OBJECTIVE

Despite the widespread use of posterior lumbar interbody fusion (PLIF) for L5-S1 isthmic spondylolisthesis (IS) with lumbar spinal stenosis (LSS), residual sagittal imbalance critically impairs long-term pain relief and functional recovery. This study analyzes the influence of residual sagittal imbalanceon health-related quality of life (HRQOL) after PLIF for L5-S1 IS with LSS, aiming to optimize surgical correction and prognostic accuracy.

METHODS

This study analyzed 103 consecutive patients with L5-S1 IS and LSS undergoing PLIF from 2020 to 2022, followed at 3 days, 3 months, and ≥ 1 year postoperatively, using SPSS 26.0 for statistical analysis. Preoperatively, patients were stratified into balanced (SVA ≤ 50 mm) and unbalanced (SVA > 50 mm) groups. Postoperatively, the unbalanced group was reclassified into postoperative balanced (SVA ≤ 50 mm) and postoperative unbalanced (SVA > 50 mm) groups. Spinal parameters-including SVA, slip degree (SD), disc height (HOD), lumbar lordosis (LL), pelvic tilt (PT), and pelvic incidence (PI)-and clinical outcomes (Oswestry Disability Index [ODI], Visual Analogue Scale [VAS]) were analyzed preoperatively and postoperatively to assess surgical efficacy. Postoperative unbalanced group.

RESULTS

In the balanced and unbalanced groups, SD and HOD significantly improved postoperatively versus preoperative values (p < 0.05). The balanced group showed no postoperative changes in SVA, LL, or PT (p > 0.05), while the unbalanced group exhibited marked improvements in these parameters (p < 0.05). At final follow-up, the balanced group maintained superior SVA, SD, HOD, LL, and PT compared to the unbalanced group (p < 0.05). Among the unbalanced group, postoperative balanced and unbalanced groups demonstrated significant improvements in SVA, SD, HOD, and PT (p < 0.05). However, LL remained unchanged in the postoperative unbalanced group (p > 0.05), whereas it improved in the postoperative balanced group (p < 0.05). The postoperative balanced group also achieved better SVA, SD, HOD, LL, and PT outcomes versus the postoperative unbalanced group (p < 0.05). ODI and VAS scores improved across all groups postoperatively, with the balanced group and postoperative balanced group outperforming their counterparts at final follow-up (p < 0.05).

CONCLUSION

Preoperative and postoperative sagittal balance are pivotal determinants of long-term functional recovery and HRQOL in patients undergoing PLIF for L5-S1 IS with LSS.