Peripheral nerve blocks for headache refers to an intervention on the nerves on the outer side of the skull. For nerve blocks, it is applied in the form of injections of local anesthetics. Moreover, their analgesic effects typically persist beyond the duration of anesthesia caused by the nerve block, providing pain relief for several weeks or even months in some patients. This prolonged analgesia after peripheral nerve blockade may be due to an effect on central pain modulation. In addition to head and neck pain, these peripheral nerve block procedures can also be effective in primary headache disorders such as migraine and cluster headache.
Radiofrequency neuroablation is the use of extreme heat to achieve the same results as cryoanalgesia and traditional nerve block injection. In this technique, a probe is placed close to the nerve and radio waves are used to generate heat between 40 and 80 0C at the tip of the probe. This causes destruction of the targeted nerve and pain relief. This procedure is usually done while the patient is under sedation.
Headaches
Nerve blocks are one of the beneficial treatment options for patients with head and neck pain. In addition, these peripheral nerve procedures can also be effective in primary headache disorders such as migraine and cluster headache. Nerve blocks for headache are usually administered in the form of injections of amide-type local anesthetics such as lidocaine and bupivacaine. Through an effect on central pain modulation, they provide long-term, several weeks or even months of pain relief, in some patients. The most common target for peripheral nerve blocks is the greater occipital nerve (GON). Other nerves commonly targeted are the lesser occipital nerve (LON) and several branches of the trigeminal nerve, including the supratrochlear (STN), supraorbital (SON) and auriculotemporal nerves (ATN). Peripheral nerve blocks are generally safe and well-tolerated procedures and can be performed in an outpatient setting. Neurostimulation usually targets the upper cervical and suboccipital regions and the greater occipital nerves.
Great occipital nerve (GON) block
The greater occipital nerve arises from the posterior root of the second cervical nerve in the neck. It is the nerve that provides sensation to the back of the head. It is located on the back of the head from the midline to the back of the ear, close to the ear. Local anesthetics are applied to a depth of about 5 mm with a fine-tipped needle. Injections can be done unilaterally or bilaterally.
Lesser occipital nerve (LON) block
The lesser occipital nerve originates in the neck from the posterior root of the second cervical nerve and sometimes from the third nerve root as part of the cervical plexus. It receives sensation of the lateral (side) part of the back of the head. The injection is given in the area of the greater occipital nerve, but this time near the center of the head. Local anesthetic injections are made with a fine-tipped needle, about 5 mm deep, unilaterally or bilaterally.
Supratrochlear (STN) and supraorbital (SON) block
These nerves are terminal branches of the frontal nerve, which is the largest branch of the ophthalmic division of the trigeminal nerve. The supraorbital nerve exits through the supraorbital foramen. The supratrochlear nerve is 2 cm more medial. These two branches provide sensory innervation to the frontal scalp and forehead, the middle part of the upper eyelid and the root of the nose. In the approach to these nerves on the forehead just above the eyeball, a block is performed with a very fine needle and local anesthetic.
Auriculotemporal nerves (ATN)
The auriculotemporal nerve is located on the upper surface of the parotid gland (salivary gland in front of the ear), temporomandibular joint, jaw joint. The cutaneous branches of this nerve provide sensory innervation to the tragus, part of the auricle adjacent to the ear and most of the temporamandibular joint (jaw joint). Just in front of the auricle, 1 ml of local anesthetic is injected at a depth of 5 mm.