Radiating for Two: Quantifying Radiation Exposure to Pregnant Urologists During Percutaneous Nephrolithotomy.

PURPOSE: Current occupational recommendations limit fetal radiation dose to 1 mSv. With increased gender diversity in urology, understanding radiation exposure during pregnancy is crucial. The purpose of this study was to determine surgeon uterine radiation dose during percutaneous nephrolithotomy (PCNL) and compare effectiveness of several radiation reduction strategies in a cadaver model. MATERIALS AND METHODS: Two cadavers were used to simulate the surgeon and patient in a PCNL model. An ion chamber was placed behind the surgeon's anterior uterine wall to measure radiation dose. Three radiation reduction methods were compared: pulsed fluoroscopy (1, 4, 8, 15, 30 pps), low-dose (LD) fluoroscopy, and surgeon shielding (none, 0.35, 0.50, 0.70 mm lead equivalents). The average radiation dose/second was recorded for 20 trials per combination. Assuming 5 minutes of fluoroscopy per PCNL, the number of cases required to exceed the fetal occupational limit was determined. RESULTS: Decreasing pulse frequency from 30 to 1 pps reduced dose by 96% (p<0.001). The LD setting decreased dose by 56% (p<0.001). A 0.35 mm lead apron resulted in a 94% dose reduction (p<0.001), and the 0.50 and 0.70 mm lead aprons further reduced dose by 12% and 47%, respectively. At conventional fluoroscopy settings of automatic exposure control and 30 pps, a surgeon could perform 12 PCNLs using no lead or 189 PCNLs using a 0.35 mm lead apron before reaching the 1 mSv limit. In addition to shielding, employing 1 pps with LD further decreased radiation exposure, allowing over 6000 cases to be performed with <1 mSv uterine radiation exposure. CONCLUSIONS: Within the limitations of this cadaver study, these data support that high volume pregnant surgeons employing active radiation reduction techniques such as pulsed, LD fluoroscopy and appropriate shielding can maintain surgical volume with relatively low risk. Fetal dosimeter use with monthly monitoring is still encouraged to confirm safety throughout pregnancy.

Liposomal versus plain bupivacaine for pain control following vaginal reconstruction.

INTRODUCTION: Liposomal bupivacaine (LB) is a depot formulation of bupivacaine, which releases the drug over 72 hours to prolong local pain control. This retrospective study compares the effect of using LB versus plain bupivacaine on postoperative pain control, length of hospital stay and cost among patients undergoing vaginal reconstructive surgery. MATERIALS AND METHODS: Patients who underwent vaginal reconstructive surgery with levatorplasty and received an injection of 20 cc of either plain bupivacaine or LB for pudendal nerve block were included. The primary outcomes included postoperative narcotic use and subjective pain score. The secondary outcome was postoperative length of stay. Comparisons between groups were performed using the T test, Mann Whitney U and Chi-square tests with p < 0.05 considered significant. RESULTS: Between June 2016 and December 2021, 25 patients had received LB as a pudendal nerve block and 25 had received plain bupivacaine. Demographics between groups were similar. There was no difference between postoperative morphine equivalent dose (MED) for plain bupivacaine versus LB (25.3 ± 65.8 vs. 24.9 ± 31.7 MED; p = 0.159) or length of hospital stay (15.8 ± 12.0 hours vs. 23.8 ± 20.0; p = 0.094). Furthermore, subjective pain was also similar between groups (0 vs. 1.6 ± 2.6, p = 0.68), (4.6 ± 2.3 vs. 4.9 ± 2.0 average POD 1 pain, p = 0.534) and (4.3 ± 2.1 for vs. 4.9 ± 2.1 average POD 2 pain, p = 0.373). CONCLUSION: LB is not superior to plain bupivacaine for controlling pain following vaginal reconstructive surgery, and justification for the exponentially greater cost of LB is not supported. Prospective investigations with larger sample sizes are needed to determine the optimal pain management for levatorplasty in vaginal reconstructive surgery.

Thulium versus holmium for in situ lower pole laser lithotripsy.

