Personalized Rapid Prototyping Template for Direct C1 Pedicle Screw Fixation of Unstable C1 Semi-Ring Fractures

Abstract Background: Placement of C1 pedicle screws carries an inherent risk of injury to the spinal cord and vertebral artery. Use of a personalized rapid prototyping template may be able to improve the safety of C1 pedicle fixation. To evaluate the clinical and radiographic outcomes of direct posterior C1 pedicle screw fixation using a personalized rapid prototyping template for unstable C1 semi-ring fractures.Methods: From May of 2010 to September of 2015, 38 patients with unstable C1 semi-ring fractures were treated with direct posterior C1 pedicle screw fixation. A standard open technique was utilized in 20 patients (Free-hand group) and 18 patients underwent C1 pedicle screw fixation with the aid of a personalized rapid prototyping template (RP group). The operative time, intraoperative blood loss, preoperative ADI, LMD and VAS were recorded. The postoperative ADI, LMD and VAS score were recorded at 180 days postoperatively.Results: No spinal cord or vertebral artery injuries were encountered in either group. Similarly, no post-operative instrumentation failures or cases of postoperative C1-2 instability were reported in either group. There was no statistically significant difference in intraoperative blood loss and operative time between RP and Free-hand group. In both groups, all patients obtained radiographic fusion at 6 months, reported no residual neck pain and were found to have a full range of motion at final follow up.Conclusion: Use of a personalized rapid prototyping template for the placement of direct posterior C1 pedicle screws is safe and effective in the treatment of unstable C1 semi-ring fractures with similar radiographic and clinical outcomes to more traditional techniques.