Ureteroscopic Performance of High Power Super Pulse Thulium Fiber Laser for the Treatment of Urolithiasis: Results of the First Case Series in North America.

OBJECTIVE: To report the first case series of ureterorenoscopy in North America using the High Power Super Pulse Thulium Fiber Laser for the treatment of upper urinary tract stones. METHODS: After Institutional Review Board approval, a multicentric retrospective chart review of patients treated with the High Power Super Pulse Thulium Fiber Laser from October 2019 to March 2020 was conducted. Basic demographic information, pre-operative, and peri-operative data were recorded. RESULTS: Seventy-six patients were included with a mean age of 60.9 ± 13.3 years. 118 stones were treated including 32 within the ureter, 49 in the lower pole, 37 in mid or upper poles. Dusting technique was commonly used (67.1%) with pulse frequencies up to 2400 Hz. Mean operative time was 59.4 ± 31.5 minutes. Mean laser time and total laser energy were 10.8 ± 14.1 minutes and 12.5 ± 19.1 KJ, respectively. Intraoperative complications were limited to 7 grade 1, 3 grade 2, and 1 grade 3 ureteral injuries and one case of renal collecting system bleeding that was adequately managed with laser coagulation settings (1J-20Hz). CONCLUSION: This initial case series in North America of the High Power Super Pulse Thulium Fiber Laser is promising for the treatment of urolithiasis. Sub-200 µm fibers and dusting settings up to 2400 Hz were utilized successfully. No specific complications related to use of the laser were seen.

Single-Use Grasper Integrated Flexible Cystoscope for Stent Removal: A Micro-Costing Analysis-Based Comparison.

Background: A single-use flexible cystoscope with integrated grasper (Isiris; Coloplast, Denmark) has recently become commercially available. The objective of our study is to compare the costs of stent removal in an outpatient clinical environment between the single-use Isiris system (Coloplast) to our existing approach using a reusable cystoscope and stent grasper. Materials and Methods: The number of stent removal procedures at our tertiary center was recorded as a proportion of all cystoscopic procedures performed between February 2016 and February 2017. Elements in the micro-cost assessment included original purchasing price of an Olympus digital reusable cystoscope, repair fee (based on a 1-year contract), sterilization equipment and accessory costs, reprocessing costs of the cystoscope, and labor costs. The costs were estimated on a per-use basis and compared to the purchasing price of Isiris. Results: A total of 1775 cystoscopic procedures were performed, and the reusable cystoscope was used for stent removal in 871 (49%) cases. The per-use cost for stent removal procedures using the reusable cystoscope was estimated to be $161.85. The single per-use purchasing price for the Isiris device is $200. Based on the current volume, the break-even point was calculated to be 704 stent pulls. After 704 stent pulls, the cost benefit favors the reusable cystoscope. Conclusion: Based on this micro-cost analysis, per-use costs appear to favor the reusable cystoscope for stent removal. It appears that centers with high volumes of stent pulls may find the reusable cystoscope and stent grasper more cost beneficial than the single-use system.

The Impact of Ureteral Access Sheath Use on the Development of Abnormal Postoperative Upper Tract Imaging after Ureteroscopy.

