Survey of the Cervical Spine in a Population of Adults with Down Syndrome

Objective: To determine the point-prevalence and natural history of cervical spine abnormalities in a population of adults with Down syndrome.

Design: A musculoskeletal, neurologic, and radiographic evaluation of 80 adults with Down syndrome was completed. Two groups were assessed. A prospective evaluation of a cohort of solicited adult Down syndrome participants (Group I = 57) consisted of volunteers with no known abnormalities of their cervical spine or symptoms related to their cervical spine. A clinical review of a series of adult Down syndrome patients (Group II = 23) consisted of patients specifically referred for suspected orthopedic/spinal problems.

Patients: Subjects were solicited from an Adult Down Syndrome Clinic via mailings. Participants ranged in age from 17 to 55 years old (mean age = 33).

Background Data: Subluxation of the upper cervical spine is well documented in children with Down syndrome. Little has been reported about the natural history of the cervical spine in adults with Down syndrome.

Methods: Evaluation consisted of a detailed history, musculoskeletal and neurologic examinations, and radiographs. An atlantodens interval (ADI) of > 5mm in any of the three lateral radiographic positions (neutral, flexion, and extension) was used to designate atlantoaxial instability (AAI). Participants were categorized into three classes according to their degenerative process: Class I = axial degeneration (Occiput-C2), Class II = subaxial degeneration (C3-C7), and Class III = combined degeneration (Occiput-C7). A radiographic control group consisted of 29 (mean age = 33; range 20 to 54) asymptomatic adults.

Results: Twenty-three (29%) possessed atlantoaxial instability (mean distance = 7.2 mm). Mean age of those classified with AAI was 40.8 years (range 22 to 55 years). Twelve (52%) of the 23 individuals identified with AAI had associated neurologic deficits. Atlanto-occipital translation was noted in fourteen (20%) of the total population. Sixteen (20%) of the total population were identified with an SAC <14mm. Congenital cervical stenosis was noted in ten (12.5%) of the total population. Eleven (13.8%) of the total population was identified with subaxial cervical instability. Forty-Five (56%) possessed moderate to severe cervical degeneration (Class I=0, Class II=24, and Class III=21). Cervical myelopathy resulting from degenerative changes in the lower cervical spine were noted in 6 subjects.

Conclusions: Data is significant for the presence of AAI and precocious degenerative changes in the subaxial cervical spine. Significant pathology is to be expected in patients over 30 years of age. AAI combined with subaxial cervical degeneration was the predominant pattern, and carried the highest neural risk.