(Kiosk 2) Inadvertent Intradiscal Contrast Flow During Transforaminal Epidural Steroid Injection: A Case Series

Case Diagnosis: Inadvertent Intradiscal Contrast Flow

Case Description or Program Description: Transforaminal epidural steroid injections (TFESIs) are a minimally invasive, non-operative treatment used to treat radicular pain. We describe two cases of intradiscal contrast flow during lumbar TFESIs despite optimal needle placement.

Setting: Outpatient spine clinic

Assessment/Results: The first case features a 61-year-old male, with a history of lumbar spondylosis with bilateral L5 pars defects status post L4-S1 fusion, who presented with progressively worsening right sided low back pain radiating to the groin and anterior thigh that persisted despite conservative treatments. MRI showed severe foraminal stenosis at L3-4, and a right L3-4 TFESI was planned. Live fluoroscopy during contrast administration revealed appropriate epidural pattern, however, contrast also flowed within the L3-4 intervertebral disc on both AP and lateral fluoroscopic views.
The second case features a 78-year-old male who had left leg pain radiating to his calf. His MRI demonstrated L5 grade 1 anterolisthesis and severe bilateral neuroforaminal stenosis at L5-S1. Given his symptoms and pain refractory to conservative treatment, a left L5 TFESI was pursued. Live fluoroscopy during contrast administration revealed appropriate epidural pattern, however, contrast was confirmed within the L5-S1 intervertebral disc on both AP and lateral views.

Discussion (relevance): Inadvertent intradiscal injections following a TFESI is a known, but infrequent complication with reported rates in two retrospective studies (Plastaras et al and Candido et al) of around 0.19% using the subpedicular approach. Studies demonstrated that intradiscal placement of the needle tip was not required for intradiscal contrast flow of medication. Because injecting steroids into an intervertebral disc can lead to discitis, it is crucial to continue proper techniques and have rigorous pre-procedure planning even for lumbar TFESIs to limit complications. In our cases, the authors were able to use contrast and imaging to prevent further complications.

Conclusions: Inadvertent disc injection can occur despite optimal technique due to far lateral disc herniations, spondylisthesis, physical defects in the annulus fibrosis that permit contrast to flow into the disc space, and negative intradiscal pressure that is associated with a severely degenerated “vacuum disc."