The trigeminal nerve or Vth (5^th) nerve is the most commonly affected sensory nerve. The nerve has three branches V1-Opthalmic (to the eye), V2 Maxillary (to the cheek) and the V3-Mandibular (to the jaw).
 

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.

There are many forms of treatment recommended but in general they fall into 3 categories:

1. Medical therapy
2. Ablative therapy
3. Microvascular decompression

Medical Therapy:

This 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 (Tegretol, Dilantin and Lamictal). These medications 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.

Ablative Therapy:

These therapies are designed to ablate or selectively destroy specific fibres of the trigeminal nerve.  The procedures represent a collection of different strategies ranging from compression of the nerve with a balloon (Balloon Rhizotomy), alcohol injection of the nerve (Alcohol Rhizotomy), and radiofrequency destruction of the fibres (RF Rhizotomy).   More recently an effort to achieve selective destruction of specific fibres has been pursued using stereotactic radiation therapy (gamma knife, cyberknife amongst others).  Each of these approaches has variable degree of effectiveness, numbness and nerve dysfunction and recurrence rates associated with procedures.  Ablative therapies may also result in Anesthesia Dolourosa when the nerve fibres are severely disrupted.  This condition creates painful numbness similar to “phantom pain syndrome” that may be difficult to treat.

Microvascular Decompression:

This procedure is intended to move the offending vessel and create a cushion or pad between the nerve and the vessel.  The decompression addresses the root cause of trigeminal neuralgia by dealing with vessel that is causing the compression.  The approach involves a minimally invasive keyhole retromastoid approach.  This approach involves making a small incision behind the ear and keyhole opening in the bone. Using the natural space that is created when the cerebrospinal fluid is drained direct access to the nerve and offending vessel is provided.  Using this space there is little need for manipulation of the brain and nerve.  Small pads of Teflon are placed between the nerve and vessel.

Figure 3: a small keyhole craniotomy (shadowed circle) is created behind the ear and a path (arrow) using the space created by the drainage of the CSF is used to access the nerve and compressing artery.  The artery is carefully mobilized using a microscope, endoscope or combination of both. Small pieces of Teflon (white circles) are placed to keep the vessel away from the nerve.

Results: