The Applied Research Of Somatosensory Evoked Potential Monitoring In Spinal Deformity Orthopedic Operation

【Objectives】1. To analysis the influencing factors of the somatosensory evoked potential (SEP)monitoring during spinal deformity correction operation application, explore theforecasting index and establish initially the prediction model of bleeding volume and meanarterial pressure when SEP amplitude become difference abnormalities.2. To study the application value of somatosensory evoked potential（SEP）monitoring during surgical correction of spinal deformities.【Methods】1. The SEP monitoring datas of86patients suffered the spinal deformity correctionoperation were analyzed retrospectively. Anomal changing of the SEP amplitude deviationas the affected SEP index was analyzed with gender, age, height, weight, mean arterialpressure range, amount of bleeding, operation time, the wire length of hypodermic needleelectrode, the application electric grinding drilling, the application gas drill grinding,operation bed (whether being connected with electric power or not) by Pearson orSpearman correlation to select the related factors for multiple linear regression analysis.2. SEP monitoring during surgical correction of spinal deformities were performedfor36cases.There were10males and26females.The average age was18.8years（range:6.5～45.2years）.The pathogenetic diagnoses of the adult scoliosis were18cases, adolescent idiopathic scoliosis14cases and congenital scoliosis4cases.The surgicaltechnique was all adopted the posterior Ponte osteotomies. The abnormal criteria of SEPmonitoring was defined as the decline of wave amplitude over50%and/or the elongationof latent period over10%.【Results】1. Statistic significant linear relationships were demonstrated among in the SEPindex (the abnormal difference of P40/N50amplitude),the amount of bleeding (P <0.01),the range of mean arterial pressure fluctuation (P <0.01), electric grinding drillwhether use or not (P <0.01), gas drill grinding whether use or not (P <0.01), theelectric operation bed whether connected with electric power or not (P <0.01). Statisticsignificant linear relationships were not demonstrated among in the SEP index (the abnormal difference of P40/N50amplitude), sex (P>0.05), age (P>0.05), height (P>0.05), weight (P>0.05), operation time (P>0.05), the wire length of percutaneousneedle electrode (P>0.05). The amplitude of the SEP will significantly changeincluding close to or even lower than the baseline level when Mean arterial pressure lessthan50mmHg or50mmHg around or bleeding more than1249ml. it similars to thePerformance of intraoperative spinal cord or nerve injury.2.8cases had abnormal SEP while making the osteotomy decompression andcorrection and the processes were paused at once until the problems were solved.2casessuffered blood pressure decline from bleeding during the osteotomy, one was inthoracolumbar segment, the other one was in middle thoracic spine.4cases wereconsidered as association of inadequate surgical manipulations,2in middle thoracicspine,and2in thoracolumbar segment.2cases in congenital scoliosis and adult scoliosisrespectively,who had abnormal SEP during surgery presented temporary postoperativeneurological function impediment.In Adult scoliosis there were2cases with abnormal SEP,but the neurological function was normal after surgery.【Conclusions】1. The bleeding volume, range of mean arterial pressure, electric grinding drillwhether use or not, Pneumatic drill whether use or not and electric operation bed whetherbeing connected with electric power or not are predictors of the abnormal changes of SEPindex (P40/N50), These are methods to predict the abnormal changes of SEP index (P40/N50), which can help with clinical works.2. SEP monitoring during the operation is an important and sensitive method to detectthe function of spinal cord.The active and proper management should be considered assoon as occurring of abnormal SEP to avoid spinal cord injury.