(466) The impact of body mass index on fluoroscopy time during lumbar epidural steroid injection: a multicenter cohort study

Abstract

Though a range of interventional and surgical procedures have been associated with longer fluoroscopy times and greater radiation exposure with increasing body mass index (BMI), few studies have analyzed this relationship during spine injections for pain management. The present study aimed to define the relationship between BMI and fluoroscopy time during lumbar epidural steroid injection (LESI) performed for lumbosacral radicular pain. This was a multicenter retrospective cohort study conducted at three academic, outpatient pain treatment centers. Mean and standard deviation (SD) fluoroscopy times were calculated, and comparisons were made between patients with normal (18.5 - 24.9 kg/m2), overweight (25.0 - 29.9 kg/m2), and obese (≥30.0 kg/m2) BMI. This cohort included a total of 2,930 patients, 598 who received interlaminar LESIs and 2,332 who received transforaminal ESIs. There was a significant difference in the mean fluoroscopy time for both interlaminar and transforaminal LESI between these BMI classes, with obese patients requiring longer fluoroscopy times (p<0.01; p<0.01). This relationship was also observed when a trainee was involved with the procedure (p<0.01) and during bilateral transforaminal LESIs (p<0.01). While longer fluoroscopy times were required in obese patients during L5-S1 transforaminal LESI (p<0.01), there was no relationship between fluoroscopy time and BMI during L4-L5 and S1 transforaminal LESI (p=0.02; p=0.13). Future study is needed to determine the relationship between BMI and radiation exposure dose in order to determine if these observed differences in fluoroscopy time change the risk of developing a malignancy.