title: An injection from the past: fluoroscopic evidence of remote injections of radiopaque substances.
abstract: OBJECTIVE
  Although uncommon, residual effects from contrast agents used more than 2 decades ago are possible. This case report is to alert clinicians to the implications of residual oil-based ionic contrast agents in the intrathecal space.
  
  
  METHODS
  A 70-year-old female with evidence of degenerative disc disease underwent a series of lumbar epidural steroid injections. Fluoroscopy during the procedure revealed diffuse residual intrathecal iophendylate (Pantopaque) dye. We were able to demonstrate unrestricted epidural spread of 1 mL iohexol (Omnipaque 180) alongside the preexisting dye.
  
  
  CONCLUSIONS
  The goal of this case report is to highlight the potential of residual myelographic dye to complicate interventional procedures. Such residual dye can increase the level of difficulty in performing interventional pain treatments and perhaps the rate of complications associated with epidural injections, such as dural puncture. The presence of large amounts of residual oil-based intrathecal dye can lead to erroneous interpretations of the dye patterns as intraspinal lipoma or hemorrhage. As a consequence, the patient can be submitted to unnecessary diagnostic and therapeutic interventions. In addition, concerns of worsening oil-based dye-induced arachnoiditis with the use of epidural steroid injections can complicate the treatment of patients with back pain.
authors.affiliation: Division of Pain Medicine, Department of Anesthesiology, Stanford University School of Medicine, Stanford, CA 94539, USA. navani@yahoo.com
authors.forename: Annu
authors.initials: A
authors.lastname: Navani
authors.forename: Carmen L
authors.initials: CL
authors.lastname: Dominguez
authors.forename: John K
authors.initials: JK
authors.lastname: Hald
authors.forename: Scott M
authors.initials: SM
authors.lastname: Fishman
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000368:Aged; D001100:Arachnoiditis / Q000139:chemically induced / Q000175:diagnosis; D003287:Contrast Media / Q000009:adverse effects*; D003937:Diagnosis, Differential; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000175:diagnosis*; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D007268:Injections, Epidural; D007278:Injections, Spinal; D007405:Intervertebral Disc Displacement / Q000175:diagnosis / Q000188:drug therapy; D007481:Iophendylate / Q000009:adverse effects*; D008159:Lumbar Vertebrae; D011843:Radiculopathy / Q000175:diagnosis / Q000188:drug therapy
chemical_list: D000305:Adrenal Cortex Hormones; D003287:Contrast Media; D007481:Iophendylate