The L4 Anterior Nerve Rootlet Injury Of Rats Affect The MEP Of Ipsilateral Tibialis Anterior

Backgroud and ObjectivesThe method that establishing an artificial somatic automatic reflex arc to treat the patiants with neurogenic bladder is effective. In thus operations, only a part of anterior nerve rootlet need to be amputate and to be made an anastomotic operation with splanchnic nerves. The objective of this study was to investigate the possibility and significance motor evoked potentials (MEP) in rats with anterior nerve rootlet injury and to estmate the suitable part of anterior nerve rootlet to be used establishing an artificial somatic automatic reflex arc.Materials and Methods24 healthy female Sprague-Dawley(SD)rats were divided into 4 groups, according to the amputation degree of the L4 anterior nerve rootlet. Thery are 1/4 amputation group,1/3 amputation group, 1/2amputation group and all amputation group. According to the operation plan remove part of nerves on one side, the other side of nerves are used as a standard of comparison. Two and twelve weeks later, evoked the L4 nerve rootlet and record the motor evoked potentials, discussed the relationship between the index of MEP and the degree of nerve root injury.Results 1. Except the cases that all the interior nerve rootlet of L4 was amputated, motor evoked potentials could be recorded in tibialis anterior muscle.2. Evoked motor evoked potential (MEP) threshold current strength and motor evoked potential (MEP) latency and anteriorroot injury was a positive correlation. Motor evoked potential (MEP) amplitude and the L4 anteriorroot injury was a negative correlation.3. After 2 weeks compared to 12 weeks after motor evoked potential (MEP) index, the threshold current intensity decreased stimulation, motor evoked potential (MEP) latency shortened,amplitude increased, but no significant difference between the majority of indicators (P>0.05)Conclusions1. Use the needle electrod stimulate the nerve rootlet with the current intensity above the threshold, the motor evoked potentials (MEP) could be monitored in the corresponding muscle, unless the anterior nerve rootlet was completely amputated.2. Stimulate the nerve root, evoked motor evoked potential (MEP) threshold current strength and motor evoked potential (MEP) latency and nerve root injury is positively related to, motor evoked potential (MEP) amplitude and nerve root injury were negatively related.3. Motor evoked potential (MEP) on the detection of nerve root injury indicators, the super-stimulation motor evoked potential (MEP) amplitude to reduce the most sensitive.