The Impact of Preoperative Sagittal Imbalance on Long-term Postoperative Outcomes Following Minimally Invasive Laminectomy

Junho Song, Andre Samuel, Pratyush Shahi, Mitchell Fourman, Daniel Shinn, Sidhant Dalal, Kasra Araghi, Dimitra Melissaridou, Avani Vaishnav, Evan Sheha, James Dowdell, Sheeraz A. Qureshi

Research output: Contribution to journalArticlepeer-review


Background: Postoperative sagittal alignment has been shown to be associated with patient-reported outcome measures (PROMs) following open lumbar decompression procedures, although it is unknown whether preoperative sagittal imbalance affects clinical outcomes of minimally invasive surgical (MIS) decompression only surgery. Purpose: We sought to evaluate the impact of preoperative pelvic incidence-lumbar lordosis (PI-LL) imbalance on PROMs after MIS laminectomy for the treatment of neurogenic claudication symptoms. Methods: We conducted a retrospective cohort study of adult patients undergoing MIS laminectomy for degenerative lumbar spinal stenosis between April 2017 and April 2021 at a single institution. Of the 52 patients included (mean follow-up, 17 months) radiographs were taken prior to surgery and assessed for sagittal alignment parameters. Patients were grouped based on the preoperative PI-LL (balanced vs unbalanced). Changes in PROMs were compared between unbalanced PI-LL and balanced PI-LL groups. Minimal clinically important difference (MCID) for Oswestry Disability Index (ODI) was also assessed. Results: Of the 52 patients, 17 (32.7%) had unbalanced age-adjusted preoperative PI-LL. There was no significant difference found in PROMs between unbalanced and balanced PI-LL groups preoperatively or at final follow-up. Compared with those with unbalanced PI-LL, patients with balanced PI-LL were shown to have no added benefit in achieving MCID for ODI at long-term follow-up and no added benefit in the time to achieving MCID. Conclusion: These retrospective findings suggest that patients with unbalanced preoperative PI-LL may experience significant benefit in long-term clinical outcomes following MIS laminectomy, similarly to those with balanced PI-LL at baseline. The findings also suggest that the presence of sagittal imbalance preoperatively may not appreciably influence the long-term clinical outcomes following MIS laminectomy. Prospective study involving a larger population is warranted.

Original languageEnglish (US)
JournalHSS Journal
StateAccepted/In press - 2023
Externally publishedYes


  • PI-LL
  • decompression
  • laminectomy
  • lumbar spine
  • minimally invasive
  • sagittal alignment

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine


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