Intermediate-Term Oncologic Outcome Assessment for Robot-Assisted Radical Prostatectomy: Comparing Retzius-Sparing with Standard Approach in a Randomized Control Cohort.

Introduction: Retzius-sparing prostatectomy was promoted with the early continence result. The long-term oncologic outcome is still unknown. In this study, we aimed to compare the intermediate-term oncologic outcomes of these two approaches in patients' cohort who were treated as part of a randomized controlled trial. Methods: A total of 120 patients were previously randomized equally to receive Retzius-sparing robot-assisted laparoscopic radical prostatectomy (RS-RARP) vs standard robot-assisted laparoscopic radical prostatectomy (S-RARP) between January 2015 and April 2016. Baseline, surgical, and pathologic characteristics as well as oncologic outcomes were assessed. The analysis was done based on the treatment received. Result: Sixty-three patients underwent S-RARP, whereas 57 patients underwent RS-RARP. There was no statistically significant difference in the baseline nor surgical characteristics. The median follow-up was 71.24 (interquartile range: 59.75-75.75) months. There were more pathologic T3 diseases in RS-RARP. There was no significant difference in the positive margin status nor in the biochemical recurrence (BCR) rate among both groups. After S-RARP and RS-RARP, 6 and 10 patients had BCR, and the 5 years BCR-free survival was 91% and 85%, respectively (p = 0.21). Conclusion: In this cohort, there was no difference in BCR in the patients who received either technique. Further multi-institutional studies with a larger sample size and longer follow-up are required.

Daily Ecological Momentary Assessments of Pain and Ability to Work After Ureteroscopy and Stenting.

Introduction: Ureteral stents can cause significant patient discomfort, yet the temporal dynamics and impact on activities remain poorly characterized. We employed an automated tool to collect daily ecological momentary assessments (EMAs) regarding pain and the ability to work following ureteroscopy with stenting. Our aims were to assess feasibility and better characterize the postoperative patient experience. Materials and Methods: As an exploratory endpoint within an ongoing clinical trial, patients undergoing ureteroscopy with stenting were asked to complete daily EMAs for 10 days postoperatively or until the stent was removed. Questionnaires were distributed through text messages and included a pain scale (0-10) and a single item from the validated Patient-Reported Outcomes Measurement Information System Ability to Participate in Social Roles and Activities instrument, as well as days missed from work or school. Results: Among the first 65 trial participants, 59 completed at least 1 EMA (overall response rate 91%). Response rates were >85% for each time point through postoperative day (POD)10. Median respondent age was 58 years (interquartile range [IQR] 50-67), and 56% were female. Stones were 54% renal and 46% ureteral, with a median diameter of 9 mm (IQR 7-10). Median stent dwell time was 7 days (IQR 6-8). Pain scores were highest on POD1 (median score 4) and declined on each subsequent day, reaching a median score of 2 on POD5. Sixty-three percent of patients on POD1 reported that they had trouble performing their usual work at least sometimes, but by POD5, this was <50% of patients. Patients who work or attend school reported a median of 1 day missed (IQR 0-2). Conclusions: An automated daily EMA system for capturing patient-reported outcomes was demonstrated to be feasible with sustained excellent engagement. Patients with stents reported the worst pain and interference with work on POD1, with steady improvements thereafter, and by POD5, the majority of patients had minimal pain or trouble performing their usual work. This work is associated with a registered clinical trial [NCT05026710].

Prostate Specific Antigen Screening on a Nationwide Level: Featuring the Contribution of Race and Life Expectancy in Decision Making.

