Trigeminal Neuralgia

According to Wikipedia, trigeminal neuralgia “is a neuropathic disorder characterized by intense pain in the face, originating from the trigeminal nerve. The trigeminal nerve is the largest nerve coming directly from the brain stem and going to the eyes, upper jaw and lower jaw. With this condition the patient can experience a hemifacial spasm known as tic douloureux, one of the most painful conditions known to mankind.

What are the treatments?

According to the National Institute of Neurological Disorders and Stroke in the article”Trigeminal Neuralgia Fact Sheet,”, ” the less severe form, TN1, “causes extreme, sporadic, sudden burning or shock-like facial pain that lasts anywhere from a few seconds to as long as two minutes per episode. These attacks can occur in quick succession in volleys lasting as long as 2 hours.” TN2 is “characterized by constant aching, burning, stabbing pain of somewhat lower intensity than Type 1. There is a long list of medications that can help manage pain, and does so more effectively in TN1 than TN2.

Surgical Options

This is an excerpt from an article “Trigeminal Neuralgia Fact Sheet” appearing in  the National Institute of Neurological Disorders and Stroke page on this condition:

 

Several neurosurgical procedures are available to treat TN, depending on the nature of the pain; the individual’s preference, physical health, blood pressure, and previous surgeries; presence of multiple sclerosis, and the distribution of trigeminal nerve involvement (particularly when the upper/ophthalmic branch is involved). Some procedures are done on an outpatient basis, while others may involve a more complex operation that is performed under general anesthesia. Some degree of facial numbness is expected after many of these procedures, and TN will often return even if the procedure is initially successful. Depending on the procedure, other surgical risks include hearing loss, balance problems, leaking of the cerebrospinal fluid (the fluid that bathes the brain and spinal cord), infection, anesthesia dolorosa (a combination of surface numbness and deep burning pain), and stroke, although the latter is rare.

A rhizotomy (rhizolysis) is a procedure in which nerve fibers are damaged to block pain. A rhizotomy for TN always causes some degree of sensory loss and facial numbness. Several forms of rhizotomy are available to treat trigeminal neuralgia:

  • Balloon compressionworks by injuring the insulation on nerves that are involved with the sensation of light touch on the face. The procedure is performed in an operating room under general anesthesia. A tube called a cannula is inserted through the cheek and guided to where one branch of the trigeminal nerve passes through the base of the skull. A soft catheter with a balloon tip is threaded through the cannula and the balloon is inflated to squeeze part of the nerve against the hard edge of the brain covering (the dura) and the skull. After about a minute the balloon is deflated and removed, along with the catheter and cannula. Balloon compression is generally an outpatient procedure, although sometimes the patient may be kept in the hospital overnight. Pain relief usually lasts one to two years.
  • Glycerol injectionis also generally an outpatient procedure in which the individual is sedated with intravenous medication. A thin needle is passed through the cheek, next to the mouth, and guided through the opening in the base of the skull where the third division of the trigeminal nerve (mandibular) exits. The needle is moved into the pocket of spinal fluid (cistern) that surrounds the trigeminal nerve center (or ganglion, the central part of the nerve from which the nerve impulses are transmitted to the brain). The procedure is performed with the person sitting up, since glycerol is heavier than spinal fluid and will then remain in the spinal fluid around the ganglion. The glycerol injection bathes the ganglion and damages the insulation of trigeminal nerve fibers. This form of rhizotomy is likely to result in recurrence of pain within a year to two years. However, the procedure can be repeated multiple times.
  • Radiofrequency thermal lesioning(also known as “RF Ablation” or “RF Lesion”) is most often performed on an outpatient basis. The individual is anesthetized and a hollow needle is passed through the cheek through the same opening at the base of the skull where the balloon compression and glycerol injections are performed. The individual is briefly awakened and a small electrical current is passed through the needle, causing tingling in the area of the nerve where the needle tips rests. When the needle is positioned so that the tingling occurs in the area of TN pain, the person is then sedated and the nerve area is gradually heated with an electrode, injuring the nerve fibers.  The electrode and needle are then removed and the person is awakened. The procedure can be repeated until the desired amount of sensory loss is obtained; usually a blunting of sharp sensation, with preservation of touch. Approximately half of the people have symptoms that reoccur three to four years following RF lesioning. Production of more numbness can extend the pain relief even longer, but the risks of anesthesia dolorosa also increase.
  • Stereotactic radiosurgery(Gamma Knife, Cyber Knife) uses computer imaging to direct highly focused beams of radiation at the site where the trigeminal nerve exits the brain stem. This causes the slow formation of a lesion on the nerve that disrupts the transmission of sensory signals to the brain. People usually leave the hospital the same day or the next day following treatment but won’t typically experience relief from pain for several weeks (or sometimes several months) following the procedure.  The International RadioSurgery Association reports that between 50 and 78 percent of people with TN who are treated with Gamma Knife radiosurgery experience “excellent” pain relief within a few weeks following the procedure. For individuals who were treated successfully, almost half have recurrence of pain within three years.
  • Microvascular decompression (MVD) is the most invasive of all surgeries for TN, but also offers the lowest probability that pain will return. About half of individuals undergoing MVD for TN will experience recurrent pain within 12 to 15 years.  This inpatient procedure, which is performed under general anesthesia, requires that a small opening be made through the mastoid bone behind the ear. While viewing the trigeminal nerve through a microscope or endoscope, the surgeon moves away the vessel (usually an artery) that is compressing the nerve and places a soft cushion between the nerve and the vessel. Unlike rhizotomies, the goal is not to produce numbness in the face after this surgery. Individuals generally recuperate for several days in the hospital following the procedure, and will generally need to recover for several weeks after the procedure.

A neurectomy (also called partial nerve section), which involves cutting part of the nerve, may be performed near the entrance point of the nerve at the brain stem during an attempted microvascular decompression if no vessel is found to be pressing on the trigeminal nerve. Neurectomies also may be performed by cutting superficial branches of the trigeminal nerve in the face. When done during microvascular decompression, a neurectomy will cause more long-lasting numbness in the area of the face that is supplied by the nerve or nerve branch that is cut. However, when the operation is performed in the face, the nerve may grow back and in time sensation may return.  With neurectomy, there is risk of creating anesthesia dolorosa.

Surgical treatment for TN2 is usually more problematic than for TN1, particularly where vascular compression is not detected in brain imaging prior to a proposed procedure. Many neurosurgeons advise against the use of MVD or rhizotomy in individuals for whom TN2 symptoms predominate over TN1, unless vascular compression has been confirmed. MVD for TN2 is also less successful than for TN1.

 

A comment:

I have a patient who has gone through one of these surgeries recently. She is doing much better but it is not fully handled for her. She reported to me that her pain was debilitating for a very long time.

According to Wikipedia, the painting “The Scream” by Edvard Munch has been used as a symbol for facial pain, specifically trigeminal neuralgia. That fact should give non-sufferers some inkling of what these patients have to endure. Fortunately, there is ongoing research into this serious condition from the NINDS.”