Outcomes of One Versus Two Level MIS Decompression With Adjacent Level Stenosis.

Study Design: Retrospective cohort study.

Objective: Decompression for the treatment of lumbar spinal stenosis (LSS) has shown excellent clinical outcomes. In patients with symptomatic single level stenosis and asymptomatic adjacent level disease, it is unknown whether decompressing only the symptomatic level is sufficient. The objective of this study is to compare outcomes between single level and dual level minimally invasive (MIS) decompression in patients with adjacent level stenosis.

Methods: The current study is a retrospective review of patients undergoing primary single or dual level MIS decompression for LSS. Radiographic stenosis severity was graded using the Schizas grading. Patients undergoing single level decompression (SLD) with moderate stenosis at the adjacent level were compared with patients undergoing dual level decompression (DLD) for multi-level LSS. Clinical outcomes, complications, and reoperations were compared. Subgroup analysis was performed on patients with the same Schizas grade at the adjacent level in the SLD group and the second surgical level in the DLD group.

Results: 148 patients were included (126 SLD, 76 DLD). There were no significant differences in patient reported outcomes between the two groups at any timepoint up to 2 years postoperatively, including in the matched stenosis severity subgroups. Operative time was longer in the DLD cohort ( < 0.001). There were no significant differences in complications or reoperation rates.

Conclusion: In patients with single level symptomatic LSS and adjacent level stenosis, decompression of only the symptomatic level provided equivalent clinical outcomes compared to dual level decompression. The additional operative time and potential incremental risk of dual level surgery may not be justified.