The effect of occipitocervical fusion for treatment of craniovertebral junction deformity with atlantoaxial instability

Abstract

Objective To investigate the effect of occipital-cervical fusion on craniocervical junction deformity with atlantoaxial instability. Methods A total of 35 patients with craniocervical junction deformity with atlantoaxial instability were analyzed retrospectively, who underwent occipitocervical fusion at Department of Neurosurgery, the First Affiliated Hospital, Zhengzhou University from January 2013 to December 2015. The patients were followed up for 6-30 months. Before and after operations, the patients received evaluations based on the Japan Orthopedic Association (JOA) score. Atlantoaxial dislocation was assessed by means of the atlantoaxial distance (ADI); the distance between the odontoid and Chamberlain's line(marked as H) was measured to evaluate the vertical displacement; and the cervicomedullary angle (CMA) was used to assess spinal cord compression. Results No complications including rupture of vertebral arteriesor nerve injuries occurred during the operations. At 7 days post surgery, the patients' mean scores of JOA, ADI, H and CMA were (11.6±1.6), (2.8±0.6) mm, (3.1±1.5) mm and (152.7±6.2) degrees, respectively. The preoperative corresponding values were (10.8±1.7), (8.2±2.9) mm, (8.1±5.5) mm and (130.1±10.3) degrees. The differences were all statistically significant (P<0.05). Postoperative findings demonstrated that 1 patient (3%) died of extensive brain stem infarction and 1 patient (3%) had undergone a revision operation due to fusion failure at the third month after surgery. The other patients reported good outcomes of bone grafting and internal fixation. The follow-up period was 6～30 months (mean, 14.8±7.8 months). Thirty-two patients reported symptom relief and 2 patients had no remission. The JOA score was (13.2±1.7) points at the last follow-up and statistically significant compared with the preoperative level(P<0.05). Conclusion The occipital-cervical fusion seems to be an effective treatment for the craniovertebral junction deformity with atlantoaxial instability. Key words: Atlanto-axial joint; Joint instability; Arthrodesis; Craniovertebral junction deformity