Slip progression in degenerative lumbar spondylolisthesis following minimally invasive decompression surgery is not associated with increased functional disability.

PURPOSE

The aim of this study is to determine whether there is a relationship between radiographic slip progression and symptomatic worsening after decompression without fusion for low-grade degenerative lumbar spondylolisthesis (DLS).

METHODS

A retrospective review of 1-2-level minimally invasive surgical decompression for grade I-II DLS was performed. Included subjects had a minimum of 1-year follow-up with prospectively collected baseline and follow-up Oswestry Disability Index (ODI) scores.

RESULTS

Fifty-six patients (33 females, 58.9%), having a mean age 65.6 years (SD 10.0), met inclusion criteria. Spondylolisthesis slip percentage increased in 55.4% (31/56) of patients. Slip percentage increased significantly (p = 0.002) from baseline (mean 17.2; SD 8.0) to follow-up (mean 20.1; SD 9.6). A logistic regression model identified that females were more likely to have progressive slips compared to males (odd ratio 6.09, 95% CI 1.77-21.01; p = 0.004). ODI scores and spondylolisthesis slip percentage did not correlate at baseline (r = 0.0170; p = 0.90) nor follow-up (r = 0.094; p = 0.49). There was no correlation between the change in ODI scores and change in slip percentage from baseline to final follow-up (r = 0.0474; p = 0.73). Of the 31 patients with slip progression, there was no difference in mean ODI score changes (p = 0.91) for those with 1-5% progression (13/31 [41.9%]; - 18.0 [SD 19.7]) compared to those with > 5% slip progression (18/31 [58.1%]; - 18.7 [SD 16.4]).

CONCLUSIONS

Despite a small degree of slip progression in the majority of patients, there was no correlation with symptom worsening, as measured by the ODI. These slides can be retrieved under Electronic Supplementary Material.