Cervical spine in patients with diastrophic dysplasia – radiographic findings in 122 patients

Abstract

Background. In previous studies, typical radiological findings in the cervical spine of patients with diastrophic dysplasia (DD) have been kyphosis, displacement of the vertebrae, spina bifida occulta (SBO), anterior hypoplasia of vertebrae C3–5, and hyperplasia and dysmorphism of the odontoid process.

Objectives. To make a radiological analysis of the cervical spine in patients with DD.

Materials and methods. The study comprised 122 patients (50 males, 72 females), with an average age of 19 years (range newborn–63 years). Follow-up was available on 62 patients (51%), for an average duration of 11 years. Cervical spine alignment was measured according to Cobb's method. The height (H) and depth (D) of the vertebral body and sagittal diameter (S) of the spinal canal were measured. H/D and S/D ratios were then calculated from the measurements. The shape of the vertebrae was assessed. Displacement and movement of cervical vertebrae in neutral and bending radiographs were measured.

Results. The average lordosis in the last radiograph was 17^° (range 4°–55^°). Five (4%) patients had a cervical kyphosis with an average of 92^° (range 10–165^°) on their last radiograph. The H/D ratio increased slowly during growth and showed significant correlation with age. There was no growth spurt at puberty. The S/D ratio was fairly stable until 7–8 years of age, when it started to decline slowly. The percentage of vertebrae with a flat vertebral body and narrow spinal canal value tended to increase with age. Vertebral hypoplasia and displacement between vertebrae were most common in the mid-cervical region and resolved spontaneously with age. Degenerative changes seemed to increase with age and were already visible during the second decade of life. SBO was noted in 79% of patients.

Conclusions. The most common alignment in the cervical spine is lordosis in adulthood. The vertebral bodies are flattened and the spinal canal is narrowed. Vertebral body hypoplasia and displacement usually resolve spontaneously during growth. Degenerative changes in the cervical spine are common, but vertebral anomalies are rare. Prevalence of SBO is high.