The Correlation Of The Changes Of Somatosensory Evoked Potentials And The Efficacy Of Oblique Lumbar Interbody Fusion In The Treatment Of Lumbar Spinal Stenosis

Objective To investigate the clinical effect of OLIF in the treatment of lumbar spinal stenosis of different severity.Intraoperative somatosensory evoked potentials（SEP）monitoring was performed,the imaging results and clinical efficacy scores of three groups of patients with mild,moderate and severe lumbar spinal stenosis were analyzed postoperatively,compared the difference of efficacy between the three groups before and after operation.Meanwhile,the correlation between intraoperative SEP changes and imaging results and clinical efficacy was analyzed.show the significance of intraoperative SEP monitoring for the treatment of lumbar spinal stenosis by OLIF,and explore the indications of severe lumbar spinal stenosis by OLIF.Methods Retrospective analysis the clinical data of 90 patients with lumbar spinal stenosis treated with indirect decompression via OLIF in department of Orthopedics,Cardiovascular and Cerebrovascular Disease Hospital of General Hospital of Ningxia Medical University from September 2017 to September2019.According to Lee et al.’s classification of lumbar spinal stenosis:grade 0,no spinal stenosis;grade 1,mild spinal stenosis;grade 2,moderate spinal stenosis;grade 3,severe spinal stenosis,the patients were divided into three groups:mild,moderate and severe;OLIF operation was performed on patients in the three groups,monitored and recorded the changes of somatosensory evoked potentials of patients before,during and after surgery,log the preoperative and postoperative imaging changes（intervertebral space height,intervertebral foramen height,dural sac area）and complications in the three groups before and 6 months after operation;Assess the preoperative and postoperative clinical outcomes before and6 months after operation by visual analogue scale（VAS）、Oswestry disability index（ODI）and Health Survey Profile（SF-36 Profile）to evaluate clinical efficacy and analyze the correlation between SEP changes and efficacy.Results A total of 90 patients with lumbar spinal stenosis of different severity were included in this study,including 30 patients with mild,moderate and severe spinal stenosis.There were no statistically significant differences in age,body mass index,fusion level and complications among the three groups（P>0.05）;1.In the mild group of 30 patients,the average improvement rate of postoperative VAS score was 72.9%,ODI 78.5%,SF-36 score 65.1%,imaging intervertebral space height 19.6%,foraminal height 12.6%,and dural sac area46.0%;Among the 30 patients in the moderate group,the average improvement rate of postoperative VAS score was 73.3%,ODI 73.4%,SF-36 score 79.8%,imaging intervertebral space height 27.0%,foraminal height 15.8%,and dural sac area 72.1%.Among the 30 patients in the severe group,the average improvement rate of postoperative VAS score was 41.2%,ODI 44.5%,SF-36 score 58.2%,imaging intervertebral space height 20.2%,foraminal height 12.9%,and dural sac area 71.6%.The VAS score and ODI improvement rate in the mild-moderate group were significantly higher than those in the severe group（P<0.05）;The improvement rate of SF-36 score in the moderate group was higher than that in the mild and severe groups,and the difference was statistically significant（P<0.05）,but there was no statistical significance between mild recombination（P>0.05）;In terms of imaging changes,the improvement rate of intervertebral space in the moderate group was higher than that in the light and heavy groups,and the difference was statistically significant（P<0.05）;The improvement rate of intervertebral foramen in moderate group was higher than that in severe group（P<0.05）;The improvement rate of dural sac in moderate group was higher than that in mild group（P<0.05）;There was no significant difference in clinical efficacy score and imaging change rate among different surgical levels,single and multiple levels（P>0.05）;2.There were statistically significant differences in SEP improvement rates among the three mild and moderate groups,and the moderate group was higher than the mild group and the severe group（P<0.05）;There was a correlation between SEP change rate and clinical efficacy and imaging change rate between the mild-moderate group and the moderate group,and the correlation was stronger than that of the mild group,the difference was statistically significant（P<0.05）;In the severe group,there was a weak correlation between SEP improvement rate and dural sac change rate,and the difference was statistically significant（P<0.05）;3.When severe SEP improvement rate was lower than P10,there was no statistical significance between SEP change rate and dural sac improvement rate.Posterior operation was recommended.Conclusion 1.All patients with mild,moderate and severe lumbar spinal stenosis treated by OLIF have good decompression effect in terms of short-term efficacy,and there is no significant difference in postoperative complications.However,the short-term overall efficacy of patients with mild and moderate spinal stenosis is better than that of patients with severe spinal stenosis.2.The change rate of SEP in mild-moderate lumbar spinal stenosis can reflect the overall effect of postoperative decompression,and the moderate reactivity is stronger,which provides certain reference value for OLIF in the treatment of mild-moderate lumbar spinal stenosis.3.When the SEP change rate of severe lumbar spinal stenosis is lower than P₁₀,OLIF combined with surgery should be considered for decompression.