Impact of morbid obesity (BMI > 40 kg/m2) on complication rate and outcome following minimally invasive transforaminal lumbar interbody fusion (MIS TLIF)

Objectives: The negative effects of obesity on the health and quality of life of those afflicted has become an important public concern. Previous studies have shown an association between obesity and higher rates of complications and unfavorable outcomes following spine surgery. This study is to identify peri- and postoperative complication rates as well as short-term and long-term outcomes in morbidly obese patients who underwent minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) in comparison to age-matched normal-weight patients. Patients and methods: We retrospectively reviewed medical records for all adult patients with a body mass index (BMI) >= 40 kg/m(2) who underwent 1- to 2-level MIS TLIF for degenerative disease between February 2009 and February 2014 at a single institution and compared them to age-matched normal-weight patients (BMI 20-25 kg/m(2)). Duration of operation, length of hospital stay, use of analgesics, minor and major complications (infections and re-operations) as well as postoperative pain reduction within 30 days of surgery were recorded. Furthermore, we collected long-term follow-up data ( > 1 year) regarding complications and pain reduction. Results: We identified 14 patients with a BMI >= 40 kg/m(2) (mean, 43.2 kg/m(2)) who underwent MIS TLIF. Both groups showed comparable complication rates and clinical results in the short term ( < 30 days). Compared to 14 normal-weight patients (mean, 23.5 kg/m(2)), morbidly obese patients had significantly longer duration of single level operations (235 vs. 168 min; P = 0.0264) as well as a longer average length of stay (7.7 vs. 5.4; P = 0.0308) and a numerically higher need for analgesics (WHO level; P = 0.0828). In the long-term follow-up of the available 13 patients, the morbidly obese group had a higher complication rate (2/7 morbidly obese vs. 0/ 6 normal weight), a greater need for analgesics and a higher score in the VAS for lower back pain (6.0 vs. 2.4). Conclusion: MIS TLIF is technically feasible in morbidly obese patients with no evidence of higher complication rates among this demographic compared to normal-weight individuals when followed-up in the short-term ( < 30 days); however, available long-term follow-up data suggest a higher complication rate, greater need for analgesics and a much lower reduction of lower back pain in the morbidly obese group.