An injection from the past: fluoroscopic evidence of remote injections of radiopaque substances.

Abstract

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. 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. 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.