Relationship Between The Changes Of Lower Limb SEP And Clinical Results Of Lumbar Spinal Stenosis After Indirect Decompression In Lumbar Lateral Interbody Fusion Surgery

Objective: To investigate the relationship between the lower limb SEP amplitude changes of SEP during indirect decompression and the clinical improvement of lumbar spinal stenosis after lateral lumbar interbody fusion.Methods: A total of 52 patients with lumbar spinal stenosis were enrolled in our hospital from February 2016 to October 2018.During the treatment of lateral lumbar fusion,the P40-N55 of the anterior lower extremity SEP was detected after the anesthesia was stabilized.The amplitude of the SEP of the lower limbs before and after the insertion of the cage was measured。The JOA score of the lumbar spine was analised 3 months after the operation,and the improvement rate of the JOA score was calculated.The improvement rate of JOA was >60% for 1 group,and the postoperative improvement rate was ≤60% for 2 groups.Statistical analysis was conducted to investigate the relationship between the improvement in SEP amplitude and the improvement rate after JOA.Results: The amplitude of P40-N55 in the lower extremity SEP of the incision was 52.15±0.7482 uv before the surgery in 52 patients.The amplitude of SEP after fusion of the intervertebral space was 1.558±0.8023 uv,There was a significant increase compared with the previous,and the difference between the two was significant(t=14.502,P<0.05).The preoperative lumbar spine JOA score was 12.25±2.543,and the lumbar spine JOA score was 23.25±3.067 at 3 months postoperatively.The difference was significant(t=24.199,P<0.05).The postoperative improvement rate of JOA score was >60%(group 1)in 34 cases,and the postoperative improvement rate was ≤60%(group 2)in 18 cases.The improvement of SEP amplitude in the two groups was(53.97±37.44)% and(23.53±14.36)%,respectively,and the difference was significant(t=4.195,P<0.05).The improvement of SEP amplitude and the improvement rate of JOA were analyzed by bivariate correlation analysis(pearson analysis).There was positive correlation between the improvement rate of JOA and the improvement of SEP amplitude(r2=0.302,P<0.05).Conclusion: The improvement of SEP amplitude in lower limbs during lateral lumbar fusion surgery may indicate the improvement of clinical results of lumbar spinal stenosis and has certain clinical value.