Influence of halo vest treatment on vital capacity.

Respiratory function (vital capacity) was studied in 20 consecutive patients with unstable cervical spine injuries treated with a halo vest. Eight patients were neurologically intact. Twelve patients had incomplete spinal cord injuries that were classified on a neurologic function scale (Sunny-brook) immediately and 3 months after injury. Spirometric tests were done within 1 week of halo vest fixation, after 3 months of treatment, and 1 week after dismounting of the halo vest. The results showed that initial vital capacity was smaller than predicted normal in all patients and 30% less in neurologically impaired patients. Both groups improved during the treatment and somewhat more after removal of the halo vest. In neurologically intact patients, the halo vest caused a respiratory restriction of 10%, which was fully regained after removal of the halo vest. The difference between the groups remained throughout the study. There was no evidence that the halo vest itself affects the vital capacity more in patients with incomplete cord lesions than in neurologically intact patients. All of the cervical spine injuries healed uneventfully.