Poster Presentation 50th International Society for the Study of the Lumbar Spine Annual Meeting 2024

Introduction: Positive spinal sagittal alignment is known to correlate with pain and disability. It remains controversy that decompressive laminectomy for lumbar spinal stenosis (LSS) could improve sagittal alignment. The purpose of this study was to evaluate the change of sagittal alignment and identify the affecting factors for the improvement after decompressive laminectomy using the EOS imaging system.

Methods: A total of 49 patients undergoing decompressive laminectomy from January 2020 to December 2020 were included in this study. Radiologic parameters including spinopelvic parameters, global alignments were assessed and compared at preoperative, postoperative 2-week and 6-month. Clinical parameters included numeric rating scale for back pain and leg pain, Oswestry disability index (ODI), and EQ-5D. Patients with reduction of more than 25mm (average of at the last follow-up) in sagittal vertical axis (SVA) were compared with patients who had difference of less than 25mm to identify the affecting factors for the improvement of sagittal alignment.

Results: Preoperative SVA was significantly improved at postoperative 2-week and 6-month (49.4 ± 51.1mm vs. 31.2 ± 45.1mm, 49.4 ± 51.1mm vs. 24.5 ± 43.8mm, all p < 0.05). All clinical outcomes were also improved at postoperative 2-week and 6-month compared with preoperative values (all p < 0.05). ODI scores continued to decrease over time after surgery (49.6 ± 21.2% vs. 35.3 ± 20.3% vs. 26.0 ± 17.9%, all p < 0.05). Twenty patients with the improvement in SVA over 25mm had significantly worse preoperative SVA and ODI than 29 patients without improvement (68.7 ± 46.6mm vs. 36.1 ± 50.5mm, p = 0.027 for SVA, 57.5 ± 19.2% vs. 44.1 ± 21.0%, p = 0.028 for ODI). Although increase of lumbar lordosis at last follow-up was also significantly greater in the improvement group (6.9 ± 7.6° vs -1.9 ± 6.1°, p = 0.000), the spinopelvic parameters were similar in both groups.

Discussion: Decompressive laminectomy for LSS might improve the sagittal alignment and clinical outcomes. Especially, patients with preoperative worse SVA and ODI could have the advantage of improving global alignment after the surgery.