Patients with type IV Ehlers-Danlos syndrome may be predisposed to atlantoaxial subluxation.

Objective. To determine if atlantoaxial subluxation is a complication of Ehlers-Danlos Syndrome (EDS). Methods. Observational study of a selected cohort of patients with EDS attending a national meeting. Twenty-six patients with EDS (19 with type III ; 3 with type IV ; 1 each with types II and I ; 2 with undefined subtypes) were radiologically evaluated. Lateral flexion-extension views of the cervical spine in each patient were read in blinded fashion by a radiologist and compared to unblinded interpretations made by a separate radiologist. Measurement was taken from the most inferior aspect of the anterior arch of Cl to the dens along a horizontal plane. The remainder of the radiograph was examined for abnormalities. Results. Two patients with EDS type IV had radiographic evidence of atlantoaxial subluxation (p=0.013 Fisher's exact test). Evidence of horizontal translation between vertebral bodies below C2 was noted in 3 patients. Cervical arthrosis was present in 9. Conclusions. Atlantoaxial subluxation may be a more common finding in persons with type IV EDS than previously thought. Examination of the cervical spine radiographically should be considered before administering general anesthesia to these patients.