RESUMEN
PURPOSE: To examine laser damage to three commercially available devices used to prevent stone retropulsion during ureteroscopic lithotripsy. MATERIALS AND METHODS: Two experiments were performed with five Accordion, Stone Cone, and NTrap devices each. All devices had a 7-mm outer diameter. The holmium:yttrium-aluminum-garnet laser was set at 8 watts. Experiment 1 was performed in an acrylic tube of 10-mm inner diameter in a saline water bath. The laser was fired against the antiretropulsion element of each device until the device could not be opened or closed. Experiment 2 was performed in a saline water bath; the laser was fired against the carrying catheter of each device until it was severed. RESULTS: For experiment 1, the mean number of laser firings against the antiretropulsion element until device failure was 2 for the NTrap, and 28.6 for the Stone Cone. The Accordion was operable after 100 laser firings. The Accordion was more laser resistant than either device (P<0.001, P<0.001), and the Stone Cone was more laser resistant than the NTrap (P<0.001). In experiment 2, mean time to break the carrying catheter was 13.6 seconds for the NTrap, 17.4 seconds for the Stone Cone, and 6.6 seconds for the Accordion. The Stone Cone and NTrap carrying catheters were more laser resistant than the Accordion (P=0.007, P=0.03 respectively), and there was no statistical difference between the Stone Cone and NTrap. CONCLUSIONS: The antiretropulsion element of the Accordion was most laser resistant, and both the Accordion and Stone Cone antiretropulsion elements were more laser resistant than the NTrap. The carrying catheters of the Stone Cone and NTrap had similar laser resistance, and both were more laser resistant than the Accordion. Urologists should be mindful of structural characteristics when using these devices.
Asunto(s)
Cálculos Renales/cirugía , Rayos Láser , Litotricia/instrumentación , UreteroscopíaRESUMEN
OBJECTIVE: To compare the efficiency of pneumatic lithotripsy with and without the Accordion antiretropulsion device (PercSys, Palo Alto, CA, USA). MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.
Asunto(s)
Litotricia/instrumentación , Cálculos Ureterales/terapia , Diseño de Equipo , Humanos , Litotricia/métodos , Modelos AnatómicosRESUMEN
PURPOSE: To examine laser damage to three commercially available devices used to prevent stone retropulsion during ureteroscopic lithotripsy. METHODS: Two experiments were performed with 5 Accordion (Percsys, Palo Alto, CA), Stone Cone (Boston Scientific, Natick, MA), and NTrap (Cook Urological, Bloomington, IN) devices each. All devices were of 7-mm outer diameter. The holmium:YAG laser was set at 8 W. Experiment 1 was performed in an acrylic tube of 10-mm inner diameter in a saline water bath. The laser was fired against the antiretropulsion element of each device until the device could not be opened or closed. Experiment 2 was performed in a saline water bath; the laser was fired against the carrying catheter of each device until it was severed. RESULTS: For Experiment 1, the mean number of laser firings against the antiretropulsion element until device failure was 2 for the NTrap, and 28.6 for the Stone Cone. The Accordion was operable after 100 laser firings. The Accordion was more laser-resistant than either device (P < 0.001, P < 0.001, respectively), and the Stone Cone was more laser-resistant than the NTrap (P < 0.001). In Experiment 2, mean time to break the carrying catheter was 13.6 seconds for the NTrap, 17.4 seconds for the Stone Cone, and 6.6 seconds for the Accordion. The Stone Cone and NTrap carrying catheters were more laser-resistant than the Accordion (P = 0.007, P = 0.03, respectively) and there was no statistical difference between the Stone Cone and NTrap. CONCLUSIONS: The antiretropulsion element of the Accordion was most laser-resistant, and both the Accordion and Stone Cone antiretropulsion elements were more laser-resistant than the NTrap. The carrying catheters of the Stone Cone and NTrap had similar laser resistance, and both were more laser-resistant than the Accordion. Urologists should be mindful of structural characteristics when using these devices.
Asunto(s)
Rayos Láser , Litotricia/instrumentación , Cálculos Ureterales/terapia , Ureteroscopía/métodos , CateterismoRESUMEN
OBJECTIVES: Stone disease is a rare complication after renal transplantation, and the management of these stones can be difficult. In many cases, the best modality to treat stones in transplanted kidneys/ureters is with a percutaneous approach. The goal of this study was to review our series of percutaneous nephrolithotomy (PNL) to evaluate the success rates and present the key technical points to achieve a successful outcome. METHODS: We retrospectively reviewed our series of PNL from January 1997 to December 2007 and identified 15 patients who had had PNL performed in a transplanted kidney. We evaluated multiple perioperative variables and how the patients' urolithiasis presented. We also collected intraoperative data. RESULTS: A total of 15 patients underwent successful PNL in a transplanted kidney. In all patients, but 3, access into an anterior, upper pole calix was achieved, and access was obtained with ultrasound guidance alone or a combination of ultrasound guidance and fluoroscopy. Ten patients had a pre-existing nephrostomy tube, and this was used in all but 1 patient. Of the 15 patients, 8 (53%) were treated with percutaneous flexible nephroscopy/ureteroscopy, and 7 had tracts dilated to 30F to perform rigid PNL. All patients were rendered stone free at the end of the procedure, no complications developed, and no patient required a blood transfusion. CONCLUSIONS: Nephrolithiasis in a transplanted kidney can be challenging to diagnose and to treat. PNL is most often the best modality to render patients stone free.