BACKGROUND: Estimation of life expectancy (LE) is important for the relative benefit of prostate specific antigen (PSA) screening. Limited data exists regarding screening for Black men with extended LE. The aim of the current study was to assess temporal trends in screening in United States (US) Black men with limited vs. extended LE, using a nationally representative dataset. MATERIALS AND METHODS: Using the National Health Institution Survey (NHIS) 2000 to 2018, men aged ≥40 without prior history of prostate cancer (PCa) who underwent PSA screening in the last 12 months were stratified into limited LE (ie, LE <15 years) and extended LE (ie, LE≥15 years) using the validated Schonberg index. LE-stratified temporal trends in PSA screening were analyzed for all men, and then in Black men. Weighted multivariable analyses and dominance analyses identified the predictors of PSA screening. RESULTS: PSA screening declined over the study period both for all eligible men with limited and extended LE, particularly between NHIS 2008 and 2013 (27.9%-20.7% in the extended). Screening increased significantly in Black men with extended LE (17.6% in 2010-25.7% in 2018). However, LE was not an independent predictor of screening in the Black cohort. Prior recipient of colonoscopy (55%-57%) and visit to health care provider (24%-32%) were the most important determinants for screening. CONCLUSION: For US men with extended LE, only 1 in 4 receive PSA screening, with a decline over the study-period. Screening rates increased for Black men. However, these changes were not driven by LE consideration itself, but participation in other screenings and access to a provider.

Admission Rates, Healthcare Utilization, and Inpatient Cost of Radiation Cystitis in the United States.

OBJECTIVE: To assess the incidence, cumulative healthcare burden, and financial impact of inpatient admissions for radiation cystitis (RC), while exploring practice differences in RC management between teaching and nonteaching hospitals. METHODS: We focused on 19,613 patients with a diagnosis of RC within the National Inpatient Sample (NIS) from 2008 to 2014. ICD-9 diagnosis and procedure codes were used. Complex-survey procedures were used to study the descriptive characteristics of RC patients and the procedures received during admission, stratified by hospital teaching status. Inflation-adjusted cost and cumulative annual cost were calculated for the study period. Multivariable logistic regression was used to study the impact of teaching status on the high total cost of admission. RESULTS: Median age was 76 (interquartile range 67-82) years. Most of the patients were males (73%; P < .001). 59,571 (61%) patients received at least one procedure, of which, 24,816 (25.5%) received more than one procedure. Median length of stay was 5days (interquartile range 2-9). Female patients and patients with a higher comorbidity score were more frequently treated at teaching hospitals. A higher proportion of patients received a procedure at a teaching hospital (64% vs 59%; P < .001). The inflation-adjusted cost was 9207 USD and was higher in teaching hospitals. The cumulative cost of inpatient treatment of RC was 63.5 million USD per year and 952.2 million USD over the study period. CONCLUSION: The incidence of RC-associated admissions is rising in the US. This disease is a major burden to US healthcare. The awareness of the inpatient economic burden and healthcare utilization associated with RC may have funding implications.

Conditional survival does not improve over time in metastatic castration-resistant prostate cancer patients undergoing docetaxel.

PURPOSE: To investigate the conditional overall survival (OS) of metastatic castration-resistant prostate cancer (mCRPC) patients receiving docetaxel chemotherapy. METHODS: We used deidentified patient-level data from the Prostate Cancer DREAM Challenge database and the control arm of the ENTHUSE 14 trial. We identified 2158 chemonaïve mCRPC patients undergoing docetaxel chemotherapy in the five randomized clinical trials. The 6-month conditional OS was calculated at times 0, 6, 12, 18, and 24 months from randomization. Survival curves of each group were compared using the log-rank test. Patients were then stratified into low- and high-risk groups based on the median predicted value of our recently published nomogram predicting OS in mCRPC patients. RESULTS: Nearly half (45%) of the study population was aged between 65 and 74 years. Median interquartile range prostate-specific antigen for the overall cohort was 83.2 (29.6-243) ng/mL, and 59% of patients had bone metastasis with or without lymph node involvement. The 6-month conditional survival rates at 0, 6, 12, 18, and 24 months for the entire cohort were 93% (95% confidence interval [CI]: 92-94), 82% (95% CI: 81-84), 76% (95% CI: 73-78), 75% (95% CI: 71-78), and 71% (95% CI: 65-76). These rates were, respectively, 96% (95% CI: 95-97), 92% (95% CI: 90-93), 84% (95% CI: 81-87), 81% (95% CI: 77-85), and 79% (95% CI: 72-84) in the low-risk group and 89% (95% CI: 87-91), 73% (95% CI: 70-76), 65% (95% CI: 60-69), 64% (95% CI: 58-70), and 58% (95% CI: 47-67) in the high-risk group. CONCLUSION: The conditional OS for patients undergoing docetaxel chemotherapy tends to plateau over time, with the main drop in conditional OS happening during the first year from initiating docetaxel treatment. That is the longer a patient survives, the more likely they are to survive further. This prognostic information could be a useful tool for a more accurate tailoring of both follow-up and therapies. PATIENT SUMMARY: In this report, we looked at the future survival in months of patients with metastatic castration resistant prostate cancer on chemotherapy who have already survived a certain period. We found that the longer time that a patient survives, the more likely they will continue to survive. We conclude that this information will help physicians tailor follow-ups and treatments for patients for a more accurate personalized medicine.