PURPOSE: Ureteral access sheaths are commonly used during ureteroscopy to facilitate stone removal, improve visibility and maintain low intrarenal pressures. However, the use of a ureteral access sheath can cause ureteral wall ischemia and ureteral tears, potentially increasing the risk of postoperative ureteral stricture and obstruction. We studied the impact of ureteral access sheath use on postoperative imaging studies. Secondary objectives included studying the impact of other intraoperative parameters on postoperative imaging studies. MATERIALS AND METHODS: A retrospective chart review was conducted of cases that underwent ureteroscopy for nephroureterolithiasis across 2 high volume institutions between January 2012 and September 2016. Patient demographics, cumulative stone size, operative time, use of ureteral access sheath, laser lithotripsy, basket extraction, preoperative ureteral stent and postoperative ureteral stent placement were extracted from the electronic medical record. Findings of followup renal ultrasound, kidney-ureter-bladder x-ray and/or computerized tomography at approximately 8 weeks after surgery were recorded. RESULTS: A total of 1,332 ureteroscopies were performed with 1,060 cases (79.6%) returning for routine upper tract imaging after ureteroscopy. Postoperative hydronephrosis was noted following 127 cases (12.0%). Factors predicting presence of hydronephrosis after ureteroscopy include lower body mass index (p=0.0016), greater cumulative stone size (p=0.0003), increased operative time (p <0.0001), preoperative ureteral stent (OR 1.49, p=0.0299) and postoperative ureteral stent placement (OR 6.43, p=0.0031). Postoperative hydronephrosis was not associated with use of ureteral access sheath, age, laser lithotripsy or basket extraction. CONCLUSIONS: Use of ureteral access sheath did not have a significant impact on development of postoperative hydronephrosis, suggesting ureteral access sheath is safe for use during ureteroscopy. Ureteral strictures remain rare following ureteroscopy, seen in only 1.0% of our cohort. With an observed prevalence of hydronephrosis of 12.0% on followup imaging at 8 weeks, routine upper tract imaging after ureteroscopy remains a valuable prognostic tool.

Laser Fibers for Holmium:YAG Lithotripsy: What Is Important and What Is New.

Holmium:YAG laser is currently the dominant lithotripter used during retrograde intrarenal surgery. The laser energy is delivered to the target via flexible optical laser fibers. The performance characteristics of laser fibers vary. The diameter, flexibility, resistance to fracture with bending, and tip configuration are all important factors that contribute to a fiber's overall performance. Understanding these characteristics assists the end user with proper fiber selection for procedures.

Reducing Fluoroscopy Time in Percutaneous Nephrolithotomy.

Introduction: Reducing fluoroscopy time (FT) during percutaneous nephrolithotomy (PCNL) is an opportunity for stewardship of ionizing radiation in stone patients. We present our initial results of a radiation reduction protocol (RRP) used during PCNL with fluoroscopy-guided access by the urologist. Materials and Methods: Retrospective chart review of all PCNL cases performed between January and October 2017, divided in two groups: pre-RRP (group 1) and post-RRP (group 2). Fluoroscopy was performed using low-dose and pulsed mode. Measures implemented to reduce FT include (1) one-spot images, (2) reliance on tactile feedback, and (3) using shorter segments of live fluoroscopy. The primary outcome was FT. Results: Eighty-nine PCNL procedures were performed in 89 patients, 45 in group 1 and 44 in group 2. Overall median (interquartile range) age, body mass index (BMI), and stone burden (largest axial diameter) was 56 (45-66) years, 31.3 (27-37.4) kg/m2, and 27.7 (19-41) mm, respectively, and were comparable in both the groups. The median (range) FT in group 1 and group 2 was 240 (56.0-916.0) and 65.5 (13.0-561.0) seconds (p < 0.0001), respectively. There was no correlation between FT and increasing BMI and stone burden. Overall stone-free rate was 57% (58% and 57% in group 1 and group 2, respectively, p = 0.5995), with 10 patients (11%) undergoing ancillary procedures. Overall and major (Clavien 3a+) complications occurred in 10 (11%) and 5 (6%) cases, respectively, in the overall cohort. Conclusion: FT in PCNL can be significantly reduced by adapting simple techniques and being increasingly vigilant of its usage, thereby reducing radiation exposure to the surgeon and the patient.

Medical dissolution therapy for the treatment of uric acid nephrolithiasis.

