PD42-10 A SMART KIDNEY STONE BASKET WITH FORCE FEEDBACK

Abstract

You have accessJournal of UrologyStone Disease: New Technology1 Apr 2015PD42-10 A SMART KIDNEY STONE BASKET WITH FORCE FEEDBACK Zahra Najafi, Thomas Tieu, Ajay M. Mahajan, and Bradley F. Schwartz Zahra NajafiZahra Najafi More articles by this author , Thomas TieuThomas Tieu More articles by this author , Ajay M. MahajanAjay M. Mahajan More articles by this author , and Bradley F. SchwartzBradley F. Schwartz More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.2595AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Ureteroscopy with stone extraction devices has become an effective treatment in the management of urolithiasis. Perforation and avulsion of the ureter wall, due to excessive force on the extraction device, are serious complications of basketing. In this paper, we design a prototype that provides instantaneous extraction forces. The proposed prototype will aid in reducing the risk of ureter wall perforation and avulsion by highlighting the safe and hazardous extraction forces. Additionally, it can be used to improve the skills of surgeons during professional training. METHODS The mechanical sensor prototype is shown in Fig.1. The basket is connected to a spring that is located inside a tube. Three regions, safe (green), cautious (yellow), and dangerous (red), are defined by the amount of perforation and avulsion forces reported by Pedro RN et al. (2007). The prototype was calibrated and bench top testing was performed by preparing a model of the ureter (polyurethane tubing). A stricture was created on the tube and a metal bead simulating the stone was placed in the tube (Fig.1). The entire system was withdrawn from the ureter model by first sweeping the stone down to the stricture and then increasing the force up to the perforation and avulsion forces. The movement of the indicator was monitored and recorded. RESULTS The spring was calibrated and used to define the different force regions. Table 1 illustrates the results of the device calibration after five repetitions. Bench top testing on the ureter model shows that the results obtained by the proposed smart device prototype are consistent with the perforation and avulsion values reported by Pedro RN et al. (2007). CONCLUSIONS A smart device was designed to feedback the instantaneous forces during basketing. Safe and hazardous regions were defined and the device was calibrated and tested on a ureter model. The same prototype can also be calibrated to be used on human ureter (we undertake this in our future work). The feedback forces provided by the prototype will lead to less complication and aid in reducing the procedure cost. Table 1. Calibration of the prototype by increasing the mass (based on forces reported by Pedro RN et al. (2007) for porcine ureter) and reading the spring extension. Region Mass (g) Extension run 1 (mm) Extension run 2 (mm) Extension run 3 (mm) Extension run 4 (mm) Extension run 5 (mm) Average Extension (mm) Green (safe) Min: 0 Max: 550 Min: 0 Max: 10.80 Min: 0 Max: 10.82 Min: 0 Max: 10.81 Min: 0 Max: 10.82 Min: 0 Max: 10.82 Min: 0 Max: 10.814 Yellow (cautious)* Min: 550 Max: 1000 Min: 10.80 Max: 20.25 Min: 10.82 Max: 20.26 Min: 10.81 Max: 20.24 Min: 10.82 Max: 20.26 Min: 10.82 Max: 20.26 Min: 10.814 Max: 20.254 Red (dangerous)** > 1000 > 20.25 > 20.26 > 20.24 > 20.26 > 20.26 > 20.254 *May lead to perforation, **Avulsion will occur © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e889-e890 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Zahra Najafi More articles by this author Thomas Tieu More articles by this author Ajay M. Mahajan More articles by this author Bradley F. Schwartz More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...