HAND IN HAND. The Journal of Urology, 201(Supplement 4). doi:10.1097/01.ju.0000556371.00104.89
• Sorensen, M., Harper, J. D., Tzou, D. T., Zetumer, S., Usawachintachit, M., Taguchi, K., Bechis, S. K., Duty, B. D., Hsi, R. S., Sur, R. L., Reliford-Titus, S., Chang, H. C., Isaacson, D., Bayne, D. B., Wang, Z. J., Stoller, M. L., & Chi, T. (2019). Computed Tomography Radiation Exposure Among Referred Kidney Stone Patients: Results from the Registry for Stones of the Kidney and Ureter. Journal of Endourology, 33(7), 619-624. doi:10.1089/end.2019.0091
• Tzou, D. T., Armas-Phan, M., Bayne, D. B., Wiener, S. V., Stoller, M. L., & Chi, T. (2019). Ultrasound guidance can be used safely for renal tract dilatation during percutaneous nephrolithotomy. BJU International, 125(2), 284-291. doi:10.1111/bju.14737
• Tzou, D. T., Metzler, I. S., Tsai, C., Goodman, J., Bayne, D. B., & Chi, T. (2019). Ultrasound-guided Morcellation During Difficult Holmium Laser Enucleation of the Prostate. Urology.
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  To demonstrate how bladder ultrasound can be useful in completing morcellation during difficult Holmium Laser Enucleation of the Prostate (HoLEP). As HoLEP has emerged as a standard of care for the treatment of benign prostatic hyperplasia, multiple studies have reported the potentially catastrophic complication of bladder injury during morcellation. This video aims to assist any urologist performing HoLEP by providing step-by-step instruction for using ultrasound to complete morcellation safely.
• Tzou, D. T., Metzler, I. S., Usawachintachit, M., Stoller, M. L., & Chi, T. (2019). Ultrasound-guided Access and Dilation for Percutaneous Nephrolithotomy in the Supine Position: A Step-by-Step Approach. Urology, 133, 245-246.
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  Ultrasound guidance for percutaneous nephrolithotomy (PCNL) has gained acceptance amongst urologists given its numerous advantages over fluoroscopy. While traditionally performed in the prone position, this video demonstrates a step-by-step approach to performing PCNL in the supine position, solely under ultrasound guidance.
• Tzou, D. T., Zetumer, S., Usawachintachit, M., Taguchi, K., Bechis, S. K., Duty, B. D., Harper, J. D., Hsi, R. S., Sorensen, M., Sur, R. L., Reliford-Titus, S., Chang, H. C., Isaacson, D., Bayne, D. B., Wang, Z. J., Stoller, M. L., & Chi, T. (2019). Computed Tomography Radiation Exposure Among Referred Kidney Stone Patients: Results from the Registry for Stones of the Kidney and Ureter. Journal of endourology, 33(7), 619-624.
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  Kidney stone patients routinely have CT scans during diagnostic work-up before being referred to a tertiary center. How often these patients exceed the recommended dose limits for occupational radiation exposure of >100 mSv for 5 years and >50 mSv in a single year from CT alone remains unknown. This study aimed to quantify radiation doses from CTs received by stone patients before their evaluation at a tertiary care stone clinic. From November 2015 to March 2017, consecutive new patients enrolled into the Registry for Stones of the Kidney and Ureter (ReSKU™) had the dose-length product of every available CT abdomen/pelvis within 5 years of their initial visit recorded, allowing for an effective dose (EDose) calculation. Multivariate logistic regression analysis identified factors associated with exceeding recommended dose limits. Models were created to test radiation reducing effects of low-dose and phase-reduction CT protocols. Of 343 noncontrast CTs performed, only 29 (8%) were low-dose CTs (calculated EDose 20 mSv and >50 mSv/year, respectively. Increased body mass index, number of scans, and multiphase scans were associated with exceeding exposure thresholds ( 50%. Stone patients referred to a tertiary stone center may receive excessive radiation from CT scans alone. Unnecessary phases and underutilization of low-dose CT protocols continue to take place. Enacting new approaches to CT protocols may spare stone patients from exceeding recommended dose limits.
• Zetumer, S., Wiener, S., Bayne, D. B., Armas-Phan, M., Washington, S. L., Tzou, D. T., Stoller, M., & Chi, T. (2019). The Impact of Stone Multiplicity on Surgical Decisions for Patients with Large Stone Burden: Results from ReSKU. Journal of endourology, 33(9), 742-749.
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  American Urological Association (AUA) guidelines recommend percutaneous nephrolithotomy (PCNL) for total stone burden greater than 20 mm, yet it is unclear if the number of stones affects adherence to this guideline. We aim to assess the impact of stone multiplicity on the choice of ureteroscopy (URS) PCNL as a first-line therapy for patients with high burden (>20 mm), and examine whether the AUA guideline-discordant care impacts patient outcomes. Data were collected from the Registry for Stones of the Kidney and Ureter (ReSKU) database, a prospectively collected registry of patients with stone disease. Multivariate logistic regression (MLR) was used to estimate the association between stone multiplicity and the decision to perform URS for high stone burden (>20 mm) patients. MLR was further used to estimate the association between performing URS and the following outcomes: stone-free rate, need for a second operation, and complications. Postoperative hospital stay was compared between patients receiving URS PCNL using Student's -test. One hundred twenty-five patients were included in this analysis. For patients with total stone burden exceeding 20 mm, those with more than three stones had roughly nine times the likelihood of undergoing URS over PCNL compared with patients with a single stone (adjusted odds ratio 9.21, confidence interval [95% CI] 2.55-40.58,  = 0.001). Stone-free rates, Clavien-Dindo scores, and frequency of second-look operations did not differ significantly between URS and PCNL patients. URS patients were discharged an average of 1.26 days earlier than patients who received PCNL (95% CI 0.72-1.81,  20 mm will undergo URS and who will undergo PCNL. These deviations from AUA guidelines do not appear to worsen patient outcomes. These results suggest that careful consideration of each patient may warrant deviation from guidelines.
• Ahmad, B. T., Ahmad, B. T., Antonelli, J., Antonelli, J., Averch, T. D., Averch, T. D., Bird, V. G., Bird, V. G., Chew, B. H., Chew, B. H., Chi, T., Chi, T., Goodman, B. J., Goodman, B. J., Nakada, S. Y., Nakada, S. Y., Paise, V. M., Paise, V. M., Penniston, R. K., , Penniston, R. K., et al. (2018). MP13-07 INCOME IS STRONGLY ASSOCIATED WITH KIDNEY STONE DISEASE-SPECIFIC QUALITY OF LIFE. The Journal of Urology, 199(4S). doi:10.1016/j.juro.2018.02.479
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  You have accessJournal of UrologyStone Disease: Epidemiology & Evaluation I1 Apr 2018MP13-07 INCOME IS STRONGLY ASSOCIATED WITH KIDNEY STONE DISEASE-SPECIFIC QUALITY OF LIFE Tessnim R. Ahmad, BS, David T. Tzou, MD, Shalonda Reliford-Titus, BA, Clinton Wu, BSc, Jeremy Goodman, BA, Jodi A. Antonelli, MD, Davis P. Viprakasit, MD, FACS, Timothy D. Averch, MD, Sri Sivalingam, MD, MSc, FRCSC, Ben H. Chew, MD, Vincent G. Bird, MD, Vernon M. Paise, Jr., MD, Necole M. Streeper, MD, Roger L. Sur, MD, Stephen Y. Nakada, MD, FACS, FRCS, Kristina L. Penniston, PhD, RD, and Thomas Chi, MD Tessnim R. Ahmad, BSTessnim R. Ahmad, BS More articles by this author , David T. Tzou, MDDavid T. Tzou, MD More articles by this author , Shalonda Reliford-Titus, BAShalonda Reliford-Titus, BA More articles by this author , Clinton Wu, BScClinton Wu, BSc More articles by this author , Jeremy Goodman, BAJeremy Goodman, BA More articles by this author , Jodi A. Antonelli, MDJodi A. Antonelli, MD More articles by this author , Davis P. Viprakasit, MD, FACSDavis P. Viprakasit, MD, FACS More articles by this author , Timothy D. Averch, MDTimothy D. Averch, MD More articles by this author , Sri Sivalingam, MD, MSc, FRCSCSri Sivalingam, MD, MSc, FRCSC More articles by this author , Ben H. Chew, MDBen H. Chew, MD More articles by this author , Vincent G. Bird, MDVincent G. Bird, MD More articles by this author , Vernon M. Paise, Jr., MDVernon M. Paise, Jr., MD More articles by this author , Necole M. Streeper, MDNecole M. Streeper, MD More articles by this author , Roger L. Sur, MDRoger L. Sur, MD More articles by this author , Stephen Y. Nakada, MD, FACS, FRCSStephen Y. Nakada, MD, FACS, FRCS More articles by this author , Kristina L. Penniston, PhD, RDKristina L. Penniston, PhD, RD More articles by this author , and Thomas Chi, MDThomas Chi, MD More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.479AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Kidney stones are a source of significant morbidity and have been shown to negatively impact health-related quality of life (HRQOL). While socioeconomic status (SES) is associated with HRQOL, it has never been examined in relation to kidney stone disease-specific HRQOL. The purpose of this study was to assess kidney stone patients’ quality of life in relation to income. METHODS This was a multi-institutional prospective cohort study where kidney stone patients at 10 stone centers across the U.S. were enrolled. They completed the Wisconsin Stone Quality of Life questionnaire (WISQOL – a validated HRQOL questionnaire specifically tailored to kidney stone patients) between June 2014 and March 2017 at the time of their first clinic visit when presenting for initial stone evaluation. Race/ethnicity was defined by self-report. Each patient’s income was estimated using census median incomes identified by zip code, then further classified into low, middle, and upper income brackets using Pew Research Center guidelines. Linear regression was used to examine the relationship between income and HRQOL, adjusting for age, gender, race, BMI, number of stone events, and number of comorbidities. RESULTS The study sample included 1,777 individuals. Older age and male gender were significantly associated with higher WISQOL scores (p