Genital Sparing Robot-Assisted Radical Cystectomy with Intracorporeal Neobladder & Paravaginal Repair.

OBJECTIVE: Vaginal prolapse is a known complication after radical cystectomy, requiring additional procedures in 10% of the patients.1 This results from loss of level I and II vaginal support due to the removal of pelvic structures. In addition, a neobladder urinary diversion, with Valsalva voiding, predisposes to vaginal prolapse. A genital-sparing approach with paravaginal repair can help prevent such complications. METHODS: The genital sparing technique preserves the uterus, fallopian tubes, ovaries, and vagina, while paravaginal repair involves suturing of the lateral vaginal wall to the arcuate fascia located on the medial aspect of the obturator internus muscle. The procedure begins by placing the patient in a lithotomy position, with a steep Trendelenburg. Standard 6 port cystectomy configuration is utilized with an additional 15 mm port for bowel anastomosis. Initially, the ureters and lateral bladder space are mobilized. Posteriorly a dissection plane is developed separating the bladder from the anterior vaginal wall. Distal dissection is carefully performed in that plane to avoid disrupting the urethral-external sphincter complex. Then the bladder is dropped from anterior attachments, the Dorsal venous complex (DVC) and bladder neck are exposed. Urethra is transected distal to the bladder neck, after circumferential mobilization, to complete the cystectomy, again avoiding disruption of the continence mechanism, and opening the endo-pelvic fascia. Cystectomy and pelvic lymph node dissection are completed in a standard fashion. The arcuate fascia is identified bilaterally for level I paravaginal repair. The lateral aspect of the paravaginal tissue is secured to this ligament, using 3 interrupted Polydioxanone (PDS) sutures, bilaterally. An ileal "Hautman's W pouch" neobladder is constructed using 50 cm of the small intestine, similar to the previously reported technique.2 Bricker-type uretero-ileal anastomosis is performed over a double J stent. Bowel continuity is restored by a side-to-side anastomosis using endo-GIA (gastrointestinal anastamosis EndoGIATM ) staplers. RESULTS: No intra or postoperative complications were noted. Robot dock time was 8 hours and 23 minutes with an EBL of 100 mL. The patient was discharged on post operative day (POD) 6 and Foley catheter with ureteral stents was removed on POD 27 after a cystogram confirmed no leaks. At 6-month follow-up, the patient reported good continence using a single pad, voiding every 3-4 hours. Fluoro-urodynamics demonstrated 651 mL capacity, low-pressure voiding, minimal residual urine, and no reflux. No prolapse was noted on fluoroscopy and pelvic examination with the Valsalva maneuver. The patient reported a good satisfaction level, regarding her urinary symptoms. CONCLUSION: We report satisfactory short-term outcomes of a feasible technique to prevent postcystectomy prolapse; however, long-term follow-up of a larger cohort can help establish its efficacy.

Who Is Shaping the Future of Academic Urology? A Descriptive Analysis of Residency Program Directors.

OBJECTIVE: To characterize the demographics, educational background, and scholarly characteristics of current urology residency program directors (PDs). METHODS: Urology programs were identified by the listing on the "Accredited US Urology Programs" section of American Urological Association website as of October 2021. Demographics and academic data were collected via publicly available department website and Google search engine. Metrics obtained included years of service as PD from time of appointment, sex, medical school/residency/fellowship, all-time H-index, dual degrees obtained, and professorial ranking. RESULTS: One hundred and forty-seven accredited urological residencies were reviewed; every PD was included. The majority were male (78%) and fellowship trained (68%). Women represented only 22% of PDs. The median active time served as PD, as of 11/2021, was 4years (IQR: 2-7). Forty (28%) were faculty at the same program they completed their residency. The median all-time H-index was 12 (IQR: 7-19; range 1-61). Twelve PDs also served as chair of their department. CONCLUSION: The vast majority of PDs are male, fellowship trained, and have served for less than 5years. Future studies are necessary to follow the trends of representation in leaders of urology residency programs.

