A Prospective, Multi-Institutional Comparative Effectiveness Study of Lumbar Spine Surgery in Morbidly Obese Patients: Does Minimally Invasive Transforaminal Lumbar Interbody Fusion Result in Superior Outcomes?

BACKGROUND: Obese and morbidly obese patients undergoing lumbar spinal fusion surgery are a challenge to the operating surgeon. Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and open-TLIF have been performed for many years with good results; however, functional outcomes after lumbar spine surgery in this subgroup of patients remain poorly understood. Furthermore, whether index MIS-TLIF or open-TLIF for the treatment of degenerative disc disease or spondylolisthesis in morbidly obese results in superior postoperative functional outcomes remains unknown. METHODS: A total of 148 (MIS-TLIF: n = 40, open-TLIF: n = 108) obese and morbidly obese patients undergoing index lumbar arthrodesis for low back pain and/or radiculopathy between January 2003 and December 2010 were selected from a multi-institutional prospective data registry. We collected and analyzed data on patient demographics, postoperative complications, back pain, leg pain, and functional disability over 2 years. Patients completed the Oswestry Disability Index (ODI), Medical Outcomes Study Short-Form 36 (SF-36), and back and leg pain numerical rating scores before surgery and then at 12 and 24 months after surgery. Clinical outcomes and complication rates were compared between both patient cohorts. RESULTS: Compared with preoperative status, Visual Analog Scale (VAS) back and leg pain, ODI, and SF-36 physical component score/mental component score were improved in both groups. Both MIS-TLIF and open-TLIF patients showed similar 2-year improvement in VAS for back pain (MIS-TLIF: 2.42 +/- 3.81 vs. open-TLIF: 2.33 +/- 3.67, P = 0.89), VAS for leg pain (MIS-TLIF: 3.77 +/- 4.53 vs. open-TLIF: 2.67 +/- 4.10, P = 0.18), ODI (MIS-TLIF: 11.61 +/- 25.52 vs. open-TLIF: 14.88 +/- 22.07, P = 0.47), and SF-36 physical component score (MIS-TLIF: 8.61 +/- 17.72 vs. open-TLIF: 7.61 +/- 15.55, P = 0.93), and SF-36 mental component score (MIS-TLIF: 4.35 +/- 22.71 vs. open-TLIF: 5.96 +/- 21.09, P = 0.69). Postoperative complications rates between both cohorts were also not significantly divergent between (12.50% vs. 11.11%, P = 0.51). CONCLUSION: MIS-TLIF is a safe and viable option for lumbar fusion in morbidly obese patients and, compared with open-TLIF, resulted in similar improvement in pain and functional disability. Postoperative complications rates between both cohorts were also not significantly divergent.