Robot-assisted Anterior Odontoid Screw for the Treatment of Type Ⅱ Odontoid Fractures: Safety and Effectiveness Analysis

Abstract Background: Anterior odontoid screw fixation is considered to be preferred surgical treatment for the type Ⅱ odontoid fractures. However, due to the high difficulty to insert odontoid screw with barehand, the high risk of screw misalignment and damage to surrounding important tissue structures, we urgently need robot-assisted screw insert navigation technology to improve the safety and accuracy of inserting odontoid screws.Methods: We retrospectively analyzed 7 patients with type II odontoid fractures who underwent Tinavi robot-assisted screw insert technology from May 2018 to May 2019 at our hospital. All patients had received 64-row CT scans and 3D reconstructions completed preoperatively, and magnetic resonance (MRI) were performed to verify the severity of odontoid fractures, soft tissue injuries and vertebral artery height. Postoperative CT was repeated in 6 months after surgery to evaluate cervical stability and confirm whether the screw had breached the bone cortex, the accuracy of screw placement based on Rampersaud A-D grade. Functional recovery was assessed using the post-traumatic Mayor scoring system for the cervical spine.Results: All 7 patients successfully completed the robot-assisted operation without nerve and blood vessel damage. What is the operation time 103.3 minutes, intraoperative blood loss 11.1 ml. The angulation and displacement of the fracture were basically corrected by closed reduction during the operation. Postoperative CT of these 7 patients showed that the cervical spine was stable, the accuracy of “perfect” and “clinically acceptable” odontoid screw implantation was 100% (7/7), none of the seven odontoid screws breached the bone cortex. Reexamination of X-rays showed that the fractures were all healed, and the average fracture healing time was average 13.7weeks (12-15weeks). During the follow-up period, 7 patients had no surgical complications, postoperative cervical spine trauma mayo score: excellent in 6 cases and good in 1 case. Conclusion: Tinavi robot-assisted screw insert technology is a minimally invasive, accurate, safe and feasible method for the treatment of type Ⅱ odontoid fractures.