Infra-adjacent Segment Disease After Lumbar Fusion: An Analysis of Pelvic Parameters

Adam Nessim, Woojin Cho, Xiuyi Alexander Yang, Ariella Applebaum, Richard Sekerak, Sam Brill, Soo Yeon Kim

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Study Design.Cross-sectional observational cohort study.Objective.The aim of this study was to determine the incidence and risk factors associated with the development of sacroiliac joint (SIJ) dysfunction following lumbosacral fusion.Summary of Background Data.Adjacent segment degeneration to both proximal and distal areas of spinal fusion is a postoperative complication of lumbar fusion. Various studies examined supra-adjacent degeneration following lumbar fusion, but few focused on infra-adjacent degeneration. In lumbosacral fusion, fusion extends to the sacrum, placing increased stress on the SIJ.Methods.A total of 2069 sequential patients who underwent lumbosacral fusion surgery from 2008 to 2018 at a single academic medical center were retrospectively reviewed. Patients who subsequently developed SIJ dysfunction were identified. SIJ dysfunction was defined as patients who met the diagnostic criteria with physical examination and received an SIJ injection with clinical evidence of improvement. Controls, without subsequent SIJ dysfunction, were matched with cases based on levels of fusion, age, sex, and body mass index. Pre-and postoperative pelvic parameters were measured, including pelvic incidence, pelvic tilt (PT), sacral slope, lumbar lordosis, lumbosacral angle, L4 incidence and L5 incidenceResults.Of 2069 patients who underwent lumbosacral fusion, 81 patients (3.9%) met criteria for SIJ dysfunction. Measurements were made for 47 of 81 patients who had SIJ dysfunction, that had both pre- and post-operative imaging. Measurements for 44 matched controls were taken. Postoperative PT was significantly lower in SIJ dysfunction patients compared to controls (20.82° ± 2.19° vs. 27.28° ± 2.30°; P < 0.05), as was L5 incidence (28.64° ± 3.38° vs. 37.11° ± 3.50°; P < 0.05).Conclusion.Incidence of the SIJ dysfunction after lumbosacral fusion surgery was 3.9% and these patients had a significantly lower PT and L5 incidence compared to the control group. Significantly low PT may be derived from weak hamstring muscles, predisposing a patient to SIJ dysfunction. Therefore, hamstring muscle strengthening exercise for patients with decreased PT after lumbosacral fusion may decrease the incidence of SIJ dysfunction.

Original languageEnglish (US)
Pages (from-to)E888-E892
Issue number16
StatePublished - Aug 15 2021


  • SIJ dysfunction
  • adjacent segment disease
  • infra-adjacent segment disease
  • lumbosacral fusion
  • sacroiliac
  • sacroiliac joint
  • spinal fusion

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Clinical Neurology


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