From the Research
A L4/5 retrodiscal transforaminal epidural steroid injection primarily addresses the L5 nerve root. This occurs because the nerve roots exit below their corresponding vertebral level in the lumbar spine. When an injection is performed at the L4/5 intervertebral disc level, the medication is delivered to the L5 nerve root as it exits through the L4/5 neural foramen. The injection delivers anti-inflammatory corticosteroid medication directly to the site where the L5 nerve root may be experiencing compression or inflammation, typically from a herniated disc or foraminal stenosis at the L4/5 level. The steroid reduces inflammation around the nerve root, potentially decreasing pain and improving function. Some key points to consider when performing this procedure include:
- The transforaminal approach specifically targets the ventral epidural space where pathology often occurs, allowing for more precise delivery of medication to the affected nerve root compared to interlaminar approaches 1.
- The procedure is typically performed under fluoroscopic guidance to ensure accurate needle placement and medication delivery to the intended nerve root.
- Studies have shown that transforaminal epidural steroid injections can be effective in reducing pain and improving function in patients with lumbar radiculopathy, with one study finding that injections at the L4-5 level were more effective than those at the L5-S1 level 2.
- The contrast spreading patterns in retrodiscal transforaminal epidural steroid injections have been studied, with one study finding that the contrast dye mostly went into the cephalic root and about 60% spread over the proximal nerve root 3. Overall, the goal of a L4/5 retrodiscal transforaminal epidural steroid injection is to deliver medication directly to the affected nerve root, reducing inflammation and relieving pain.