Impact of preexisting opioid dependence on morbidity, length of stay, and inpatient cost of urological oncological surgery.

OBJECTIVES: To determine the incidence of preexisting opioid dependence in patients undergoing elective urological oncological surgery. In addition, to quantify the impact of preexisting opioid dependence on outcomes and cost of common urologic oncological procedures at a national level in the USA. METHODS: We used the National Inpatient Sample (NIS) to study 1,609,948 admissions for elective partial/radical nephrectomy, radical prostatectomy, and cystectomy procedures. Trends of preexisting opioid dependence were studied over 2003-2014. We use multivariable-adjusted analysis to compare opioid-dependent patients to those without opioid dependence (reference group) in terms of outcomes, namely major complications, length of stay (LOS), and total cost. RESULTS: The incidence of opioid dependence steadily increased from 0.6 per 1000 patients in 2003 to 2 per 1000 in 2014. Opioid-dependent patients had a significantly higher rate of major complications (18 vs 10%; p < 0.001) and longer LOS (4 days (IQR 2-7) vs 2 days (IQR 1-4); p < 0.001), when compared to the non-opioid-dependent counterparts. Opioid dependence also increased the overall cost by 48% (adjusted median cost $18,290 [IQR 12,549-27,715] vs. $12,383 [IQR 9225-17,494] in non-opioid-dependent, p < 0.001). Multivariable analysis confirmed the independent association of preexisting opioid dependence with major complications, length of stay in 4th quartile, and total cost in 4th quartile. CONCLUSIONS: The incidence of preexisting opioid dependence before elective urological oncology is increasing and is associated with adverse outcomes after surgery. There is a need to further understand the challenges associated with opioid dependence before surgery and identify and optimize these patients to improve outcomes.

Top 100 Urology Influencers on Twitter: Is Social Media Influence Associated with Academic Impact?

BACKGROUND: Social media use in medicine has exploded, with uptake by most physicians and patients. There is a risk of dissemination of inaccurate information about urological conditions on social media. Physicians, as key opinion leaders, must play a role in sharing evidence-based information through social media. OBJECTIVE: To identify and describe the top 100 urology influencers on the Twitter social media platform and to correlate Twitter influence with academic impact in urology. DESIGN, SETTING, AND PARTICIPANTS: Twitter influence scores for the search topic "urology" were collected in April 2022 using published methodology. The top 100 personal accounts with the highest computed scores were linked to individuals' names, all-time h index, geographic location, specialty, attributed sex, and board certification status in this cross-sectional study. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We examined the correlation between influence rank and h index. RESULTS AND LIMITATIONS: Of the top 100 Twitter influencers on the topic of urology, the majority are from the USA (64%), male (85%), and practicing urologists (91%). Some 93% of US urology influencers are board-certified. Only 22 of the 50 US states are represented. The second most frequent country is the UK, with ten urology influencers. The median all-time h index is 42 (interquartile range 28.25-58). There is a weak positive correlation between influence rank and h index (r = 0.23; p = 0.02). Limitations of the study include the inability to validate the accuracy of the proprietary ranking algorithm and investigation of just one social media platform. CONCLUSIONS: The top Twitter influencers in urology are mostly board-certified US urologists. Collectively, influencers have a relatively greater academic impact in comparison to the average urologist, although there is a weak positive correlation between Twitter influence and h index among top Twitter influencers. PATIENT SUMMARY: Given the explosion of medical information on Twitter, we report the personal accounts with the greatest impact for the topic of "urology". We found that most urology influencers on Twitter are US board-certified urologists with a strong research history.

Time to second biochemical recurrence as a prognostic indicator in postprostatectomy patients who undergo salvage radiation therapy: An RTOG 9601 based post hoc analysis.

