Robotic assisted fixation of sacral fractures: A pilot study

Objectives Sacral fractures that require fixation are a challenge for the orthopaedic surgeon. Due to anatomical consideration, implant insertion is not risk free, and requires a steep learning curve. A robotic system has been successfully used in pedicle screws insertion and can be also used for iliosacral screws. The aim of the study was to demonstrate the use of the robot in the treatment of unstable sacral fractures. Design Retrospective case series. Setting An academic level I trauma center. Patients Fourteen patients with sacral fractures were eligible for robotic assisted treatment. These included 9 high-energy fractures, 4 osteoporotic fractures, and 1 pathological fracture. Intervention Fixation constructs included iliosacral screws, transiliac screws, lumbopelvic fixation, sacroplasty, or a combination of the above techniques. A Renaissance robot was mounted on a multidirectional bridge that was attached to the patients spine and implant trajectories were planned either on preoperative or intraoperative 3D scans. Guide wires were inserted percutaneously and screws were placed subsequently. Main outcome measurements Accuracy of implant placement, operating room and fluoroscopy time. Results Mean patient age was 36 (17-84), and number of screws, including iliosacral and pedicular ranged 1-14 per patient (average 4.25). Mean operative time was 150 minutes (range 90-300). Average fluoroscopic time was 18 seconds (7-42) for 2D and 40 seconds (12-72) for 3D imaging. All fractures healed, no hardware failure was observed. All hardware was always within bony confines, and no procedure-related neurological deficits were observed. Conclusion Robotic assisted fixation of sacral fracture is a safe and reproduceable method, allowing precise and accurate implant placement.