Lumbar Epidural Lipomatosis is Increased in Patients With Morbid Obesity and Subsequently Decreases After Bariatric Surgery

Abstract

Spinal epidural lipomatosis (SEL) is characterized by symptomatic neurogenic compression from adipose tissue in the spinal canal. The question arises whether patients with morbid obesity have higher volumes of epidural adipose tissue (EAT) in their lumbar spinal canal compared with patients with a normal weight, and to what extent this decreases after bariatric surgery. In this explorative study the lumbar EAT volume was assessed in 25 patients with morbid obesity (body mass index [BMI] >40) using available lumbar magnetic resonance imaging (MRI) prior to their bariatric surgery. An age- and sex-matched control group (n= 25) of patients with a normal weight (BMI 20-25) was used for comparison. Participants from the obesity group underwent a postoperative control MRI. The mean volume of EAT per MRI slice of the group of patients with obesity was significantly higher than for the group of patients with normal weight (mean: 83.3 ± 30.7 mm3 vs. mean 56.5 ± 25 mm3; P < 0.001). Fifteen participants with obesity (15 of 25) agreed to undergo a follow-up MRI. There was a significant decrease in EAT volume per MRI slice for these 15 participants (mean 82 ± 25.5 mm3 vs. 46 ± 20.0 mm3; P < 0.001) over time up to 3.6 (range: 1.2-6.0) years after bariatric surgery. Patients with obesity have significantly larger volumes of EAT in comparison with patients with normal weight. After bariatric surgery, a significant weight loss coincided with a significant volumetric reduction of this adipose tissue in the spinal canal. Future prospective studies in patients with symptomatic SEL may elucidate whether decreases in EAT volume influence concurrent neurogenic claudication symptoms.