INTRODUCTION AND OBJECTIVE: The prognostic significance of a "second" biochemical recurrence (sBCR) after salvage radiation therapy (sRT) with/without hormonal therapy following primary radical prostatectomy in men with prostate cancer has not been examined. We hypothesized that a shorter time to sBCR will be associated with worse cancer control outcomes. METHODS: The RTOG 9601 study included 760 patients with tumor stage pT2/T3, pN0, who had either persistently elevated prostate-specific antigen (PSA) postradical prostatectomy or developed subsequent biochemical recurrence with PSA levels between 0.2 and 4.0 ng/ml. All patients received sRT (with or without 2 years of Bicalutamide) from 1998 to 2015. For our study, we focused on 421 patients who had sBCR after sRT-which was defined as a PSA increase of at least 0.3 ng/ml over the first nadir. Patients were divided into two categories: early sBCR (n = 210) and late sBCR (n = 211) using median time to sBCR (3.51 years). All patients who experienced sBCR received salvage hormonal therapy. Competing-risk analysis was used to examine the impact of early versus late sBCR on prostate cancer specific mortality (CSM), after accounting for available covariates. RESULTS: The majority of patients were age 60 years or older (75.8%), had pT3 disease (74.8%), and Gleason score 7 (75.2%). Overall, 13.8% had persistent PSA initially after surgery. At 10 years, starting at the time of sBCR, CSM rate was 31.3% in the early sBCR group versus 20.0% in the late sBCR group. In competing-risk analysis, time to sBCR was an independent predictor of CSM, where patients with early sBCR had 1.7-fold higher CSM risk (p = 0.026) than their counterparts with late sBCR. CONCLUSIONS: Time to sBCR after sRT (with or without concomitant Bicalutamide) is a significant predictor of CSM following initial radical prostatectomy. This information can be used to guide subsequent treatments, and to counsel patients.

A novel prognostic model predicting overall survival in patients with metastatic castration-resistant prostate cancer receiving standard chemotherapy: A multi-trial cohort analysis.

PURPOSE: Generalizable, updated, and easy-to-use prognostic models for patients with metastatic castration-resistant prostate cancer (mCRPC) are lacking. We developed a nomogram predicting the overall survival (OS) of mCRPC patients receiving standard chemotherapy using data from five randomized clinical trials (RCTs). METHODS: Patients enrolled in the control arm of five RCTs (ASCENT 2, VENICE, CELGENE/MAINSAIL, ENTHUSE 14, and ENTHUSE 33) were randomly split between training (n = 1636, 70%) and validation cohorts (n = 700, 30%). In the training cohort, Cox regression tested the prognostic significance of all available variables as a predictor of OS. Independent predictors of OS on multivariable analysis were used to construct a novel multivariable model (nomogram). The accuracy of this model was tested in the validation cohort using time-dependent area under the curve (tAUC) and calibration curves. RESULTS: Most of the patients were aged 65-74 years (44.5%) and the median (interquartile range) follow-up time was 13.9 (8.9-20.2) months. At multivariable analysis, the following were independent predictors of OS in mCRPC patients: sites of metastasis (visceral vs. bone metastasis, hazard ratio [HR]: 1.24), prostate-specific antigen (HR: 1.00), aspartate transaminase (HR: 1.01), alkaline phosphatase (HR: 1.00), body mass index (HR: 0.97), and hemoglobin (≥13 g/dl vs. <11 g/dl, HR: 0.41; all p < 0.05). A nomogram based on these variables was developed and showed favorable discrimination (tAUC at 12 and 24 months: 73% and 72%, respectively) and calibration characteristics on external validation. CONCLUSION: A new prognostic model to predict OS of patients with mCRPC undergoing first line chemotherapy was developed. This can help urologists/oncologists in counseling patients and might be useful to better stratify patients for future clinical trials.

Risk-Based Assessment Of the Impact Of Intravesical Therapy on Recurrence-Free Survival Rate Following Resection of Suspected Low-grade, Non-muscle-invasive Bladder Cancer (NMIBC): A Southwest Oncology Groups (SWOG) S0337 Posthoc Analysis.

