title: Fluoroscopically guided transforaminal epidural steroid injections at a quaternary-care teaching institution: effect of trainee involvement and patient body mass index on fluoroscopy time and patient dose.
abstract: OBJECTIVE
  To investigate whether there are differences in fluoroscopy time and patient dose for fluoroscopically guided lumbar transforaminal epidural steroid injections (TFESIs) performed by staff radiologists versus with trainees and to evaluate the effect of patient body mass index (BMI) on fluoroscopy time and patient dose, including their interactions with other variables.
  
  
  METHODS
  Single-level lumbar TFESIs (n=1844) between 1 January 2011 and 31 December 2013 were reviewed. Fluoroscopy time, reference point air kerma (Ka,r), and kerma area product (KAP) were recorded. BMI and trainee involvement were examined as predictors of fluoroscopy time, Ka,r, and KAP in models adjusted for age and gender in multivariable linear models. Stratified models of BMI groups by trainee presence were performed.
  
  
  RESULTS
  Increased age was the only significant predictor of increased fluoroscopy time (p<0.0001). Ka,r and KAP were significantly higher in patients with a higher BMI (p<0.0001 and p=0.0009). When stratified by BMI, longer fluoroscopy time predicted increased Ka,r and KAP in all groups (p<0.0001). Trainee involvement was not a statistically significant predictor of fluoroscopy time or Ka,r in any BMI category. KAP was lower with trainees in the overweight group (p=0.0009) and higher in male patients for all BMI categories (p<0.02).
  
  
  CONCLUSIONS
  Trainee involvement did not result in increased fluoroscopy time or patient dose. BMI did not affect fluoroscopy time; however, overweight and obese patients received significantly higher Ka,r and KAP. Male patients received a higher KAP in all BMI categories. Limiting fluoroscopy time and good collimation practices should be reinforced in these patients.
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Electronic address: tiegsheiden.christin@mayo.edu.
authors.forename: C A
authors.initials: CA
authors.lastname: Tiegs-Heiden
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: N S
authors.initials: NS
authors.lastname: Murthy
authors.affiliation: Biomedical Statistics and Informatics, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Geske
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: F E
authors.initials: FE
authors.lastname: Diehn
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Schueler
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Wald
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Kaufmann
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: V T
authors.initials: VT
authors.lastname: Lehman
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Carr
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: K K
authors.initials: KK
authors.lastname: Amrami
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Morris
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: K R
authors.initials: KR
authors.lastname: Thielen
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: T P
authors.initials: TP
authors.lastname: Maus
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D007268:Injections, Epidural; D007270:Injections, Intra-Articular; D017116:Low Back Pain / Q000000981:diagnostic imaging / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D050177:Overweight / Q000150:complications; D011829:Radiation Dosage; D013256:Steroids / Q000008:administration & dosage*; D013997:Time Factors
chemical_list: D013256:Steroids