STEREOTACTIC MECHANICAL PERCUTANEOUS RENAL ACCESS

Obtaining accurate percutaneous renal access when treating intrarenal disease requires substantial skill. Robotic devices have been used in a variety of surgical applications and have been successful in facilit ating percutaneous puncture while improving accuracy, Laboratory model s of robotic devices for percutaneous renal access have also been deve loped. However, several technical hurdles need to be addressed. One re lates to the device-patient interface. As a first step in creating a c omplete robotic system, a mechanical arm (PAKY) with active translatio nal motion for percutaneous renal access has been developed and clinic ally assessed. The PAKY consists of a passive mechanical arm mounted o n the operating table and a radiolucent needle driver that uses a nove l active translational mechanism for needle advancement. The system ut ilizes real-time fluoroscopic images provided by a C-arm to align and monitor active needle placement. In vitro experiments to test needle p lacement accuracy were conducted using a porcine kidney suspended in a garose gel. Seven copper balls 3 to 12.5 mm diameter were placed in th e collecting system as targets, and successful access was confirmed by electrical contact with the ball, The BABY was then used clinically i n nine patients. The number of attempts, target calix location, calix size, and time elapsed were evaluated. In the in vitro study, successf ul needle-ball contact occurred the first time in all 70 attempts, inc luding 10 attempts at the 3-mm balls. Clinically, percutaneous access to the desired calix was attained on the first attempt in each case. T he mean target calix diameter was 14.7 mm (range 7-40 mm), The mean ti me elapsed while attempting access was 8.2 minutes. No perioperative c omplications attributable to needle access occurred. Early experience indicates that the PAKY provides a steady needle holder and an effecti ve and safe end-effector for percutaneous renal access. This device ma y provide the mechanical platform for the development of a complete ro botic system capable of creating percutaneous renal access.