Study On The Neural Mechanism Of Unspecified Functional Anorectal Pain Based On The Rectal Sensory Evoked Potential

ObjectiveObserve the clinical features of unspecified functional anorectal pain,and explore the Possible mechanism of unspecified functional anorectal pain through rectal cerebral evoked potentials(RCEP)and anorectal manometry(ARM).Contents and methods(1)32 unspecified functional anorectal pain patients were recruited from the outpatient clinic of the Anorectal Center of Nanjing Hospital of Traditional Chinese Medicine.The patient ’s medical history was collected and all patients filled out the functional anorectal pain history collection form,visual analogue score(VAS),self-rating anxiety scale(SAS),self-rating depression scale(SDS),and Simple SF-36 health survey(SF-36).(2)Recruit 32 healthy volunteers.(3)All subjects were examined with RCEP and ARM,and the differences of RCEP and ARM parameters between the two groups were compared.Statistical analysis was performed using SPSS 20.0 software.Results(1)The age of 32 patients ranged from 27 to 76(51.13±12.51)years old.In terms of nature of the pain,there were 24 cases of falling pain,5 cases of stabbing pain and 3 cases of burning pain.In terms of the area of pain,the pain was located in the anus in 23 cases and perianal in 9 cases.Among the female patients,17 female patients had a history of vaginal delivery,and 3 of them had a history of multiple vaginal delivery.In terms of TCM syndrom,there were 16 cases of pectoral qi collapse,7 cases of qi stagnation and blood stasis,5 cases of liver-qi depression and 4 cases of liver-kidney yin deficiency.(2)In the control group,the latencies of P1,N1 and P2 were 45.11 ± 3.27ms,99.23 ± 13.67ms and 201.98 ± 31.30ms,respectively;the amplitudes of P1/N1 and N1/P2 were 5.62±1.58uv and 8.26 ± 2.48uv,respectively.In the experimental group,the latencies of P1,N1 and P2 were 52.86 ± 14.46ms,117.84 ± 37.41ms and 190.03 ± 50.32ms,respectively;the amplitudes of P1/N1 and N1/P2 were 3.92 ± 2.15uv and 5.10 ± 2.89uv,respectively.The latency of P1 wave in patients was significantly longer(P<0.01)and the latency of N1 wave was longer than that in healthy volunteers(P<0.05);there was no significant difference in the latency of P2 wave between the two groups(P>0.05);compared with control group,the amplitude of P1/N1 wave and N1/P2 wave in patients were significantly lower(P=0.000).The P1 latency of patients with pectoral qi collapse syndrome was significantly longer than that of patients with qi stagnation and blood stasis syndrome(P<0.01).(3)18 of 32 patients and 23 of 32 healthy volunteers completed the ARM examination.Compared with healthy volunteers,the maximum voluntary squeeze pressure of patients was lower(P<0.05),the anal diastolic pressure and rectal pressure during straining were significantly lower(P<0.01).In terms of sensory threshold,the maximum tolerance threshold of the patients was lower than that of the control group(P<0.01).In terms of nerve reflex,the rate of abnormal defecation reflex in patients was higher than that in the control group(P<0.01),and larger volum was needed to induce anorectal inhibition reflex(P<0.01).(4)The latency of P1 wave was negatively correlated with resting pressure(P<0.05).Conclusion(1)RCEP examination can be a simple and effective way to evaluate the rectal sensory pathway,and can provide an objective basis for the evaluation of brain-gut interaction.(2)Compared with healthy volunteers,the rectum-cerebral cortex nerve signal transduction pathway in patients with unspecified functional anorectal pain is abnormal and the conduction was prolonged,especially in patients with pectoral qi collapse.(3)The results of ARM examination showed that low pelvic floor muscle activity,abnormal pelvic floor muscle coordination function and decreased tension may also be one of the pathogenesis of unspecified functional anorectal pain.The correlation between resting pressure and P1 latency suggests that the change of anal sphincter tension may be related to the abnormality of neural pathway.