Cervical motion after adding a posterior pad to the halo vest

Investigators have shown that significant segmental motion occurs in patients immobilized in halo vests. One cadaver study showed that this is decreased with a posterior pad added to the construct. To improve nonoperative care of patients with cervical trauma, segmental cervical motion was evaluated in normal volunteers immobilized in a halo vest with and without a posterior pad. Two commonly used methods to measure sagittal angulation were used. Thirty normal volunteers were placed in halo vests by using positioning pins on the cranium. A sphygmomanometer attached to the posterior uprights of the vest inflated to 40 mm Hg was used as a posterior pad at the greatest visible lordosis. Lateral radiographs of the cervical spine were taken with volunteers in the upright and supine positions with and without the posterior pad inflated. Radiographs were randomly sorted and were each read twice by 3 readers. Measurements of the posterior atlantodental interval, sagittal displacement, and sagittal rotation were recorded using 2 different methods: the Buetti-Bauml method, which uses lines drawn along the posterior vertebral bodies, and the method of White and colleagues, which uses lines drawn along the inferior vertebral bodies. Inflation status of the pad showed no statistically significant difference in any of the measured variables. This was true for both methods of measurement. Application of a posterior pad to the halo vest did not show any change in the segmental motion of the cervical spine in normal volunteers.