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MEDICAL CONDITIONS AND TREATMENT OPTIONS
Home » Trygeminal neuralgia

TRYGEMINAL NEURALGIA

Also known as tic douloureux, it is a painful disorder that is described as among the most acute and intense known to humankind. It is referred to by many as the “suicidal disease”. It is a disorder of the fifth cranial (trigeminal) nerve and induces excruciating, lightning strikes of facial pain, typically near the nose, lips, eyes, or ears. Simple things such as brushing the teeth, putting on make-up, or even a slight breeze can trigger an attack, resulting in acute pain. The trigeminal nerve conducts sensation from the upper, middle and lower portions of the face, and also the oral cavity to the brain. Its branches are:

  • Upper, 1st branch or ophthalmic: eyebrow, forehead and frontal portion of the scalp.

  • Middle, 2nd branch or maxillary: upper lip, upper teeth, upper gum, cheek, lower eyelid and side of the nose.

  • Lower, 3rd branch or mandibular: lower lip, lower teeth, lower gum, side of the tongue and a narrow area that extends from the lower jaw in front of the ear to the side of the head.
Cutaneous distribution of the 1st branch of the trigeminal nerve
Cutaneous distribution of the 2nd branch of the trigeminal nerve
Cutaneous distribution of the 3rd branch of the trigeminal nerve
Cutaneous distribution of the 1st branch of the trigeminal nerve
Cutaneous distribution of the 2nd branch of the trigeminal nerve
Cutaneous distribution of the 3rd branch of the trigeminal nerve

The painful attacks of trigeminal neuralgia can involve one or more branches, but commonly involves the middle or the lower branch. In rare instances all three branches may be involved. The right side of the face is more frequently affected than the left. In a small percentage of patients, pain occurs on both sides of the face, but rarely at the same time.


Since in most patients the middle and lower branches are involved, some of the initial symptoms are felt in the teeth and gums. Many patients experience a dull, continuous aching and gum sensitivity to heat and cold prior to the onset of the more intense, classic symptoms of trigeminal neuralgia. This period present a considerable diagnostic challenge, especially for the dentist, since this is, quite often, the first health professional to see the patient. While true dental abnormalities produce pain, the pain of trigeminal neuralgia is not caused by dental problems. What may appear as a toothache may actually be an early symptom of trigeminal neuralgia. It is not unusual for a trigeminal neuralgia patient to see several dentists, oral surgeons, ear, nose and throat and temporo-mandibular joint specialists, etc. Many modes of treatment – root canals, extractions, oral surgeries, etc. – are pursued, to no avail, while the pain steadily worsens and more classic symptoms of trigeminal neuralgia develop.


CAUSE OF TRIGEMINAL NEURALGIA

Vascular compression causing the passage of nerve impulses from one nerve fiber to another and thereby causing pain
In this disease the protective covering (myelin sheath) of the trigeminal nerve deteriorates, allowing abnormal messages (pain) to be sent along the nerve. These changes in the covering of the nerve may be caused by pressure from blood vessels or tumours, multiple sclerosis (which causes a breakdown in the myelin sheath of the nerve) or injury to the nerve. These abnormalities disrupt the normal signal of the nerve and cause pain. Some causes of facial pain are caused by the herpes virus following cases of shingles, but are more correctly identified as post-herpetic neuralgia rather than trigeminal neuralgia. This form of neuralgia is treated by other modes of treatment, usually with anti-viral medications and anti-depressant drugs which alter nerve transmission and help decrease the pain.
Vascular compression causing the passage of nerve impulses from one nerve fiber to another and thereby causing pain
 

WHO IS AFFECTED?


It affects 1 in 25.000 people and occurs slightly more frequently in women than in men. Most patients are over the age of 40 with the majority being in their 50’s and 60’s, but it can occur at any age.


HOW IS IT DIAGNOSED?


Classic trigeminal neuralgia has distinct symptoms which clearly separate it from other forms of facial pain:

  • Pain in short, acute bursts rather than a dull, constant ache. Often described as electric shock-like in nature.

  • Pain is usually triggered by light touch or sensitivity to vibrations – brushing one’s teeth, shaving, a light breeze, a soft kiss, talking, etc.

