The Application Of Sympathetic Skin Reaction In Neruopathic Pain

Background and objective:Sympathetic skin response(SSR)is the skin surface potential that occurs after the human body is stimulated by the excitement of the sympathetic nervous system,and it can detect C-type unmyelinated small fibers of sympathetic nerve.With the advantages of high sensitivity,being fast,noninvasive and easy to operate,SSR is currently used to assess the autonomic nervous function of a variety of diseases.The current study has found that the Abnormal sympathetic nervous system plays an important role in the pathogenesis of neuropathic pain(Ne P),and the C-type unmyelinated small fibers are involved in most parts.In our study,SSR was performed on healthy volunteers and patients with Ne P in order to:1.explore the presence of autonomic dysfunction in patients with Ne P.2.explore whether Ne P patients have evidence of small fibers’ s damage.3.investigate whether there are differences in SSR performance between different types of Ne P,such as trigeminal neuralgia and herpes zoster-associated pain.4.provide inspiration for the mechanism、diagnosis and treatment of Ne P.Methods:Twenty-one healthy volunteers and 41 patients with Ne P(including 14 patients with trigeminal neuralgia,14 patients with herpes zoster-related pain and 21 patients with other types of Ne P)with an average age of 56-62 were selected as control group,Trigeminal neuralgia group,herpes zoster-associated pain group,and other neuropathic pain group.Record the basic information and medical history of the subject.We use the Shanghai haishen electromyography evoked potentiometer to perform a sympathetic skin reaction test for every subject,affix the recording electrode to the palms of both hands and feet,then post the reference electrode on the back of both hands and feet,and post the ground electrode on the left wrist stripes.We put the stimulus electrode on the left median nerve at about 3cm from the wrist,and adjust the Stimulus intensity to 30 m A,Stimulation duration to 0.15 ms,Sensitivity to 0.5m V / D.Give a stimulus Randomly and measure the latency and amplitude values,and then get the results.Compared with the control group,the SSR abnormal criteria of the case group were as follows: 1.No waveforms were drawn;2.Latency> Control group mean +1 times standard deviation;3.Amplitude: less than 1/2 of the mean value of the control group,or> Control group mean +1 times the standard deviation.Use SPSS19.0 software to analyse,T test for different groups,and Chi-square test for comparising the Rates.Results:1.The difference in age and gender between the control group and the three pain groups has no statistical significance,which makes it feasible for the comparison.2.Compared with the control group,the SSR amplitude of the trigeminal neuralgia group increased,in which the upper extremity amplitude increased,and the difference was significant(P <0.01);the lower extremity amplitude increased,and the difference was statistically significant(P <0.05).Besides there was no significant difference in the incubation period between the trigeminal neuralgia group and the control group.3.Compared with the control group,the SSR rate of the herpes zoster-associated pain group was lower,and the latency was prolonged,in which the latency of the upper limb was prolonged,and the difference was significant(P <0.01);the latency of the lower limb was prolonged and the difference was statistically significant(P <0.05).Besides there was no significant difference in volatility between the herpes zoster-related pain group and the control group.4.Compared with the control group,the latency of the other neuropathic pain group was prolonged,and the difference was significant(P <0.01).The amplitude of the other neuropathic pain group was not significantly different from that of the control group.5.The rate of SSR waveforms in the four groups was: control group(100%)= trigeminal neuralgia group(100%)> other neuropathic pain group(85.7%)> herpes zoster associated neuralgia group(64.3%).Use Chi-square test for comparising the rates,and there was no statistical significance on the comparison in the rate between the other neuropathic pani group and the control group(P = 0.139> 0.05).The rate of herpes zoster-associated pain group was statistically significant compared with the control group(P = 0.014 <0.05).There was no statistical significance in the rate between the herpes zoster-associated pain grouphe and the other neuropathic pani group(P=0.139>0.05).Conclusions:1.The patients with Neuropathic pain are suffering with autonomic nervous system dysfunction,which is worth clinical attention.2.The Sympathetic excitability of patients with Trigeminal neuralgia increased.3.Patients with herpes zoster-associated pain may have damages of C-type unmyelinated small fibers.Among them,herpes zoster is more obvious than herpes zoster neuralgia.4.Sympathetic skin reactions can be used as objective electrophysiological means to assess the autonomic nerve function of pain patients.