Robotic Assisted Fixation of Sacral Fractures

Abstract: Unstable sacral fractures are challenging for orthopaedic trauma surgeons. In most cases percutaneous fixation techniques are utilized after reduction. However, these techniuqes are not risk free mainly due to anatomical considerations. Screw misplacement is quite common and concerning. As spine surgery evolved, a miniature robotic guidance system was successfully utilized in pedicular screw insertion. The aim of the study was to demonstrate the use of the miniature robot in the fixation of unstable sacral fracutres.

Patients and Methods: 10 patients with unstable sacral fracutres without significant displacement were eligible for percutaneous fixation. These included 8 traumatic fractures and 2 pathological fractures. Nine fixation constructs were planned using a preoperative CT scans and one case was done with an intraoperative CT. The patients were placed prone and the robot was mounted on a Dynamic Reference Bridge (DRB), in cases of the preoperative CT- 2 verification fluoroscopic images were taken in the case of the intraoperative imaging a 3D scan was performed intraoperative after fracture reduction. The robot was mounted on the DRB and was sent by the robotic computer to the desired screw(s) trajectory. The guide wires were inserted through stab wounds and screws were placed subsequently. CT scans were made postoperatively and fluoroscopic and operative time were recorded intraoperatively. Results: Mean patient age was 29 (17-63) number of screws ranged 1-8 (average 2.5). Mean operative time was 50 min (range 15-90), and average fluoroscopic time was 18 sec (7-42). None was the screws was misplaced.

Conclusion: Robotic assisted fixation of sacral fracture is promising. In displaced fractures intra operative reduction and fixation can be used as well.