Purpose of a nerve block injection for neuropathic pain (neuropathy):
A nerve block is an injection of an anesthetic directly in the area of the affected nerve. The purpose of a nerve block in treating neuropathic pain is to interrupt transmission of the pain signal to the brain. If the pain signal does not get to the brain, then pain is not actually felt or perceived by the patient.
Injections in the following locations can sometimes produce short-term pain relief: trigger points, peripheral nerves, plexi, dorsal roots, and sympathetic nervous system.
Agents that may be injected include opioids, local anesthetics, and steroids.
- Steroid injections may decrease the inflammation and irritation to that nerve and may decrease pain
- Local anesthetics may also break the cycle of pain and provide some relief of the patient’s chronic pain
- Opioids injections can also provide powerful, short-term pain relief.
Fluoroscopy (live x-ray) is usually used to help the specialist guide the needle into the exact location. The frequency of the therapeutic nerve blocks depends primarily on how effective they are in reducing pain for the individual patient.
Nerve block injections – a conservative treatment before surgery:
Therapeutic nerve blocks (i.e. an epidural steroid injection) are used as a first line treatment in acute disc herniations in an effort to avoid surgery. In this situation, the medication is placed in the epidural space under fluoroscopic control. A newer version of this is an extraforaminal selective steroid block, which may be more effective in situations where a herniated disc involves a nerve root and spread of the drug in the epidural space would be hampered.
Recent studies have shown that these injections only cause short term pain relief and have no long-term effect.