Spontaneous EMG Monitoring On Spinal Nerve Roots Of Rats

Background and objective: The injury of the spinal nerve root caused a severe consequence in the operation of lumbar spine.Recently, to reduce the injuries,there were many studies on intraoperative evoked potential monitoring,which was not general application due to many influention factors.The objective of this study was to investigate the possibility and significance on real-time monitoring in the rats operation of lumbar spine,and to use evoked potential to estimate the damage.Methods: 18 healthy female Sprague-Dawley (SD) rats were respectively exposed left and right 4,5,6 lumber spinal nerve roots,which were drawed by cotton bud or surgical instruments,and simultaneously recorded spontaneous muscles electromyogram with stylus puted in gastrocnemius.Once recorded spontaneous electromyogram,the stimulus must be ceased. Compare before exposure,after exposure and after stretch of the somatosensory evoked potential(SEP) amplitude and latency measured in the same spinal nerve roots, and compare before and after the stretch of the motor nerve conduction velocity amplitude and latency, as well as compare spinal nerve root morphology before and after stretch in order to the assessment of spinal nerve root injury.At last,half-severed spinal nerve root and measured the SEP and motor nerve conduction velocity,discussed the sensitivity of the index of nerve root injury.Results:1. Stretch stimulus all produced the motor unit potential with stylus puted in gastrocnemius,speakers send out the voices at the same time.2. There were no significant changes in amplitude and N and P point latency of SEP before exposure,after exposure and after stretch spinal nerve roots,which recorded spontaneous muscles electromyogram(P>0.05). There were no significant changes in amplitude and latency of compound muscle electromyogram(P>0.05).3. Compared before and after stretch spinal nerve roots HE stained and observed by optical microscopy, there were no injury performances, the structures remain intact.4. In a state of semi-severed spinal nerve roots,the amplitude of SEP compared with before exposure,after exposure and after stretch,the differences were significant (P<0.05).Conclusions:1. When stretching the exposed spinal nerve root by surgical instruments or cotton bud,the muscle dominated by the spinal nerve root can be recorded spontaneous EMG,with a 100% positive rate.2. The spinal nerve root produced spontaneous EMG, both in structure or function,do not cause injuries,so spontaneous EMG play a monitoring role in the the operation of lumbar spine.3. During somatosensory evoked potentials injure monitoring,the most sensitive index is the amplitude.