Abstract
Introduction: Fluoroscopy is routinely used for real-time intra-operative localization of patient anatomy and surgical instrument positioning. Using this radiographic information the orthopedic surgeon inserts different implants into bone. Despite its utility, however, fluoroscopy does have disadvantages. The most notable is potential occupational radiation exposure. Conventional fluoroscopy usually provides only one plane at a time, whereas at least two planes are needed for optimal placement of an implant. By combining a standard C-arm fluoroscopy with computer aided surgical technology, radiation exposure can be eliminated and four different planes can be visualized simultaneously. This study presents data of preliminary clinical experience using this new technology.
Material and methods: The Stealth Station Treatment Guidance Platform System by Medtronic was used. The calibration target was attached to a C-arm fluoroscope. The static reference arc which was attached to the patient and various surgical tools. All with affixed light emitting diodes (LEDs) which were seen by the Infra Red camera. After a short registration process in which the relevant anatomy images were acquired, the C-arm was withdrawn and the entry point to the operated anatomy was determined using the navigation capabilities of the system.
During a period of six months, 31 patients underwent different surgical procedures in which a guided wire was used for: percutaneous fixation of unstable pelvis and hip fractures (13 patients), inserting and locking of an intrameduallry nail (12 patients), inserting pedicular screws (2 patients), or removing foreign-bodies or internal fixations (4 patients). In all cases the placement of the hardware was approved by conventional fluoroscopy as well.
Results: Excellent correlation between the virtual fluoroscopic imaging and live fluoroscopy was observed, thus the placement of the wire in all cases was satisfactory and there was no need to change the position of the wire following the live fluoroscopic confirmation. The number of fluoroscopic buttoning was smaller than the average number in similar surgery using conventional fluoroscopy.
Discussion: According to our preliminary clinical experience it seems that virtual fluoroscopy offers several advantages over conventional fluoroscopy while providing acceptable targeting accuracy. Our impression is that its saves fluoroscopic radiation exposure and improves exactness of the procedure. However, since currently only one reference arc can be detected at a time by the guidance system it can be used only in a stable anatomical situations (such as non-displaced fractures or pedicular screw placements). The use of better-oriented surgical instrumentation and more than one reference point detection will significantly improve the clinical potential of this method.
The abstracts were prepared by Orah Naor. Correspondence should be addressed to him at the Israel Orthopaedic Association, PO Box 7845, Haifa 31074, Israel.
