Ureteral Access Sheath Placement Research Articles

MP17-02 URETERAL STRICTURE FORMATION AFTER USE OF URETERAL ACCESS SHEATH – 4 YEAR FOLLOW-UP DATA

INTRODUCTION AND OBJECTIVES:Recent studies have described ureteral lesions caused by placement of ureteral access sheaths during ureteroscopy. However, the long-term sequelae of these lesions is un...

A Prospective Study Analyzing the Association Between High-grade Ureteral Access Sheath Injuries and the Formation of Ureteral Strictures

ObjectiveTo assess the intermediate- and long-term effect of high-grade ureteral injuries from ureteral access sheaths. MethodsPatients undergoing ureteroscopy for upper tract calculi were prospectively enrolled at 2 sites from 2010 to 2015. A 12/14 French sheath was used and the ureter was inspected with a flexible ureteroscope during withdrawal of the sheath and recorded. The videos were then evaluated by 2 blinded endourologists, and any injuries were graded per the Traxer ureteral injury scale. Only high-grade injuries were included. The primary endpoint was defined as ongoing hydronephrosis without an obstructing stone on follow-up imaging indicating a ureteral stricture. Logistic regression analysis was used to assess the relationship between hydronephrosis, ureteral injury, and other patient variables. ResultsFifty-six patients were identified with high-grade ureteral injuries. Sixteen patients (28.6%) were female. Median age was 56.4 years (range 14-85). Median follow-up was 35.8 months (range 0-88). Three patients (5.5%) had hydronephrosis on follow-up imaging, only 1 of whom developed a de novo ureteral stricture. On univariate analysis, hydronephrosis was associated with a shorter stent duration (P = .11) and older age (P = .17). ConclusionEndoscopically identified high-grade ureteral lesions following ureteral access sheath placement do not lead to clinically significant sequelae on intermediate term follow-up, with a stricture rate comparable to those without visible injuries of 1.8%.

Can alpha blockers facilitate the placement of ureteral access sheaths in retrograde intrarenal surgery?

To investigate the effects of alpha blocker treatment on the placement of ureteral access sheaths (UAS) during retrograde intrarenal surgery (RIRS). This study was a retrospective analysis of prospectively collected data. Patients who underwent RIRS due to renal stones between November 2015 and December 2017 were seperated into two groups. Age, gender, body mass index (BMI), stone size, laterality, hydronephrosis degree, and renal stone density were recorded. Tamsulosin (0.4 mg/day) was prescribed to the study group (n=25) 2 weeks before the operation. The control group (n=25) underwent the operation without any additional treatment. All the operations were performed using a 7.5 Fr flexible ureteroscope and 9.5/11.5 Fr (Cook, Blooming, USA) UAS. Two patients in the study group were excluded from the study as they suffered from dizziness and retrograde ejaculation. No statistically significant difference was found between the patients in the study group (n=23) and control group (n=25) in terms of age, gender, BMI, stone size, laterality, hydronephrosis, and renal stone density (p=0.470, p=0.536, p=0.456, p=0.102, p=0.555, p=0.732, and p=0.317, respectively). The UAS could be successfully placed on the first attempt in 15 (65.2%) patients in the study group and 11 (44%) patients in the control group during the first attempt itself. Even though the successful UAS placement rate was higher in the study group, no statistically significant values were observed (p=0.141). The data obtained from the present study showed that the use of alpha blockers prior to RIRS did not improve the UAS placement rates. It is considered that studies conducted on more patients might be able to achieve significant values.

Efficacy and Safety of Ultrasonic Longitudinal-Axis Vibration for the Reduction of Ureteral Access Sheath Insertion Force: A Randomized Controlled Trial in a Porcine Model.

Excessive bulking force during ureteral access sheath (UAS) placement may induce injury. The sliding friction between surfaces can be reduced with the application of ultrasonic vibration. We investigated the efficacy and safety of an ultrasonic vibration transducing device for reducing the maximal ureteral access sheath insertion force (UASIF). A device was developed for transducing ultrasonic longitudinal-axis vibration onto the UAS at an adjustable amplitude and frequency while measuring the degree of UASIF. In the pilot study, six porcine models were used to investigate the optimal amplitude and frequency of vibration and to calculate sample size. Twelve porcine models were utilized in a randomized controlled trial. Resected ureters were pathologically evaluated for ureteral injury. The transduction of ultrasonic vibration at an amplitude of 0.04 g and a frequency of 18,000 Hz resulted in a maximal UASIF reduction of 36.4% (interquartile range 32.7-43.1). Maximal UASIF tended to decrease with increasing vibration frequency. No significant differences in UASIF reductions were observed according to amplitude. In the randomized controlled trial, the maximal UASIF reduction was 37.0% (interquartile range 21.4-44.2). Grade II injury was pathologically diagnosed in 8.3% (1/12) of the ureters in both groups. The transduction of ultrasonic longitudinal-axis vibration onto the UAS reduces maximal UASIF and does not harm the ureter. Reducing the velocity of sheath insertion may further reduce maximal UASIF.