  • The pain has a tendency to come and go with periods of intense, sometimes totally debilitating pain, followed by complete pain-free periods of remission lasting from weeks to months or possibly longer.

  • Most patients experience pain during the day while they are up and about, and generally, they are pain-free while asleep unless triggered by the touch of bed linens or changes in position.

The patient history and description of symptoms area are physician’s major aids in confirming a diagnosis of trigeminal neuralgia. Most doctors will recommend a head/brain MRI or CAT scan along with other laboratory tests. These are conducted mainly to rule out other possible causes of the pain such as tumours, multiple sclerosis, etc. There is no specific test available to confirm the diagnosis of trigeminal neuralgia.


MEDICAL TREATMENT


There is a growing arsenal of ways to treat trigeminal neuralgia, including medications and surgical treatments. The fist universally accepted treatment option is usually through medications. Surgical procedures are used for those patients who are unable to tolerate the medications, exhibit serious side effects, or if the medications do not control the problem. Medications are initially effective for many patients, bur over a period of time their effectiveness may diminish and a surgical procedure required.


The patient must understand the need to maintain a therapeutic blood level of medication for effective pain relief. Taking the medications irregularly is not effective. Abrupt withdrawal of medications can cause serious side effects.


Analgesics (i.e. aspirin, Tylenol, etc.) are not effective in addressing the pain of trigeminal neuralgia as it is of lightning-like intensity and the attacks are of brief duration. In general, narcotics have not been recommended as first line therapy for trigeminal neuralgia, as they have not been found to be effective for the characteristics of trigeminal neuralgia pain.


The primary drug used to treat trigeminal neuralgia is carbamazepine. It is also used to treat seizures. Initial relief is so readily achieved that many physicians consider its use as a means to confirm the diagnosis of trigeminal neuralgia. The drug is introduced slowly and increased to a level where the patient is pain-free or side effects occur. Carbamazepine is available as Tegretol. A newer medication is oxcarbazepine, available as Trileptal. Extended release carbamazepine is available as Carbatrol and Tegretol XR.


Other medications used in the treatment of trigeminal neuralgia may include baclofen (Lioresal), gabapentin (Neurontin), clonazepam (Klonopin), sodium valproate (Depakote), lamotrigine (Lamictal), and topiramate (Topamax).


SURGICAL TREATMENT


While medications provide effective management for many trigeminal neuralgia patients, medical therapy is often not a permanent solution for this problem. Fortunately there are several neurosurgical procedures that are available if medication no longer provides the desired results.

 

We consider the possibility of surgical treatment is not effective when the drug treatment or pain control is inadequate despite the high doses of medication or when high doses of medication cause undesirable side effects. Once you have decided you need to intervene, you must decide between several possibilities. Basically, you can choose to delete the underlying cause of pain (compression by the artery, vein or tumor) by opening the skull behind the ear, nerve injury by percutaneous procedures across the face, apply radiosurgery or stimulate nerve, their branches or the ganglion by electrical currents.


The dilemma for the trigeminal neuralgia patient considering surgery is how to select a surgical procedure since there are several modes of surgical intervention available. Procedures vary from nerve blocks or injections, percutaneous surgery (through the check), to open skull surgery and pinpoint radiation. Each procedure has certain advantages and disadvantages – ease of the procedure, effectiveness, long-term results, recurrences, complications, etc. There is no one medical or surgical treatment that is effective in all patients. The choice between a procedure done as a one-day or outpatient (e.g., radiofrequency thermocoagulation or glycerol injection) or one requiring several days in the hospital (microvascular decompression) depends on the patient’s preference, physical well-being, previous surgeries, presence of multiple sclerosis, and area of trigeminal nerve involvement (some procedures are particularly indicated when the upper/ophthalmic branch is involved). Undoubtedly, recommendations by the referring physician and by the neurosurgeon play a strong part in the patient’s decision-making process.


