Poster Presentation 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025

Fusion is associated with improved patient-reported outcome measures in patients with degenerative spondylolisthesis and hypolordotic distribution index when compared to decompression alone. (#192)

Brandon Herrington 1 2 , Jennifer Urquhart 3 , Renan Rodrigues Fernandes 1 2 , Y. Raja Rampersaud 4 5 , Chris S Bailey 1 2
  1. Western University, London, ONTARIO, Canada
  2. London Health Sciences Centre, London, Ontario, Canada
  3. Lawson Health Research Institute, London Health Sciences Centre, London, Ontario, Canada
  4. Toronto Western Hospital, Toronto, Ontario, Canada
  5. Divisions of Orthopaedic and Neurosurgery, University of Toronto, Toronto, Ontario, Canada

Introduction: With conflicting level I evidence on the functional outcomes after DF and DA, the question on when to fuse in patients with DLS remains unclear. LDI has been linked to the development of adjacent segment disease after single-level lumbar fusion. It is not known whether LDI plays a role in influencing PROMs after DF or DA in patients with DLS. We sought to compare patient-reported outcome measures (PROMs) among patients with degenerative lumbar spondylolisthesis (DLS) who underwent either decompression alone (DA) or decompression and fusion (DF) after stratifying by pre-operative lordosis distribution index (LDI).

Methods: Patients with DLS from two centres in the Canadian Spine Outcomes and Research Network (CSORN) between 2015 and 2022 were analyzed. Patients were stratified into whether they underwent DF or DA. Radiographic parameters were obtained from pre-operative full-length lateral spine radiographs and included global lumbar lordosis, lower lumbar lordosis, and LDI. PROMs were obtained at 3, 12, and 24 months post-operatively and included the Oswestry Disability Index (ODI) and Numeric Rating Scale (NRS) for back and leg pain.

Results: In patients with LDI <50%, the minimal clinically important difference (MCID) for back pain was achieved at 24 months in more patients with DF than with DA (85.7% vs. 48.3%, p=0.002), as well as for ODI (91.4% vs. 62.1%, p=0.006). This difference was not seen in patients with LDI 50-80%. Multiple logistic regression in patients with LDI <50% demonstrated DF to be associated with achieving MCID for back pain at 24 months post-operatively (OR 15.181, 95% CI 2.584-89.190, p=0.003) as well as for ODI (OR 6.324, 95% CI 1.212-33.000, p=0.029). This association was not present in patients with LDI 50-80%.

Discussion: In this two-centre retrospective analysis, with pre-operative LDI <50%, clinically significant improvement in back pain and ODI was seen in more patients who underwent DF than those who underwent DA. This effect was not seen with pre-operative LDI 50-80%. Pre-operative LDI <50% may be an indication for fusion.