Computer-aided trauma surgery: preliminary report of 32 cases

Abstract

This prospective study on the use and advantages of virtual fluoroscopy in trauma surgery involves 32 patients for tibial, femoral nails and femoral neck screwing. The purpose of this study was to evaluate the advantages of this technique, reduction of radiation exposure, and setup and exposure time as compared to conventional technique. During winter 2001/2002, 32 patients who had sustained a ski injury were operated on using fluoroscopic navigation for distal interlocking of tibial and femoral nails or insertion of femoral neck screws. For virtual fluoroscopy, a grid is mounted on the receptor of the image intensifier to correct distortions of fluoroscopic images. The digitized images allow real-time visualization of the tools in use. Tools are visualized in space; they are fitted with diodes which are identified by an optical tracker. Technical steps include insertion of the nail, placement of the reference bow, identification of the image intensifier diodes and bow (AP and lateral) by the camera, recognition of the drill guide used and, finally, virtual representation of the tool on the screen. The operative technique in operative theater is reported. We have evaluated the overall operative time, and exposure time according to the type of fracture. For distal interlocking of a tibial nail, exposure time with the free hand technique ranges from 17 to 30 s. For triple locking, exposure time with fluoroscopic navigation is decreased from 1 min to 25 s. Additional time for fluoroscopic navigation system setup was significantly reduced after the fifth procedure, as we got familiar with the equipment and the software. All screws were correctly inserted except for one distal tibial screw. Exposure of the surgeons' hands to X-rays during distal interlocking or insertion of femoral neck screws is significantly reduced. Other advantages such as intraoperative assessment of the axes of rotation are expected in the near future.