To remove the cause, it opens the skull behind the ear. A small window in the bone of the skull and enters the nerve at the point where they exit the brain. Here is sought artery, vein or tumor causing the pain. The tumor is removed, the artery or vein is moving to not touch the nerve and placing a plastic pad that touch the nerve again. It is a very effective procedure that usually retain full functionality of the nerve, but that requires a craniotomy and therefore can not be done in older people because of their poor condition.
Craniotomy for microvascular decompression in trigeminal neuralgia
Trigeminal nerve compression by an artery in the trigeminal neuralgia
Blood vessel being separated from the trigeminal nerve
Craniotomy for microvascular decompression in trigeminal neuralgia
Trigeminal nerve compression by an artery in the trigeminal neuralgia
Blood vessel being separated from the trigeminal nerve
In the percutaneous needle is inserted through the cheek until you reach the point where the third branch leaves the skull. By that point the needle is inserted inside the skull to reach the trigeminal ganglion. Once there are different forms of injury. In the partially burned frequency branch of the nerve where the pain originates. The more are injured longer lasting nerve pain relief, but also loses more and more strength sensitivity of the masticatory muscles. It is generally recommended for neuralgia of the II and III branches and not those of the I. The second option is to place a ball which compress the ganglion. It treats all three branches, but during the procedure usually induces a significant bradycardia, which can not be applied to people with heart disease. The third option is to inject glycerol. As the nerve is less damaging than the other two techniques are recommended for neuralgia of the I branch. However it should be noted that all percutaneous procedures are temporary, but that can be applied in the elderly and poor general condition.
Puncture of the trigeminal nerve
Needle placement in the trigeminal ganglion
After thermocoagulation of the trigeminal nerve root
Puncture of the trigeminal nerve
Needle placement in the trigeminal ganglion
After thermocoagulation of the trigeminal nerve root
Neurostimulation, applying a stimulating electrode or a branch of the trigeminal nerve ganglion, is often applied in refractory cases to other treatments. It is especially useful in post-traumatic or postoperative neuralgia.


All this procedures show varying degrees of immediate success and periods of long-term relief from pain. Generally, the average overall rate of success is 85% with about 25% of this group having some level of recurrence in 1-5 years. Many patients respond quite well when additional measures are pursued if the initial procedure in not successful or if the pain returns. There is no one procedure that is 100% effective in all cases.


RADIOSURGERY TREATMENT IN TRIGEMINAL NEURALGIA

Radiosurgery with gamma-knife
Radiosurgery uses many weak beams of radiation, all aimed at a single spot to provide a large dose at that target. The gamma knife is a device with 201 such beams, aimed through holes that are precision drilled in a large metal helmet. The Cyberknife uses a large number of beams by moving an x-ray machine around the patient, emitting one beam at a time. In either case, the beam focuses radiation directly onto the trigeminal nerve, although there is controversy about which part of the nerve gives optimal results.
Radiosurgery with gamma-knife
 

Treatment with a gamma knife involves attaching a rigid head frame to the skull early in the morning, followed by an MRI scan, followed by a painless and quiet treatment lasting about one hour. The Cyberknife involves a CT scan obtained several days before the treatment and requires about one to two hours. In either case, there is no hair loss as occurs with standard radiotherapy.


The list of complications that can occur with radiosurgery include those of any surgery – death, brain damage, damage to nerves, numbness, etc. – but the risk of any of these is much lower than that of other procedures. Although radiosurgery may be safer than surgical procedures, the results are not quite as good. Excellent results are not obtained about 50-60% of the time, and there is a recurrence rate that can be as high as 30%. It is important to know that the results of radiosurgery are not immediate – it may take several weeks or even months to obtain pain relief, so that radiosurgery might not be the best treatment for those in crisis. The good news is that radiosurgery for trigeminal neuralgia can be repeated, conferring benefit to an additional 10-20% of patients.


In addition to the very small risk of catastrophe, any radiosurgery (and any radiation treatment) carries with it a risk of future malignancy. The risk is very small, but not zero.


The advantages of radiosurgery, however, are real. It is not a surgery, so that there is minimal danger of infection and no danger of bleeding. It can be repeated in case the first treatment does not work and can be used when other medical conditions prevent ordinary surgery. It is often tried and often successful when other surgery for trigeminal neuralgia has failed and can confer benefits for trigeminal neuralgia due to multiple sclerosis and facial pain due to tumours.

 

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