Effect of immediate decompression in complete spinal cord injury in rats.

The value of decompression surgery after complete spinal cord injury is controversial. This study examines whether decompression is useful in paraplegic (not paraparetic) rats and, if so, what the optimim time is after injury. The spinal cords of 126 female rats were compressed at thoracic level 9 with a mini Yasargil clips. Rats were assigned to 5 case groups, and one sham-operated group. Clips were removed after 3 seconds (3s), 1 hour (1h), 6h, 3 weeks (3w), or no decompression. Locomotor behavior scoring categories ranked based on the BBB Locomotor Rating Scale. Under histopathologic evaluation, the maximum surface (%) of damaged area was measured and the severity of inflammation, congestion and hemorrhage, necrosis, fibrosis and gliosis were evaluated in double-blind manner. There was not significant difference in survival among all groups of compressed spinal cord. There was neither statistically meaningful difference nor progressive changes in BBB except for 3s group at 4, 11, 18, 25, 32, 39, 46-days (p<0.05). In complete spinal cord injured rats, a good correlation between absence of tail reflex and consistency of zero BBB was found. Mean ranking percent of damaged surface area revealed significant difference between damaged groups (P=0.039). Very early spinal cord decompression is useful in traumatic paraplegia in rats. Absence of tail reflex shows poor prognosis.