• Bayne, D. B., Usawachintachit, M., Tzou, D., Taguchi, K., Shindel, A., & Chi, T. (2018). Increasing Body Mass Index Steepens the Learning Curve for Ultrasound-guided Percutaneous Nephrolithotomy.. Urology, 68-73. doi:10.1016/j.urology.2018.07.033
• Chi, T., Chi, T., Isaacson, D., Isaacson, D., Reliford-Titus, S., Reliford-Titus, S., Sherer, B. A., Sherer, B. A., Stoller, M. L., Stoller, M. L., Taguchi, K., Taguchi, K., Tzou, D. T., Tzou, D. T., Usawachintachit, M., Usawachintachit, M., Zetumer, S., & Zetumer, S. (2018). PD37-10 RADIATION EXPOSURE FROM CT SCANS FOR UROLITHIASIS: RESULTS FROM THE REGISTRY FOR STONES OF THE KIDNEY AND URETER (RESKU). The Journal of Urology. doi:10.1016/j.juro.2018.02.1745
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  You have accessJournal of UrologyImaging/Radiology: Uroradiology III1 Apr 2018PD37-10 RADIATION EXPOSURE FROM CT SCANS FOR UROLITHIASIS: RESULTS FROM THE REGISTRY FOR STONES OF THE KIDNEY AND URETER (RESKU) David T. Tzou, Manint Usawachintachit, Samuel Zetumer, Kazumi Taguchi, Dylan Isaacson, Shalonda Reliford-Titus, Benjamin A. Sherer, Marshall L. Stoller, and Thomas Chi David T. TzouDavid T. Tzou More articles by this author , Manint UsawachintachitManint Usawachintachit More articles by this author , Samuel ZetumerSamuel Zetumer More articles by this author , Kazumi TaguchiKazumi Taguchi More articles by this author , Dylan IsaacsonDylan Isaacson More articles by this author , Shalonda Reliford-TitusShalonda Reliford-Titus More articles by this author , Benjamin A. ShererBenjamin A. Sherer More articles by this author , Marshall L. StollerMarshall L. Stoller More articles by this author , and Thomas ChiThomas Chi More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.1745AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Patients with kidney stones routinely have computed tomography (CT) scans as part of their diagnostic workup. The recommended yearly dose limit for occupational radiation exposure by the International Commission on Radiological Protection is 50 mSv, yet how often this limit is exceeded for stone patients remains unknown. Radiation exposure beyond this limit may impart long-term risks of secondary malignancies. This study aimed to identify annual effective radiation doses received by consecutive stone patients referred to a tertiary care stone clinic. METHODS From October 2015 to March 2017, new stone patients were prospectively enrolled into the Registry for Stones of the Kidney and Ureter - ReSKU at the University of California San Francisco (UCSF) for this cohort study. For each patient, all available CT scans of the abdomen/pelvis done prior to their initial visit were reviewed. Measures of radiation exposure such as volume CT dose index (CTDIvol) and dose-length-product (DLP) were recorded. Effective dose (ED) was calculated by multiplying the DLP by a validated conversion factor (0.015), appropriate for a CT abdomen/pelvis. Univariate and multivariate regression analyses were performed to determine factors associated with patient ED, and a logistic model was used to dichotomize patients receiving >50mSv/year cumulative ED. RESULTS Of 594 patients enrolled into ReSKU, 458 patients had ≥ 1 CT abdomen/pelvis available for review. CT scans were performed at 135 unique radiologic centers. Only 5.5% of the 819 CT scans performed met criteria for a low dose CT scan (ED 50 mSv/year (mean 77 mSv, range 51 to 210 mSv). Univariate logistic analysis demonstrated a statistically significant association of body mass index (BMI) (OR 1.1), number of scans (OR 3.8), performing location (OR 2.6), and multi-phase scans (OR 3.7) with patients receiving a >50mSv/year cumulative ED (p
• Funk, J., & Tzou, D. (2018). Response to Stutz et al. re: "Management of Suspected Bladder Injury and Capsular Perforation After Holmium Laser Enucleation of the Prostate".. Journal of Endourology Case Reports, 4(1), N/A-Epublication.
• Lwin, A., Hynes, K., Tzou, D., & Funk, J. (2018). Management of Suspected Bladder Injury and Capsular Perforation After Holmium Laser Enucleation of the Prostate. Journal of Endourology Case Reports, 4(1), 87-90. doi:https://doi.org/10.1089/cren.2018.0021
• Taguchi, K., Harper, J. D., Stoller, M. L., Duty, B. D., Sorensen, M. D., Sur, R. L., Usawachintachit, M., Tzou, D. T., Wenzler, D. L., Isaacson, D., Xu, A., Chu, C., Zaid, U. B., Taylor, E. R., Ramaswamy, K., & Chi, T. (2018). Identifying factors associated with need for flexible ureteroscope repair: a Western Endourology STone (WEST) research consortium prospective cohort study. Urolithiasis, 46(6), 559-566.
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  Maintenance of flexible ureteroscopes can involve high costs and administrative burden. Instrument fragility necessitates eventual repair, rendering scopes inaccessible during refurbishment. We conducted a multi-institutional prospective cohort study to identify perioperative factors influencing flexible ureteroscope durability. Patients undergoing flexible ureteroscopy (URS) at six United States endourology centers were enrolled between August 2014 and June 2015. Surgeon self-reported concern and satisfaction with scope performance as well as upward and downward angles of deflection for each scope tip were measured before and after each procedure. The need for scope repair was determined by the operating surgeon at the time of the procedure and recorded. 424 URS cases using 74 flexible ureteroscopes were identified. Scope repair was required in 28 cases (6.6%) involving 26 scopes (35.1%). Upon univariate analysis, shorter patient height, absence of guidewire use, presence of a ureteral access sheath (UAS), longer procedure time, larger stone size, lithotrite type, surgeon training level, and self-reported concern were associated with scope repair. Upon multivariate analysis, UAS use (OR = 2.53, p = 0.005) and degree loss of scope upward flexion during a case (OR = 1.02, p = 0.03) increased the odds of a scope needing repair while the use of safety guidewire decreased the odds of a scope repair (OR = 0.50, p = 0.045). Lithotrite use and surgeon concern were associated with degree loss of scope upward flexion. The use of a UAS, absence of a safety guidewire, and the loss of upward ureteroscope flexion should be considered when evaluating means of optimizing reusable ureteroscope durability.
• Taguchi, K., Usawachintachit, M., Tzou, D. T., Sherer, B. A., Metzler, I., Isaacson, D., Stoller, M. L., & Chi, T. (2018). Micro-Costing Analysis Demonstrates Comparable Costs for LithoVue Compared to Reusable Flexible Fiberoptic Ureteroscopes. Journal of endourology, 32(4), 267-273.
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  Reusable ureteroscope durability and need for repair are significant sources of expense and inefficiency for patients and urologists. Utilization of LithoVue™, a disposable flexible digital ureteroscope, may address some of these concerns. To identify its economic impact on clinical care, we performed a micro-cost comparison between flexible reusable fiberoptic ureteroscopes (URF-P6™) and LithoVue.
• Tzou, D. T., & Chi, T. (2018). Editorial Comment. The Journal of urology, 200(5), 972.
• Tzou, D. T., Cadwell, C., Simko, J. P., Chi, T., & Stoller, M. L. (2018). Management of Inverted Papilloma During Holmium Laser Enucleation of the Prostate. Urology, 116, e5-e6.
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  Inverted papilloma of the prostatic urethra is an especially rare finding. A 75-year-old man with urinary retention wished to proceed with a holmium laser enucleation of the prostate (HoLEP) and was found to have a mass arising from his prostate vs bladder on preoperative imaging. Cystourethroscopy revealed the mass arising from the median lobe of the prostate. After transurethral resection and frozen analysis confirmed the benign pathology of an inverted papilloma, the patient subsequently underwent a successful HoLEP during the same surgical setting. Images of this rare prostatic mass are presented to increase urologist recognition and to assist management during HoLEP.
• Tzou, D. T., Isaacson, D., Usawachintachit, M., Wang, Z. J., Taguchi, K., Hills, N. K., Hsi, R. S., Sherer, B. A., Reliford-Titus, S., Duty, B., Harper, J. D., Sorensen, M., Sur, R. L., Stoller, M. L., & Chi, T. (2018). Variation in Radiologic and Urologic Computed Tomography Interpretation of Urinary Tract Stone Burden: Results From the Registry for Stones of the Kidney and Ureter. Urology, 111, 59-64.
