Morphological analysis of the cervical pedicles, lateral masses, and laminae in developmental canal stenosis

Retrospective cross-sectional study.

This study aimed to elucidate the relationship between developmental spinal canal stenosis (DCS) and morphologic features in the cervical spine by comparing the features between DCS and nondevelopmental spinal canal stenosis (NDCS).

DCS is an important predisposing factor for cervical myelopathy. Further, various posterior cervical spinal instrumentations have been developed. However, no study has specifically addressed the cervical posterior morphology of DCS.

A total of 52 consecutive patients underwent cervical spine computed tomography myelography. Axial images of the largest pedicle diameter were selected from C3 to C7 vertebrae and 260 images were analyzed. The following parameters were measured: spinal canal longitudinal diameter (SCLD), spinal canal transverse diameter, osseous spinal canal area, dural sac area, spinal cord area, pedicle outer width, pedicle axis length, pedicle transverse angulation, lateral mass longitudinal diameter, lateral mass transverse diameter, lamina outer width, and lamina axis length. The participants were classified into 2 groups: DCS group (SCLD <12 mm at any level) and NDCS group (SCLD ≧12 mm at all levels).

The mean osseous spinal canal area and dural sac area at C3-C5 in the DCS group were less than those in the NDCS group. The mean spinal cord area did not differ significantly at C3-C7 between the groups. The mean pedicle outer width at C6 and C7 in the DCS group was less than that in NDCS group. The mean lateral mass transverse diameter at C5 and mean lateral mass longitudinal diameter at C3, C5, and C6 in the DCS group were less than those in the NDCS group.

Myelopathy is expected to progress in patients with DSC and these patients with severe neurologic symptoms may need cervical operation. However, posterior screw insertions should be considered more carefully than in NDCS patients.