EVALUATION OF SERUM OSTEOBLAST MITOGENIC ACTIVITY IN SPINAL-CORD AND HEAD-INJURY PATIENTS WITH ACUTE HETEROTOPIC OSSIFICATION

Study Design. This was a blind, prospective study of the effect of ser a from patients with spinal cord and head injuries on osteoblast proli feration. Objectives. The authors studied whether a humoral factor tha t stimulates the formation of heterotopic bone is released into the ci rculation after a neural injury. Background Data. Other authors have s hown that a humoral osteoinductive factor may be released after head a nd spinal cord injuries. Methods. Serum was obtained at certain times throughout the first 12 weeks post-injury and from control subjects. I t was incubated with osteoblasts harvested from fetal rats, as well as with fibroblast controls. Results. There was a significant rise in se rum mitogenic activity after injury in both groups. When patients that developed heterotopic ossification were compared to other patients an d controls, no significant differences were seen. Conclusions. This in vitro study fails to support a humoral mechanism for heterotopic ossi fication after spinal cord or brain injuries.