BACKGROUND: Nonmuscle invasive bladder cancer (NMIBC) has an elevated risk of recurrence, and immediate postresection intravesical instillation of chemotherapy (IVC) significantly reduces the risk of recurrence. Questions remain about which subpopulation may maximally benefit from IVC. Our aim was to develop risk groups based on recurrence risk in NMIBC, and then evaluate the impact of a single, postoperative instillation of IVC on the subsequent risk of recurrence for each risk group. MATERIAL AND METHODS: Using the SWOG S0337 trial cohort, we performed a posthoc analysis of 345 patients who were diagnosed with suspected low-grade NMIBC, underwent transurethral resection of the bladder tumor (TURBT), and received post-operative IVC (gemcitabine vs. saline). Using regression tree analysis, the regression tree stratified patients based on their risk of recurrence into low-risk - single tumor and aged < 57 years, intermediate-risk - single tumor and aged ≥ 57 years, and high-risk - multiple tumors. We used Cox proportional hazard models to test the impact of recurrence-free rate, and after adjustment to available covariates. RESULTS: Median age of the cohort was 66.5 (IQR: 59.7-75.8 years) with 85% of patients being males. Median overall follow-up time was 3.07 years (IQR: 0.75-4.01 years). When testing the impact of treatment in each risk group separately, we found that patients in the intermediate-risk treated with gemcitabine had a 24-month recurrence free rate of 77% (95% CI: 68%-86%) vs. 59% (95% CI: 49%-70%) in the saline group. This survival difference was confirmed on multivariable analysis (hazard ratio: 0.39, 95% CI: 23%-66%, P < 0.001). This group represented 53% of our cohort. Conversely, we did not observe a significant difference in recurrence-free survival among patients in the low- (P = 0.7) and high-risk (P = 0.4) groups. CONCLUSION: Our findings indicate that older patients with a single tumor of suspected low-grade NMIBC at TURBT maximally benefit from immediate postresection IVC (gemcitabine).

Moses 2.0 for High-Power Ureteroscopic Stone Dusting: Clinical Principles for Step-by-Step Video Technique.

Introduction: We present our initial experience using the Moses 2.0 system for flexible-ureteroscopy (f-URS) high-frequency renal stone dusting, including a step-by-step video guide of our clinical principles for dusting technique. Materials and Methods: Twelve consecutive patients undergoing f-URS with Moses 2.0 (Lumenis) for a single renal stone by a single surgeon at an ambulatory center were reviewed. Stone-free rates (SFRs) and Clavien grade complications were assessed. Operative steps with illustrative examples are provided in an accompanying video. Results: Mean (range) stone size and lithotripsy time were 10.4 (5.3-17.2) mm and 15.0 (5-26) minutes, respectively. Complete SFR and <2 mm residual fragments were 82% and 18%, respectively. One patient had a Clavien Grade 1 complication. Operative steps reviewed include instrumentation, stone control, laser settings, and stent omission criteria. The preferred laser settings for renal stone dusting were 0.2-0.3 J and 100-120 Hz. Limitation of this early experience study is the small sample size. Larger studies are needed to confirm our initial findings. Conclusions: Early experience of Moses 2.0 for f-URS renal stone dusting demonstrated effective and efficient laser lithotripsy in patients with renal stones <2 cm.

The Efficiency of Moses Technology Holmium Laser for Treating Renal Stones During Flexible Ureteroscopy: Relationship Between Stone Volume, Time, and Energy.

Introduction: There are limited data on how stone factors relate to flexible ureteroscopy (f-URS) laser lithotripsy efficiency and outcomes when using the Moses Technology Ho:YAG system. We examined the relationship of stone volume and density to lithotripsy, lasing times, and energy used to treat a single renal stone. We also assessed short-term clinical outcomes. Methods: We analyzed patients undergoing f-URS by a single surgeon using high-power Moses Technology Ho:YAG system (Lumenis). We only included cases with a CT confirming a solitary renal stone. Ureteral stones, staged and bilateral procedures were excluded. Stone dimensions and HU were obtained. Volume (mm3) was calculated using European Association of Urology criteria. Laser energy (J), lithotripsy, and lasing times were obtained. Laser activity was calculated by dividing lasing time by lithotripsy time. Relationships between time, stone density, volume, and energy were assessed using Spearman correlation. Complications were assessed using Clavien-Dindo grade. Residual fragments (RF) were determined on imaging within 3 months. Results: Twenty-nine patients met the inclusion criteria. Mean (range) stone volume and density were 290 mm3 (42-1700) and 814 HU (170-1675), respectively. Mean lithotripsy and lasing times were 11.9 (3.6-26.0) and 6.0 (0.6-19.6) minutes, respectively. Mean laser activity was 47%. Mean fragmentation speed was 0.9 mm3/s. Mean energy used per unit stone volume was 38.2 J/mm3. Time taken to perform fragmentation had a stronger association with the stone volume vs stone density. Three (10.3%) and 2 (6.9%) patients had a Clavien Grade 1 and 2 complications, respectively. At follow-up the zero-fragment rate was 79.3%. Conclusions: When using the Moses Technology laser to ablate a single renal stone with f-URS, the fragmentation speed was ∼1 mm3/s. Stone volume, not density was correlated to lasing time. We propose mm3/s be considered a measure that has implications for technique efficiency and comparing laser platforms.