INTRODUCTION: Uric acid (UA) nephrolithiasis represents 10% of kidney stones in the US with low urine pH and high saturation of UA as the main risk factors for stone development. Dissolution therapy for UA kidney stones via urinary alkalization has been described as a treatment option. We present our experience in treating UA nephrolithiasis with medical dissolution therapy. METHODS: A retrospective review was performed of UA stone patients referred for surgery but treated with dissolution therapy between July 2007 and July 2016. Patients were identified using ICD-9 codes. Patients were treated with potassium citrate alone or in combination with allopurinol. Serial imaging and urine pH were obtained at follow-up. Demographics, aggregate stone size, time to stone clearance, urine pH (office dip), and complications were recorded. RESULTS OBTAINED: Twenty-four patients (14 men and 10 women) were identified that started medical dissolution therapy for UA nephrolithiasis after initial referral for surgical management. Three patients (13%) did not tolerate the initiation of dissolution therapy and discontinued this treatment. Of the 21 patients that were maintained on dissolution therapy, 14 patients (67%) showed complete resolution of nephrolithiasis and 7 patients (33%) showed partial reduction. Patients with partial response had a mean reduction in stone burden of 68%. There were 3 recorded complications (UTI, GI upset with therapy, and throat irritation) and 4 recorded stone recurrences among these 21 patients. CONCLUSION: Based on our study population, medical dissolution therapy is a well-tolerated, non-invasive option for UA nephrolithiasis.

Holmium-YAG laser: impact of pulse energy and frequency on local fluid temperature in an in-vitro obstructed kidney calyx model.

During laser lithotripsy, energy is transmitted to both the stone and the surrounding fluid. As the energy is delivered, the temperature will rise. Temperatures ≥60 ° C can cause protein denaturation. The objective of this study is to determine the time it takes from body temperature (37°C) to 60°C at various laser power settings. A Flexiva TracTip 200 optical fiber was submerged alongside a negative temperature coefficient-type thermistor in 4 mL of saline in a glass test tube. A Lumenis VersaPulse Powersuite 100-W holmium:yttrium aluminum garnet laser was activated at 0.2- to 1.5-J pulse energies, 6- to 50-Hz frequencies, and 2- to 22.5-W average power. Temperature readings were recorded every second from 37°C until 60°C. Time and heating rate were measured. The procedure was repeated three times for each setting. Average time from 37°C to 60°C for settings (1) 0.2 J/50 Hz, (2) 0.6 J/6 Hz, (3) 1 J/10 Hz, and (4) 1.5 J/10 Hz was 60.3, 172.7, 58, and 43.3 s, respectively. Time from 37°C to 60°C decreased as frequency increased for every given pulse energy. Average heating rate increased proportionally to power from 0.06°C/s at 2 W to 0.74°C/s at 22.5 W. During laser lithotripsy, there is a rapid increase in the temperature of its surrounding fluid and temperatures ≥60 ° C may be reached. This could have local tissue effects and some caution with higher power settings should be employed especially where irrigation is limited. Further studies incorporating irrigation and live tissue models may aid to further define the risks.

Dusting versus Basketing during Ureteroscopy-Which Technique is More Efficacious? A Prospective Multicenter Trial from the EDGE Research Consortium.

PURPOSE: There is scant evidence in the literature to support dusting vs active basket extraction during ureteroscopy for kidney stones. We prospectively evaluated and followed patients to determine which modality produced a higher stone-free rate with the fewest complications. MATERIALS AND METHODS: Members of the Endourologic Disease Group for Excellence research consortium prospectively enrolled patients with a renal stone burden ranging from 5 to 20 mm in this study. A holmium laser was used and all patients were stented postoperatively. Ureteral access sheaths were used in 100% of basketing cases while sheaths were optional when dusting. The primary study outcome was the stone-free rate at 6 weeks as determined by x-ray and ultrasound. RESULTS: A total of 84 and 75 patients were enrolled in the basketing and dusting arms, respectively. Stones in the dusting group were significantly larger (mean ± SD stone area 96.1 ± 65.3 vs 63.3 ± 46.0 mm2, p <0.001). The stone-free rate was significantly higher in the basketing group on univariate analysis (74.3% vs 58.2%, p = 0.04) but not on multivariate analysis (1.9 OR, 95% CI 0.9-4.3, p = 0.11). In patients who underwent a basketing procedure operative time was 37.7 minutes longer than in those treated with a dusting procedure (95% CI 23.8-51.7, p <0.001). There was no statistically significant difference in complication rates, hospital readmissions or additional procedures between the groups. CONCLUSIONS: The stone-free rate was higher for active basket retrieval of fragments at short-term followup on univariate analysis but not on multivariate analysis. There was no difference in postoperative complications or procedures. The 2 techniques should be in the armamentarium of the urologist.

