Trigeminal Neuralgia
Trigeminal Neuralgia Can be Challenging to Diagnose and Treat
In some patients, it can take years to achieve a diagnosis. Furthermore, there are various medical and surgical treatments which must be tailored to each patient.
The trigeminal nerve is the 5th cranial nerve, and among other things, it provides sensation to the face through three branches: V1-Opthalmic (to the eye), V2-Maxillary (to the cheek) and the V3-Mandibular (to the jaw). Trigeminal neuralgia refers to a facial pain syndrome typically caused by 5th nerve irritation from a blood vessel that courses along the brainstem. Other causes can include multiple sclerosis, brain tumors (typically benign), infections (herpes virus) and trauma. It is postulated that when a blood vessel comes in contact with the root of the nerve, the pulsations from the vessel create erratic stimulation and a hyperactive syndrome (trigeminal neuralgia).
Figure 1: Demonstrates the trigeminal nerve with its 3 divisions (V1,V2, and V3). Note that in this picture there is no blood vessel in contact with the root of the trigeminal nerve.
Figure 2: A blood vessel can be seen (circled area) compressing the root or origin of the nerve. Given the way the nerve is organized, surprisingly, this most commonly affects the mandibular branch or jaw region.
Diagnosis
The resulting pain is often described as electrical shocks that come and go throughout the face and jaw. The pain is described as one of the worst pains known and is often triggered by chewing, eating, talking and cold air. The pain may be seasonal with a peak in the fall and spring. Often patients believe this is related to teeth or gums in origin and undergo dental procedures prior to being diagnosed. An MRI is necessary for a thorough diagnosis to rule out other etiology likes tumors and multiple sclerosis. A high-resolution MRI is also helpful to identify the artery or other vessels that may be causing trigeminal neuralgia.
Treatment
There are many forms of treatment recommended but in general they fall into 3 categories:
- Medical therapy
Medication is the front line treatment and involves the use of a variety of medications intended to calm or improve the function of the nerve. In general, these are medications often used for seizures of the brain (carbamazepime, phenytoin, oxycarbamazepime). They may fail or create unwanted side-effects, such as, sedation, lethargy, cognitive impairment amongst others. Under these circumstances patients may wish to consider other therapies. Typically, if patients do not respond or cannot tolerate these medications, we consider more invasive therapies for this condition. - Microvascular decompression
This procedure is intended to move the offending vessel and create a cushion or pad between the nerve and the offending vessel(s). The decompression addresses the root cause of trigeminal neuralgia by dealing with vessel that is irritating the nerve. - Ablative therapy
This technique is used to selectively destroy the tissue that is causing pain. The procedure consists of a variety of approaches of cutting or sectioning the nerve. In our experience these are unsuccessful, may close the door for subsequent definitive therapy and should be kept as a last resort.