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  To compare the measured stone burden recorded between urologists and radiologists, and examine how these differences could potentially impact stone management. As current urologic stone surgery guideline recommendations are based on stone size, accurate stone measurements are crucial to direct appropriate treatment. This study investigated the discrepant interpretation that often exists between urologic surgeons and radiologists' estimation of patient urinary stone burden.
• Tzou, D. T., Metzler, I. S., Stoller, M. L., & Chi, T. (2018). Ultrasound-Guided Morcellation During Holmium Laser Enucleation of the Prostate. Journal of Endourology Case Reports, 4(1), 133-135. doi:10.1089/cren.2018.0057
• Tzou, D. T., Metzler, I. S., Stoller, M. L., & Chi, T. (2018). Ultrasound-Guided Morcellation During Holmium Laser Enucleation of the Prostate. Journal of endourology case reports, 4(1), 133-135.
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  Holmium laser enucleation of the prostate (HoLEP) has emerged as an accepted standard of care for the treatment of benign prostatic hyperplasia. This surgery relies on morcellation of the prostate adenoma once enucleation of the transition zone has been completed. Caution is required during this portion of the operation, as engaging bladder mucosa within the morcellator can result in bladder injury, a rare but potentially catastrophic complication of HoLEP. Morcellation of the prostatic tissue can be additionally challenging if visualization is poor from either equipment failure or increased bleeding from a highly vascularized prostate. We report the case of a 66-year-old Caucasian man with an estimated 158 g prostate who underwent HoLEP at our institution. Enucleation was uneventful; however, upon placement of the nephroscope to begin morcellation, it was immediately evident that the lens of the nephroscope was damaged as there was extremely poor visualization. Without a replacement nephroscope available, this would have normally resulted in aborting the case and returning another day to complete the morcellation. Concurrent bladder ultrasonography was performed and allowed for additional visual feedback to the operator, helping guide the morcellator to safely engage the enucleated adenoma and complete the operation. This case report demonstrates the ability of performing the morcellation portion of HoLEP mainly with the visualization provided by concurrent bladder ultrasonography. By providing additional imaging feedback to the operator, ultrasound can be a complementary tool to assist in safely performing morcellation in situations of suboptimal cystoscopic visualization during HoLEP.
• Tzou, D. T., Villaneda, M. A., Zetumer, S., Reliford-Titus, S., Taguchi, K., Usawachintachit, M., Stoller, M. L., & Chi, T. (2018). PD35-10 RENAL TRACT DILATION IS A SIGNIFICANT SOURCE OF RADIATION EXPOSURE DURING PERCUTANEOUS NEPHROLITHOTOMY: RESULTS FROM THE REGISTRY FOR STONES OF THE KIDNEY AND URETER (RESKU). The Journal of Urology, 199(4S). doi:10.1016/j.juro.2018.02.1721
• Tzou, D., & Chi, T. (2018). Editorial Comment. The Journal of Urology, 200(5). doi:https://doi.org/10.1016/j.juro.2018.05.161
• Tzou, D., Cadwell, C., Simko, J. P., Chi, T., & Stoller, M. L. (2018). Management of Inverted Papilloma During Holmium Laser Enucleation of the Prostate.. Urology. doi:10.1016/j.urology.2018.01.009
• Tzou, D., Isaacson, D., Usawachintachit, M., Wang, Z. J., Taguchi, K., Hills, N. K., Hsi, R. S., Sherer, B. A., Reliford-Titus, S., Duty, B., Harper, J. D., Sorensen, M., Sur, R. L., Stoller, M. L., & Chi, T. (2018). Variation in Radiologic and Urologic Computed Tomography Interpretation of Urinary Tract Stone Burden: Results From the Registry for Stones of the Kidney and Ureter.. Urology, 59-64. doi:10.1016/j.urology.2017.10.002
• Tzou, D., Lwin, A., & Funk, J. (2018). Response to Stutz et al. re: “Management of Suspected Bladder Injury and Capsular Perforation After Holmium Laser Enucleation of the Prostate”. Journal of Endourology Case Reports, 4(1), 205-205. doi:10.1089/cren.2018.0089
• Usawachintachit, M., Sherer, B., Hudnall, M., Tzou, D. T., Taguchi, K., Hsi, R. S., Stoller, M., & Chi, T. (2018). Clinical Outcomes for Cystinuria Patients with Unilateral Versus Bilateral Cystine Stone Disease. Journal of endourology, 32(2), 148-153.
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  Cystinuria is a genetic disorder marked by elevated urinary cystine excretion and recurrent cystine nephrolithiasis. Interestingly, despite seemingly similar contralateral renal anatomy, a subset of cystinuric patients consistently form stones in only one kidney. The aim of this study is to evaluate clinical outcomes in unilateral vs bilateral cystine stone formers.
• Chi, T., Chi, T., Chu, C., Chu, C., Stoller, M. L., Stoller, M. L., Taguchi, K., Taguchi, K., Tzou, D. T., Tzou, D. T., Usawachintachit, M., & Usawachintachit, M. (2017). MP01-06 PREDICTORS OF FLANK PAIN IN PATIENTS WITH A NON-DILATED COLLECTING SYSTEM: RESULTS FROM RESKU, THE REGISTRY FOR STONES OF THE KIDNEY AND URETER. The Journal of Urology. doi:10.1016/j.juro.2017.02.081
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  You have accessJournal of UrologyStone Disease: Epidemiology & Evaluation I1 Apr 2017MP01-06 PREDICTORS OF FLANK PAIN IN PATIENTS WITH A NON-DILATED COLLECTING SYSTEM: RESULTS FROM RESKU, THE REGISTRY FOR STONES OF THE KIDNEY AND URETER Carissa Chu, Manint Usawachintachit, David T. Tzou, Kazumi Taguchi, Marshall Stoller, and Thomas Chi Carissa ChuCarissa Chu More articles by this author , Manint UsawachintachitManint Usawachintachit More articles by this author , David T. TzouDavid T. Tzou More articles by this author , Kazumi TaguchiKazumi Taguchi More articles by this author , Marshall StollerMarshall Stoller More articles by this author , and Thomas ChiThomas Chi More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.081AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Classically, acute flank pain and renal colic in nephrolithiasis is attributed to the presence of hydronephrosis and distention of the renal capsule. Patients often present with stones and no collecting system dilation, however, creating a therapeutic dilemma for urologists. Given that the biophysical mechanisms of visceral flank pain are not well understood, we aimed to characterize predictors of renal colic among stone patients without hydronephrosis. METHODS From October 2015 to May 2016, new stone patients at the University of California, San Francisco (UCSF) were prospectively enrolled into the Registry for Stones of the Kidneys and Ureter (ReSKU). This electronic medical record (EMR) based stone registry captures patient clinical and imaging data for research purposes. For this study, we identified all patients with imaging-confirmed upper tract urinary stones and absence of hydronephrosis based on ultrasound or cross-sectional computed tomography imaging. Data analysis was performed on STATA Version 14.1 to identify factors associated with flank pain. RESULTS During the study period, 116 patients with nephrolithiasis and no hydronephrosis were identified. 62.7% (n=74) had no flank pain associated with an ipsilateral stone, while 35.6% (n=42) had flank pain with an ipsilateral stone. There were no statistically significant differences between patients with and without flank pain with respect to age (60.0±2.1 vs. 57.3±2.6 years old), gender (51 vs. 45% male), smoking history (28.2 vs. 32.4% smoker), drinking history (48.7 vs. 42.3% none), BMI (28.4±1.0 vs. 26.4±1.5), or stone burden (1.86±2.6 vs. 1.80±4.0 cm). For patients with flank pain, those with renal stones were more likely to have flank pain compared with patients with ureteral stones (78.7 vs. 21.4%, p=0.018, Pearson chi-squared test). CONCLUSIONS Stones in the renal pelvis or calyces are more likely to cause pain in patients without hydronephrosis when compared with ureteral stones. Alternate mechanisms for acute renal colic must exist beyond obstruction and renal capsule distension. Understanding these mechanisms is critical to developing effective treatments for a subgroup of difficult-to-treat patients and warrants additional study. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e3 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Carissa Chu More articles by this author Manint Usawachintachit More articles by this author David T. Tzou More articles by this author Kazumi Taguchi More articles by this author Marshall Stoller More articles by this author Thomas Chi More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...
• Chi, T., Usawachintachit, M., Weinstein, S., Kohi, M. P., Taylor, A., Tzou, D. T., Chang, H. C., Stoller, M., & Mongan, J. (2017). Contrast Enhanced Ultrasound as a Radiation-Free Alternative to Fluoroscopic Nephrostogram for Evaluating Ureteral Patency. The Journal of urology, 198(6), 1367-1373.
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  We compared contrast enhanced ultrasound and fluoroscopic nephrostography in the evaluation of ureteral patency following percutaneous nephrolithotomy.
• Hudnall, M., Usawachintachit, M., Metzler, I. S., Tzou, D. T., Harrison, B., Lobo, E., & Chi, T. (2017). Ultrasound guidance reduces percutaneous nephrolithotomy cost compared to fluoroscopy. Urology, 103, 52-58.