Ureteroscopy: accessory devices.

The incidence of stone disease continues to rise. Surgical management options including shockwave laser lithotripsy, percutaneous nephrolithotomy, and ureteroscopy with stone extraction and/or lithotripsy. The technology associated with the ureteroscopic treatment of stones has advanced significantly over the past decade and this review focuses on many of the accessory devices that can be employed to aid in the procedure.

Natural History, Complications and Re-Intervention Rates of Asymptomatic Residual Stone Fragments after Ureteroscopy: a Report from the EDGE Research Consortium.

PURPOSE: Fragments 4 mm or smaller after ureteroscopy historically have been considered clinically insignificant but there is a reported 20% event rate on followup even with stones 4 mm or smaller. In this study we examine the natural history, complications and re-intervention rates of fragments after ureteroscopy. MATERIALS AND METHODS: Data from 6 centers were collected retrospectively from members of the Endourology Disease Group for Excellence in 232 patients who had residual fragments after ureteroscopy between 2006 and 2013. Patients with fragment(s) of any size on imaging within 12 months were eligible. The primary outcome measured was stone events, and secondary outcomes included stone growth, stone passage, re-intervention and complications. RESULTS: Of the 232 subjects with fragments 131 (56%) required no further intervention and remained asymptomatic, 34 (15%) experienced complications requiring no intervention and 67 (29%) required intervention, ie the primary outcome stone event rate was 44%. Fragments larger than 4 mm were more likely to grow with time (p <0.001) and were associated with more complications (p=0.039). Fragments larger than 2 mm were more likely to grow (p <0.001) but were not associated with complications or re-intervention. Re-intervention was predictable based on fragment size (p=0.017). In a multivariable logistic regression model there was no significant difference between the techniques of dusting stones or basket extraction. CONCLUSIONS: This study suggests that fragment size larger than 4 mm after ureteroscopy is associated with significantly higher rates of stone growth, complications and the need for re-intervention. Ensuring complete stone-free status is the most effective strategy to reduce stone events after ureteroscopy.

Desflurane Allows for a Faster Emergence When Compared to Sevoflurane without Affecting the Baseline Cognitive Recovery Time.

AIMS: We compared the effect of desflurane and sevoflurane on anesthesia recovery time in patients undergoing urological cystoscopic surgery. The Short Orientation-Memory-Concentration Test (SOMCT) measured and compared cognitive impairment between groups and coughing was assessed throughout the anesthetic. METHODS AND MATERIALS: This investigation included 75 ambulatory patients. Patients were randomized to receive either desflurane or sevoflurane. Inhalational anesthetics were discontinued after removal of the cystoscope and once repositioning of the patient was final. Coughing assessment and awakening time from anesthesia were assessed by a blinded observer. STATISTICAL ANALYSIS USED: Statistical analysis was performed by using t-test for parametric variables and Mann-Whitney U test for non-parametric variables. RESULTS: The primary endpoint, mean time to eye-opening, was 5.0 ± 2.5 min for desflurane and 7.9 ± 4.1 min for sevoflurane (p < 0.001). There were no significant differences in time to SOMCT recovery (p = 0.109), overall time spent in the post-anesthesia care unit (PACU) (p = 0.924) or time to discharge (p = 0.363). Median time until readiness for discharge was 9 min in the desflurane group, while the sevoflurane group had a median time of 20 min (p = 0.020). The overall incidence of coughing during the perioperative period was significantly higher in the desflurane (p = 0.030). CONCLUSION: We re-confirmed that patients receiving desflurane had a faster emergence and met the criteria to be discharged from the PACU earlier. No difference was found in time to return to baseline cognition between desflurane and sevoflurane.

