7.P.07 COMPUTER ASSISTED SURGERY (CAS) IN ORTHOPAEDIC ONCOLOGY, TOMTOM OR TOYS FOR THE BOYS?

Abstract

In orthopaedic oncology surgical precision is important and intraoperative imaging is often necessary. CAS may enhance precision and provide continuous 3D imaging without radiation. The goal of this work is to report our experience with CAS.

Since 2006 we used CAS (Stryker) in 26 patients with a bone tumour: 11 chondrosarcomas, three osteosarcomas, seven osteochondromas and five miscellaneous. Twelve lesions were located in the femur, six in the pelvis, five in the lower leg and three in the upper extremity. In 18 cases a tumour was excised, in six of these a prosthesis was placed. In eight cases a curettage was done. In 23 cases the navigation was image-based (CT and/or MRI based) and in three cases image-less (no image-preparation necessary preoperatively).

CAS was successfully employed in 23 cases. In three cases the procedure was aborted. In two cases, both in the ulna, we were unable to reconstruct the exact dimensions and in one case (image-less) the tracker was to far away from the work-field. There were no complications related to CAS. Mean precision is 0.5 mm. The time CAS takes is about 15 minutes during the procedure (7–60). In the eight curettages it proved helpful. We did not measure radiation time. In the six resections were tumour-prostheses were placed it was really helpful in rotation and length determination. In three of these, image-less navigation was performed (all distal femur). In osteochondroma resections it is helpful in four of seven cases. All surgical margins were adequate in the resections; after curettage, all MRI controls at three months did not show residual tumour. Oncology follow-up is too short yet; there was one local recurrence after two years in a parosteal osteosarcoma.

We conclude that CAS can be our navigator in orthopaedic oncology; it is successful in providing precision and continuous 3D imaging. The indication area needs further study.