• Hudnall, M., Usawachintachit, M., Metzler, I., Tzou, D. T., Harrison, B., Lobo, E., & Chi, T. (2017). Ultrasound Guidance Reduces Percutaneous Nephrolithotomy Cost Compared to Fluoroscopy. Urology, 103, 52-58. doi:10.1016/j.urology.2016.12.030
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  Objective To examine the cost factors associated with ultrasound and fluoroscopic guidance for percutaneous nephrolithotomy (PCNL) and to determine which method can be performed at a lower cost per case. Methods A cost comparison study was performed utilizing clinical data from a prospectively maintained research database. We included the most recent 33 consecutive ultrasound-guided PCNL cases in 2016 and the most recent 40 consecutive fluoroscopy-guided PCNL cases before the operative surgeon transitioned to ultrasound guidance in May 2014. The total operative time and clinical outcomes were examined. Costs were extracted from the institution accounting systems and given a uniform multiplier to protect institutional financial reporting confidentiality. Comparisons were made using the Student t test and the chi-squared test. Results After excluding outliers, 71 PCNL procedures were included in the analysis. Demographic data and stone characteristics were not different between ultrasound-guided and fluoroscopy-guided groups. However, the mean operative time for ultrasound-guided PCNL was significantly shorter (99.8 ± 27.0 vs 144.9 ± 55.1 minutes, P < .05). When capital equipment costs were included, the mean total cost per case of ultrasound-guided PCNL was approximately 30% less than fluoroscopy-guided PCNL (simulated costs with a uniform multiplier; $5258.90 ± 957.12 vs $7508.60 ± 1163.83, P < .05). Postoperative clinical outcomes were comparable between the 2 groups. Conclusion When capital costs are included, ultrasound-guided PCNL can produce comparable clinical outcomes to fluoroscopy-guided procedures at a lower cost to the institution. Shorter operative time drives significant savings with the adoption of ultrasound guidance, which may be magnified with increasing case volume. Using ultrasound imaging during PCNL may be more cost-effective compared to fluoroscopy and warrants further study. To examine the cost factors associated with ultrasound and fluoroscopic guidance for percutaneous nephrolithotomy (PCNL) and to determine which method can be performed at a lower cost per case. A cost comparison study was performed utilizing clinical data from a prospectively maintained research database. We included the most recent 33 consecutive ultrasound-guided PCNL cases in 2016 and the most recent 40 consecutive fluoroscopy-guided PCNL cases before the operative surgeon transitioned to ultrasound guidance in May 2014. The total operative time and clinical outcomes were examined. Costs were extracted from the institution accounting systems and given a uniform multiplier to protect institutional financial reporting confidentiality. Comparisons were made using the Student t test and the chi-squared test. After excluding outliers, 71 PCNL procedures were included in the analysis. Demographic data and stone characteristics were not different between ultrasound-guided and fluoroscopy-guided groups. However, the mean operative time for ultrasound-guided PCNL was significantly shorter (99.8 ± 27.0 vs 144.9 ± 55.1 minutes, P < .05). When capital equipment costs were included, the mean total cost per case of ultrasound-guided PCNL was approximately 30% less than fluoroscopy-guided PCNL (simulated costs with a uniform multiplier; $5258.90 ± 957.12 vs $7508.60 ± 1163.83, P < .05). Postoperative clinical outcomes were comparable between the 2 groups. When capital costs are included, ultrasound-guided PCNL can produce comparable clinical outcomes to fluoroscopy-guided procedures at a lower cost to the institution. Shorter operative time drives significant savings with the adoption of ultrasound guidance, which may be magnified with increasing case volume. Using ultrasound imaging during PCNL may be more cost-effective compared to fluoroscopy and warrants further study.
• Isaacson, D., Ahmad, T., Metzler, I., Tzou, D. T., Taguchi, K., Usawachintachit, M., Zetumer, S., Sherer, B., Stoller, M., & Chi, T. (2017). Defining the Costs of Reusable Flexible Ureteroscope Reprocessing Using Time-Driven Activity-Based Costing. Journal of endourology, 31(10), 1026-1031.
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  Careful decontamination and sterilization of reusable flexible ureteroscopes used in ureterorenoscopy cases prevent the spread of infectious pathogens to patients and technicians. However, inefficient reprocessing and unavailability of ureteroscopes sent out for repair can contribute to expensive operating room (OR) delays. Time-driven activity-based costing (TDABC) was applied to describe the time and costs involved in reprocessing.
• Taguchi, K., Harper, J. D., Stoller, M. L., Duty, B., Sorensen, M. D., Sur, R. L., Usawachintachit, M., Tzou, D. T., Wenzler, D., Isaacson, D., Xu, A., Chu, C., Zaid, U. B., Taylor, E. R., Ramaswamy, K., & Chi, T. (2017). Identifying factors associated with need for flexible ureteroscope repair: a Western Endourology STone (WEST) research consortium prospective cohort study. Urolithiasis, 46(6), 559-566. doi:10.1007/s00240-017-1013-y
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  Maintenance of flexible ureteroscopes can involve high costs and administrative burden. Instrument fragility necessitates eventual repair, rendering scopes inaccessible during refurbishment. We conducted a multi-institutional prospective cohort study to identify perioperative factors influencing flexible ureteroscope durability. Patients undergoing flexible ureteroscopy (URS) at six United States endourology centers were enrolled between August 2014 and June 2015. Surgeon self-reported concern and satisfaction with scope performance as well as upward and downward angles of deflection for each scope tip were measured before and after each procedure. The need for scope repair was determined by the operating surgeon at the time of the procedure and recorded. 424 URS cases using 74 flexible ureteroscopes were identified. Scope repair was required in 28 cases (6.6%) involving 26 scopes (35.1%). Upon univariate analysis, shorter patient height, absence of guidewire use, presence of a ureteral access sheath (UAS), longer procedure time, larger stone size, lithotrite type, surgeon training level, and self-reported concern were associated with scope repair. Upon multivariate analysis, UAS use (OR = 2.53, p = 0.005) and degree loss of scope upward flexion during a case (OR = 1.02, p = 0.03) increased the odds of a scope needing repair while the use of safety guidewire decreased the odds of a scope repair (OR = 0.50, p = 0.045). Lithotrite use and surgeon concern were associated with degree loss of scope upward flexion. The use of a UAS, absence of a safety guidewire, and the loss of upward ureteroscope flexion should be considered when evaluating means of optimizing reusable ureteroscope durability.
• Taguchi, K., Usawachintachit, M., Hamamoto, S., Unno, R., Tzou, D. T., Sherer, B. A., Wang, Y., Okada, A., Stoller, M. L., Yasui, T., & Chi, T. (2017). Optimizing RNA Extraction of Renal Papilla Biopsy Tissue in Kidney Stone Formers: A New Methodology for Genomic Study. Journal of endourology, 31(9), 922-929.
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  Endoscopic tools have provided versatile examination and treatment for kidney stone procedures. Despite endourologists researching urinary stone disease using endoscopes to collect tissue, this tissue collection method is limited. Endoscopically removed tissues are small in size, restricting the types of genome-based examination possible. We investigated a new method of renal papilla biopsy and RNA extraction to establish a genomic research methodology for kidney stone disease.
• Tzou, D. T., Tzou, D. T., Isaacson, D., Isaacson, D., Usawachintachit, M., Usawachintachit, M., Taguchi, K., Taguchi, K., Sherer, B. A., Sherer, B. A., Stoller, M. L., Stoller, M. L., Chi, T., & Chi, T. (2017). MP18-16 THE IMPORTANCE OF UROLOGIST ESTIMATION OF STONE BURDEN: RESULTS FROM THE REGISTRY FOR STONES OF THE KIDNEY AND URETER (RESKU™). The Journal of Urology, 197(S4). doi:10.1016/j.juro.2017.02.626
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  You have accessJournal of UrologyImaging/Radiology: Uroradiology III1 Apr 2017MP18-16 THE IMPORTANCE OF UROLOGIST ESTIMATION OF STONE BURDEN: RESULTS FROM THE REGISTRY FOR STONES OF THE KIDNEY AND URETER (RESKU™) David T. Tzou, Dylan Isaacson, Manint Usawachintachit, Kazumi Taguchi, Benjamin A. Sherer, Marshall L. Stoller, and Thomas Chi David T. TzouDavid T. Tzou More articles by this author , Dylan IsaacsonDylan Isaacson More articles by this author , Manint UsawachintachitManint Usawachintachit More articles by this author , Kazumi TaguchiKazumi Taguchi More articles by this author , Benjamin A. ShererBenjamin A. Sherer More articles by this author , Marshall L. StollerMarshall L. Stoller More articles by this author , and Thomas ChiThomas Chi More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.626AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES A discrepancy often exists between urologists′ and radiologists′ estimation of a patient′s true stone burden. Current AUA guidelines recommend treatment based on stone size thresholds and therefore accurate stone measurements are critical in directing patients to the most appropriate surgery. With an increasing trend towards determining quality of care based on the amount of stone removed, accurate stone burden estimation is essential to defining operative success. This study aimed to compare the number, size, and location of stones recorded by urologists and radiologists, and determine what discrepancies exist and how these differences could impact stone management. METHODS From October 2015 to August 2016, 371 new stone patients at University of California, San Francisco were prospectively enrolled into the Registry for Stones of the Kidney and Ureter (ReSKUTM). Treating urologists personally reviewed all computed tomography (CT) imaging, recording stone number, location, and total stone burden. Stone burden was based on the largest aggregate linear dimension from axial and coronal views. A blinded, retrospective review of the corresponding radiologic reports for these patients was then performed, comparing how often these key attributes were mentioned. A report was categorized as unclear for each characteristic when it failed to specifically mention the number, location or total stone burden. RESULTS A total of 219 patients had both CT images and a report available for review. With regard to stone number, 57/219 (26%) of reports were considered unclear. Radiologists reported significantly smaller stone burden than urologists for both single stones (8.8 ± 9.2 mm vs 10.7 ± 11.8 mm, p
• Tzou, D. T., Usawachintachit, M., Taguchi, K., & Chi, T. (2017). Ultrasound Use in Urinary Stones: Adapting Old Technology for a Modern-Day Disease. Journal of Endourology, 31(S1), S89-S94. doi:10.1089/end.2016.0584
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  Ultrasound has become a mainstay tool in urologists' armamentarium for the diagnosis and management of nephrolithiasis. From starting as a rudimentary form of imaging, it has come to play a more prominent role over time, paralleling evolution in ultrasound technology. Throughout the medical community there is a growing emphasis on reducing the amount of ionizing radiation delivered to patients during routine imaging. As such there has been a resurgence of interest in ultrasound given its lack of associated radiation exposure and proven effectiveness as a diagnostic and therapeutic imaging modality. Herein, we provide a review of the history of ultrasound, how the use of ultrasound is expanding in both diagnosis and treatment of urinary stone disease, and finally how promising applications of ultrasound are shaping the future of kidney stone management.