INTRODUCTION: During in situ lower pole laser lithotripsy, the dependent location may result in increased challenge fragmenting stones and a risk for stone regrowth if residual fragments remain. The purpose of this study was to compare the thulium fiber laser (TFL) with the holmium laser (HL) for in situ lower pole lithotripsy. MATERIALS AND METHODS: In a 3D printed kidney benchtop model, sixty 1 cm BegoStones were placed in the lower pole and fragmented in situ until fragments passed through a 2 x 2 mm mesh. Laser lithotripsy was performed using twelve energy, frequency and fiber size combinations and residual fragments were compared. In addition, laser fiber diameters and subsequent ureteroscope deflections and flow rates were compared between fibers. RESULTS: The TFL resulted in decreased residual fragments compared to the HL (11% vs. 17%, p < 0.001) and the three settings with least residual fragments were all TFL. Compared to the 150 µm TFL (265° deflection), there was a loss of 9° and 34° in the 200 µm TFL and 272 µm HL fibers, respectively. The measured fiber sizes were greater than manufacturer specified fiber size in every instance. Irrigation rates inversely correlated with fiber size. CONCLUSION: The TFL resulted in 35% less residual stone fragments, up to 34° additional deflection, and an increased irrigation rate when compared to the HL. Optimal fragmentation settings are identified to further improve lower pole lithotripsy. The combination of reduced residual fragments, improved deflection, and better flow rates make the TFL advantageous for in situ lower pole lithotripsy.

Does qSOFA score predict ICU admission and outcomes in patients with obstructed infected ureteral stones?

INTRODUCTION: Obstructing stones with infection represent a true urologic emergency requiring prompt decompression. Historically the systemic inflammatory response syndrome (SIRS) criteria has been used to predict outcomes in patients with sepsis. The quick Sequential Organ Failure Assessment (qSOFA) score has been proposed as a prognostic factor in patients with acute pyelononephritis associated with nephrolithiasis. However there has been limited application of qSOFA to patients undergoing ureteral stenting with obstructive pyelonephritis. The purpose of this study was to evaluate the predictive value of the qSOFA score for postoperative outcomes following renal decompression in this patient population. MATERIALS AND METHODS: A retrospective review was conducted at three medical centers within one academic institution to identify patients with obstructive pyelonephritis secondary to ureteral stones. All patients underwent emergent ureteral stent placement for decompression. The primary outcome was the predictive value of preoperative qSOFA score ≥ 2 for intensive care unit (ICU) admission postoperatively. Univariate analysis and multivariate regression analysis were performed to identify factors associated with postoperative outcomes, with p < 0.05 considered significant. RESULTS: Of the 289 patients who had ureteral stents placed, 147 patients met inclusion criteria. Twenty-four (16.3%) patients required ICU admission and there were 3 (2%) mortalities, all of these within the ICU admission group. The sensitivity and specificity of the qSOFA score ≥ 2 for ICU admission was 70.8% and 79.5% respectively which outperformed SIRS criteria, which had a sensitivity and specificity of 100% and 33.6% respectively. CONCLUSION: A preoperative qSOFA score ≥ 2 was a significant predictor for postoperative ICU admission in patients undergoing ureteral stent placement for obstructive pyelonephritis. The qSOFA score can be used to determine which patients will require ICU admission.

Guidewire type and prior use affects ureteral stent insertion force.

INTRODUCTION: To improve the success rate and safety of ureteral stent insertion, we sought to identify the effect of guidewire type and prior use upon the force needed to advance a 6Fr ureteral stent over various guidewires. MATERIALS AND METHODS: Two-hundred forty stent insertion trials were performed in an ex vivo porcine urinary tract model. Ten trials were randomly performed over 12 new and 12 used guidewires. For each trial, the force required to advance a 6Fr Cook double-pigtail ureteral stent was recorded. Guidewires included the Olympus Glidewire, Cook Fixed Core, and Boston Scientific Amplatz Super Stiff, Sensor, ZIPwire, and Zebra wire. RESULTS: The mean force needed for stent advancement was the lowest for the new Glidewire (0.18N) and ZIPwire (0.22N), with no significant difference to each other (p = 0.90). The following new wires required increasingly higher stent insertion forces compared to the Glidewire, the Zebra (0.60N; p < 0.01), Fixed Core (1.25N; p < 0.01), Sensor (1.43N; p < 0.01), and Amplatz Super Stiff wires (2.03N; p < 0.01). There was no statistical difference between new and used Glidewires (0.18N versus 0.29N; p = 0.14) and Zebra wires (0.59N versus 0.60N; p = 0.88). All other used wires required a significantly greater advancement force than their new counterparts (p < 0.01). CONCLUSIONS: For the same stent, the force required for stent advancement varies greatly between guidewire types. In addition, used guidewires typically required more force compared to new guidewires. In long or difficult cases, switching to a new wire may improve the ease of stent placement and reduce potential complications.

