An Articulating Tool for Endoscopic Screw Delivery

Abstract

This paper describes the development of an articulating endoscopic screw driver that can be used to place screws in osteosynthetic plates during thoracoscopic surgery. The device is small enough to be used with a 12 mm trocar sleeve and transmits sufficient torque to fully secure bone screws. The articulating joint enables correct screw alignment at obtuse angles, up to 60 deg from the tool axis. A novel articulating joint is presented, wherein a flexible shaft both transmits torque and actuates the joint; antagonist force is provided by a superelastic spring. Screws are secured against the driver blade during insertion with a retention mechanism that passively releases the screw once it is securely seated in the bone. The prototype has been fitted with a blade compatible with 2.0 and 2.3 mm self-drilling screws, though a different driver blade or drill bit can be easily attached. Efficacy of the tool has been demonstrated by thoracoscopically securing an osteosynthetic plate to a rib during an animal trial. This tool enables minimally invasive, thoracoscopic rib fixation.