Influence of Obesity on Complications, Clinical Outcome, and Subsidence After Anterior Lumbar Interbody Fusion (ALIF): Prospective Observational Study

BACKGROUND: The complications associated with obesity have been well described for posterior lumbar spinal surgery. However, the influence of obesity on anterior lumbar interbody fusion (ALIF) is not well established. We aimed to compare complication risks, functional outcomes, and subsidence rates in normal-weight, overweight, and obese patients who underwent ALIF. METHODS: A total of 137 consecutive patients undergoing ALIF surgery from 2012 to 2014 were followed prospectively. Patients were categorized into 3 groups according to their body mass index (BMI). Patients were evaluated preoperative and postoperatively. Outcome measures included Short Form-12, Oswestry Disability Index, surgical complications, and subsidence. RESULTS: There was no significant difference between the BMI groups in terms of baseline age, proportion of men, levels operated, smoking status, diabetes status, or anterior, posterior, or average disc height. There was no difference in operative duration, blood loss, or hospital stay. At 12-month follow-up, no difference was found in terms of total complications, change in Short Form-12 mental or physical component scores, or Oswestry Disability Index scores. Average disc height was significant lower for the obese group (11.3 mm) compared with the normal-weight (14.4 mm) group. Fusion rate was also significantly lower for patients who were obese (60%) compared with normalweight (88.2%) and overweight patients (76%) (P = 0.014). Delayed subsidence rates also were similar between normal-weight and overweight patients. CONCLUSIONS: There were no differences in functional outcomes or complications in patients with elevated BMI compared with normal-weight patients. Fusion rates were lower for patients were obese. Obesity should not be considered a contraindication to surgery in patients with appropriate indication to undergo ALIF.