938 NEEDLE STEERING SYSTEM USING DUTY-CYCLED ROTATION FOR PERCUTANEOUS KIDNEY ACCESS

Abstract

You have accessJournal of UrologyTechnology & Instruments: Robotics/Laparoscopy1 Apr 2011938 NEEDLE STEERING SYSTEM USING DUTY-CYCLED ROTATION FOR PERCUTANEOUS KIDNEY ACCESS Khaled Shahrour, Michael Ost, Nathan Wood, Stephen Jackman, Timothy Averch, and Cameron Riviere Khaled ShahrourKhaled Shahrour Pittsburgh, PA More articles by this author , Michael OstMichael Ost Pittsburgh, PA More articles by this author , Nathan WoodNathan Wood Pittsburgh, PA More articles by this author , Stephen JackmanStephen Jackman Pittsburgh, PA More articles by this author , Timothy AverchTimothy Averch Pittsburgh, PA More articles by this author , and Cameron RiviereCameron Riviere Pittsburgh, PA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.856AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES A novel technique of percutaneous renal access (PRA) is needed to overcome the drawbacks of using rigid needles. If a flexible needle with a beveled tip is inserted into tissue, it will bend in the direction of the tip. The curve depends on the needle flexibility and tissue resistance. If the needle spins constantly during insertion, it follows a straight path as the bevel is negated. Alternating periods of spinning and stopping (duty-cycling) allows for proportional control of the trajectory in order to steer the needle in tissue non-traumatically. Our objective is to test the ability of the duty-cycled steerable needle system to follow a specific trajectory in vitro using phantom and swine kidneys. METHODS The nitinol needle has a 0.52mm diameter with a 7° bevel and is attached to a motor for inserting motion and to another motor for spinning. The system is controlled using a graphical user interface to automatically select tip orientation, insertion and spinning speeds based on the actual needle position. A PRA phantom kidney training model was used in which the minor calyces were set as target points and needle is followed in real-time by a camera. In swine experiments, needle is followed fluoroscopically into the contrast-filled calyces. The distance between the actual path of the needle and the planned path (cross track error) and the final needle position were the objective and subjective outcomes respectively. RESULTS The needle successfully entered the phantom and swine kidneys during all attempts. Mean cross track error was 0.71mm with a range between 0.05mm and 1.4mm in phantoms. In swine kidneys, the mean cross track error was 1.38 mm. CONCLUSIONS Duty-cycled needle can be successfully steered along a pre-planed path in vitro and in swine kidney. Further studies on cadaveric and live animals are warranted prior to clinical investigation. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e376 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Khaled Shahrour Pittsburgh, PA More articles by this author Michael Ost Pittsburgh, PA More articles by this author Nathan Wood Pittsburgh, PA More articles by this author Stephen Jackman Pittsburgh, PA More articles by this author Timothy Averch Pittsburgh, PA More articles by this author Cameron Riviere Pittsburgh, PA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...