The effect of ureteral stenting before flexible ureteroscopic lithotripsy: a Meta-analysis

Purpose To evaluated the effect of ureteral stent placement before flexible ureteroscopic lithotripsy(FURL). Methods A systematic search of PubMed, Cochrane Library, Embase, Scopus, VIP, CNKI, Wanfang database from databases establishment to February 2017 was performed to identify all clinical trials on the effect of ureteral stenting before flexible ureteroscopic lithotripsy. The outcomes included stone-free rate, mean operative time, success rate of ureteral access sheath placement and postoperative complications. RevMan 5.3 software was used to complete the Meta statistical analysis. Results Three randomized and four non-randomized studies were analyzed, which consisted of 1 176 patients including 788 cases in experimental group , 388 cases in control group. Meta-analysis showed significant differences between experimental group and control group in stone-free rate(OR=1.88, 95%CI 1.30-2.71, P<0.001). There was no statistically significant difference in mean operative time between experimental group and control group(WMD=-0.99, 95%CI -10.63-8.65, P=0.84). The success rate of ureteral access sheath placement was significantly higher in experimental group than that in the control group(OR=8.24, 95%CI 3.17-21.45, P<0.001). In term of postoperative complications, two groups had significant differences (OR=0.57, 95%CI 0.33-0.99, P=0.04). Conclusions Preoperative ureteral stenting can increase the stone-free rate and the success rate of ureteral access sheath placement, and reduce complications of FURL. There is no statistically significant difference in mean operative time. Key words: Calculus; Flexible ureteroscopic; Ureteral stent; Meta-analysis

Histological changes caused by the prolonged placement of ureteral access sheaths: an experimental study in porcine model.

The objective is to evaluate the histological damage to the ureteral wall caused by the prolonged placement of an access sheath in porcine model. Six ureters from three female pigs were randomized into three groups. In each group, an UAS with different indwelling time was inserted. 9.5/11.5Fr Flexor® ureteral access sheaths were inserted in both ureters with left indwelling for 30min and right for 60min. The ureteral access sheath was advanced up to the proximal ureter. No resistance was observed during the insertion. Ureters were harvested in immediately after the sheath placement process in one pig. The ureters of the remaining two pigs were removed at 1 and 2weeks after the procedure, respectively. Histological examination took place also in these specimens. Ureters with an indwelling time of 30min: histological examination of the ureter after immediate dissection revealed signs of acute inflammation at the distal ureter. The ureter dissected at 1week showed minimal focal transmural inflammation along its length with minimal epithelial hyperplasia. The ureter dissected at 2weeks, no signs of inflammation. Ureters with an indwelling time of 60min: histological examination of the immediately dissected ureter revealed signs of acute inflammation at the distal ureter. At 1week, chronic transmural inflammation was predominantly observed in the distal ureter. At 2weeks, minimal transmural inflammation was observed. The use of UAS did not cause any severe histological damage on porcine ureters. Acute signs of inflammation gradually recovered within 2weeks.

114 - Histological changes caused by the prolonged placement of ureteral access sheaths: An experimental study in porcine model

114 - Histological changes caused by the prolonged placement of ureteral access sheaths: An experimental study in porcine model

65 - Insertion forces of ureteral access sheath placement in three patients undergoing flexible ureteroscopy

65 - Insertion forces of ureteral access sheath placement in three patients undergoing flexible ureteroscopy

Endovisually guided zero radiation ureteral access sheath placement during ureterorenoscopy

Background: Almost all endourologic procedures use fluoroscopic imaging in some steps, which exposes both the patient and the surgical team to considerable amounts of radiation. Primary reports on results of a simple direct visual endoscopic access sheath placement technique which does not use fluoroscopy at all are presented.Material and methods: First a semi-rigid ureteroscopy was carried out up to the renal pelvis, then the access sheath (36 cm, 11/13 Fr) without the obturator was placed over a 7.5 Fr semi-rigid ureteroscope and ureteroscopy was repeated over the guide wire to the point where the sheath could be inserted without force as if the ureteroscope would act as the guide wire (rod), which is controlled under direct endoscopic vision.Results: Eighty-eight cases out of 106 procedures were successful regarding the insertion of the ureteral access sheath (UAS) under direct vision using a 36 cm 13/11 Fr sheath. Fourteen ureters had non-negotiable strictures needing stenting for passive dilation. The mean time for UAS insertion was 19 s. The stone free-rate was 78.12%. Among our 106 cases, there were six cases of the upper tract urothelial cancers.Conclusion: Ureteral access sheath placement could be safely performed using a semi-rigid ureteroscope under direct visual control and resulted in shorter operative time, without radiation exposure during the RIRS procedure of both the patient and the surgery team.

