Spontaneous regression of periodontoid pannus mass in psoriatic atlantoaxial subluxation - Case report

Study Design. A case report of a 41-year-old man with psoriasis who had cervical myelopathy caused by atlantoaxial subluxation and periodontoid pannus mass. Objective. To describe the possible mechanism underlying the periodontoid pannus formation and the optimal treatment for such cases. Summary of Background Data. Atlantoaxial subluxation causing spinal cord compression at the craniocervical junction may develop in patients with rheumatoid or psoriatic arthritis. Periodontoid pannus formation plays an important role in compromising the anteroposterior diameter of the spinal canal and in causing neurologic deficits. Transoral transpharyngeal excision of the pannus is sometimes thought necessary for anterior decompression of the spinal cord. Spontaneous resolution of the periodontoid pannus after posterior atlantoaxial fusion and fixation has been documented in rheumatoid arthritis, but not in psoriatic arthritis. Methods. The patient underwent posterior atlantoaxial fusion and Halifax fixation. Results. The patient experienced clinical improvement. Regression of the periodontoid pannus mass was observed on magnetic resonance imaging. Conclusions. Posterior fusion and instrumentation resulted in spontaneous regression of the pannus mass and symptomatic relief. This report provides evidence that atlantoaxial instability may be the sine qua non for the formation of periodontoid pannus, and that amelioration of such instability leads to spontaneous resolution of the pannus mass.