Patient Outcomes following Short-segment Lumbar Fusion Are Not Affected by PI-LL Mismatch

Srikanth N. DIvi, Christopher K. Kepler, Alan S. Hilibrand, Dhruv K.C. Goyal*, Victor E. Mujica, Kristen E. Radcliff, David Greg Anderson, Mark F. Kurd, Jeffrey A. Rihn, Ian D. Kaye, Barrett R. Woods, Alexander R. Vaccaro, Gregory D. Schroeder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Study Design:This is a retrospective cohort study.Objective:The objective of this study was to further elucidate the relationship between pelvic incidence-lumbar lordosis (PI-LL) mismatch and surgical outcomes in patients undergoing short segment lumbar fusions for degenerative lumbar disease.Summary of Background Data:There are few studies examining the relationship between spinopelvic parameters and patient reported outcome measurements (PROMs) in short segment lumbar degenerative disease.Materials and Methods:A retrospective review was conducted at single academic institution. Patients undergoing 1- or 2-level lumbar fusion were retrospectively identified and separated into 2 groups based on postoperative PI-LL mismatch ≤10 degrees (NM) or PI-LL mismatch >10 degrees (M). Outcomes including the Physical Component Score (PCS)-12, Mental Component Score (MCS)-12, Oswestry Disability Index (ODI), Visual Analog Scale (VAS) back and leg scores were analyzed. Absolute PROM scores, the recovery ratio and the percentage of patients achieving minimum clinically important difference between groups were compared and a multiple linear regression analysis was performed.Results:A total of 306 patients were included, with 59 patients in the NM group and 247 patients in the M group. Patients in the M group started with a higher degree of PI-LL mismatch compared with the NM group (22.2 vs. 7.6 degrees, P<0.001) and this difference increased postoperatively (24.7 vs. 2.5 degrees, P<0.001). There were no differences between the 2 groups in terms of baseline, postoperative, or Δ outcome scores (P>0.05). In addition, having a PI-LL mismatch was not found to be an independent predictor of any PROM on multivariate analysis (P>0.05).Conclusion:The findings in this study show that even though patients in the M group had a higher degree of mismatch preoperatively and postoperatively, there was no difference in PROMs.Level of Evidence:Level III.

Original languageEnglish (US)
Pages (from-to)73-77
Number of pages5
JournalClinical spine surgery
Issue number2
StatePublished - Mar 2021
Externally publishedYes


  • degenerative disease
  • lumbar fusion
  • patient reported outcome measurements (PROMs)
  • pelvic incidence-lumbar lordosis (PI-LL)
  • spinopelvic mismatch

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine
  • Clinical Neurology


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