Prospective Analysis of a Complete Retrograde Ureteroscopic Technique with Holmium Laser Stent Cutting for Management of Encrusted Ureteral Stents.

Purpose: To propose and evaluate a new endoscopic technique using only a retrograde ureteroscopic approach for the removal of heavily encrusted ureteral stents. Methods: Data from 51 consecutive patients with encrusted and retained ureteral stents were prospectively collected. Description of the successive steps of surgery is detailed. The holmium yttrium aluminum garnet (Ho:YAG) laser properties offer the opportunity for fragmentation of stent-attached encrustation and the ability to cut the stent itself. Reducing the length of the stent is critical to creating space in the ureter and to allow free access for ureteroscopes or ureteral access sheath placement. The primary outcome of this study was the feasibility and the safety of this retrograde intrarenal approach. Some factors of encrustation and outcomes are also discussed in comparison with lithotripsy, percutaneous, laparoscopic, open surgery, or a combination of these techniques. Results: The removal of the encrusted stent was possible with only this retrograde technique in 98% of patients. The transection of the encrusted stent with the Ho:YAG laser was useful in 71% of the patients. Mean operative time was 110 minutes and mean hospital stay was 2.33 days. Postoperative complications were mainly nonobstructive pyelonephritis (10%). The most significant predictor of this life-threatening complication was the presence of struvite stones with the encrusted stent (p = 0.018). Contrariwise, operative time, body mass index, gender, and encrustation rate were not associated with postoperative pyelonephritis. Both cystine stone disease and pregnancy led to faster stent encrustation. Conclusions: Retrograde ureteroscopic surgery is efficient and safe for removing retained stents and associated stone burdens. The Ho:YAG laser is essential to perform the encrustation removal and sectioning of the stent.

Comparison of New Single-Use Digital Flexible Ureteroscope Versus Nondisposable Fiber Optic and Digital Ureteroscope in a Cadaveric Model

Purpose: To evaluate LithoVue, the new single-use digital flexible ureteroscope, in a human cadaveric model and compare it with a nondisposable fiber optic and digital flexible ureteroscopes.Materials and Methods: LithoVue, a conventional fiber optic, and digital flexible ureteroscopes were each tested in four renal units of recently deceased female cadavers by three surgeons. The following parameters were analyzed: accessibility to the kidney and navigation of the entire collecting system with and without ureteral access sheath (UAS), lower pole access measuring the deflection of the ureteroscope with the working channel empty, and with inside two different baskets and laser fibers. A subjective evaluation of maneuverability and visibility was assessed by each surgeon at the end of every procedure.Results: Kidney access into the Renal unit 1 was not possible without UAS for all ureteroscopes because of noncompliant ureter at the level of sacroiliac joint. The reusable digital ureteroscope was unable to reach one calix of the lower pole and one calix of the upper pole (Renal units 2 and 3) without UAS placement. Lower pole access with baskets and laser fibers was possible for each ureteroscope after UAS placement. No statistically significant differences were detected in angle deflection between ureteroscopes. The digital ureteroscope was preferred for visibility in all procedures: LithoVue for maneuverability in six procedures, fiber optic in five procedures, and the digital ureteroscope in one procedure.Conclusions: LithoVue seems to be comparable with conventional ureteroscopes in terms of visibility and manipulation into the collecting system in fresh human cadavers. Further studies in humans are needed to determine the clinical value of this new instrument.

