Somatosensory evoked potential changes and decompression timing for spinal cord function recovery and evoked potentials in rats with spinal cord injury.

OBJECTIVE

The study aimed to evaluate changes of somatosensory evoked potentials and the effects of decompression timing on spinal cord recovery and evoked potentials by measuring the somatosensory evoked potentials of rats with spinal cord injury at different time points.

METHODS

A total of 70 SD rats were divided into the control group (group A) and the experimental group. The experimental groups included group B-D according to the severity of spinal cord injury. Somatosensory evoked potentials were evaluated in the 4 study groups after the spinal cord was opened and spinal anesthesia. Continuous operations were performed to establish the rat models of spinal cord injury until surgical trauma was detected for stable somatosensory evoked potentials. The somatosensory evoked potentials of rats were determined before injury, and 5 min, 1 and 6 h, 3 and 7 days after injury. Evoked potentials were measured before decompression, and 5 min, 1 and 6 h, 3 and 7 days after decompression in the rat models. Latency and amplitude were determined.

RESULTS

There was no significant change in latency and amplitude of somatosensory evoked potentials before and after anesthesia and operation in the control group (P > 0.05). At 1 and 6 h after spinal cord injury, the more severe the spinal cord were hit, the more significant extension and decreases were observed in latency and in amplitude, respectively. Significant changes were identified in latency and vibration amplitude at 5 min after spinal cord injury in group B, C, and D than before injury with even more obvious changes in amplitude. The latency and amplitude of the somatosensory evoked potentials in the control group and each spinal cord injury group had great difference before increasing the spinal cord injury. The rats in the 30-minute compression group had significant longer latency than those in other groups after 7 days of compression; the somatosensory evoked potential amplitude recovered faster in rats with less time for compression. The wave amplitude was significantly lower in rats with 30 min' compression than that in the other groups after 7 days.

CONCLUSIONS

Somatosensory evoked potential can well reflect the severity of spinal cord injury. The longer the spinal cord was compressed, the more significant were changes in somatosensory evoked potential. Changes in the amplitude of somatosensory evoked potential following spinal cord injury are more sensitive than latency changes for early diagnosis and prompt assessment of spinal cord injury.