Elevated Renal Pelvic Pressures during Percutaneous Nephrolithotomy Risk Higher Postoperative Pain and Longer Hospital Stay.

PURPOSE: Renal pelvic pressure may vary during percutaneous nephrolithotomy. We sought to determine the relationship of postoperative pain to endoscope caliber, renal pelvic pressure and hospital stay. MATERIALS AND METHODS: We reviewed the records of 20 percutaneous nephrolithotomies done under ureteroscopic guidance with renal pelvic pressure monitoring. The ureteroscope working channel was connected to a pressure transducer and used to determine renal pelvic pressure at baseline, when irrigating with a 26Fr rigid nephroscope and a 16Fr flexible nephroscope, and during suction. Patient demographics, operative characteristics, Likert pain scores and length of hospital stay were compared as stratified by average renal pelvic pressure. The Mann-Whitney U and Fisher exact tests were used with p <0.05 considered significant. RESULTS: A total of 220 measurements were recorded in 20 patients undergoing single access percutaneous nephrolithotomy. Mean patient age was 55.2 years (range 20 to 77) and mean body mass index was 32.4 kg/m2 (range 18 to 53.3). Rigid nephroscopy resulted in significantly higher average renal pelvic pressure than flexible nephroscopy (30.3 vs 12.9 mm Hg, p = 0.007). Average renal pelvic pressure was 30 mm Hg or greater in 7 patients (35%) undergoing rigid nephroscopy and in none (0%) undergoing flexible nephroscopy (p <0.01). Patients exposed to an average renal pelvic pressure of 30 mm Hg or greater during rigid nephroscopy had significantly higher average pain scores (p = 0.004) and longer hospital stays (p = 0.04) than patients with renal pelvic pressure less than 30 mm Hg. Average renal pelvic pressure 30 mm Hg or greater during rigid nephroscopy was also associated with a longer skin to calyx distance (105.5 vs 79.7 mm, p = 0.03). CONCLUSIONS: Knowledge of the factors that influence renal pelvic pressure and methods to control pressure extremes may improve patient outcomes during percutaneous nephrolithotomy.

Predictors of narcotic use after percutaneous nephrolithotomy.

INTRODUCTION: Percutaneous nephrolithotomy (PCNL) is associated with significant variability in postoperative pain and subsequent narcotic use. The purpose of this study was to determine the factors associated with high narcotic use following PCNL. MATERIALS AND METHODS: A single-center retrospective review of patients undergoing initial PCNL between 2004 and 2014 was performed. Preoperative, intraoperative and postoperative factors associated with postoperative narcotic usage were analyzed. The primary outcome variable was mean narcotic usage, standardized to intravenous morphine-equivalents. Patients in the lowest 75th percentile were compared to those in the highest 25th percentile. Univariate and multivariate statistical analyses were performed, with p < 0.05 considered significant. RESULTS: When the 243 patients were compared from lowest to highest quartile, total narcotic use during the first 48 hour period was 2.3, 8.4, 15.6, and 41.7 mg of morphine-equivalents. On univariate analysis, predictors of high narcotic use included age 20-39 (p < 0.001), preoperative narcotic use (p < 0.001), presence of a postoperative complication (p = 0.044), and high stone burden (p = 0.002). Age < 20 (p < 0.001) and > 60 years (p = 0.014) were associated with low narcotic use. On multivariate analysis, age 20-39 (OR 6.87, 95% CI 2.22-21.23, p = 0.001), male gender (OR 2.47, CI 1.05-5.81, p = 0.037), and preoperative narcotic use (OR 3.27, CI 1.41-7.60, p = 0.006) were associated with higher opioid requirement. CONCLUSION: Patients who were aged 20-39, males, and those with prior narcotic exposure used the highest doses of narcotics postoperatively. Knowledge of the factors predictive of high narcotic usage may allow better preoperative management of patient expectations and more effective postoperative care to prevent the complications of high narcotic usage.