Current Standard Technique for Modern Flexible Ureteroscopy: Tips and Tricks

BackgroundThanks to advancements in the endoscopic armamentarium, flexible ureteroscopy (fURS) has become a viable and attractive option for the treatment of renal stones because of its high stone-free rates (SFRs) and low morbidity. ObjectiveTo describe our surgical technique for fURS, step-by-step, for the treatment of renal stones and to assess its effectiveness and safety. Design, setting, and participantsA retrospective analysis of 316 consecutive patients who underwent fURS for renal stones at our institution between March 2014 and September 2015 was performed. Surgical procedureUreteroscopy and laser lithotripsy using a standardized technique with last-generation flexible ureteroscopes. Outcome measurements and statistical analysisClinical data were collected in a dedicated database. Intraoperative and postoperative outcomes were assessed. A descriptive statistical analysis was performed. Results and limitationsThe mean overall stone size was 16.5 ± 7.9mm. Ureteral access sheath placement was possible in 287 patients (90.8%). At 1-mo follow-up, the overall primary SFR was 79.1%; the secondary and tertiary SFRs were 89.5% and 91.5%, respectively. The mean operative time was 72.6 ± 27.5min. The mean number of procedures was 1.27. Complications were reported in 92 patients (29.1%) overall, with Clavien grade 1 in 55 patients (17.4%), grade 2 in 30 patients (9.5%), grade 3 in 6 patients (1.9%), grade 4 in 1 patient (0.3%), and grade 5 in none. The main limitation of the study was the retrospective nature. ConclusionsThe fURS procedure is safe and effective for the treatment of renal stones. A staged procedure is necessary to achieve stone-free status with large calculi. Patient summaryFlexible ureteroscopy is an effective treatment with low complication rates for the majority of renal stones. Both the modern highly technological armamentarium and surgical know-how should be available.

124 Comparison of insertion forces during ureteral access sheath placement in an experimental model with different commercially available access sheaths

124 Comparison of insertion forces during ureteral access sheath placement in an experimental model with different commercially available access sheaths

Rigid Ureteroscope Aided Insertion of Ureteral Access Sheath in Retrograde Intrarenal Surgery

To compare the outcomes of the ureteral access sheath (UAS) placement techniques in patients undergoing retrograde intrarenal surgery. The patients were divided into two groups with respect to placement method of UAS. UAS was placed with the classical method, through the guidewire, in the first group of the patients (group I). The outer sheath of UAS was worn on the semirigid endoscope and placed into the ureter under direct vision in the second group (group II). The number of patients was the same in two groups (n = 42). Overall, 70 of 84 (83.3%) patients were stone free after the initial treatment. The success rates were comparable between the two groups (80.9% vs 85.7%, P = .859) 1 month after surgery. Fluoroscopy screening time (11.7 ± 5.7 seconds vs 0 second), UAS placement time (245 ± 138.4 seconds vs 40 ± 17.9 seconds; P < .001), and operation time (58.7 ± 17.1 minutes vs 51.2 ± 16.7 minutes; P = .046) were significantly longer in group I when compared to group II. The complication rate was higher in group I when compared to group II (23.8% vs 9.5%), but the difference was not statistically significant (P = .079). Introducing UAS into ureter under direct vision while it was precisely worn on ureteroscope makes this step safer, and protects the surgeon and patient from radiation exposure by shortening fluoroscopy and operation times.

Systematic Evaluation of Hybrid Guidewires: Shaft Stiffness, Lubricity, and Tip Configuration

To conduct a comparison of physical and mechanical properties for 5 commonly used guidewires to assess advantages of wires for specific applications. Tests on guidewires (0.035" diameter; straight, flexible tip) included tip bending, shaft buckling, lubricity, and tip puncture measurements. Guidewires included 2 hybrid wires: the U-Nite (Bard Urological, Covington, GA) and the Sensor (Boston Scientific, Natick, MA). Our aim was to compare the stiffness of these hybrid wires with the standard Amplatz SuperStiff (Boston Scientific). Our second aim was to compare the hydrophilic tip of the hybrid wires with 2 traditional hydrophilic guidewires: the NiCore (Bard Urological) and RadiFocus glidewire (Boston Scientific). The Amplatz SuperStiff had a significantly stiffer shaft than either hybrid wire, with a buckling force of 1.81 ± 0.91 N compared with the Sensor (0.80 ± 0.29 N, P = .0002) and the U-Nite (0.77 ± 0.29 N, P < .0001). The Boston Scientific guidewire tips were less stiff than the Bard guidewires, requiring up to 48% less force to bend when encountering resistance (P < .0001). The U-Nite had the highest lubricity (0.09 ± 0.03 N, P < .0001) and roundest tip of all the guidewires tested. The RadiFocus required the greatest puncture force (1.80 ± 0.27 N, P < .0001) of all the guidewires tested. Hybrid wires offer a combination of a stiffer shaft and hydrophilic tip. The Amplatz SuperStiff remains the stiffest wire and as such is best suited for placement of ureteral access sheaths or larger stents. The Boston Scientific wires require less force to "bend" around a point of obstruction compared with the Bard wires. The Boston Scientific RadiFocus requires the greatest force to puncture aluminum foil.