Occipitoatlantoaxial fusion utilizing a rectangular rod.

Atlantoaxial subluxation has been treated conventionally by Gallie posterior fusion. This technique, however, has disadvantages such as the frequent occurrence of pseudarthrosis, a high probability of relapse, and the necessity of long-standing strict external fixation until bone fusion. To overcome these problems, posterior occipitoatlantoaxial fusion was performed using a rectangular rod that assures strong internal fixation in 16 patients with atlantoaxial subluxation. The condition was complicated by superior migration of the dens in five patients. Clinical and roentgenographic examinations before and after the operation showed improvements in neurological symptoms and in pain in the neck and occipital region in all patients. Bone fusion was observed in all patients and reduction, performed to the extent possible during the operation, was retained adequately. The present method, which provides strong internal fixation, allows bone fusion and early initiation of rehabilitation with a simple external support of the neck. It also facilitates laminectomy of C1 in patients with associated myelopathy. This procedure, therefore, is particularly effective in patients with marked instability or with rheumatoid arthritis and makes postoperative application of a halo vest or skull traction unnecessary.