What is Trigeminal Neuralgia?
Trigeminal neuralgia (TN), also called tic douloureux, is a chronic pain condition that causes extreme, episodic, sudden burning or shock-like pain on one side of face. The pain seldom lasts more than a few seconds or a minute or two per episode in the initial stages. Episodes can last for days, weeks, or months at a time and then disappear for months or years. The attacks often worsen over time, with fewer and shorter pain-free periods before they recur. The pain can be triggered by contact with the cheek (such as when shaving, washing the face, or applying makeup), brushing teeth, eating, drinking, talking, or being exposed to the wind. TN occurs most often in people over age 50, but it can occur at any age, and is more common in women than in men.
Although debilitating, the disorder is not life-threatening. The pain of trigeminal neuralgia is often falsely attributed to pathology of dental origin. Extractions do not help. There is a variant of trigeminal neuralgia called atypical trigeminal neuralgia. In atypical trigeminal neuralgia, the sufferer experiences a severe, relentless underlying pain in addition to the stabbing pains. In other cases, the pain is stabbing and intense, but may feel like burning or prickling, rather than a shock.
Several theories exist to explain the possible causes of this pain syndrome. Leading research indicates that it is a blood vessel - possibly the superior cerebellar artery - compressing the trigeminal nerve near its connection with the pons. Such a compression can injure the nerve's protective myelin sheath and cause erratic and hyperactive functioning of the nerve. This can lead to pain attacks at the slightest stimulation of any area served by the nerve. This type of injury may rarely be caused by an aneurysm (an outpouching of a blood vessel) or by a tumor in the cerebellopontine angle. It is also seen in patients with Multiple Sclerosis.
Once the correct diagnosis is made, typical trigeminal neuralgia can be effectively treated. Many people find relief from medication or one of the surgical options. Atypical trigeminal neuralgia, which involves a more constant and burning pain, is more difficult to treat, both with medications and surgery.
Common hurdles to receiving treatment
Many physicians and dentists are unfamiliar with Trigeminal Neuralgia symptoms. As a result, TN is often misdiagnosed.
It is thought that the longer a patient suffers from TN, the harder it may be to reverse the neural pathways associated with the pain. Therefore it is essential that physicians are made aware of the seriousness of TN, and the level of pain that their patient is in.
Dentists that suspect TN should proceed in the most conservative manner possible, and should ensure that all tooth structures are "truly" compromised before performing extractions or other procedures. Because of the hurdles noted above, it is essential for patients who believe they are suffering from TN to seek the advice of a TN specialist or neurologist if they find their primary care physician to be dismissive of their pain.
Surgery may be recommended, either to relieve the pressure on the nerve or to selectively damage it in such a way as to disrupt pain signals from reaching the brain. Microvascular decompression is the gold standard treatment aimed at fixing the presumed cause of the pain. In this procedure, the surgeon enters the skull through a opening behind the ear. The nerve is then explored for an offending blood vessel, and when one is found, the vessel and nerve are separated with a small pad made of teflon or muslin. When successful, MVD procedures can give permanent pain relief with little to no facial numbness.
Percutaneous procedures:These procedures use needles and/or catheters that enter through the face into the opening at the base of skull where the nerve enters. Excellent success rates using a cost effective percutaneous surgical procedure known as Balloon compression has been noted. This technique has been helpful in treating the elderly for whom surgery may not be an option due to coexisting health conditions. Balloon compression is also the best choice for patients who have ophthalmic nerve pain or have experienced recurrent pain after microvascular decompression. Similar success rates have been reported with Glycerol injections and Radiofrequency rhizotomies. Glycerol injections involve injecting an alcohol-like substance into the cavern that bathes the nerve.This liquid is corrosive to the nerve fibers and can mildly injure the nerve enough to hinder the errant pain signals.
In a Radiofrequency rhizotomy, the surgeon uses an electrode to heat the selected division or divisions of the nerve. Done well, this procedure can target the exact regions of the errant pain triggers and disable them with minimal numbness.
The nerve can also be damaged to prevent pain signal transmission using linear accelerator-based radiation therapy (Novalis Tx) or Gamma Knife. No incisions are involved in this procedure. It uses very precisely targeted radiation to bombard the nerve root, this time targeting the area where vessel compressions are often found. This option is used especially for those people who are medically unfit for a long general anaesthetic, or who are taking medications for prevention of blood clotting (e.g., warfarin, heparin, aspirin).
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