Evaluation of 16 New Holmium:Yttrium-Aluminum-Garnet Laser Optical Fibers for Ureteroscopy.

OBJECTIVE: To test the performance of 16 new single-use holmium:yttrium-aluminum-garnet (YAG) laser fibers. MATERIALS AND METHODS: Small and medium core fibers were evaluated for flexibility, true diameter, connector temperature, and failure threshold. A flexible ureteroscope was deflected with the fiber in the working channel to measure flexibility. Diameter was measured by micrometer and connector temperature by infrared thermometer. Failure threshold was determined by bending the fiber to 180°, beginning with a radius of 1.25 cm. A 100 W holmium:YAG laser was operated at 1.2 J/10 Hz for 30 seconds or until fiber fracture. The radius was decreased in 0.25-cm increments until a minimum bend radius of 0.4 cm was attained or until fiber fracture. RESULTS: Of the small core-fibers, the Cook-HLF-S150 (Cook Medical) had the smallest diameter and the Flexiva TracTip 200 (Boston Scientific) the largest. The Cook-HLF-S150 and S200 were the most flexible and the SlimLine EZ200 (Lumenis) the least. The SlimLine EZ200 failed at the largest bend radius, whereas the Flexiva 200 and Flexiva TracTip 200 did not fracture. Of the medium-core fibers, the ScopeSafe 300 had the smallest diameter and the Flexiva 365 the largest. The ScopeSafe 300 was the most flexible and the SlimLine 365 the least. The ScopeSafe 365 failed at the largest radius of 1.25 cm, and the Flexiva 365 did not fail in 6 of 9 trials at the tightest radius. CONCLUSION: Performance characteristics of these new holmium:YAG optical fibers differed significantly but performance was on par or better than historical controls.

Optimizing use of the holmium:YAG laser for surgical management of urinary lithiasis.

The holmium:yttrium aluminum garnet (Ho:YAG, holmium) laser is an intracorporeal lithotrite that is widely used in the surgical management of urinary lithiasis. The Ho:YAG laser is capable of fragmenting urinary stones of all compositions while maintaining a wide margin of safety. The 2140-nm wavelength of energy is transmitted from the generator to the stone using specialized silica optical fibers. The effectiveness of the laser can be impacted by the type of laser fiber used, the pulse energy and frequency settings, and the composition of the stone. This paper provides an overview of Ho:YAG laser fibers utilized for lithotripsy during ureteroscopy. We will also review current data regarding optimal energy settings and discuss our experience with different fragmentation techniques.

Evaluation of a new 240-µm single-use holmium:YAG optical fiber for flexible ureteroscopy.

BACKGROUND AND PURPOSE: Numerous holmium:yttrium-aluminum-garnet laser fibers are available for flexible ureteroscopy. Performance and durability of fibers can vary widely among different manufacturers and their product lines with differences within a single product line have been reported. We sought to evaluate a newly developed nontapered, single-use 240-µm fiber, Flexiva™ 200 (Boston Scientific, Natick, MA), during clinical use and in a bench-testing model. MATERIALS AND METHODS: A total of 100 new fibers were tested after their use in 100 consecutive flexible ureteroscopic lithotripsy procedures by a single surgeon (B.K.). Prospectively recorded clinical parameters were laser pulse energy and frequency settings, total energy delivered and fibers failure. Subsequently, each fiber was bench-tested using an established protocol. Parameters evaluated for were fibers true diameter, flexibility, tip degradation, energy transmission in straight and 180° bend configuration and fibers failure threshold with stress testing. RESULTS: The mean total energy delivered was 2.20 kJ (range 0-18.24 kJ) and most common laser settings used were 0.8 J at 8 Hz, 0.2 J at 50 Hz, and 1.0 J at 10 Hz, respectively. No fiber fractured during clinical procedures. The true fiber diameter was 450 µm. Fiber tips burnt back an average of 1.664 mm, but were highly variable. With laser setting of 400 mJ at 5 Hz, the mean energy transmitted was 451 and 441 mJ in straight and 180° bend configuration, respectively. Thirteen percent of fibers fractured at the bend radius of 0.5 cm with a positive correlation to the total energy transmitted during clinical use identified. CONCLUSION: Fiber performance was consistent in terms of energy transmission and resistance to fracture when activated in bent configuration. Fiber failure during stress testing showed significant correlation with the total energy delivered during the clinical procedure. The lack of fiber fracture during clinical use may reduce the risk of flexible endoscope damage due to fiber failure.

