866 - Incidental Discogram Following an Interlaminar Epidural Steroid Injection

Case Diagnosis: Incidental discogram following L4-5 interlaminar injection

Case Description: The patient is a 38-year-old female with lower back pain radiating to her right lower extremity. Symptoms initially presented on the left side two years ago and were unresponsive to conservative treatment. MRI at that time revealed L4-5 disc herniation, prompting two interlaminar epidural steroid injections (ILESI), which provided pain relief in the left leg. Over the past year, symptoms shifted to the right side with increasing lower back pain radiating down the leg with no interval trauma. Pain, described as aching, throbbing, and burning, reached 5-8 out of 10. An updated MRI revealed similar findings to the first. A right L4-5 ILESI was then performed. During the procedure, an incidental discogram was noted under fluoroscopy. The patient had no complications following the procedure, and at a follow-up visit, she noted she had 50% relief for two weeks.

Discussions: Incidental discograms occur during TFESI with a rate of 2.3-2.5%, in contrast to ILESI, which has only a handful of mentions in literature. In this case, a right-of-midline ILESI approach was employed. Subsequent MRI review unveiled right L4-L5 disc extrusion, potentially facilitating needle access and subsequent discogram. Previous cases suggest discograms may occur in patients with prior back surgery, in patients with acute changes in pain, or access via a triangle composed of the nerve root laterally, dura medially, and pedicle at the base. Theoretically, inadvertent discogram could increase the risk of discitis. Applying aseptic measures similar to discography or implementing post-injection antibiotics might mitigate infectious complications. Repeat imaging studies not only for qualitatively new symptoms but also after a sustained quantitative increase in pain may reduce the complication of incidental discogram during ILESI.

Conclusions: Further research is needed to develop protocols to prevent inadvertent discograms during ILESI and the potential complications.