Cystic Deterioration of the C1-2 Articulation: Clinical Implications and Treatment Outcomes

Object: Synovial cysts of the cervical spine are rare. Further, synovial cysts of the C1-2 articulation, or retroodontoid cysts, are very rare, with fewer than 20 cases reported overall. The authors report on a single-institution series of 10 patients with C1-2 retroodontoid synovial cysts.

Methods: The charts of 10 patients with pathologically confirmed synovial cysts following resection between January 1998 and June 2009 were reviewed. The clinical presentation, radiographic findings, surgical management, and pre- and postoperative functional levels (reported as a modified Rankin outcome) are reported.

Results: All 10 patients underwent attempts at complete resection of the synovial cyst; none of the lesions were simply aspirated. All 4 patients with an initial recommendation of observation alone ultimately underwent surgery because of their swift neurological deterioration. The mean age at surgery was 75.4 ± 4.6 years (range 54-81 years). The mean presenting cyst volume was 4.6 ± 1.7 cm(3). Nine of 10 patients underwent transoral resection of the cyst with posterior fusion. Six of the 10 patients underwent additional posterior laminectomy for decompression. The hospital length of stay varied from 2 to 45 days, with a mean of 19 ± 7 days. All patients undergoing transoral decompression had varying degrees of difficulty with postoperative dysphagia, diagnosed using videofluoroscopy. All patients improved in their modified Rankin Scale score after surgical intervention with a mean follow-up of 42 months (95% CI 12-72 months).

Conclusions: Synovial cysts of the atlantoaxial joint are rare. They occur in older patients in whom clinical deterioration is likely to occur. In most cases, these cysts can be diagnosed preoperatively. Transoral decompression with posterior fusion is an effective treatment for C1-2 degenerative cysts and can be accomplished with few complications. However, the ideal treatment for these lesions remains unknown.