Multicenter experience with metallic ureteral stents for malignant and chronic benign ureteral obstruction.

BACKGROUND AND PURPOSE: A new coil-based metallic ureteral stent offers greater radial strength with longer indwelling time compared with plastic stents. This multicenter retrospective study reviews the clinical experience with this stent for malignant or benign chronic ureteral obstruction. PATIENTS AND METHODS: Patients had stent placement in a retrograde fashion. We analyzed preplacement and postplacement renal imaging to determine degree of hydronephrosis. Stent encrustation was determined by either visual inspection at the time of stent change or plain abdominal radiography. Preoperative and follow-up serum creatinine values were compared for each patient. RESULTS: A total of 76 stents in 59 renal units (40 patients) were successfully placed. Creatinine value follow-up on 54 renal units showed 20 (37%) units to have stable, 15 (28%) improved, and 19 (35%) with worsening values. No stent showed encrustation on plain radiography despite it being seen on two during direct visualization. Three stents needed operative removal with either percutaneous nephrolithotomy or cystolitholapaxy. Fifteen of 41 (37%) metallic stents placed because of an obstructed plastic stent also became obstructed. At last follow-up, 6 of 40 patients were kept from nephrostomy tubes because of the metallic stent. CONCLUSIONS: Metallic stents are a viable alternative to nephrostomy tubes in patients in whom conventional stents fail because of malignant obstruction, but patients need to be followed closely. Stent encrustation that resulted in retained stents was poorly visualized on plain radiography. Patients still remain at risk for obstruction, urinary tract infections, and lower urinary tract symptoms from the metallic stent.

Assessment of hydrodissection, holmium:YAG laser vaporization of renal tissue, and both combined to facilitate laparoscopic partial nephrectomy in porcine model.

OBJECTIVES: To evaluate the modalities of electrocautery, holmium:yttrium-aluminum-garnet (YAG) laser, hydrodissection, and combined holmium:YAG laser with hydrodissection applied to laparoscopic partial nephrectomy (LPN) in a porcine model. METHODS: A total of 16 Yorkshire pigs were divided into 4 equal groups (electrocautery, hydrodissection, holmium:YAG laser, and combined hydrodissection/holmium:YAG laser) and underwent unilateral LPN. The total operative time, partial nephrectomy time, hemostasis modality, and intraoperative complications were recorded. The pre- and postoperative hemoglobin was measured. Abdominal computed tomography was performed 2 weeks postoperatively. Representative specimens from each arm were examined for histologic findings. RESULTS: The mean total operative time and the time to perform partial nephrectomy was lower for the combined hydrodissection/holmium:YAG laser arm (66 minutes and 13 minutes, respectively) compared with the electrocautery arm (93 and 30 minutes, respectively), holmium:YAG laser-only arm (77 and 19 minutes, respectively), and hydrodissection-only arm (129 and 35 minutes, respectively). The mean decrease in hemoglobin was the least for the combined hydrodissection/holmium:YAG laser arm (5.3 g/L) followed by the holmium:YAG-only (15.3 g/L), hydrodissection-only (16.8 g/L), and electrocautery (35.5 g/L) arms, respectively. The histologic examination demonstrated an increased depth of tissue injury in the electrocautery arm. CONCLUSIONS: In a porcine model, the combined use of the hydrodissection/holmium:YAG laser to perform LPN had the shortest operative time and the lowest decrease in hemoglobin and appears to warrant additional clinical evaluation in human trials for LPN.

Quantification of holmium:yttrium aluminum garnet optical tip degradation.

