Morphometric evaluation of the cervico-thoracic junction. Practical considerations for posterior fixation of the spine.

Abstract

Linear and angular measurements were performed on 128 vertebrae (16 spines) from C5 to T5. Vertebrae were studied to characterize vertebral shape and size changes in the cervico-thoracic region. Analysis of vertebral anatomy has been extensive and well characterized. Regions of transitional anatomy necessitate further study due to the often abrupt changes in anatomic relationships. Two observers performed linear and angular measurements including pedicle width, height, and length, as well as pedicle-body, pedicle-lamina, lamina-transverse process, and pedicle-lamina angular measurements. Pedicle axis projection on the posterior aspect of the lamina was also calculated. The mean pedicle width ranged from 7.8 mm (T1) to 4.4 mm (T5). The body-pedicle angle decreased > 4 degrees per level in the transverse plane, from 50 degrees (C5) to 11 degrees (T5). The axial projection of the pedicle changed throughout the region (compared with level above) and was significant for T1. Because of the complexities of the cervico-thoracic junction, additional characterization increases the knowledge of the anatomic relationships in this region.