Medical Student Virginia Mason Medical Center, University of Washington School of Medicine Anchorage, AK, US
Disclosure(s):
Jack Sedwick, BA: No financial relationships to disclose
Introduction: Lumbar spinal stenosis (LSS) often leads to a loss of lumbar lordosis due to chronic forward leaning. Lumbar decompression surgery is commonly performed to relieve symptomatic LSS, but its impact on adjacent segmental and disc angles without fusion is not well understood. This study investigates changes in sagittal alignment at adjacent segments following decompression surgery for LSS.
Methods: This retrospective study included 31 patients who underwent isolated L4-L5 laminectomies, discectomies, or both between 2015 and 2024. Preoperative imaging was within a year of surgery, and postoperative imaging was within six months. Patients with prior spine surgeries were excluded. Pre- and postoperative segmental and disc angles at L1-L2, L2-L3, L3-L4, L4-L5, and L5-S1 were measured using weight-bearing lateral radiographs. Lumbar lordosis (LL) was measured from L1 to S1. Univariate and multivariate linear analyses were conducted to predict changes in adjacent angles at L3-L4 (cranial) and L5-S1 (caudal), with predictors including age, sex, BMI, surgical approach, type of procedure, preoperative LL, and changes at L4-L5.
Results: The cohort included 31 patients, with 17 females and 14 males. Among them, 23 underwent laminectomies and 8 had combined laminectomy and discectomy procedures. Greater preoperative LL significantly predicted decreased disc angle (β = -0.27, P = 0.01) and segmental angle (β = -0.25, P = 0.003) at L5-S1. Additionally, changes at L4-L5 were significantly associated with disc angle changes at L5-S1 (β = 0.73, P = 0.001). No significant predictors were found for changes at L3-L4.
Conclusion : Lumbar decompression surgery without fusion can lead to changes in adjacent segmental and disc angles, particularly at L5-S1. Greater preoperative lumbar lordosis was associated with reduced lordosis at L5-S1 postoperatively. These findings suggest that isolated decompression can influence adjacent segment alignment, warranting further research on the long-term effects and clinical outcomes.