INTRODUCTION: Optical laser fibers are utilized to transmit energy to the surface of a stone during holmium:yttrium aluminum garnet (Ho:YAG) laser lithotripsy. During lithotripsy, fiber tip degradation (burn back) can occur. Fiber burn back may diminish fragmentation efficiency, increase operative time, and increase cost because of fiber replacement. We hypothesize that fiber tip degradation (burn back) varies among different commercially available Ho:YAG laser fibers. METHODS: Fibers of varying core diameter sizes for Ho:YAG lithotripsy were evaluated from different manufacturers. Fibers were cleaved, stripped, polished, and inspected for tip uniformity. Fibers were initially tested without contact followed by contact testing using artificial Bego stones. Pre- and postcontact energy outputs were measured by energy detector. Distal tip degradation (burn back) was measured by digital micrometer. Testing was performed on two Ho:YAG lasers (Lumenis VersaPulse 100W and Dornier Medilas H20). All fibers were tested while submerged in water. RESULTS: No burn back was observed in any fiber tested in still water (without contact). Before and after lithotripsy, a trend existed with fibers demonstrating high burn back and high preablation energy outputs. The majority of these fibers were <300 microm diameter. Conversely, fibers with low burn back showed low preablation energy outputs and were >300 microm diameter. CONCLUSION: Fiber burn back and energy transmission varied among the fibers tested. Burn back only occurred during lithotripsy. Burn back may be reduced by fiber selection or using low pulse energy. Fiber burn back may affect the efficiency of fragmentation and contribute to decreased longevity of the fiber.

Preoperative custom carbon fiber operating table for endourologic surgery.

PURPOSE: Numerous options for operating tables exist for percutaneous nephrolithotomy (PCNL), but none of the tables suited our specific needs. Therefore a new custom PCNL table was developed. METHODS: An existing carbon fiber table design was extensively modified to make it suitable for both PCNL and endoscopic urologic procedures. The goals of the design were to create a large imaging window and eliminate any metallic side rail interference during PCNL procedures with the patient in a split-leg prone position. A secondary objective was that the table be suitable for endourologic procedures in the lithotomy position. RESULTS: A custom carbon fiber operating table was successfully developed and implemented in the clinical care of our patients. CONCLUSIONS: The modified custom carbon fiber operating table was successfully developed and now used as the primary table for our endourologic procedures. Future refinements to further optimize the table design are underway.

Evaluation of 24 holmium:YAG laser optical fibers for flexible ureteroscopy.

PURPOSE: Prior study has shown that holmium:YAG laser fiber performance differs among manufacturers. We determined the performance and threshold for failure of 24 commercially available holmium:YAG laser fibers. MATERIALS AND METHODS: Single use and reusable fibers were tested in small (150 to 300 microm) and medium (300 to 400 microm) core diameter sizes. All fibers were evaluated for flexibility, failure threshold and true fiber diameter. Flexibility was measured by maximally deflecting a Stryker U-500 ureteroscope with the fiber in the working channel. The diameter of each fiber was measured by a digital micrometer. The failure threshold was assessed by bending the fibers to 180 degrees, beginning with a radius of 1.25 cm. A VersaPulse 100 W holmium:YAG laser was operated at 1.2 J and 10 Hz for 1 minute or until fiber fracture. The bend radius was decreased in 0.25 cm increments and testing was repeated until a minimum bend radius of 0.5 cm was attained or until the fiber failed. RESULTS: Of the small core fibers the SureFlex LLF-150 and LLF-273, OptiLite SMH1020F and Dornier LG Super 270 had the highest threshold for failure. The Accuflex 200 had the lowest failure threshold failing at the largest bend radius (1.75 cm). Of the medium core fibers the SureFlex LLF-365, Accuflex 365 and Lumenis SL 365 had the highest failure threshold, while the Dornier LG 400 and Lumenis EZ SL 365 were the lowest. The reusable Lumenis 365 fiber had a higher failure threshold than the single use Lumenis 365 fiber. CONCLUSIONS: Commercially available holmium:YAG laser fibers differ significantly in their performance characteristics.