Profile of metabolic and infectious stone-formers in a contemporary PCNL cohort.

INTRODUCTION: To identify factors associated with stone composition in patients undergoing percutaneous nephrolithotomy (PCNL). MATERIAL AND METHODS: A retrospective analysis of patients who underwent PCNL at two academic institutions between 2002 and 2014. Stone composition, stone characteristics based on non-contrast computer tomography (NCCT), patient demographics, and the S.T.O.N.E nephrolithometry scores were compared. Stones were characterized as either infection or metabolic. Metabolic stones were classified as calcium phosphate-containing and all others. RESULTS: A total of 192 renal units underwent PCNL. Retrieved stones were found to be 75% (144) metabolic and 25% (48) infection by stone analysis. Of the metabolic stones, 51% (73) were phosphate-containing calculi. Overall, infection stones were found to have a significantly higher S.T.O.N.E nephrolithometry score than metabolic stones (9.2 versus 8.1, p < 0.001). Average Hounsfield units (HU) were significantly lower in infection stones (765 versus 899, p < 0.05). Sixty-three percent of patients with infection stones were female as compared to 46% of patients with metabolic stones. Patients with phosphate-containing stones in the metabolic group were significantly more likely to be female (56% versus 35%, p < 0.01), younger (mean 49 versus 60 years of age, p < 0.02), and have lower BMI's (30 versus 32, p < 0.02) compared with other metabolic stones. CONCLUSIONS: Patient demographics including age, sex and BMI differ between patients with phosphate and non-phosphate containing metabolic stones. Higher S.T.O.N.E nephrolithometry scores were found in infection stones. These findings may serve as useful tools in the identification of stone compositions that are being seen more frequently in large and complicated stones undergoing PCNL.

Direct Endoscopic Visualization Combined with Ultrasound Guided Access during Percutaneous Nephrolithotomy: A Feasibility Study and Comparison to a Conventional Cohort.

PURPOSE: Percutaneous nephrolithotomy access may be technically challenging and result in significant radiation exposure. In an attempt to reduce percutaneous nephrolithotomy radiation exposure, a novel technique combining ultrasound and direct ureteroscopic visualization was developed and reviewed. MATERIALS AND METHODS: Ureteroscopy without fluoroscopy was used to determine the optimal calyx for access, which was punctured with a Chiba needle under percutaneous ultrasound guidance. Next a wire was passed into the collecting system and ureteroscopically pulled into the ureter using a basket. Tract dilation and sheath and nephrostomy tube placement were performed under direct ureteroscopic visualization. Twenty consecutive patients undergoing this novel technique were reviewed and compared to 20 matched patients treated with conventional percutaneous nephrolithotomy. Mann-Whitney U and Pearson chi-square tests were used for comparisons with p <0.05 considered significant. RESULTS: Using this novel technique mean fluoroscopy access time was 3.5 seconds (range 0 to 27.9) and mean total fluoroscopic time was 8.8 seconds (range 0 to 47.1). Mean operative time was 232 minutes (range 87 to 533), estimated blood loss was 111 ml, the stone-free rate was 65% and the complication rate was 25%. Compared to 20 matched conventional percutaneous nephrolithotomy cases, there was no difference in operative time (p=0.76), estimated blood loss (p=0.64), stone-free rate (p=0.50) or complications (p=1.00). However, the novel technique resulted in a significant reduction in fluoroscopy access time (3.5 vs 915.5 seconds, p <0.001) and total fluoroscopy time (8.8 vs 1,028.7 seconds, p <0.001). CONCLUSIONS: This study demonstrates the feasibility of combined ultrasound and ureteroscopic assisted access for percutaneous nephrolithotomy. A greater than 99% reduction in fluoroscopy time was achieved using this technique.

