Use of Intraoperative Imaging to Preserve C1-C2 Mobility in Complex Atlas-Hangman Fractures

Background: Combination fractures of the C1-C2 complex especially atlas and hangman are relatively uncommon and management usually compromises C1-C2 mobility. Objective: To evaluate the treatment of combined C1- hangman's fracture with and without intraoperative O -arm based navigation system, and its outcome in terms of preserving C1-C2 mobility. Methods: This was a case series of patients with combined C1 and hangman's fracture, managed at a tertiary care hospital during February 2009 to December 2016. Neurological function assessed with American Spine Injury Association (ASIA) impairment scale. Radiological fusion of the operated segment assessed with computed tomographic scan, criteria used for successful fusion included formation of callus across the fracture. Preservation of rotational motion between C1 and C2 was assessed by cervical flexion rotation (CFR) test. Results: We included 10 patients (male/female: 9/1; mean 47.7 +/- 17.5 years) in our study. Operative intervention was performed in 9 patients. We used intraoperative computed tomogram (CT) scan with navigation in 5 patients. The mean follow-up period was 28.7 months (range 6 to 70 months). Neurological recovery occurred in all 4 patients with preoperative neurological deficits. Radiological fusion occurred in all cases. Rotation at C1-2 was preserved in all 5 cases operated under O-arm guidance and in one patient with type 1 fracture who was managed conservatively. Conclusions: The goals in treating these complex fractures are to achieve early maximum stability and preserving maximum range of motion. These are often competing phenomena, which can be achieved by using intra operative CT scan and navigation system.