Effect Of Cervical Spinal Cord Injury On The Nerve Conduction Function In Lower Limbs

BackgroundSpinal cord injury(SCI)is a devastating disorder in central nervous system,causing sensory and motor impairments and even paralysis.Despite the physical and financial burden and prevalence of SCI,there is currently no cure for it and few treatments are available.In order to promote the improvement of limb function and improve the activity of daily living in patients with SCI,previous studies have been focused on how to reconstruct the reconstruction of the injured axons.However,it is very difficult to re-establish the link between the broken ends of SCI,and its growth rate is slower than that of peripheral nerve.It has been found that,even though the injured spinal cord regeneration,it is difficult to establish an effective pathway between the regeneration of axons and remote motor neuron.The damage of the remote motor neurons in the injury site may be related to the difficulty of the conduction pathway establishment.Clinically,it is found that some patients with SCI have the characteristics of soft paralysis,such as the decrease of muscle tone and muscle atrophy.Electrophysiological examination found neurogenic injury of muscle below the level of injury.Nerve conduction showed motor nerve axonal damage,and sensory nerve conduction was normal.Electromyography(EMG)began in the 50s of the last century,refers to the electrodes placed on the corresponding muscles,and then stimulate the electrode to give sufficient stimulation intensity,the acquisition of electrical signals are excited muscles.The function of neurons,peripheral nerve,neuromuscular junction and muscle itself can be determined by this test.EMG plays an important role in the diagnosis and evaluation of nerve and muscle diseases,and can be used as a supplement to the evaluation of SCI.At present,the study focused on the changes of local function in the spinal cord injury site and how to make the regenerated axons cross the injury end,but ignore the changes of the peripheral nerve.Therefore,through the nerve conduction examination about the neck SCI lower limbs peripheral nerve of the existence of such secondary damage,not only helps us to develop more targeted rehabilitation programme but also judge the prognosis of the patients.ObjectiveTo observe the changes of peripheral nerve conduction function of lower limbs in patients with cervical spinal cord injury(SCI),and to compare the differences between complete cervical SCI and incomplete cervical SCI.To understand the functional status of lower limb peripheral nerve after SCI,and to provide the basis for rehabilitation program.Methods20 cases of complete cervical SCI patients,20 cases of incomplete cervical SCI patients and 20 cases of normal adult were selected.Danish Keypoint EMG evoked potential instrument was used.?Motor nerve:To detect the neural conduction latency,amplitude and velocity of the tibial nerve and peroneal nerve of subjects.?Sensory nerve:To detect the neural conduction latency,amplitude and velocity of the sural nerve and saphenous nerve of subjects.Result?Motor nerve:The distal motor latency(DML)of complete injury group and incomplete injury group was prolonged and there was no significant difference between the two groups(P>0.05),but there was significant difference between the two groups and normal group(P<0.05).The abnormal rate of DML of complete injury group and incomplete injury group was below 10%and there was no significant difference between the two groups(P>0.05).The motor conduction velocity(MCV)of complete injury group and incomplete injury group was diminished and there was no significant difference between the two groups(P>0.05),but there was significant difference between the two groups and normal group(P<0.05),The abnormal rate of MCV of complete injury group and incomplete injury group was below 10%and there was no significant difference between the two groups(P>0.05).The compound muscle action potential(CM AP)of complete injury group and incomplete injury group was diminished and there was statistical difference between the three groups(P<0.05).The abnormal rate of CMAP of complete injury group and incomplete injury group was beyond 20%.And the abnormal rate of complete injury group is higher than incomplete injury group(P<0.05).?Sensory nerve:There was no statistical difference between the latency of three groups and the abnormal rate of latency was O.The sensory nerve conduction velocity(SNCV)of complete injury group and incomplete injury group was diminished and there was no significant difference between the two groups(P>0.05),but there was significant difference between the two groups and normal group(P<0.05).The abnormal rate of latency was O.The sensory nerve action potential(SNAP)of complete injury group was diminished.There was significant difference between the two groups and complete injury group(P<0.05).There was a significant difference in the SNAP of the sural nerve in the incomplete injury group compared with the normal group.There was no significant difference in the SNAP of the saphenous nerve in the incomplete injury group compared with the normal group.the abnormal rate of SNAP was 0.ConclusionThere is axonal degeneration in the lower limbs of the patients with cervical SCI and the axonal degeneration of complete cervical SCI is more severe than the incomplete cervical SCI.There is no obvious abnormality in sensory nerve.