Identification and localization of intramedullary nail holes for orthopedic procedures using cone beam reconstruction and simulation techniques

Abstract

Closed intramedullary nailing is the common technique for treatment of femur and tibia fractures. The most challenging step in this procedure is the precise placement of the lateral screws that stabilize the fragmented bone. In the present work, the possibility to accurately identify in the 3D space the axis that connects the nail holes is investigated using simulations. The procedure includes obtaining a set of fluoroscopic images as from a common mobile C-arm. An interactive selection of point marks on two of the projection images then provides an initial guess for the axes of the holes. A CBCT reconstruction, with manual or automatic localization of the centres of the nail holes on the tomograms, gives much more accurate estimation of the drilling axes. Successful localization can be further used to guide a surgeon or a robot for correct drilling the bone along the nail openings. Programming is done in MatlabTM and C++. Results confirm very good localization accuracy, at no radiation excess.