Correction of Spinal Sagittal Alignment after Posterior Lumbar Decompression: Does Severity of Central Canal Stenosis Matter?

Study Design: This study adopted a retrospective study design. Purpose: Our study aimed to investigate the impact of central canal stenosis severity on surgical outcomes and lumbar sagittal cor-rection after lumbar decompression. Overview of Literature: Studies have evaluated sagittal correction in patients with central canal stenosis after lumbar decompres-sion and the association of stenosis severity with worse preoperative sagittal alignment. However, none have evaluated the impact of spinal stenosis severity on sagittal correction. Methods: Patients undergoing posterior lumbar decompression (PLD) of <4 levels were divided into severe and non-severe central canal stenosis groups based on the Lee magnetic resonance imaging (MRI) grading system. Patients without preoperative MRI or inadequate visualization on radiographs were excluded. Surgical characteristics, clinical outcomes, and sagittal measurements were compared. Multivariate logistic regression was performed to determine the predictors of pelvic tilt (PT), sacral slope (SS), lumbar lor-dosis (LL), and pelvic incidence minus lumbar lordosis (PI-LL). Results: Of the 142 patients included, 39 had severe stenosis, and 103 had non-severe stenosis. The mean follow-up duration for the cohort was 4.72 months. Patients with severe stenosis were older, had higher comorbidity indices and levels decompressed, and lon-ger lengths of stay and operative times (p <0.001). Although those with severe stenosis had lower lordosis, lower SS, and higher PI-LL mismatch preoperatively, no differences in Delta LL, SS, PT, or PI-LL were observed between the two groups (p >0.05). On multivariate regression, severe stenosis was a significant predictor of a lower preoperative LL (estimate=-5.243, p=0.045) and a higher preopera-tive PI-LL mismatch (estimate=6.192, p=0.039). No differences in surgical or clinical outcomes were observed p >0.05). Conclusion: Severe central lumbar stenosis was associated with greater spinopelvic mismatch preoperatively. Sagittal balance improved in both patients with severe and non-severe stenosis after PLD to a similar degree, with differences in sagittal parameters remaining after surgery. We also found no differences in postoperative outcomes associated with stenosis severity.