What is a Nerve Block?
When a spinal facet joint (in your neck or lower back) is injured in a car accident, trip and fall or other personal injury, if conservative physical therapy does not work, a nerve block injection procedure may be recommended by your treating doctor.
A nerve block should be performed by a board-certified anesthesiologist. The doctor will inject a local anesthetic such as lidocaine (usually lasts about an hour) or bupivacaine (lasts about three hours) onto a group of target nerves to interrupt the electric signal along that group of nerves. When the nerve block wears off, normal nerve function is expected to resume.
For example, a brachial plexus nerve block involves an injection in the armpit that will allow a surgeon to operate on the same-sided arm or hand. A stellate ganglion block involves an injection to the front of the neck and is typically used to treat Reflexive Sympathetic Dystrophy (also known as Complex Regional Pain Syndrome – RSD/CRPS). Here is a video explaining What is RSD? in more detail.
Since the origin of one’s pain can sometimes come from various locations, nerve blocks can also be used diagnostically. For example, lumbar pain can originate from a intervertebral disc, a vertebral facet joint (facet joints are innervated by medial branch nerves), a vertebral body itself, interspinal ligaments, spinal muscles or sacroiliac joint. When someone has chronic pain and the doctor is unsure of the specific origin of that pain a diagnostic nerve block may assist the treating physician. In this scenario the anesthesiologist will use a smaller amount of lidocaine or bupivacaine in a series of suspected nerve sites. Using this method, a treating physician can locate or rule out different nerve groups (and therefore corresponding pain origin/pain generator) depending on whether the patient reports a decrease, or no decrease, in symptoms.
Once the pain origin is located, it can be treated with further nerve blocks, the more aggressive radiofrequency lesioning (also called medial branch neurotomy, discussed below) or even more aggressive surgery. When patients have chronic pain from a personal injury in the neck or back, cortisone injections in to the facet joints may only provide temporary relief. For lasting relief, it may be necessary to destroys the medial branch nerves that supply the injured facet joint using radiofrequency lesioning.
Nerve Blocks are generally performed under fluoroscopy (essentially a live-action x-ray). The procedure may not be under sedation if the doctor wants immediate feedback from the patient as to whether the painful symptoms have significantly diminished. Fortunately, side effects and complications (other than soreness in the area for several days) are relatively rare.
What Is Radiofrequency Lesioning?
Also called, Medial Branch Neurotomy, or RF, radiofrequency lesioning is also performed under fluoroscopy and will generally be conducted under sedation, including local anesthesia. These radiowaves, adminstered via an electrode, produce significant heat at high frequencies and this heat can be applied to specific medial-branch nerves, for only a few minutes, in order to kill the tissue surrounding and including the nerve, thereby destroying the pain pathway. RF can last for a few months to over a year (the body heals itself and will regrow the destroyed nerves). RF Lesioning is usually recommended when the pain originates from a spinal facet joint and doctors will always test how you respond to a diagnostic nerve block before attempting the radiofrequency lesioning procedure.