Authors: Andrew K. Chan, MD; Erica Bisson, MD, MPH; Mohamad Bydon, MD; Steven Glassman, MD; Eric Potts, MD; Domagoj Coric, MD; Jonathan Slotkin, MD; Michael Virk, MD, PhD; Panagiotis Kerezoudis, MD; Praveen Mummaneni, MD (San Francisco, CA)

Introduction: The factors driving the best outcomes following minimally invasive surgery (MIS) for grade 1 lumbar spondylolisthesis are not clearly elucidated. This study investigates the factors that drive the best 24-month patient reported outcomes (PRO) following MIS lumbar spondylolisthesis surgery. Methods: 310 patients from the Quality Outcomes Database (QOD) Lumbar Spondylolisthesis Module underwent surgery for degenerative grade 1 lumbar spondylolisthesis utilizing MIS techniques. Surgeries were classified as MIS if any of the following were involved: MIS laminectomy, MIS pedicle screws, MIS interbody grafts, or percutaneous screws. Baseline and 24-month follow-up parameters were collected. 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. Results: The cohort included 233 (75.2%) fusions and 77 (24.8%) decompression only procedures. The mean age was 64.0±11.3 years. The cohort demonstrated significant improvement in ODI, NRS back pain, NRS leg pain, and EQ-5D at 24 months ( p <0.001, all relative to baseline). In multivariate analyses, aside from baseline PROs, only three factors were significantly associated with multiple PRO change scores: employment, independent ambulation at presentation, and the addition of fusion to surgery. Employment was associated with superior postoperative ODI (OR=0.002;95%CI[0.0002-0.28]; p =0.01), NRS back pain (OR=0.39;95%CI [0.19-0.78]; p =0.008), and NASS satisfaction (OR=0.36;95%CI[0.18-0.68]; p =0.002). Independent ambulation was associated with superior NRS leg pain (OR=0.34;95%CI[0.12-0.91]; p =0.03) and EQ-5D (OR=1.11;95%CI[1.04-1.18]; p <0.001). The addition of a fusion was associated with superior NRS back pain (OR=0.41;95%CI [0.17-0.93]; p =0.03) and NASS satisfaction (OR=0.35;95%CI[0.17-0.73]; p =0.005). Education was also associated with superior outcomes for a single outcome, ODI (OR=0.002;95%CI[0.0002-0.13]; p =0.004). Conclusion: Multiple factors influence outcomes following lumbar spondylolisthesis surgery.For MIS, preoperative active employment, higher education, independent ambulation at presentation, and fusion surgery were significant predictors of superior outcomes across the domains of disability, back pain, leg pain, quality of life, and satisfaction.