Development and Testing of an Anatomic in vitro Kidney Model for Measuring Intrapelvic Pressure During Ureteroscopy.

OBJECTIVES: To create an in vitro anatomic bench model that can mimic in vivo intrapelvic pressure (IPP) during ureteroscopy (URS) and compare it against existing in vivo and ex vivo data. METHODS: A silicone kidney model (Simagine Health) that permits intrarenal endoscopic navigation was engineered to have a fluid-tight seal for the ureteral opening and a Tuohy-Borst valve in the renal pelvis incorporating a 0.2 mm pressure sensor (Opsens). To calibrate the model, a Cobra ureteroscope (Wolf) was inserted to the pelvis with 200cmH2O irrigation, and the valve adjusted until an IPP of 54cmH2O was obtained (prior human data). All experiments were conducted with a laser fiber in the working channel, with and without ureteral access sheaths (UAS) (11/13F, 13/15F) at irrigation setting of 61, 102, 153, and 193cmH2O using an automated system (Rocamed). Study outcome was mean steady-state IPP for each UAS/irrigation condition. RESULTS: Fluid leakage through the Tuohy-Borst valve, which could be adjusted, was critical to simulate ureteric outflow during URS. IPP values for each condition corresponded with data from in vivo and ex vivo models. In the no UAS condition, IPP increased with increasing irrigation pressures, and surpassed 40cmH2O when ≥153cmH2O. When using a UAS, IPP was below 40cmH2O for all irrigation pressures. CONCLUSIONS: An in vitro kidney model can simulate in vivo and ex vivo IPP profiles, and be tailored to different conditions by controlling fluid outflow. This bench model can be useful for testing of new technologies and their impact on IPP.

Patterns of Laser Activation During Ureteroscopic Lithotripsy: Effects on Caliceal Fluid Temperature and Thermal Dose.

Introduction: Characterizing patterns of laser activation is important for assessing thermal dose during laser lithotripsy. The objective of this study was twofold: first, to quantify the range of operator duty cycle (ODC) and pedal activation time during clinical laser lithotripsy procedures, and second, to determine thermal dose in an in vitro caliceal model when 1200 J of energy was applied with different patterns of 50% ODC for 60 seconds. Methods: Data from laser logs of ureteroscopy cases performed over a 3-month period were used to calculate ODC (lasing time/lithotripsy time). Temporal and rolling 1-minute average power tracings were generated for each case. In vitro experiments were conducted using a 21 mm diameter glass bulb in a 37°C water bath, simulating a renal calix. A LithoVue ureteroscope with attached thermocouple was inserted and 8 mL/min irrigation was delivered with a 242 µm laser fiber within the working channel. In total, 1200 J of laser energy was applied in five different patterns at 20 W average power for 60 seconds. Thermal dose was calculated using the Sapareto and Dewey t43 method. Results: A total of 63 clinical cases were included in the analysis. Mean ODC was 32% overall and 63% during the 1-minute of greatest energy delivery. Mean time of pedal activation was 3.6 seconds. In vitro studies revealed longer pedal activation times produced higher peak temperature and thermal dose. Thermal injury threshold was reached in 9 seconds when 40 W was applied at 50% ODC with laser activation patterns of 30 seconds on/off and 15 seconds on/off. Conclusion: ODC was quantified from clinical laser lithotripsy cases: 32% overall and 63% during 1-minute of peak power. Time of pedal activation is an important factor contributing to fluid heating and thermal dose. Awareness of these concepts is necessary to reduce risk of thermal injury during laser lithotripsy procedures.

Pulse modulation with Moses technology improves popcorn laser lithotripsy.

