Application of Somatosensory EvoKed Potential Monitoring in Posterior vertebral Column Resection of Severe Spinal Deformities

Abstract：Objective To study application value and influential factors of somatosensory evoked potential monitoring in posterior vertebral column resection of severe spinal deformities. Methods SEP monitoring in posterior vertebral column re-section of severe spinal deformities were performed in 9 7 cases . There were 4 7 males and 5 0 females ,The average age was 17. 8 years(range,6 ~ 46 years). The pathogenetic diagnoses of spinal deformities were congenital in 91 cases,ankylosing spondylitis kyphosis in 5 cases,tuberculous kyphosis in 1 case. The abnormal criteria of SEP monitoring was defined as the de-cline of wave amplitude over 50% and/ or the elongation of latent period over 10% . To analysis the correlation between decline rate of SEP wave amplitude and operative factors. Results In all patients,12 cases had abnormal SEP,and of them,10 cases had developed a neurological complications,2 Cases were false positive. 1 case was false negative whom had normal SEP,but had developed a neurological complications after surgical. In this study,SEP monitoring had sensitivity of 90. 9% ,specificity of 97. 7% ,false positive rate of 2. 3% and false negative rate of 9. 1% . There were linear correlations between decline rate of SEP wave amplitude and operation time,blood loss,number of vertebrae fixed(P = 0. 000,P = 0. 000,P = 0. 000),blood loss had most significant influence to SEP wave amplitude. Conclusion SEP monitoring is an sensitive method to detect the func-tion of spinal cord,but there are many influencing factors. Independent employment of SEP monitority has its own flaw. There-fore,we need to reasonable use a variety of monitoring methods during surgical,and analysis influential factors.