Renal Vascular Clamp Placement: A Potential Cause of Incomplete Hilar Control during Partial Nephrectomy.

PURPOSE: Previous benchtop studies have shown that robotic bulldog clamps provide incomplete vascular control of a Penrose drain. We determined the efficacy of robotic and laparoscopic bulldog clamps to ensure hemostasis on the human renal artery. The effect of clamp position on vascular control was also examined. MATERIALS AND METHODS: Fresh human cadaveric renal arteries were used to determine the leak point pressure of 7 bulldog clamps from a total of 3 manufacturers. Five trials were performed per clamp at 4 locations, including the fulcrum, proximal, middle and distal positions. Comparison was done using the Kruskal-Wallis test with p <0.05 considered significant. RESULTS: None of the bulldog clamps leaked at a pressure less than 215 mm Hg when applied at the proximal, middle or distal position. In general leak point pressure decreased as the artery was positioned more distal along the clamp. The exception was when the vessel was placed at the fulcrum position. At that position 80% to 100% of trials with the Klein laparoscopic, 100% with the Klein robotic (Klein Robotic, San Antonio, Texas) and 60% to 80% with the Scanlan robotic (Scanlan International, Saint Paul, Minnesota) clamp leaked at pressure below 215 mm Hg. CONCLUSIONS: Each vascular clamp adequately occluded flow at physiological pressure when placed at the proximal, middle or distal position. Furthermore, these results demonstrate that there is leakage at physiological pressure when the artery is placed at the fulcrum of certain clamp types. These results suggest that applying a bulldog clamp at the fulcrum could potentially lead to inadequate vessel occlusion and intraoperative bleeding.

Techniques for Minimizing Radiation Exposure During Evaluation, Surgical Treatment, and Follow-up of Urinary Lithiasis.

Patients receive significant radiation exposure during the diagnosis, treatment, and follow-up of urinary stone disease. This radiation exposure may result in patient harm and is believed to contribute to the risk for malignancy. This review will present current information to allow surgeons to optimize their diagnostic, treatment, and follow-up regimens to allow optimal care of stone disease patients at the lowest radiation dose possible.

The Second Endourological Society Census Report.

Introduction and Objective: As part of the Endourological Society's (ES) initiative to continuously enhance the field of endourology, the second annual census was circulated after the World Congress of Endourology and Uro-Technology 2022 (WCET22). Methods: An anonymous survey was created using Qualtrics XM and was disseminated via email to all ES members (n = 1502) between October 4, 2022, and January 26, 2023. A total of 46 questions were included in the survey and covered different aspects, including demographics, practice patterns, satisfaction, impact of COVID-19, WCET22 attendance, and future opportunities. Results: A total of 404 (26.9%) ES members (91.8% male and 8.2% female), representing 63 different countries, participated in the survey. Fellowship-trained endourologists constituted 58.9% of respondents, and the most common practice setting was academic (55.2%). The most common practice scope was complex retrograde endoscopy (83.4%), followed by percutaneous nephrolithotomy (79.5%) and medical management of urolithiasis (72.5%). Work schedules were variable, with 51.1% working 40-60 hours/week and 35.3% working >60 hours/week. More than 80% were satisfied with t heir practice; however, 42.4% indicated that COVID-19 made satisfaction worse. Of the participants, 49.5% were satisfied with their compensation, and 7.3% plan to retire within the next 5 years. When asked about the future of endourology, 92.9% had a positive outlook. Of the respondents, only 36.8% attended WCET22, with the most chosen reason for attendance being an interest in learning new research and technology. For lack of attendance, the cost of travel and lodging was reported as a determining factor by 45.4%. Conclusion: These survey results report important trends within the field of endourology and demonstrate the robust outlook of ES members for the future. By demonstrating important practice patterns and member needs, this information can be used to improve the responsiveness of its members and to continually strengthen the ES.

Does Blacklight Illumination Improve Speed and Accuracy of Foot Pedal Activation in the Low-Light Operating Room?

