Erosive and subluxing cervical spine disease in patients with psoriatic arthritis.

Cervical spine involvement with psoriatic arthritis has been reported to occur in about 35% of patients and to be primarily ankylosing in nature. This previously described pattern is characterized by syndesmophytes, ankylosis and ligamentous ossification. Our study defines the incidence and clinical characteristics of a rheumatoid-like form of inflammatory cervical spine involvement. This pattern is characterized by apophyseal and odontoid erosions, and axial and subaxial subluxations. Clinical histories were obtained from 28 patients with both psoriasis and inflammatory arthritis between the years of 1971 and 1984. Cervical spine involvement was found in 75% of the group, 13/21 had ankylosing and 8/21 inflammatory characteristics. Three of our patients developed cervical myelopathy, one in the ankylosing and 2 in the inflammatory subgroup.