• Tzou, D. T., Usawachintachit, M., Taguchi, K., & Chi, T. (2017). Ultrasound use in urinary stones: adapting old technology for a modern-day disease. Journal of Endourology, 31(S1), S89-S94.
• Tzou, D. T., Weinstein, S., Usawachintachit, M., Mongan, J., Greene, K. L., & Chi, T. (2017). Contrast Enhanced Ultrasound Detects Recurrent Renal Cell Carcinoma in the Setting of Chronic Renal Insufficiency. Clinical genitourinary cancer, 15(4), e735-e737.
• Usawachintachit, M., Isaacson, D. S., Taguchi, K., Tzou, D. T., Hsi, R. S., Sherer, B. A., Stoller, M. L., & Chi, T. (2017). A Prospective Case-Control Study Comparing LithoVue, a Single-Use, Flexible Disposable Ureteroscope, with Flexible, Reusable Fiber-Optic Ureteroscopes. Journal of endourology, 31(5), 468-475.
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  LithoVue™ is a novel, single-use, digital flexible ureteroscope that was released to the US market in January 2016. There are scant data regarding its performance in humans. Procedural outcomes comparing LithoVue with reusable ureteroscopes are presented in patients undergoing ureteroscopy for upper urinary tract pathology.
• Usawachintachit, M., Tzou, D. T., Hu, W., Li, J., & Chi, T. (2017). X-ray-free ultrasound-guided percutaneous nephrolithitomy: how to select the right patient?. Urology, 100, 38-44.
• Usawachintachit, M., Tzou, D. T., Hu, W., Li, J., & Chi, T. (2017). X-ray–free Ultrasound-guided Percutaneous Nephrolithotomy: How to Select the Right Patient?. Urology, 31(2), 38-44. doi:10.1016/j.urology.2016.09.031
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  Objective To identify factors associated with successful ultrasound guidance for each surgical step of ultrasound-guided percutaneous nephrolithotomy (PCNL). Patients and Methods Consecutive patients undergoing PCNL between March 2015 and June 2016 were prospectively enrolled. An attempt was made to use ultrasound guidance in renal access, tract dilation, and nephrostomy tube placement for each patient. For steps during which ultrasound guidance was unsuccessful, fluoroscopic screening was applied. Regression analysis identified patient characteristics associated with successful use of ultrasound guidance. Results A total of 96 patients composed this cohort, with a mean body mass index of 28.7 kg/m2. Mean stone size was 33.1 ± 18.9 mm, and no hydronephrosis was found in 63.5% of cases. Fluoroscopic screening was required for renal access in 27 cases (28.1%), tract dilation in 38 (39.6%), and nephrostomy tube placement in 80 (83.3%). Multivariate analysis demonstrated that successful ultrasound guidance was significantly associated with the presence of hydronephrosis for renal access and the absence of staghorn calculi for tract dilation. Ultrasound-guided nephrostomy tube placement appeared linked to surgeon experience. Conclusion To achieve completely x-ray–free ultrasound-guided PCNL, the ideal patient should have a hydronephrotic collecting system with no staghorn stone present. For practitioners looking to adopt ultrasound guidance into their PCNL practice, these represent the most appropriate patients to safely initiate a surgical experience. To identify factors associated with successful ultrasound guidance for each surgical step of ultrasound-guided percutaneous nephrolithotomy (PCNL). Consecutive patients undergoing PCNL between March 2015 and June 2016 were prospectively enrolled. An attempt was made to use ultrasound guidance in renal access, tract dilation, and nephrostomy tube placement for each patient. For steps during which ultrasound guidance was unsuccessful, fluoroscopic screening was applied. Regression analysis identified patient characteristics associated with successful use of ultrasound guidance. A total of 96 patients composed this cohort, with a mean body mass index of 28.7 kg/m2. Mean stone size was 33.1 ± 18.9 mm, and no hydronephrosis was found in 63.5% of cases. Fluoroscopic screening was required for renal access in 27 cases (28.1%), tract dilation in 38 (39.6%), and nephrostomy tube placement in 80 (83.3%). Multivariate analysis demonstrated that successful ultrasound guidance was significantly associated with the presence of hydronephrosis for renal access and the absence of staghorn calculi for tract dilation. Ultrasound-guided nephrostomy tube placement appeared linked to surgeon experience. To achieve completely x-ray–free ultrasound-guided PCNL, the ideal patient should have a hydronephrotic collecting system with no staghorn stone present. For practitioners looking to adopt ultrasound guidance into their PCNL practice, these represent the most appropriate patients to safely initiate a surgical experience.
• Usawachintachit, M., Tzou, D. T., Mongan, J., Taguchi, K., Weinstein, S., & Chi, T. (2017). Feasibility of Retrograde Ureteral Contrast Injection to Guide Ultrasonographic Percutaneous Renal Access in the Nondilated Collecting System. Journal of Endourology, 31(2), 129-134. doi:10.1089/end.2016.0693
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  Objectives: Ultrasound-guided percutaneous nephrolithotomy (PCNL) has become increasingly utilized. Patients with nondilated collecting systems represent a challenge: the target calix is often difficult to visualize. Here we report pilot study results for retrograde ultrasound contrast injection to aid in percutaneous renal access during ultrasound-guided PCNL. Patients and Methods: From April to July 2016, consecutive patients over the age of 18 years with nondilated collecting systems on preoperative imaging who presented for PCNL were enrolled. B-mode ultrasound imaging was compared with contrast-enhanced mode with simultaneous retrograde injection of Optison™ via an ipsilateral ureteral catheter. Results: Five patients (four males and one female) with renal stones underwent PCNL with retrograde ultrasound contrast injection during the study period. Mean body mass index was 28.3 ± 5.6 kg/m2 and mean stone size was 24.5 ± 12.0 mm. Under B-mode ultrasound, all patients demonstrated nondilated renal collecting systems that appeared as hyperechoic areas, where it was difficult to identify a target calix for puncture. Retrograde contrast injection facilitated delineation of all renal calices initially difficult to visualize under B-mode ultrasound. Renal puncture was then performed effectively in all cases with a mean puncture time of 55.4 ± 44.8 seconds. All PCNL procedures were completed without intraoperative complications and no adverse events related to ultrasound contrast injection occurred. Conclusion: Retrograde ultrasound contrast injection as an aide for renal puncture during PCNL is a feasible technique. By improving visualization of the collecting system, it facilitates needle placement in challenging patients without hydronephrosis. Future larger scale studies comparing its use to standard ultrasound-guided technique will be required to validate this concept.
• Usawachintachit, M., Tzou, D. T., Mongan, J., Taguchi, K., Weinstein, S., & Chi, T. (2017). Feasibility of retrograde ureteral contrast injection to guide ultrasonographic percutaneous renal access in the non-dilated collecting system. Journal of Endourology, 31(2), 129-134.
• Usawachintachit, M., Tzou, D. T., Mongan, J., Weinstein, S., & Chi, T. (2017). Antegrade ultrasound contrast injection facilitates accurate nephrostomy tube positioning during percutaneous nephrolithotomy. International Journal of Urology, 24(3), 239-240.
• Usawachintachit, M., Tzou, D. T., Washington, S. L., Hu, W., Li, J., & Chi, T. (2017). Ultrasound-Guided Renal Access and Tract Dilation. Videourology (New Rochelle, N.Y.), 31(1).
