Use of an antiretropulsion device to prevent stone retropulsion significantly increases the efficiency of pneumatic lithotripsy: an in vitro study
ABSTRACT To compare the efficiency of pneumatic lithotripsy with and without the Accordion antiretropulsion device (PercSys, Palo Alto, CA, USA).
The study comprised two in vitro experiments: in experiment 1, 10 trials were conducted using stone phantoms (6 x 6 x 10 mm), placed in a horizontal acrylic tube submerged in normal saline. Pneumatic lithotripsy was applied using a Swiss LithoClast (Boston Scientific Corporation, Natick, MA, USA). Each phantom was hit with repeated single firings of the LithoClast until it had travelled 20 cm (control group). The same experiment was then repeated with the Accordion antiretropulsion device positioned proximal to a new stone phantom. In experiment 2, stone phantoms (5 x 5 x 5 mm) were placed in a model ureter made of silicone and submerged in normal saline. Pneumatic lithotripsy was applied continuously on 10 stones for 20 s (200 strikes) without the Accordion device (control group) and on 10 stones with the Accordion device in place (experimental group). The distance of retropulsion was recorded. All stone phantoms were weighed before and after pneumatic lithotripsy.
In both experiments the Accordion group had a significantly greater percentage weight loss than the control group (experiment 1; 11% vs 3%; experiment 2, 53% vs 16%, both P < 0.001).
The Accordion device significantly increased the fragmentation efficiency in both in vitro models. Preventing retropulsion and increasing fragmentation efficiency has the potential to increase the success rate, decrease secondary procedures for migrated stones, and shorten operative times.
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ABSTRACT: Purpose To evaluate the clinical efficacy, safety and costs of percutaneous occlusive balloon catheter assisted ureteroscopic lithotripsy (POBC-URSL) for large impacted proximal ureteral calculi. Patients and Methods: 156 patients with impacted proximal ureteral stones ≥1.5 cm in size were randomized to ureteroscopic lithotripsy (URSL), POBC-URSL and percutaneous nephrolithotomy (PNL) group between May 2010 and May 2013. For URSL, the calculi were disintegrated with the assistance of anti-retropulsion devices. POBC-URSL was performed with the assistance of an 8F percutaneous occlusive balloon catheter. PNL was finished with the combination of ultrasonic and pneumatic lithotripter. Flexible ureteroscope and 200µm laser fiber were used to achieve stone free to a large extent for each group. Variables studied were mean operative time, auxiliary procedure, postoperative hospital stay, operation-related complications, stone clearance rate and treatment costs. Results: The mean lithotripsy time for POBC-URSL was shorter than URSL, but longer than PNL (42.6±8.9 min vs 66.7±15.3 min vs 28.1±6.3 min, P=0.014). The auxiliary procedure rate and postoperative fever rate for POBC-URSL were signiﬁcantly lower than URSL and comparable to PNL (P＜0.01, P =0.034). And POBC-URSL was superior to URSL in regard to the stone clearance rate at 3 days postoperatively, and as good as PNL (98.1% vs 75.0% vs 96.2%, P＜0.01). The postoperative hospital stay and hematuria rate were lower in POBC-URSL group than PNL group and similar to URSL group (P =0.016, P＜0.01). The treatment costs were lowest in POBC-URSL group (1205.0±113.9 $ vs 1731.7±208.1 $ vs 2446.4±166.4 $, P =0.004). Conclusions: For large impacted proximal ureteral calculi, POBC-URSL was associated with a higher stone clearance rate, fewer complications and costs. POBC-URSL combined the advantages of URSL and PNL.Journal of endourology / Endourological Society 04/2014; DOI:10.1089/end.2014.0167 · 2.10 Impact Factor
Article: Antiretropulsion devices[Show abstract] [Hide abstract]
ABSTRACT: Stone migration during the treatment of ureteral stones can prove frustrating and increases both healthcare cost and patient morbidity. Antiretropulsion devices have been engineered to prevent stone migration. Improvements in antiretropulsion devices allow for efficient prevention of stone migration during ureteroscopic lithotripsy with minimal adverse effects or complications. Multiple devices are now available each with advantages and disadvantages. New devices are currently engineered to prevent stone migration and maintain ureteral access. Antiretropulsion devices appear to be cost-effective to prevent stone migration during intracorporeal lithotripsy. Antiretropulsion devices have been safely and effectively used during ureteroscopic procedures. These tools increase stone-free rates, decrease morbidity and new studies have demonstrated their cost-effectiveness.Current opinion in urology 01/2014; 24(2). DOI:10.1097/MOU.0000000000000032 · 2.12 Impact Factor
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ABSTRACT: Our objective was to evaluate the feasibility and initial performance of Backstop reverse thermosensitive polymer to prevent antegrade stone fragment migration during percutaneous nephrolithotomy. Backstop was used during 5 percutaneous nephrolithotomy procedures to prevent stone migration into the ureter. Backstop was placed into the upper ureter under direct vision with a flexible nephroscope or with fluoroscopic guidance. Ultrasonic lithotripsy was then performed. Each patient was evaluated for the following: stone-free rate (postoperative computed tomography), rate of antegrade fragment migration, need for subsequent procedures, and complication rate. The average stone burden was 806 mm(2). Backstop was successfully deployed in all cases. Average procedure length was 106 minutes. Three patients were rendered stone free, 1 patient retained 2 1-mm fragments in the kidney, and 1 patient retained multiple fragments in the kidney, distal ureter, and bladder, all of which were <3 mm. No patient required a secondary procedure, and there were no adverse events. Backstop appears to be feasible, safe, and easy to use. Backstop should be administered every 45 minutes for longer cases, and warm saline should be used during the case to prevent dissolution. A randomized controlled trial with a larger study population is needed to further evaluate these initial findings.Urology 12/2013; 83(2). DOI:10.1016/j.urology.2013.10.005 · 2.13 Impact Factor