Background: Urologists frequently activate foot pedals in a low-light operating room (OR). Pedal activation in low-light conditions poses the potential for incorrect pedal activation, potentially leading to increased radiation exposure, patient burns, or OR fires. This study compares speed, accuracy, dark adaptation, and surgeon preference for pedal activation in 4 lighting conditions. Materials and Methods: During a simulated percutaneous nephrolithotomy (PCNL), pedals for C-arm, laser, and ultrasonic lithotripter (USL) were randomized to 3 different positions. Urology attendings, residents, and medical students activated pedals in a randomized order in 4 settings: a dark OR with no illumination, an OR with overhead illumination, a dark OR with glowstick illumination, and a dark OR with blacklight illumination. Endpoints included pedal activation time; number of attempted, incomplete, and incorrect activations; dark adaptation; and subjective pedal preference. ANOVA was used for analysis with p < 0.05 considered significant. Results: In our study with 20 participants, the mean pedal activation times were significantly faster when using glowstick illumination (6.77 seconds) and blacklight illumination (5.34 seconds) compared with the no illumination arm (8.47 seconds, p < 0.001). Additionally, individual pedal activations for the C-arm, laser, and USL were significantly faster with glowstick and blacklight illumination compared with a dark OR (p < 0.001 for all). The blacklight illumination arm demonstrated decreased attempted (0.30 vs. 3.45, p < 0.001), incomplete (1.25 vs. 7.75, p < 0.001), and incorrect activations (0.35 vs. 1.25, p < 0.001) compared with the dark setting, while demonstrating no difference compared with having room lights on. Dark adaptation was significantly improved with blacklight illumination compared with having the room lights on (134.5 vs. 140.5 luminance, p < 0.001). All participants (100%) preferred illuminated pedals compared with the dark OR, with 90% favoring the blacklight illumination. Conclusions: During a simulated PCNL, blacklight illumination significantly improved accuracy and efficiency of pedal activation compared with the conventional dark OR, while maintaining the surgeon's dark adaptation.

Do Flat Panel Detector C-Arms Decrease Radiation Exposure Compared to Conventional Image Intensifiers?

OBJECTIVE: To compare the radiation dose and image quality between flat panel detector (FPD) and traditional image intensifier (II) C-arms at their lowest radiation settings. METHODS: In a ureteroscopy simulation using a cadaver model, the radiation exposure was compared between FPD and II at 4 pulses-per-second (pps) using both low dose and automatic exposure control (AEC) settings. Additionally, the lowest dose settings for each machine were compared (4 pps with low dose in the FPD and 1 pps with low dose in the II). Five trials of 5 minutes were conducted for each setting. Four new optically stimulated luminescent dosimeters were used in each trial to record radiation exposure. Ten blinded urologists completed a survey rating image quality for each setting. RESULTS: When comparing the FPD and II at their lowest possible settings, the FPD produced significantly more radiation (P <.05). Using both machines at 4 pps in low dose mode resulted in no significant difference between C-arms (P >.05). Conversely, operating the C-arms at 4 pps and AEC resulted in significantly higher radiation exposure from the FPD compared to the II (P <.05). There was no significant difference in image quality at each setting. CONCLUSION: FPDs produce significantly more radiation at the lowest settings compared to IIs. Surgeons should employ IIs when reducing radiation exposure as low as possible is imperative, such as when operating on pediatric and pregnant patients.

Time Efficiency and Performance of Single-Use vs Reusable Cystoscopes: A Randomized Benchtop and Simulated Clinical Assessment.

