[Treatment strategy and curative effect analysis of os odontoideum complicated with atlantoaxial joint dislocation]

To explore the treatment strategy and clinical efficacy for os odontoideum complicated with atlantoaxial dislocation.

The clinical data of 17 patients with os odontoideum complicated with atlantoaxial dislocation surgically treated from January 2006 to January 2015 were retrospectively analyzed, including 7 males and 10 females, aged 17 to 53 (43.1±11.3) years old;course of disease was 3 to 27(10.2±6.9) months. All patients received cranial traction before operation, 12 of 14 patients with reducible dislocation were treated by posterior atlantoaxial fixation and fusion, and 2 patients with atlantooccipital deformity were treated by posterior occipitocervical fixation and fusion;3 patients with irreducible alantoaxial dislocation were treated by transoral approach decompression combined with posterior atlantoaxial fixation and fusion. The operation time, intraoperative blood loss and perioperative complications were recorded. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score were used to evaluate the change of neck pain and neurological function. Atlantoaxial joint fusion rate was evaluated by CT scan.

The operation time of posterior fixation and fusion ranged from 86 to 170 (92.2±27.5) min, and the intraoperative blood loss was 200-350 (250.7±65.2) ml. No vertebral artery injury and spinal cord injury were recorded. Among the patients underwent atlantoaxial fixation and fusion, 1 patient with reducible dislocation fixed by C₂ laminar screw lost reduction after primary operation, and received anterior release again and finally occipitocervical fusion. All patients were followed up for 15 to 58 (32.0±12.2) months. VAS score was decreased from preoperative 4.2±0.9 to 1.3±0.7 at final follow up and the JOA score was improved from preoperative 11.2±1.2 to 16.9±0.8 at final follow-up. CT scan confirmed that the atlantoaxial or occipitocervical fusion wasgood, and the fusion time was 5 to 9 (6.7±0.6) months.

Surgical treatment of os odontoideum complicated with atlantoaxial dislocation can achieve satisfactory results, improve the patient's neurological function and improve the quality of life, however the surgical options needs to be individualized.