Effect of trauma dose on spinal cord edema

Abstract

The spinal cord of anesthetized cats was subjected to impact trauma of different intensities to determine how changes in trauma magnitude affect the formation and distribution of edema. All animals underwent a laminectomy to expose the cord segments corresponding to the T5-7 vertebrate. Fourteen cats were injected with fluorescein-labeled albumin and subjected to 260, 360, 500 or 700 g-cm injury to the spinal cord. They were sacrificed at 8 h after trauma. Twelve cats were injected with fluorescein-labeled dextrans of 20,000, 40,000, 70,000 or 150,000 MW prior to 500 g-cm injury and sacrificed 8 h after trauma. Serial cord sections from both groups were studied by fluorescence microscopy. In 9 cats, sections of cord were removed 8 h after trauma of 260, 360 or 500 g-cm impact, and 1-cm sections were assayed for dry weight. Extravasated tracers were present in areas of hemorrhage at the site of impact in all animals. Extensin of tracers and increases in tissue water rostrally and caudally from the site of impact were observed consistently with time only in animals receiving 500 or 700 g-cm trauma. The distance of migration was similar for all tracers. The longitudinal distribution of increased tissue water was consistent with the distribution of fluorescent markers. The longitudinal extension of posttraumatic edema evidently is directly related to the amount of initial trauma.