How Does Cervical Sagittal Balance Change After Hangman Fracture Treated with Anterior or Posterior Approach Surgery?

Objective: To assess and compare clinical outcomes and sagittal balance after unstable hangman fracture between C2-C3 anterior discectomy and fusion (ACDF) and posterior C2-C3 short-segment fixation and fusion.

Methods: A total of 45 patients underwent ACDF (20 patients) and posterior C2-C3 short-segment fixation and fusion (25 patients) between March 2005 and June 2013. Visual analog scale, Neck Disability Index, Odom grading system, American Spinal Injury Association Impairment Scale (AIS), C2-C3 angle, displacement of C2-C3 (D), occiput-C2 angle (O-C2 angle), cervical lordosis (CL), and C2-C7 sagittal vertical axis (cSVA) were assessed preoperatively and at final follow-up.

Results: The follow-up duration was 20.0 months (range, 18.0-21.0 months) in the anterior group and 19.0 months (range, 18.0-20.0 months) in the posterior group. Satisfactory bony fusions were achieved in 2 groups. The VAS score and NDI score were significantly lower than their respective preoperative score in each group (P < 0.001), whereas there was no difference between 2 groups (P = 0.78; P = 0.85). A statistically significant decrease of O-C2 angle and cSVA between preoperative and postoperative data was found in each group (P < 0.001), and CL increased statistically (P < 0.001). For O-C2 angle, CL, and cSVA, the changes of parameters after the posterior approach were more significant than after the anterior approach (P < 0.05).

Conclusions: Both anterior and posterior surgical techniques are effective for unstable hangman fracture and both can restore the sagittal balance of the cervical spine. Furthermore, the posterior approach has an advantage over the anterior approach in promoting recovery of cervical sagittal balance.