Motor and Sensory Evoked Potentials in Normal and Acute Spinal Cord Injured Rats.

Ji, Chul; Lee, Jae Soo; Ha, Young Soo; Choi, Chang Rak; Song, Jin Un

Original Article

Journal of Korean Neurosurgical Society 1987;16(4): 1171-1182.

Chul Ji, Jae Soo Lee, Young Soo Ha, Chang Rak Choi, Jin Un Song

Department of Neurosurgery, Catholic University Medical College, Seoul, Korea.

ABSTRACT

Electrical monitoring of the nervous system offers the potential for the detection of injury, intraoperatively. The relationship of MEP(Motor Evoked Potential) and SEO(Sensory Evoked Potential) taken in 30 rats before and after spinal cord injury is reported. MEP was obtained from distal portion to the site of spinal cord injury by electrical stimulation of the cerebral motor cortex after insertion of a ball electrode in the cerebral motor cortex. SEP was collected at the cerebral somatosensory cortex during the sciatic nerve stimulation. Experimental animals were divided into a 20 gcm spinal cord-trauma group and a 50 gcm spinal cord-trauma group. Changes of cardiopulmonary function after cerebral motor cortex stimulation and pre-and post-injury MEP and SEP were obtained at constant time interval. The results were follows : 1) Significant changes in blood pressure, pulse rate, and respiratory rate were noted to be elevated after stimulation of cerebral motor cortex and these were returned to normal in 10 minutes after stimulation. 2) MEP in control group showed that the latency was 8.6+/-1.54 msec and the amplitude was 20.60+/-3.2 microV. In MEP of 20 gcm spinal cord trauma group, the latency was increased to 30% (11.26+/-2.76 msec) compared to control group at 10 minutes after the injury and the amplitude was decreased to 29% (14.60+/-1.99 microV). The latency was slowly decreased with the passage of time, to 21% increase. (10.42+/-1.84 msec) at 1 hour after injury but the amplitude was not changes. In 50 gcm spinal cord-trauma group the latency was decreased to 75% (4.9+/-1.52 microV) compared to control group. With the passage of time. no change was revealed in latency but amplitude was decreased. The amplitude was decreased to 80% (4.00+/-1.49 microV) compared to control group. Change of MEP was marked in 50 gcm spinal cord-trauma group. With the passage of time MEP was slightly improved in 20 gcm spinal cord-trauma group but deteriorated in 50 gcm spinal cord-trauma group. 3) The latency of SEP in control group was 12.22+/-0.7 msec and the amplitude of those was 20.00+/-2.21 microV. No significant statistical change was recorded in the SEP of each spinal cord-trauma group compared to control group. MEP might be more important indicator than SEP in estimation and evaluation of the functional change of spinal cord injury.