Effects of BMI on Spondylolisthesis Surgery and Associated Patient Reported Outcomes A Retrospective Review

Introduction: The influence of body mass index (BMI) on lumbar fusion outcomes in spondylolisthesis patients remains an elusive topic. While some literature suggests worse outcomes in obese populations, there is limited understanding of how BMI impacts patient-reported outcomes, particularly disability and pain. This study evaluates the effects of BMI on postoperative outcomes after lumbar fusion.

Methods: This retrospective review included patients diagnosed with degenerative and isthmic spondylolisthesis. Patients were classified by BMI using NIH categories. Pain and disability outcomes were assessed using Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) scores. Statistical analysis involved ANOVA with post hoc Bonferroni comparisons to evaluate differences between BMI groups over a one-year follow-up period.

Results: Patients with a BMI < 30 demonstrated the most sustained improvement in ODI scores over the follow-up period (p = .003). In contrast, those with BMI ≥40 showed early improvements in both pain (2.4-point improvement) and disability (7.20-point improvement), but a parabolic trend was observed, with diminished progress at the 12-month mark (p = .06 and .12, respectively). Despite this, nearly half of the patients with BMI ≥40 achieved the minimum clinically important difference (MCID) for disability outcomes. VAS scores did not show statistically significant differences across BMI groups (p = .93). ODI scores did not show statistically significant differences across BMI groups (p = .31)

Conclusion : Our findings challenge the assumption that obesity should be a strict contraindication for lumbar fusion surgery, as significant improvements in disability were observed across all BMI categories. These results emphasize the importance of personalized treatment strategies, including preoperative weight optimization, to enhance long-term outcomes for obese patients. Further research is warranted to validate these findings and explore potential interventions for improving recovery in patients with higher BMI.