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  Ultrasound guidance is a unique alternative to fluoroscopy for percutaneous renal access. Besides being free of ionizing radiation exposure to the patient and intraoperative personnel, it offers several advantages including easier identification of the posterior renal calix and surrounding visceral structures. In this video, we demonstrate how ultrasound can be used to guide percutaneous nephrolithotomy (PCNL) in a step-by-step manner. From March to June 2016, 16 consecutive patients of age 18 and more with kidney or proximal ureteral stones underwent completely X-ray-free ultrasound-guided PCNL. No patients were excluded during the study period. Under general anesthesia, we place an externalized ureteral catheter through a flexible cystoscope with the patient in a frog-leg position. Retrograde saline injection is used to distend the collecting system only when needed. Then the patient is placed in a prone position. An ultrasound machine with a 3.5-MHz convex abdominal probe (Hitachi Aloka Medical America) is used to guide all steps of PCNL. For renal access, a longitudinal approach for needle insertion is usually chosen. An 18-gauge Echotip needle (Cook Medical) is slowly advanced through the skin either in front of or behind the probe. On the ultrasound screen, the entire needle should be fully seen from skin to kidney and into the targeted calix. Entry into the collecting system is confirmed with either aspiration of urine or efflux of urine through the puncture needle. Then, the needle stylet is removed and a J-tip coaxial guidewire (Bard Medical) is inserted into the renal pelvis or down the proximal ureter under ultrasound monitoring. Gently moving the wire back and forth will help identify the location of the wire tip relative to the collecting system. Subsequently, the needle is withdrawn, a 1-cm skin incision is made surrounding the wire, and a 10F fascial dilator and a safety wire introducer are then passed over the wire. Although the wire appears with a bright echogenic signal, the dilator and the safety wire introducer are not echogenic. Their advancement over the wire can be observed ultrasonographically as they obscure the echogenic appearance of the wire. A second wire is subsequently advanced into the collecting system through the safety wire introducer. A high-pressure balloon dilator (BARD X-Force, Bard Medical) is then advanced into the collecting system over one of the wires. Because the deflated balloon tip can be difficult to identify on the ultrasound screen, the wire should be moved back and forth while passing the balloon and the operative surgeon should look for a change in the wire contour to judge where the balloon tip is relative to the wire. The placement of the tip of this balloon dilator is crucial, as ideally, it should be just within the collecting system of the target calix. A working tract is then dilated and the access sheath is carefully advanced until the back end of the balloon is seen. Then the balloon is withdrawn, an offset rigid nephroscope is inserted, and the stone is treated. The mean age of patients was 48.8 ± 19.9 years. Forty-four percent of patients were male with a mean body mass index of 29.9 ± 7.9 kg/m and a mean stone size of 33.7 ± 15.0 mm. All procedures were effectively performed with ultrasound guidance with a mean operative time of 101.3 ± 32.2 minutes. Patients and intraoperative personnel were not exposed to any ionizing radiation during the surgery. No patients experienced any significant immediate postoperative complication. All patients were stone free (no visible stone fragments) based on intraoperative visual inspection using a flexible nephroscope and a renal ultrasound and KUB at 30 days after surgery, and no secondary procedures were required. Ultrasound guidance for renal access and tract dilation in prone PCNL is feasible and efficient. Although some situations such as obese patients or nondilated collecting system may present a challenge, the benefits of adopting this technique-namely eliminating ionizing radiation exposure and live imaging of anatomy surrounding the collecting system-provide value during PCNL. This study was supported by the NIH R21-DK-109433 (TC) and the NIH NIDDK K12-DK-07-006: Multidisciplinary K12 Urologic Research Career Development Program (TC). No competing financial interests exist. Runtime of video: 5 mins 12 secs.
• Washington, S. L., Eslami, A., & Tzou, D. T. (2017). Cystoscopic Evaluation of Bladder Leiomyoma. Urology, 106, e1-e2.
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  We report the case of a 40-year-old woman with a history of uterine polyps and 3 months' worth of gross hematuria who was found to have a bladder mass on cystoscopy. Although this mass appeared benign visually, it demonstrated enhancement on axial imaging, with increased internal vascularity on Doppler ultrasound. A transurethral resection demonstrated bladder leiomyoma. This case increases the urologist's recognition of a well-described but previously underrepresented condition by showcasing its visual appearance on cystoscopy.
• Chang, H. C., Tzou, D. T., Usawachintachit, M., Duty, B. D., Hsi, R. S., Harper, J. D., Sorensen, M. D., Stoller, M. L., Sur, R. L., & Chi, T. (2016). Rationale and design of the registry for stones of the kidney and ureter (ReSKU): a prospective observational registry to study the natural history of urolithiasis patients.. Journal of Endourology, 30(12), 1332-1338.
• Chang, H., Tzou, D. T., Usawachintachit, M., Duty, B., Hsi, R. S., Harper, J. D., Sorensen, M. D., Stoller, M. L., Sur, R. L., & Chi, T. (2016). Rationale and Design of the Registry for Stones of the Kidney and Ureter (ReSKU): A Prospective Observational Registry to Study the Natural History of Urolithiasis Patients. Journal of Endourology, 30(12), 1332-1338. doi:10.1089/end.2016.0648
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  Objectives: Registry-based clinical research in nephrolithiasis is critical to advancing quality in urinary stone disease management and ultimately reducing stone recurrence. A need exists to develop Health Insurance Portability and Accountability Act (HIPAA)-compliant registries that comprise integrated electronic health record (EHR) data using prospectively defined variables. An EHR-based standardized patient database—the Registry for Stones of the Kidney and Ureter (ReSKU™)—was developed, and herein we describe our implementation outcomes. Materials and Methods: Interviews with academic and community endourologists in the United States, Canada, China, and Japan identified demographic, intraoperative, and perioperative variables to populate our registry. Variables were incorporated into a HIPAA-compliant Research Electronic Data Capture database linked to text prompts and registration data within the Epic EHR platform. Specific data collection instruments supporting New patient, Surgery, Postoperative, and Follow-up clinical encounters were created within Epic to facilitate automated data extraction into ReSKU. Results: The number of variables within each instrument includes the following: New patient—60, Surgery—80, Postoperative—64, and Follow-up—64. With manual data entry, the mean times to complete each of the clinic-based instruments were (minutes) as follows: New patient—12.06 ± 2.30, Postoperative—7.18 ± 1.02, and Follow-up—8.10 ± 0.58. These times were significantly reduced with the use of ReSKU structured clinic note templates to the following: New patient—4.09 ± 1.73, Postoperative—1.41 ± 0.41, and Follow-up—0.79 ± 0.38. With automated data extraction from Epic, manual entry is obviated. Conclusions: ReSKU is a longitudinal prospective nephrolithiasis registry that integrates EHR data, lowering the barriers to performing high quality clinical research and quality outcome assessments in urinary stone disease.
• Tzou, D. T., Taguchi, K., Chi, T., & Stoller, M. L. (2016). Animal models of urinary stone disease. International Journal of Surgery, 36(Pt D), 596-606.
• Usawachintachit, M., Tzou, D. T., Mongan, J., Weinstein, S., & Chi, T. (2016). Antegrade ultrasound contrast injection facilitates accurate nephrostomy tube positioning during percutaneous nephrolithotomy. International Journal of Urology, 24(3), 239-240. doi:10.1111/iju.13258
• Michalak, J., Tzou, D., & Funk, J. (2015). HoLEP: the gold standard for the surgical management of BPH in the 21(st) Century. American Journal of Clinical and Experimental Urology, 3(1), 36-42.
• Tzou, D. T., Bohnenkamp, S., & Nguyen, M. (2013). 425 HOW THE QUALITY OF UROLOGIC RESIDENT CARE AFFECTS PATIENTS' OVERALL HOSPITAL STAY SATISFACTION. The Journal of Urology.
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  You have accessJournal of UrologyGeneral & Epidemiological Trends & Socioeconomics: Practice Patterns, Cost effectiveness (III)1 Apr 2013425 HOW THE QUALITY OF UROLOGIC RESIDENT CARE AFFECTS PATIENTS' OVERALL HOSPITAL STAY SATISFACTION David Tzou, Susan Bohnenkamp, and Mike Nguyen David TzouDavid Tzou Tucson, AZ More articles by this author , Susan BohnenkampSusan Bohnenkamp Tucson, AZ More articles by this author , and Mike NguyenMike Nguyen Tucson, AZ More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.1815AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES As one of the ACGME's 6-core competencies, interpersonal and communication skills are an important component of the quality of care provided by resident physicians. We examine factors that influence patient satisfaction with the quality care they receive from residents and determine the association between satisfaction with urologic resident care and overall hospital stay satisfaction. METHODS 605 surveys were collected over 20 months from hospitalized urology patients. Surveys included information on patient demographics, patient satisfaction with care provided by residents, overall hospital stay satisfaction, and patient comments on what was done well or not done well in regards to resident care. Fisher's exact tests were performed to evaluate the association between patient characteristics and resident care or visit satisfaction. Linear regression was performed to determine the association between satisfaction with the quality of resident care and overall hospital stay satisfaction. Analyses were performed using Stata 10.1. RESULTS There was a significant association between patients' satisfaction with resident care and their overall visit satisfaction (p
• Tzou, D. T., Dalkin, B. L., Christopher, B. A., & Cui, H. (2009). The failure of a nerve sparing template to improve urinary continence after radical prostatectomy: attention to study design. Urologic Oncology, 27(4), 358-362.
• Tzou, D., Tan, Y., Hwang, J., Florero, M., Ewing, C., Esserman, L., Hwang, S., Morita, E., & Leong, S. (2006). The Number of Lymphatic Channels Does Not Affect Metastasis to the Sentinel Lymph Node in Breast Cancer. Journal of Investigative Medicine, 54(2_suppl), 385-385. doi:10.1177/108155890605402s150

Proceedings Publications

• Taguchi, K., Chen, L., Usawachintachit, M., Hamamoto, S., Kang, M., Unno, R., Tzou, D. T., Sherer, B. A., Yasui, T., Ho, S. P., Stoller, M. L., & Chi, T. (2019). Discovery of fatty acid binding protein 4 as an essential molecule for the development of kidney stones: A new understanding of the relationship between obesity and nephrolithiasis. In EAU (European Association of Urology).
