title: Evaluation of magnetic resonance imaging following neuraxial steroid administration: does epidural injection produce pathologic findings?
abstract: OBJECTIVE
  Infection or hematoma following epidural anesthesia is a rare but potentially devastating complication unless diagnosed early. In order to diagnose spinal cord involvement, the currently recommended imaging test is magnetic resonance imaging (MRI). Despite this, no previous studies have been performed to define typical MRI findings following uneventful epidural injection. The purpose of this pilot study was to compare magnetic resonance images before and after epidural injection to define the characteristic appearance of MRI following an uneventful epidural steroid injection.
  
  
  METHODS
  Ten patients were prospectively enrolled and received an MRI study before and after an epidural injection of steroids plus local anesthetic for chronic low back pain using a loss of resistance to air technique. The magnetic resonance images were reviewed by 2 neuroradiologists who were blinded as to whether the scan was performed before or after the epidural injection.
  
  
  RESULTS
  Review of 20 MRI studies revealed no fluid collections, hematomas, or mass effect on the thecal sac. A needle track and a small amount of epidural air was seen in the majority of post-epidural scans, but did not cause indentation of the thecal sac in any patient. None of the findings observed by the radiologists in the post-epidural scans were considered clinically significant.
  
  
  CONCLUSIONS
  The results of this pilot study demonstrated that after uneventful epidural injection in otherwise healthy patients, there were no new pathologic findings on MRI scans. Further MRI studies in large populations and in different clinical situations should be performed to confirm these preliminary findings.
authors.affiliation: Department of Anesthesiology, Perioperative Medicine and Pain Management, Miller School of Medicine, University of Miami, Miami, FL, USA.
authors.forename: Elyad M
authors.initials: EM
authors.lastname: Davidson
authors.forename: Evelyn M
authors.initials: EM
authors.lastname: Sklar
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Ginosar
authors.forename: Salahadin
authors.initials: S
authors.lastname: Abdi
authors.forename: Rita G
authors.initials: RG
authors.lastname: Bhatia
authors.forename: Lester
authors.initials: L
authors.lastname: Garcia
authors.forename: Rachel B
authors.initials: RB
authors.lastname: Hulen
authors.forename: Kristopher L
authors.initials: KL
authors.lastname: Arheart
authors.forename: David J
authors.initials: DJ
authors.lastname: Birnbach
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage*; D000328:Adult; D005260:Female; D006801:Humans; D007268:Injections, Epidural / Q000009:adverse effects*; D017116:Low Back Pain / Q000188:drug therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D013116:Spinal Cord / Q000473:pathology*
chemical_list: D000305:Adrenal Cortex Hormones