In the pain management field, “nerve block” is a generic term, referring to the injection of a local anesthetic into or in the close proximity of a peripheral nerve, sympathetic nerve, or pain trigger point, in order to temporarily inactivate it. In addition to anesthetics, such as lidocaine or prilocaine, corticosteroids are made use of in combination with nerve blocks if there is inflammation present, as in a herniated disc.
Carried out as a single injection or a continuous nerve block infusion, nerve can relieve pain from several hours to several months. Nerve blocks are used for many types of pain in addition to headaches. Nerve blocks are given for control of back pain, leg pain, facial pains, ocular pain and dental pain. There are a few types of nerve blocks in use specifically for headaches.
Greater Occipital Nerve Blocks
Occipital neuralgia is described as a severe pain in the posterior head and neck region; it can be associated with either tension headaches, migraine headaches or organic diseases of the craniocervical region.
Occipital nerve blocks can provide near immediate relief. The procedure involves injecting a small amount of anesthetic and anti-inflammatory medicine under the skin around one or both of the greater occipital nerves.The greater occiptal nerve is a spinal nerve located in the back of the head at the rear of the ear.
The patient may feel a reproduction of their neurralgia as the area is injected. However, relief will be felt within a few seconds to a few minutes, depending on the specific anesthetic agent used. The relief gained is somewhat unpredictable and may last weeks in some patients, or only hours in others. For a more acute cases, both sides of the head may need to be injected. Research is ongoing.
Cervical Epidural Nerve Block
A cervicogenic headache is associated with nerve, muscle or bones in the neck or back of the head. The headache pains typically manifest in the neck and occipital area, and may radiate to the forehead, temples, eyes, or ears. They may be triggered or aggravateed by head or neck movement or posture.
In these cases, a cervical epidural nerve block, performed by pain management specialists, may be helpful in treating pain and avoiding additional pain. Patients have reported significant pain cessation from this procedure. It involves injecting small amounts of a corticosteroid and anesthetic into spaces between the vertebrae in the neck (the cervical epidural space).
Nerves run through the cervical epidural space to the neck, shoulder, and arm, and the inflammation of these nerves can cause pain. Cervical epidural nerve blocks inject an anti-inflammatory medication into this epidural space for the purpose of decreasing the inflammation of the nerve roots. It typically takes 7-10 days for the steroid in the nerve block to be fully effective. A single treatment may effect a relief of symptoms, however, occasionally a second or third follow-up injection is needed in order to achieve the full benefit.
Alternatives to Anesthetic Drugs
Pain management specialists have begun to employ extreme cold or heat in nerve blocks in place of anesthetics or corticosteroids. Not all conditions are suited to treatment with cryoanalgesia and rf ablation, but they represent added options for pain management now coming into play and those suffering from chronic headaches may wish to keep then in mind.
In Cryoanalgesia (the use of extreme cold), a probe is placed very close to the nerve, and the temperature is lowered blow zero for 60 to 90 seconds, sometimes in multiple cycles. As a result the nerve freezes and pain is eliminated for an extended period of time, in the range of weeks to months. The most critical aspect of this procedure is locating the specific nerve causing the pain.
Benefits of this technique over injection include the lower risk of complications, and the ability to be performed on an outpatient or office visit basis.
Radiofrequency neuroablation is the use of extreme heat to achieve the same ends as cryonanalgesia and traditional nerve block injection. A probe is placed close to the nerve, and radio waves are used to generate extreme heat at the tip of the probe for 40 to 90 seconds, resulting in the destruction of the targeted nerve and cessation of pain. This procedure is usually performed with the patient under sedation.