From the Research
A L4/5 subpedicular transforaminal epidural steroid injection primarily addresses the L5 nerve root. This is because the nerve root exits below the corresponding vertebral level, meaning the L5 nerve root exits through the L4/5 neural foramen. When performing this injection, the needle is placed in the superior and anterior aspect of the foramen (subpedicular approach) to deliver anti-inflammatory medication directly to the affected nerve root. The medication typically includes a long-acting corticosteroid (such as dexamethasone 10mg, betamethasone 6-12mg, or methylprednisolone 40-80mg) mixed with a small amount of local anesthetic (like lidocaine 1% or bupivacaine 0.25%) 1. This approach is particularly effective because it delivers the medication directly to the site of inflammation where the nerve root may be compressed or irritated, often by a herniated disc or foraminal stenosis. The steroid reduces inflammation while the local anesthetic provides immediate pain relief and helps confirm proper medication placement. Understanding this anatomical relationship is crucial for proper needle placement and effective treatment of radicular pain originating from the L5 nerve root. Some key points to consider when performing this procedure include:
- The use of image guidance to ensure accurate needle placement and minimize the risk of complications 2
- The selection of the appropriate approach, such as the subpedicular or retrodiscal approach, based on the individual patient's anatomy and pathology 1
- The importance of monitoring the patient's response to the injection and adjusting the treatment plan as needed 3
- The potential benefits and risks of using particulate versus non-particulate steroids in transforaminal epidural injections 2