Durability Of Flexible Ureteroscopes Research Articles

Durability of Flexible Ureteroscopes: A Prospective Evaluation of Longevity, the Factors that Affect it, and Damage Mechanisms

BackgroundFlexible ureteroscopy is an established treatment modality for evaluating and treating abnormalities in the upper urinary tract. Reusable ureteroscope (USC) durability is a significant concern. ObjectiveTo evaluate the durability of the latest generation of digital and fiber optic reusable flexible USCs and the factors affecting it. Design, setting, participantsSix new flexible USCs from Olympus and Karl Storz were included. The primary endpoint for each USC was its first repair. Data on patient and treatment characteristics, accessory device use, ureteroscopy time, image quality, USC handling, disinfection cycles, type of damage, and deflection loss were collected prospectively. InterventionUreteroscopy. Outcome measurements and statistical analysisUSC durability was measured as the total number of uses and ureteroscopy time before repair. USC handling and image quality were scored. After every procedure, maximal ventral and dorsal USC deflection were documented on digital images. Results and limitationsA total of 198 procedures were performed. The median number of procedures was 27 (IQR 16–48; 14h) for the six USCs overall, 27 (IQR 20–56; 14h) for the digital USCs, and 24 (range 10–37; 14h) for the fiber optic USCs. Image quality remained high throughout the study for all six USCs. USC handling and the range of deflection remained good under incremental use. Damage to the distal part of the shaft and shaft coating was the most frequent reason for repair, and was related to intraoperative manual forcing. A limitation of this study is its single-center design. ConclusionsThe durability of the latest reusable flexible USCs in the current study was limited to 27 uses (14h). Damage to the flexible shaft was the most important limitation to the durability of the USCs evaluated. Prevention of intraoperative manual forcing of flexible USCs maximizes their overall durability. Patient summaryCurrent flexible ureteroscopes proved to be durable. Shaft vulnerability was the most important limiting factor affecting durability.

LithoVue™: A new single-use digital flexible ureteroscope.

LithoVue™: A new single-use digital flexible ureteroscope.

Techniques to maximize flexible ureteroscope longevity

Objectives To assess methods to improve the longevity and durability of flexible ureteroscopes by using the ureteral access sheath, 200-μm holmium laser fiber, and nitinol baskets or graspers during routine ureteroscopic procedures. Despite adequate advances in fiberoptics and endoscope design, the decreased size of currently available flexible ureteroscopes makes damage inevitable after repeated use. However, new auxiliary tools may be able to enhance ureteroscope durability. Methods The indications for performing flexible ureteroscopy were proximal ureteral stones (n = 32), renal calculi (n = 59), treatment of upper tract transitional cell carcinoma (n = 3), evaluation of hematuria or filling defect (n = 7), and treatment of ureteral strictures or ureteropelvic junction obstruction (n = 8). Using four new 7.5F flexible ureteroscopes, we prospectively evaluated the number of passes of each ureteroscope until more than 20 optical fibers were broken, more than a 25° loss of deflection in either direction had occurred, or the instrument sustained injury requiring repair by the manufacturer. Results One hundred nine flexible ureteroscopic procedures (average 27.5 procedures per instrument; range 19 to 34) were performed with the four new flexible ureteroscopes before being sent for repair. Adjuncts to reduce scope damage during these procedures were the use of the ureteral access sheath (n = 109), nitinol devices allowing lower pole stone retrieval (n = 27), and the 200-μm holmium laser fiber for stone fragmentation, tumor ablation, and incision of ureteropelvic junction/ureteral stenoses (n = 91). The average number of passes until more than 20 optical fibers were broken was 15.3 (range 12 to 20), until more than a 25° loss of deflection occurred was 50.3 (range 42 to 66), or until the scope required repair was 66.7 (range 46 to 82). Conclusions Flexible ureteroscopy will be used increasingly to manage upper urinary tract pathologic findings. Historically, the number of procedures performed before a flexible ureteroscope requires repair averaged 6 to 15. By incorporating the new ureteroscopic accessories, such as nitinol devices, a ureteral access sheath, and the 200-μm holmium laser fiber into common practice, one can reduce the strain on these fragile 7.5F endoscopes, thereby maximizing their longevity.

DOSE A URETERAL ACCESS SHEATH FACILITATE URETEROSCOPY?

Ureteral access sheaths were initially developed to facilitate difficult ureteroscopic access. However, to our knowledge no formal evaluations have been performed to assess the routine use of ureteral access sheaths. Therefore, we prospectively analyzed intraoperative time, symptomatic outcome, major complications, stone-free rate and overall costs related to the routine use of a new ureteral access sheath during standard ureteroscopic procedures. Patients undergoing 6.5Fr semirigid or 7.5Fr flexible ureteroscopy were prospectively randomized to unaided ureteroscopy with no access sheath or ureteroscopy via a 12-14Fr ureteral access sheath. Patients who required ureteral dilatation were randomized to the ureteral access sheath used as a dilator or a standard 18Fr ureteral balloon dilator. Patients were evaluated postoperatively on days 0, 1 and 6 with a questionnaire to assess pain, irritative symptoms and complications. The stone-free rate and long-term complications were determined by excretory urography or computerized tomography at 3 months. Enrolled in the study were 59 consecutive patients, who underwent a total of 62 ureteroscopic procedures. Of the 47 patients (76%) who did not require ureteral dilatation 23 (49%) underwent ureteroscopy via the ureteral access sheath and 24 (51%) underwent unaided ureteroscopy. Seven of the 15 patients (28%) who required ureteral dilatation underwent access sheath dilatation, while balloon dilatation was performed in 8. There was no significant difference in postoperative symptoms, complication rate or stone-free status in the access sheath and nonaccess sheath groups in patients not requiring ureteral dilatation (p <0.05). A significant increase in postoperative symptoms was noted when the balloon was used as a dilator compared to the access sheath. Operative time and costs in all patients who underwent access sheath dilatation were less than in those in whom the access sheath was not used. In the 15 patients who required dilatation 71% of access sheath and 100% of balloon dilatations were successful. Routine use of a ureteral access sheath appears to facilitate semirigid and flexible ureteroscopy by decreasing operative time and costs, allowing direct visualization of ureteroscope insertion with simple ureteral re-entry and assisting renal and ureteral access with minimal associated morbidity. A ureteral access sheath should be considered for routine ureteroscopic procedures.