• Tzou, D. T., Tzou, D. T., Chang, H., Chang, H., Usawachintachit, M., Usawachintachit, M., Hsi, R. S., Hsi, R. S., Stoller, M. L., Stoller, M. L., Chi, T., & Chi, T. (2016). PD47-07 DEVELOPMENT AND IMPLEMENTATION OF AN ELECTRONIC MEDICAL RECORD-BASED PROSPECTIVE URINARY STONE REGISTRY: RESKU, THE REGISTRY FOR STONES OF THE KIDNEY & URETER. In The Journal of Urology, 195.
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  You have accessJournal of UrologyStone Disease: Epidemiology & Evaluation II1 Apr 2016PD47-07 DEVELOPMENT AND IMPLEMENTATION OF AN ELECTRONIC MEDICAL RECORD-BASED PROSPECTIVE URINARY STONE REGISTRY: RESKU, THE REGISTRY FOR STONES OF THE KIDNEY & URETER David T. Tzou, Helena Chang, Manint Usawachintachit, Ryan S. Hsi, Marshall L. Stoller, and Tom Chi David T. TzouDavid T. Tzou More articles by this author , Helena ChangHelena Chang More articles by this author , Manint UsawachintachitManint Usawachintachit More articles by this author , Ryan S. HsiRyan S. Hsi More articles by this author , Marshall L. StollerMarshall L. Stoller More articles by this author , and Tom ChiTom Chi More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.2695AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Registry-based clinical research in nephrolithiasis is critical to advancing quality in urinary stone disease management because as a non-malignant chronic condition, there is heterogeneity in its presentation, treatment, and outcomes. Electronic medical records (EMR) are now widespread, however their primary design is not as a research platform. There is a need to develop HIPAA-compliant registries comprised of integrated EMR data using prospectively defined variables. The ideal registry would be accurate, detailed, easy to populate, and rapidly scalable to multiple centers with low maintenance costs. We developed an EMR-based standardized patient database - Registry for Stones of the Kidney & Ureter (ReSKU) - and herein describe our implementation outcomes. METHODS Interviews with academic and community endourologists in the United States, Canada, China, and Japan identified essential demographic, intraoperative, and peri-operative variables to populate our registry. Variables were incorporated into a HIPAA compliant REDCap database that was linked to text prompts and registration data within the Epic EMR platform. For each variable, data input click-boxes eliminated free-text entry and standardized data queries. Branched logic provided more efficient and accurate collection. Specific data collection instruments supporting New patient, Surgery, Post-op, and Follow-up clinical encounters were created within Epic to facilitate automated data extraction into ReSKU. RESULTS The ReSKU registry was approved by local IRBs and data collection is ongoing at 3 medical centers. The number of potential variables for each instrument includes: New patient - 51, Surgery - 70, Post-op - 57, Follow-up - 72. With manual data entry, the mean times to complete each of the clinic based instrument were (minutes): New patient - 12.06 ± 2.30, Post-op - 7.18 ± 1.02, Follow-up - 8.10 ± 0.58. With automated data extraction from Epic, manual entry is obviated. Providers in each clinic reported minimal impact in patient care workflow during initial implementation. CONCLUSIONS ReSKU is an integrative, prospective nephrolithiasis registry that captures EMR data for clinical research. This platform can be implemented with minimal clinical care disruption and is scalable to multiple EMR platforms. Clinical research generated from ReSKU will facilitate high quality longitudinal studies, allow large-scale examination of quality outcomes, and facilitate robust multi-institutional collaboration. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e1172-e1173 Advertisement Copyright & Permissions© 2016MetricsAuthor Information David T. Tzou More articles by this author Helena Chang More articles by this author Manint Usawachintachit More articles by this author Ryan S. Hsi More articles by this author Marshall L. Stoller More articles by this author Tom Chi More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...
• Tzou, D. T., Tan, Y., Hwang, J. S., Florero, M., Ewing, C., Esserman, L., Hwang, S. H., Morita, E., & Leong, S. P. (2006, Jan). 502 THE NUMBER OF LYMPHATIC CHANNELS DOES NOT AFFECT METASTASIS TO THE SENTINEL LYMPH NODE IN BREAST CANCER.. In Western Medical Research Conference - American Federation of Medical Research (AFMR).
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  Introduction The lymphatic channels are the routes by which cancer metastasizes. This study investigates whether a correlation exists between the number of channels and the likelihood of metastasis from the primary breast cancer site to the sentinel lymph node (SLN). Further, it examines the relationship of primary tumor characteristics with respect to these channels and SLN metastasis. Materials and Methods This study was a retrospective review of a large database of 695 patients with primary invasive breast carcinoma undergoing selective sentinel lymphadenectomy at a single institution from November 1997 to June 2005. Only patients with successful preoperative lymphoscintigraphy (with either channels or nodes identified) and pathology-determined SLN status were included. There were 532 patients who fit our study criteria. Results One hundred thirty-seven patients (24.8%) had one or more positive SLNs. A comparison of the percentages of positive SLN versus negative SLN for the different channel groups showed 0 channels, 25/137 (18.2%) with positive SLN vs 62/395 (15.7%) with negative SLN, p = .4865; 1 channel, 78/137 (56.9%) with positive SLN vs 244/395 (61.8%) with negative SLN, p = .3182; 2 or more channels, 34/137 (24.8%) with positive SLN vs 89/395 (22.5%) with negative SLN, p = .5845. No significant statistical relationship was found between number of lymphatic channels and frequency of SLN metastasis. The quadrant, type, and size of the tumor were also found to have no significant statistical relationship with the number of lymphatic channels. Metastasis was significantly associated with tumor size greater than 15 mm, poor tubular formation, and lymphovascular invasion. Conclusion An increased number of lymphatic channels identified by preoperative lymphoscintigraphy does not appear to predict a higher likelihood of metastasis within the sentinel lymph node for all types of breast cancer. Metastasis to the sentinel lymph nodes is governed by the primary characteristics of the tumor rather than the number of lymphatic channels.

Presentations

• Chien, A. L., On, T. A., Paster, I. C., Culpepper, L. E., & Tzou, D. T. (2024, Oct). Feasibility and Safety of X-ray Free Ultrasound-Guided PCNL for Staghorn Stones - a Prospective Single Institution Experience. 100th Annual Western Section American Urological Association - Podium Presentation. Kauai, Hawaii: WSAUA.
• Tzou, D. T. (2024, Aug). Program Chairman - Arizona Urological Society (AZUS) Annual Meeting. AZUS. Tucson, AZ.
• Tzou, D. T. (2024, Jan). Culture Negative Kidney Stones Harbor Diverse Bacteria & Bacterial Endotoxins. Research on Calculus & Kinetics (ROCK) Annual Meeting. Minneapolis, MN.
• Tzou, D. T. (2024, October). Culture-Negative Kidney Stones Harbor Diverse Bacteria and Bacterial Endotoxins. UTI HourUrinary Tract Infection Global Alliance (UTIGA).
• Tzou, D. T. (2024, Sept). Ureteral Stenosis: How can we prevent?. 4th Annual TALENTS - Trans-Atlantic Leaders in Endourological Technologies.
• Tzou, D. T., & De, S. (2024, August). Ask the Expert - HoLEP: Discussant - Plenary Presentation. 40th World Congress of Endourology and Uro-Technology / Moderated Poster Session. Seoul, Korea: World Congress of Endourology and Uro-Technology.
• Tzou, D. T. (2023, Aug). Program Chairman - Arizona Urological Society (AZUS) Annual Meeting. AZUS. Tucson, AZ.
• Tzou, D. T. (2023, August). Course Director: University of Arizona & Mayo Arizona Urology Resident & Simulation Symposium. University of Arizona & Mayo Arizona Urology Resident & Simulation Symposium. Arizona Simulation Technology & Education Center (ASTEC) - Tucson, AZ.
• Tzou, D. T. (2023, October). 24-Hour Urine Abnormalities Amongst Patients with Infection Renal Calculi. 99th Annual Western Section American Urological Association (WSAUA) Meeting. Lake Tahoe, CA.
• Royal, C. R., Anwar, F., Robishaw-Denton, J. K., Vedantam, G., Lainhart, W. D., & Tzou, D. (2022, Nov). Determining Optimal Kidney Stone Culture Microbiology Protocols. 98th Annual Meeting of the Western Section American Urological Association / Calculi Podium Session. Kauai, HI: Western Section American Urological Association.
• Tzou, D. (2022, Dec). What is Dust?. 3rd Annual Trans-Atlantic Leaders in Endourological Technologies (The TALENTS) Meeting. Rome, Italy.
• Tzou, D. (2022, July). Course Director: University of Arizona & Mayo Arizona Urology Resident & Simulation Symposium. University of Arizona & Mayo Arizona Urology Resident & Simulation Symposium. Arizona Simulation Technology & Education Center (ASTEC) - Tucson, AZ.
• Tzou, D. (2022, May). Course Faculty: Instructional Course 027IC - Adaptive PCNL: Utilizing a Contemporary Toolbox. 117th Annual Meeting of the American Urological Association. New Orleans, LA: American Urological Association.