PURPOSE: Moses™ technology has been developed to improve holmium laser fragmentation at 1-2 mm distance from the stone. Because popcorn lithotripsy is a non-contact technique, we compared short pulse (SP) and Moses distance (MD) modes in an in vitro model. METHODS: BegoStones were fragmented using a 120 W Ho:YAG laser (P120 Moses) and a 230 µm core fiber introduced through a ureteroscope. 20 W (1 J × 20 Hz; 0.5 J × 40 Hz) and 40 W (1 J × 40 Hz; 0.5 J × 80 Hz) settings (total energy 4.8 kJ) were tested using SP and MD modes. We assessed fragment size distribution and mass lost in fluid (initial mass-final dry mass of all sievable fragments). High-speed video analysis of fragmentation strike rate and vapor bubble characteristics was conducted for 1 J × 20 Hz and 0.5 J × 80 Hz. Laser strike rate (number of strikes divided by frequency) was categorized as: (1) direct-a visual plume of dust ejected from stone while in contact with fiber tip; (2) indirect-a visual plume of dust ejected with distance between stone and fiber tip. RESULTS: For 1 J × 20 Hz (20 W), MD resulted in more mass lost in fluid and a lower distribution of fragments ≥ 2 mm compared to SP (p < 0.05). 0.5 J × 80 Hz (40 W) produced no fragments ≥ 2 mm, and there were no significant differences in fragment distribution between MD and SP (p = 0.34). When using MD at 1 J × 20 Hz, 96% of strikes were indirect vs 61% for SP (p = 0.059). In contrast to the single bubble of SP, with MD, there was forward movement of the collapsing second bubble, away from the fiber-tip. CONCLUSIONS: For lower frequency and power popcorn settings, pulse modulation results in more fragmentation through true non-contact laser lithotripsy.

In Vivo Evaluation of a Novel Pigtail Suture Stent.

OBJECTIVE: To compare pressure, dilation, and histology in a porcine model after stenting with a pigtail suture stent (PSS)-where the ureteral and bladder component consists of a suture and a double J (DJ) stent. METHODS: Twelve pigs were studied with a PSS (4.8F/MiniJFil®) and DJ stent (4.8F/RocaJJ Soft) inserted in both sides, except in one where the DJ was not placed to serve as control. Intrapelvic pressure (IPP) and ureteral pressures were recorded. Five pigs were stented for 7 days, and the next 7 for 13-15 days, where a retrograde study was performed after stent removal. Ureteral histology in 4 and 3 pigs stented for 7- and 13-15 days, respectively, were assessed in a blinded manner. RESULTS: In total, 11 renal units were stented with PSS and DJ, respectively. There was a rise in IPP and ureteral pressure after stenting. There were no significant differences in post-stenting pressures between DJ and PSS systems. Ureteral dilation occurred in 100% of DJ and 83% of PSS units. PSS suture migration occurred in 3 of 11. Gross edema at the ureteral orifice was greater with the DJ compared to the PSS (82% vs 18%; p = .003). Histology demonstrated greater inflammation at the ureteral orifice in the DJ group (2.3 vs 1; p = .016) when stented for 13-15 days. CONCLUSION: There was no difference in IPP after stenting with a PSS compared to a DJ stent. When stented for 13-15 days, the PSS resulted in ureteral dilation, but with less edema and inflammation at the ureteral orifice.

Assessing the Role of Light Absorption in Laser Lithotripsy by Isotopic Substitution of Kidney Stone Materials.

Understanding the chemical characteristics of kidney stones and how the stone composition affects their fragmentation is key to improving clinical laser lithotripsy. During laser lithotripsy, two mechanisms may be responsible for stone fragmentation: a photothermal mechanism and/or microexplosion mechanism. Herein, we carry out an isotopic substitution of crystal H2O with D2O in calcium oxalate monohydrate and struvite stones to alter their optical properties to study the relationship between the absorption of the stones, at the wavelength of the Ho:YAG (2.12 µm) laser, and the fragmentation behavior. Changing the absorption of the stones at 2.12 µm changes the extent of fragmentation, whereas changing the absorption of the bulk medium has a negligible effect on fragmentation, leading to the conclusion that kidney stone ablation is dominated by a photothermal mechanism.