Pre- and postoperative MRI analysis of central decompression in MIS fusion with lumbar stenosis

Objectives: Mini-invasive approaches have grown substantially these last decades in spinal surgery, notably for lumbar decompressions and fusion, with advantages over open approaches in terms of morbidity reduction. However, to our knowledge, no study has measured on MRI the amount of cen-tral decompression obtained by MIS approach. The goal of this study was to precisely measure the decompression of central stenosis by unilateral MIS approaches.Methods: The files of 42 patients that had a MIS lumbar fusion with central decompression for central stenosis were reviewed. All patients had a pre-and postoperative MRI that allowed on T2 axial images to classify the central stenosis, according to Schizas' classification, and measure the dural sac cross-sectional area (DSCA) and the anteroposterior diameter (DAP). The statistical analysis was made with paired t-test.Results: Fifty-six levels were analyzed, mostly L4L5 (58%). The mean preoperative DSCA was 70.53 mm2 and the mean postoperative DSCA was 172.2 mm2. The mean preoperative DAP was 6.15 mm and post-operative was 10.68 mm. Preoperatively, the levels analyzed were rated B, C or D according to Schizas for 53 out of 56 levels and A1-4 for 51 out of 56 levels in postoperative. All the results were statistically significant (p < 0.001).Conclusion: Decompression, assessed by MRI, seems to be equivalent by MIS approach to open lam-inarthrectomy. MIS approaches have been studied clinically in these indications with very satisfying results. As a conclusion, MIS approaches seems to be a relevant and efficient option in the treatment of lumbar degenerative stenosis. Level of evidence: IV, retrospective study.(c) 2022 Elsevier Masson SAS. All rights reserved.

Automated summary

The goal of this study was to precisely measure the decompression of central stenosis by unilateral MIS approaches using MRI. The analysis of 42 patients showed that the dural sac cross-sectional area and anteroposterior diameter increased significantly postoperatively, indicating a successful decompression.