WHAT’S THIS TRIGEMINAL NEURALGIA THING?
WHAT’S THIS TRIGEMINAL NEURALGIA THING?
Several people have recently asked about trigeminal neuralgia (TN) and how it may relate to chronic headaches. Trigeminal neuralgia is classically thought of as being caused by compression of the trigeminal nerve (root) near the pons (a part of the brain) or the trigeminal sensory ganglion (its sensory component) in the middle cranial fossa (another part of the inner skull) near another part of the brain. The primary cause of TN is thought to be compression of the trigeminal nerve by an abnormal blood vessel inside the skull. There is sometimes another term used, trigeminal neuropathy, which usually relates to TN caused by issues other than blood vessel compression such as herpes zoster, post-traumatic pain, or other space occupying lesions such as brain tumors, benign or malignant. Hence this problem is typically thought of as a central nervous system issue. Again, the central nervous system to doctors simply means brain or spinal cord.
The symptoms of trigeminal neuralgia are very narrowly defined and include severe, unilateral, paroxysmal, electric or stabbing attacks that last a few seconds to a few minutes, in the distribution of one or more divisions of the trigeminal nerve and in the absence of other identifiable neurologic disorders. In this regard, TN is very much like occipital neuralgia whose symptoms are defined in extremely specific ways. These two disorders thus stand in sharp contradistinction to other headache disorders like migraines, cluster headaches and tension headaches whose symptoms are often generic, quite varied and hence overlap significantly. It is for this reason among others that I feel ON and TN are extremely misunderstood and underdiagnosed.
So how does TN relate to headaches? Well, the trigeminal nerve is the primary sensory nerve to the face, forehead and temporal scalp. Therefore, injury to this nerve can cause facial pain, or frontal/temporal pain, the latter often perceived as forehead or temporal headaches. The supraorbital, supratrochlear, auriculotemporal and zygomaticotemporal nerves are all branches of the trigeminal nerve. The first two are responsible for sensation to the forehead and above/between the eyes and the latter two for sensation to the anterior and posterior temporal scalp. Hence compression or irritation of these sensory nerve branches can cause pain in their distributions. For example, as I have posted before (photos included), the auriculotemporal nerve is often compressed by the adjacent superficial temporal artery.
Hence there can be compression both in the central nervous system as noted above and in the peripheral nervous system as in the example just cited, but both involving the trigeminal nerve. The former requires a neurosurgeon because in order to access the compressive element (blood vessel or tumor) near the brain, the skull must be cut and the compressive element removed. This compression usually involves the entire trigeminal nerve or a large part thereof. The latter doesn’t require anything be done to the skull and is performed on the tissues (e.g. nerves, blood vessels, connective tissue) external to it, addressing one or more trigeminal nerve branches. Therefore, I believe the more precise term for compression/irritation of these peripheral nerves should be trigeminal branch neuralgia and it is these compression syndromes that I and Drs. Guyuron, Ducic, Hagan, Janis, etc. treat with our decompression procedures.
One last point: several people have wondered whether these peripheral nerve decompression procedures are “minimally invasive” and the answer is, “It’s all relative”. I guess compared with using a saw to remove part of the skull and exposing the brain and other nerve roots, the answer is yes. That type of procedure is done in a hospital and often requires a multi-day hospital stay. However, even though the peripheral nerve decompression procedures noted above are outpatient cases and are performed at accredited surgery centers, they are real operations and are not to be taken lightly. They require skill and experience as the nerves are quite small peripherally. They require general anesthesia because the patient must be positioned carefully and be perfectly still because the nerves are so small. And they require incisions, so compared with an MRI or trigger point injection, they are invasive. Having said that, like the procedures for ON, they can be very effective with relatively low complication rates and risks.
For more information about peripheral nerve surgery, and migraine surgery in San Francisco, CA, visit www.peledmigrainesurgery.com today, and call 415-751-0583 to schedule an appointment.