Abstract: [Abstract]Objective:To compare the curative effect of minimally invasive bilateral decompression fixation via unilateral approach and open bilateral decompression fixation in the treatment of single level lumbar spinal stenosis.Methods:86 patients with single level lumbar spinal stenosis treated in our hospital during the period were selected as the subjects，and they were divided into the observation group and the control group with 43 cases in each group by the random number table method.The two groups were treated by minimally invasive bilateral decompression fixation via unilateral approach and open bilateral decompression fixation respectively.The situation of operation and postoperative recovery were compared between the two groups，and the incidence of postoperative complications in the two groups was statistically analyzed.The operation effect was evaluated with modified Macnab criteria.The pain degree and improvement of lumbar function were evaluated by the visual analogue scale（VAS）and Oswestry disability index（ODI）before and after operation.A followup survey of 1 year was performed，and changes in intervertebral height index at different time after operation were determined.Results:The length of incision，intraoperative blood loss，postoperative ambulation time and hospitalization time in the observation group were shorter or less than those in the control group [（1.90±0.34）cm vs（12.81±2.41）cm，（98.25±16.74）ml vs（180.45±20.26）ml，（1.72±0.36）d and（6.32±1.07）d vs（2.81±0.52）d and（8.90±0.96）d ]（P<0.05）.There was no significant difference in the incidence of postoperative complications or the curative effect of operation between the observation group and the control group（2.33% vs 9.30%，90.70% vs 86.05%）（P>0.05）.VAS scores of the two groups were decreased at 1 day and 3 months after operation，and the VAS score of observation group at 1 day after operation was lower than that of control group [（3.04±1.26）points vs（3.91±1.75）points]（P<0.05）.ODI scores of two groups were decreased at 6 months and 12 months after operation [（13.51±2.26）points and（10.79±3.52）points in the observation group，（14.11±3.23）points and（10.94±2.47 points）in the control group].Compared with those before operation [（32.14±5.15）points in the observation group，（33.31±4.98）points in the control group]，there were statistically significant difference（P<0.05），but there was no significant difference between the two groups（P>0.05）.There was no significant difference in the intervertebral space height index between the observation group and the control group at different time after operation（P>0.05）.Conclusion:The curative effect of minimally invasive bilateral decompression fixation via unilateral approach is similar to that of open bilateral decompression fixation in treatment of single level lumbar spinal stenosis.However，the trauma of the former is smaller and pain is milder，which can shorten the recovery time after operation，and it has little effect on the longterm stability of the spine.

Key words: lumbar spinal stenosissingle levelunilateral approach, minimally invasive, open operation