• Tzou, D. (2022, May). Course Faculty: Instructional Course 102HO - Interventional Ultrasonography: A New Urology Paradigm for Using Renal Ultrasound to Guide Renal Access and Biopsies. 117th Annual Meeting of the American Urological Association. New Orleans, LA: American Urological Association.
• Tzou, D. (2022, Nov). State of the Art Lecture: Ultrasound and Endourology - Reducing Radiation and Increasing Patient Safety. 98th Annual Western Section American Urological Association (WSAUA) Meeting. Kauai, HI: Western Section American Urological Association.
• Tzou, D. (2022, Oct). Course Faculty: Hands-On Ultrasound PCNL Access. 39th World Congress of Endourology and Uro-Technology. San Diego, CA: World Congress of Endourology and Uro-Technology.
• Tzou, D., Anwar, F., Badowski, M., Jernigan, B., Harris, D. T., Chi, T., & Vedantam, G. (2022, May). Kidney Stone Endotoxin Concentration Correlates with Post-Operative Sepsis Following Percutaneous Nephrolithotomy. 117th Annual Meeting of the American Urological Association/Podium Session. New Orleans, LA: American Urological Association.
• Muse, A., Sloss, M., Shah, S., Jauregui, C., Wong, A., & Tzou, D. (2021, November). Feasibility of Performing X-ray Free Percutaneous Nephrolithotomy for Staghorn Stones. 97th Annual Western Section American Urologic Association / Calculi Podium Session. Indian Wells, CA: Western Section AUA.
• Tzou, D., & Vedantam, G. (2021, November). Kidney Stone Endotoxin Concentration Correlates with Post-Operative Sepsis Following Percutaneous Nephrolithotomy. 97th Annual Western Section American Urological Association Meeting / Calculi Podium Session. Indian Wells, CA: Western Section AUA.
• Tzou, D., Hinkel, C., Ahn, J., Tsai, C., & Chi, T. (2020, Fall). Tips And Tricks For Ultrasound-guided Access In Obese Patients During Percutaneous Nephrolithotomy (pcnl) In The Supine Position. Western Section American Urological Assocation.
• Cobb, K., Tzou, D., Sorensen, M., Duty, B., Dibianco, J., Friedlander, D., Bechis, S., & Sur, R. (2019, Nov./Fall). Indications for Stent Omission After Ureteroscopic Lithotripsy – A Multi Center Prospective Study.. 95th Annual Western Section American Urological Association Annual Conference. Monterey, CA: Western Section American Urological Association.
• 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.
• Tzou, D., Badowski, M., Jernigan, B., Chaus, F., Lee, B. R., Harris, D. T., & Ghishan, F. K. (2019, Nov./Fall). Feasibility of Detecting Both Superficial and Intra-renal Stone Endotoxin Concentrations.. 95th Annual Western Section American Urological Association Annual Conference. Monterey, CA: Western Section American Urological Association.
• Tzou, D., Metzler, I. S., Tsai, C., Goodman, J., & Chi, T. (2019, May, Spring). Ultrasound-guided morcellation during difficult holmium laser enucleation of the prostate (HoLEP). 114th Annual Meeting of the American Urological Association. Chicago, IL: American Urological Association.
• Tzou, D. (2018, November/Fall). Ultrasound-guided percutaneous nephrolithotomy (PCNL) in both the prone and supine positions: a step-by-step approach.. 94th Annual Meeting of the Western Section American Urological Association - Moderated Video Session. Maui, HI: Western Section American Urological Association (WSAUA).
• Tzou, D. (2018, October/Fall). Ultrasound-guided morcellation during difficult holmium laser enucleation of the prostate (HoLEP). 94th Annual Meeting of the Western Section American Urological Association - Moderated Video Session. Maui, HI: Western Section American Urological Association (WSAUA).
• Tzou, D. T., Zetumer, S., Usawachintachit, M., Reliford-Titus, S., Taguchi, K., Sherer, B., Stoller, M., & Chi, T. (2018, May). Radiation Exposure from CT scans for Urolithiasis: Results from the Registry for Stones of the Kidney and Ureter (ReSKU). 113th Annual Meeting of the American Urological Association - Podium Presentation. San Francisco, CA: American Urological Association.
• Tzou, D., Armas-Phan, m., Reliford-Titus, S., Zetumer, s., Taguchi, K., Usawachintachit, M., Stoller, M., & Chi, T. (2018, May). Renal Tract Dilation is a significant source of radiation exposure during PCNL: Results from the Registry for Stones of the Kidney and Ureter (ReSKU). 113th Annual Meeting of the American Urological Association. San Francisco, CA: American Urological Association.

Poster Presentations

• Chien, A. L., On, T. A., Paster, I. C., Culpepper, L. E., & Tzou, D. T. (2024, August). Feasibility and Safety of X-ray Free Ultrasound-Guided PCNL for Staghorn Stones - a Prospective Single Institution Experience. 40th World Congress of Endourology and Uro-Technology / Moderated Poster Session. Seoul, Korea: World Congress of Endourology and Uro-Technology.
• Paster, I. C., Chien, A. L., On, T. A., Culpepper, L. E., Deal, C. J., Hsu, C., Funk, J. T., & Tzou, D. T. (2024, August). Bladder Calculi Are Not Associated with Prostate Volume or Severity of Bladder Trabeculations - Results from a Prospective HoLEP Registry. 40th World Congress of Endourology and Uro-Technology / Moderated Poster Session. Seoul, Korea: World Congress of Endourology and Uro-Technology.
• Tzou, D., Stern, K. L., Duty, B. D., Hsi, R. S., Canvasser, N. E., De, S., Wong, A. C., Royal, C. R., Sloss, M. L., Ziemba, J. B., Harper, J. D., Bechis, S. K., Zampini, A., Borofsky, M. S., Bell, J. R., Friedlander, J., Leavitt, D. A., Nevo, A., Patel, N., , Patel, R. M., et al. (2022, Nov). Stone Culture Practice Patterns Amongst Fellowship Trained Endourologists - A Multi-Institutional Study. 98th Annual Meeting of Western Section American Urological Association / Moderated Poster Session. Kauai, HI: Western Section American Urological Association.
• Tzou, D., Stern, K. L., Duty, B. D., Hsi, R. S., Canvasser, N. E., De, S., Wong, A. C., Royal, C. R., Sloss, M. L., Ziemba, J. B., Harper, J. D., Bechis, S. K., Zampini, A., Borofsky, M. S., Bell, J. R., Friedlander, J., Leavitt, D. A., Nevo, A., Patel, N., , Patel, R. M., et al. (2022, Oct). Stone Culture Practice Patterns Amongst Fellowship Trained Endourologists - A Multi-Institutional Study. 39th World Congress of Endourology and Uro-Technology / Moderated Poster Session. San Diego, CA: World Congress of Endourology and Uro-Technology.
• Muse, A., Sloss, M., Shah, S., Sandberg, D., Wong, A., Lwin, A., Hinkel, C., Arif, H., & Tzou, D. (2020, Fall). Understanding the Barriers to Implementing and Achieving Low-Dose Computerized Tomography for Patients with Nephrolithiasis. Western Section American Urological Association.
• Tzou, D. (2018, October/Fall). Renal Tract Dilation is a significant source of radiation exposure during PCNL: Results from the Registry for Stones of the Kidney and Ureter (ReSKU). 94th Annual Meeting of the Western Section American Urological Association - Moderated Poster Presentation. Maui, HI: Western Section American Urological Association (WSAUA).
• Tzou, D., Armas-Phan, M., Wiener, S., Bayne, D., Reliford-Titus, S., Stoller, M., & Chi, T. (2018, September). Relationship between Calcium Oxalate Stone Analysis and 24-Hour Urine: Results from the Registry for Stones of the Kidney and Ureter (ReSKU). 36th World Congress of Endourology Meeting - Moderated Poster Presentation. Paris, France: World Congress of Endourology.
• Sherer, B., Frenandez, A., Tzou, D. T., Ho, S., & Stoller, M. (2017, September). Biomineralization in Kidney Stone Formers. 35th World Congress of Endourology Meeting - Moderated Poster Presentation. Vancouver, BC: World Congress of Endourology.
• Sherer, B., Isaacson, D., Kornberg, Z., Usawachintachit, M., Tzou, D., Taguchi, K., Chi, T., & Stoller, M. (2017, September). Pharmaceutical Burden and Medication Compliance in Patients with Cystinuria. 35th World Congress of Endourology Meeting - Moderated Poster Presentation. Vancouver, BC: World Congress of Endourology.
• Tzou, D. T., Isaacson, D., Usawachintachit, M., Wang, Z., Taguchi, T., Sherer, B., Stoller, M., & Chi, T. (2017, May). The Importance of Urologist Estimation of Stone Burden: Results from the Registry for Stones of the Kidney and Ureter (ReSKU). 112th Annual Meeting of the American Urological Association - Moderated Poster Presentation. San Francisco, CA: American Urological Association.
• Tzou, D., Usawachintachit, M., Isaacson, D., Taguchi, K., Sherer, B., Stoller, M., & Chi, T. (2017, September). Radiation Exposure from CT scans for Urolithiasis: Results from the Registry for Stones of the Kidney and Ureter (ReSKU). 35th World Congress of Endourology Meeting - Moderated Poster Presentation. Vancouver, BC: World Congress of Endourology.