Analysis of the Cervical Sagittal Alignment in Patients with Unstable Hangman Fracture Under C2∼3 Anterior Discectomy and Fusion

Abstract

To investigate the changes in the sagittal parameters of the cervical spine and the clinical efficacy of C2∼3 anterior cervical discectomy and fusion (ACDF) combined with internal fixation for unstable hangman's fractures. The clinical data of 46 patients with unstable hangman's fractures treated with both C2∼3 ACDF combined with internal fixation between May 2012 and May 2017 were analyzed retrospectively. The upper cervical angle (C0∼2), the forward translation of the C2 vertebral body (C2-T), C2∼3 local kyphosis angle (C2∼3 LK), C2∼7 cervical curvature (C2∼7 CC), C2 sagittal vertical axis (C2-SVA), and T1 slope angle (T1S) were compared preoperatively, postoperatively, and at the last follow-up to evaluate the clinical therapeutic effects. A total of 46 patients were followed-up for an average of 16 months. No aggravation of the spinal cord, nerve injury, cerebrospinal fluid leakage, or other complications occurred. Six patients had American Spinal Injury Association (ASIA) grade C preoperatively; 4 improved to grade E, and 2 improved to grade D postoperatively. Twelve patients with ASIA grade D preoperatively improved to grade E postoperatively. C0∼2, C2-T, C2∼3 LK, C2∼7 CC, and C2-SVA measurements were significantly improved postoperatively and at the last follow-up, but there was no significant change in T1S between preoperative and postoperative values. For patients with unstable hangman's fractures, C2∼3 ACDF combined with internal fixation can achieve immediate stability of the upper cervical vertebrae, effectively correct the forward displacement and angulation of C2, and restore the sagittal balance of the cervical spine. The rate of osseous intervertebral fusion is high, and there are few complications. This method can effectively promote the recovery of spinal nerve function and preserve the motor function of the cervical vertebrae.