title: The Impact of Body Mass Index on Fluoroscopy Time During Lumbar Epidural Steroid Injection; A Multicenter Cohort Study.
abstract: This study aimed to assess the relationship between BMI and fluoroscopy time during lumbar epidural steroid injections (LESIs) performed for lumbosacral radicular pain.
  
  
  
  Multicenter retrospective cohort study.
  
  
  
  Three academic, outpatient pain treatment centers.
  
  
  
  Patients who underwent fluoroscopically guided LESI.
  
  
  
  Mean and standard deviation (SD) fluoroscopy time were compared between patients with normal (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (≥30.0 kg/m2) BMI. Statistical significance was set at P=0.01 due to multiple comparisons.
  
  
  
  A total of 2,930 procedure encounters were included, consisting of 598 interlaminar LESIs and 2,332 transforaminal LESIs. Fluoroscopy time was significantly longer in the obese patients compared to normal and overweight patients during interlaminar LESI (P < 0.01). Fluoroscopy time was significantly longer with each increasing BMI category in during transforaminal LESI (P < 0.01). These relationships remained when a trainee was involved (P < 0.01; P<0.01), during repeat injections (P < 0.01; P < 0.01), and during bilateral transforaminal LESIs (P < 0.01). While longer fluoroscopy times were required in high BMI categories 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). Fluoroscopy time during interlaminar LESI compared to transforaminal LESI was significantly lower within all BMI categories (all P<0.01).
  
  
  
  The findings of this study indicate that fluoroscopy time is increased during interlaminar LESIs and during L5-S1 transforaminal LESIs in patients who are obese. These relationships are not affected by injection number, performance of bilateral injections, or trainee involvement. Further study is needed to determine if this increase in fluoroscopy time is indicative of a clinically significant associated increase in radiation dose.
authors.affiliation: Department of Physical Medicine & Rehabilitation/Department of Anesthesia, Northwestern Feinberg School of Medicine/the Rehabilitation Institute of Chicago, Chicago, Illinois, USA.
authors.forename: Zachary L
authors.initials: ZL
authors.lastname: McCormick
authors.affiliation: Department of Anesthesia, Northwestern Feinberg School of Medicine, Chicago, Illinois, USA.
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Choxi
authors.affiliation: Department of Medicine, University of Illinois College of Medicine, Chicago, Illinois, USA.
authors.forename: David T
authors.initials: DT
authors.lastname: Lee
authors.affiliation: Midwestern University, School of Medicine, Downers Grove, Illinois, USA.
authors.forename: Austin
authors.initials: A
authors.lastname: Marcolina
authors.affiliation: Department of Physical Medicine & Rehabilitation, the Rehabilitation Institute of Chicago, Chicago, Illinois, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Press
authors.affiliation: Department of Orthopaedics, Stanford University, Palo Alto, California, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Kennedy
authors.affiliation: Department of Orthopaedics, Stanford University, Palo Alto, California, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Smuck
authors.affiliation: Department of Anesthesia, Northwestern Feinberg School of Medicine, Chicago, Illinois, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Walega
authors.affiliation: Department of PM&R, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Cushman
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005471:Fluoroscopy; D005938:Glucocorticoids / Q000008:administration & dosage; D006801:Humans; D007268:Injections, Epidural / Q000379:methods*; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D050177:Overweight; D011843:Radiculopathy / Q000188:drug therapy; D015641:Radiography, Interventional / Q000379:methods*; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D005938:Glucocorticoids
keywords: Body Mass Index; Epidural; Fluoroscopy; Injections; Interlaminar; Lumbar; Obesity; Overweight; Radiation; Transforaminal