Predictors of the Best Outcomes Following Minimally Invasive Surgery for Grade 1 Lumbar Spondylolisthesis

Abstract

Abstract INTRODUCTION The factors driving the best outcomes following minimally invasive surgery (MIS) for degenerative lumbar spondylolisthesis (DLS) are not clearly elucidated. This study investigates the factors that drive the best patient reported outcomes (PRO) following MIS for DLS. METHODS A total of 608 patients from the prospective Quality Outcomes Database (QOD) Lumbar Spondylolisthesis Registry underwent surgery for grade 1 DLS of whom 259 underwent surgery with MIS techniques [187 fusions (72.2%)]. Surgeries were classified as MIS if any of the following were involved: MIS laminectomy, MIS pedicle screws, MIS interbody grafts, or percutaneous screws. Outcomes were assessed at 24 mo postoperatively. PROs included the Oswestry Disability Index (ODI), numeric rating scale (NRS) Back Pain, NRS Leg Pain, EuroQoL-5D (EQ-5D) Questionnaire, and North American Spine Society (NASS) Satisfaction Questionnaire. Multivariate models were constructed adjusting for patient characteristics, presentation characteristics, surgical variables, socioeconomic characteristics, and baseline PRO values. RESULTS The mean age of the MIS cohort was 64.2 ± 11.5 yr [148 (57.1%) women and 111 (42.9%) men]. In multivariate analyses, aside from baseline PRO values, only 3 factors were significantly associated with multiple 24-mo PRO change scores: employment, age, and the addition of fusion to surgery. Employment was associated with superior postoperative ODI (ß-7.8; 95% CI [−12.9- −2.6]; P = .003), NRS back pain (ß-1.2; 95% CI [−2.1- −0.4]; P = 0.004), EQ-5D (ß0.1; 95% CI [0.01-0.1]; P = .03), and NASS satisfaction (OR = 0.27; 95% CI [0.12-0.58]; P < .001). Increasing age was associated with superior NRS leg pain (ß-0.1; 95% CI [minus;0.1- minus;0.01]; P = .03) and NASS satisfaction (OR = 0.95; 95% CI [0.92-0.99]; P = .02). The addition of a fusion was associated with superior ODI (ß-6.7; 95% CI [minus;12.7- minus;0.7]; P = .03), NRS back pain (ß-1.1; 95% CI [minus;2.1- minus;0.2]; P = .02), and NASS satisfaction (OR = 0.28; 95% CI [0.12-0.62]; P = .002). CONCLUSION Preoperative active employment, at least 4 yr of college education, and surgeries including a fusion were significant predictors of superior outcomes across the domains of disease-specific disability, back pain, leg pain, quality of life, and patient satisfaction. Increasing age was predictive of superior outcomes for leg pain and satisfaction.