This paper presents a novel image-guided robot-based system to assist orthopedic surgeons in performing distal locking of long bone intramedullary nails. The system consists of a bone-mounted miniature robot fitted with a drill guide that provides rigid mechanical guidance for hand-held drilling of the distal screws' pilot holes. The robot is automatically positioned so that the drill guide and nail distal locking axes coincide, using a single fluoroscopic X-ray image. Since the robot is rigidly attached to the intramedullary nail or bone, no leg immobilization or real-time tracking is required. We describe the system and protocol and present a method for accurate and robust drill guide and nail hole localization and registration. The in vitro system accuracy experiments for fronto-parallel viewing show a mean angular error of 1.3° (std = 0.4°) between the computed drill guide axes and the actual locking holes axes, and a mean 3.0 mm error (std = 1.1 mm) in the entry and exit drill point, which is adequate for successfully locking the nail.
Bibliographical noteFunding Information:
Manuscript received March 31, 2004; revised December 1, 2004. This work was supported by grants from the Israel Ministry of Industry and Trade, the IZMEL Consortium on Image-Guided Therapy, and by the Israel Ministry of Science and Technology. The Associate Editor responsible for coordinating the review of this paper and recommending its publication was P. Cinquin. Asterisk indicates corresponding author. *Z. Yaniv is with the Imaging Science and Information Systems (ISIS) Center, Department of Radiology, Georgetown University Medical Center, 2115 Wisconsin Ave., Suite 603, Washington, DC 20007 USA (e-mail: firstname.lastname@example.org).
- Fluoroscopic X-ray
- Robot guidance