Does obesity impact lumbar sagittal alignment and clinical outcomes after a posterior lumbar spine fusion?

ABSTRACT

PURPOSE: The purpose of this study is to compare clinical patient-reported outcomes and radiographic sagittal parameters between obese and non-obese patients following open posterior lumbar spine fusion (PLSF). METHODS: A retrospective cohort study was conducted for patients who underwent open PLSF from 2011 to 2018. Patients were classified as obese as per Center for Disease Control and Prevention guidelines if their body mass index (BMI) ≥ 30 kg/m2. Preoperative and final visual analog scale (VAS) back pain, VAS leg pain, and Oswestry Disability Index (ODI) were obtained for both obese and non-obese groups. Achievement of minimal clinically important difference was evaluated. Preoperative, immediate postoperative, and final lumbar plain radiographs were assessed to measure spinopelvic parameters. Additionally, postoperative complication measures were collected. RESULTS: A total of 569 patients were included; 290 (50.97%) patients with BMI < 30 (non-obese) and 279 (49.03%) patients with BMI ≥ 30 (obese). Patients classified as obese were more likely to have a diagnosis of diabetes mellitus (p < 0.001), and American Society of Anesthesiologists Physical Status Classification System of ≥ 3 (p < 0.001). Obese patients had significantly longer operative times (p < 0.001) compared to non-obese patients. There was no difference in radiographic measurements, patient-reported outcomes, postoperative complications, or reoperations between groups. CONCLUSION: Obese patients had significantly more comorbidities and longer operative time compared to non-obese patients. However, sagittal parameters, patient-reported outcomes, inpatient complications, length of hospital stay, and reoperations were similar between groups. Given these findings, open PLSF can be considered safe and effective in obese patients after thorough consideration of related comorbidities. These slides can be retrieved under Electronic Supplementary Material.