Introduction: A flexible cystoscope is an indispensable tool for urologists, facilitating a variety of procedures in both the operating room and at bedside. Single-use cystoscopes offer benefits including accessibility and decreased burden for reprocessing. The aims of this study were to compare time efficiency and performance of single-use and reusable cystoscopes. Methods: Ten new Ambu® aScope™ 4 Cysto single-use and two Olympus CYF-5 reusable cystoscopes were compared in simulated bedside cystoscopy and benchtop testing. Ten urologists performed simulated cystoscopy using both cystoscopes in a randomized order. Times for supply-gathering, setup, cystoscopy, cleanup, and cumulative time were recorded, followed by a Likert feedback survey. For benchtop assessment, physical, optical, and functional specifications were assessed and compared between cystoscopes. Results: The single-use cystoscope demonstrated shorter supply-gathering, setup, cleanup, and cumulative times (824 vs 1231 seconds; p < 0.05) but a comparable cystoscopy time to the reusable cystoscope (202 vs 212 seconds; p = 0.32). The single-use cystoscope had a higher image resolution, but a narrower field of view. Upward deflection was greater for the single-use cystoscope (214.50° vs 199.45°; p < 0.01) but required greater force (2.5 × ). The working channel diameter and irrigation rate were greater in the reusable cystoscope. While the single-use cystoscope lacked tumor enhancing optical features, it had higher Likert scale scores for Time Efficiency and Overall Satisfaction. Conclusion: The single-use cystoscope demonstrates comparable benchtop performance and superior time efficiency compared to reusable cystoscopes. However, the reusable cystoscope has superior optical versatility and flow rate. Knowledge of these differences allows for optimal cystoscope selection based on procedure indication.

Is Bigger Better? Comparison of 150 µm and 200 µm Thulium Fiber for In Situ Lower-Pole Lithotripsy.

Introduction: The thulium fiber laser (TFL) generates a focused beam, which can be transmitted to laser fibers with small core diameters and may facilitate in situ lower-pole lithotripsy. This study compares lithotripsy performance of the 150 and 200 µm TFL in a lower pole benchtop kidney model. Materials and Methods: Using a 3D model printed from an actual kidney, in situ laser lithotripsy was performed on 1 cm lower-pole BegoStones (calcium oxalate monohydrate consistency) using four different settings (all 20W) and two fiber sizes (150 and 200 µm). Procedure time, laser time, total pulse energy, and fiber stripping were compared between the two fibers using an ANOVA or independent t-test. Results: The 150 µm fiber at 0.2 J × 100 Hz had the shortest lasing and procedure time (17.3 and 18.5 minutes) and lowest total pulse energy (20.75 kJ) compared with other study arms (p < 0.001). Overall procedure time, lasing time, and total pulse energy were significantly different between the 8 settings (p < 0.001 for all). At higher frequency (100 and 200 Hz), lasing time was significantly faster compared with 20 and 50 Hz (19.9 vs 27.3 minutes; p < 0.001). Furthermore, the average total procedure time was shorter with 150 µm compared with 200 µm regardless of settings (23.2 vs 29.8 minutes; p < 0.001). Conclusion: The 150 µm fiber results in shorter procedure and lasing time at lower total energy levels during lower-pole in situ lithotripsy. Overall, the fastest setting was 0.2 J and 100 Hz with the 150 µm fiber. Smaller laser fibers can potentially allow more efficient in situ laser lithotripsy with better irrigation and visibility at higher deflection angles.

Not All Flat-Panel C-Arms Are Created Equal: A Comparison of Three Major Manufacturers.

Introduction: Flat-panel detector C-arms (FCs) are reported to reduce radiation exposure and improve image quality compared with conventional image intensifier C-arms (CCs). The purpose of this study was to compare radiation exposure and image quality between three commonly used FCs. Materials and Methods: A cadaver model was placed in the prone position to simulate percutaneous nephrolithotomy. We compared the following three FCs: OEC Elite CFD from GE HealthCare, Zenition 70 from Philips, and Ziehm Vision RFD from Ziehm Imaging. To measure the radiation dose, optically stimulated luminescence dosimeters (OSLDs) were utilized during five 300-second trials, conducted under three settings: automatic exposure control (AEC), AEC with low dose (LD), and LD with the lowest pulse rate (LDLP). Ten blinded urologists evaluated the image quality. Data were statistically analyzed using the analysis of variance (ANOVA) and Tukey's B post hoc tests. Results: In the AEC setting, the Philips C-arm demonstrated lower ventral OSLD exposure (42,446 mrad) compared with both the GE (51,076 mrad) and Ziehm (83,178 mrad; p < 0.001) C-arms. Similarly, in the LD setting, the Philips C-arm resulted in less ventral OSLD exposure (25,926 mrad) than both the Ziehm (30,956 mrad) and GE (38,209 mrad; p < 0.001) C-arms. Meanwhile, in the LDLP setting, the Ziehm C-arm showed less ventral OSLD exposure (4019 mrad) than both the GE (7418 mrad) and Philips (8229 mrad; p < 0.001) C-arms. All three manufacturers received adequate image quality ratings at the AEC and LD settings. However, at LDLP, the Ziehm C-arm received inadequate ratings in 8% of images, whereas both the GE and Philips C-arms received 100% adequate ratings (p = 0.016). Conclusions: Radiation produced by flat-panel C-arms varies dramatically, with the highest exposure (Ziehm) being almost double the lowest (Philips) in AEC. Improved picture quality at the lowest settings may come at the cost of increased radiation dose. Surgeons should carefully select the machine and settings to minimize radiation exposure while still preserving the image quality.

Prone vs supine percutaneous nephrolithotomy: does position affect renal pelvic pressures?

The purpose of this study was to measure and compare renal pelvic pressure (RPP) between prone and supine percutaneous nephrolithotomy (PCNL) in a benchtop model. Six identical silicone kidney models were placed into anatomically correct prone or supine torsos constructed from patient CT scans in the corresponding positions. A 30-Fr renal access sheath was placed in either the upper, middle, or lower pole calyx for both prone and supine positions. Two 9-mm BegoStones were placed in the respective calyx and RPPs were measured at baseline, irrigating with a rigid nephroscope, and irrigating with a flexible nephroscope. Five trials were conducted for each access in both prone and supine positions. The average baseline RPP in the prone position was significantly higher than the supine position (9.1 vs 2.7 mmHg; p < 0.001). Similarly, the average RPP in prone was significantly higher than supine when using both the rigid and flexible nephroscopes. When comparing RPPs for upper, middle, and lower pole access sites, there was no significant difference in pressures in either prone or supine positions (p > 0.05 for all). Overall, when combining all pressures at baseline and with irrigation, with all access sites and types of scopes, the mean RPP was significantly higher in the prone position compared to the supine position (14.0 vs 3.2 mmHg; p < 0.001). RPPs were significantly higher in the prone position compared to the supine position in all conditions tested. These differences in RPPs between prone and supine PCNL could in part explain the different clinical outcomes, including postoperative fever and stone-free rates.

Reducing hand radiation during renal access for percutaneous nephrolithotomy: a comparison of radiation reduction techniques.

Percutaneous nephrolithotomy confers the highest radiation to the urologist's hands compared to other urologic procedures. This study compares radiation exposure to the surgeon's hand and patient's body when utilizing three different techniques for needle insertion during renal access. Simulated percutaneous renal access was performed using a cadaveric patient and separate cadaveric forearm representing the surgeon's hand. Three different needle-holding techniques were compared: conventional glove (control), a radiation-attenuating glove, and a novel needle holder. Five 300-s fluoroscopy trials were performed per treatment arm. The primary outcome was radiation dose (mSv) to the surgeon's hand. The secondary outcome was radiation dose to the patient. One-way ANOVA and Tukey's B post-hoc tests were performed with p < 0.05 considered significant. Compared to the control (3.92 mSv), both the radiation-attenuating glove (2.48 mSv) and the needle holder (1.37 mSv) reduced hand radiation exposure (p < 0.001). The needle holder reduced hand radiation compared to the radiation-attenuating glove (p < 0.001). The radiation-attenuating glove resulted in greater radiation produced by the C-arm compared to the needle holder (83.49 vs 69.22 mGy; p = 0.019). Patient radiation exposure was significantly higher with the radiation-attenuating glove compared to the needle holder (8.43 vs 7.03 mSv; p = 0.027). Though radiation-attenuating gloves decreased hand radiation dose by 37%, this came at the price of a 3% increase in patient exposure. In contrast, the needle holder reduced exposure to both the surgeon's hand by 65% and the patient by 14%. Thus, a well-designed low-density needle holder could optimize radiation safety for both surgeon and patient.