Trigeminal Nevralji

What is the Trigeminal Nerve?

The trigeminal nerve is a group of cranial nerves in the head. It is the nerve responsible for providing sensation to the face. One trigeminal nerve runs to the right side of the head and the other to the left. Each of these nerves has three different branches. “Trigeminal” is derived from the Latin word “tria” meaning three and “geminus” meaning twin. After the trigeminal nerve leaves the brain and enters the skull, it divides into three smaller branches that control facial sensations:

• Ophthalmic Nerve (V1): The first branch controls sensation in the eye, upper eyelid, and forehead.
• Maxillary Nerve (V2): The second branch controls sensations in the lower eyelid, cheek, nostril, upper lip and upper gum.
• Mandibular Nerve (V3): The third branch controls sensation in the jaw, lower lip, lower gum, and some muscles used for chewing.

Prevalence and Incidence

It is reported that 150,000 people are diagnosed with trigeminal neuralgia (TN) each year. Although the disorder can occur at any age, it is most common in people over the age of 50. The National Institute of Neurological Disorders and Stroke (NINDS) states that TN is twice as common in women than men. One form of TN is associated with multiple sclerosis (MS).

Causes of Trigeminal Neuralgia

There are two types of Trigeminal Neuralgia as primary and secondary TN. The exact cause of TN is still unknown, but the pain associated with it represents irritation of the nerve. Primary trigeminal neuralgia has typically been associated with compression of the nerve at the base of the head, where the brain connects with the spinal cord. This is usually caused by contact between a healthy artery or vein and the trigeminal nerve at the base of the brain. This puts pressure on the nerve as it enters the brain and causes the nerve to misfire. Secondary TN is caused by a tumor that damages the myelin sheaths, multiple sclerosis (MS), a cyst, facial injury, or other medical condition pressing on the nerve.

Symptoms of Trigeminal Neuralgia

Most patients report that their pain started spontaneously and suddenly. Other patients say their pain is after an accident, a blow to the face, or dental surgery.

TN pain is defined as type 1 (TN1) or type 2 (TN2). TN1 is characterized by intense sharp, throbbing, sporadic, burning, or shock-like pain around the eyes, lips, nose, chin, forehead, and scalp. TN1 can get worse and cause more episodes of pain that last longer. TN2 pain is usually present as constant, burning, aching, and may also be less severe stabbing than TN1.

TN tends to run in cycles. Patients usually have long periods of frequent periods of pain, followed by little or no pain for weeks, months, or even years. Some patients have fewer than one attack per day, while others have a dozen or more attacks every hour. The pain typically begins with an electric shock sensation that results in excruciating stabbing pain in less than 20 seconds. Pain often leaves patients with uncontrollable facial twitching, so the disorder is also known as tic douloureux.

The pain may be focused on a single point or radiate to the entire face. Typically on only one side of the face; however, in rare cases and sometimes associated with multiple sclerosis, patients may feel pain on both sides of their face. Areas of pain include cheeks, jaw, teeth, gums, lips, eyes, and forehead.

Trigeminal Neuralgia attacks can be triggered by:

• Touching the skin lightly
• Wash face
• Shaving
• Brushing teeth
• blowing your nose
• Drinking hot or cold drinks
• Encountering a gentle breeze
• applying makeup
• smile
• Talk

The symptoms of several pain disorders are also similar to those of trigeminal neuralgia. The most common mimic of TN is trigeminal neuropathic pain (TNP). TNP results from injury or damage to the trigeminal nerve. TNP pain is often described as constant, dull, and burning. Attacks of sharp pain, usually triggered by touch, may also occur.

The differential diagnosis includes:

temporal tendinitis
Ernest syndrome (injury of the stylomandibular ligament)
occipital neuralgia
Cluster headaches/migraines
Giant cell arteritis
Toothache
Post-herpetic neuralgia
Glossopharyngeal neuralgia
sinus infection
ear infection
temporomandibular joint syndrome

Diagnosing Trigeminal Neuralgia

TN can be very difficult to diagnose because there are no specific diagnostic tests and the symptoms are very similar to other facial pain disorders. This is why you may also be experiencing unusual, sharp pain around the eyes, lips, nose, chin, forehead, and scalp, especially if you haven’t had dental or other facial surgery recently.

Examinations

Magnetic resonance imaging (MRI) can detect whether a tumor or MS has affected the trigeminal nerve. A high-resolution, thin-section or three-dimensional MRI can show whether a blood vessel is pressing on the nerve. Tests can help rule out other causes. There is no specific diagnostic test for TN, so the diagnosis of TN is made largely on the basis of symptoms and history, type of pain (sudden, sudden and shock-like), location of pain and pain triggers, exclusion of other causes, and clinical evaluation.

Treatment of Trigeminal Neuralgia

Non-Surgical Trigeminal Neuralgia Treatments

There are several effective ways to relieve pain, including various medications. Drugs are usually started at low doses and gradually increased according to the patient’s response to the drug.

Carbamazepine, an anticonvulsant drug, is the most common drug doctors use to treat TN. Carbamazepine controls pain for most people in the early stages of the disease. When a patient does not show any relief from this drug, there is reason for the doctor to doubt whether it is TN. However, the effectiveness of carbamazepine decreases over time. Possible side effects include dizziness, double vision, drowsiness, and nausea.

Gabapentin, an anticonvulsant drug most commonly used to treat epilepsy or migraine, can also treat TN. The side effects of this drug are few and include dizziness and/or drowsiness that go away on their own.

A newer drug, oxcarbazepine, has recently been used as a first-line treatment. It is structurally similar to carbamazepine and can be preferred because it generally has fewer side effects. Possible side effects are dizziness and double vision.

Other drugs are baclofen, amitriptyline, nortriptyline, pregabalin, phenytoin, valproic acid, clonazepam, sodium valporate, lamotrigine, topiramate, phenytoin, and opioids.

Apart from the side effects, these drugs also have disadvantages. Some patients may require relatively high doses to relieve pain, and side effects may become more pronounced at higher doses. Anticonvulsant drugs may lose their effect over time. Some patients may require a higher dose or a second anticonvulsant to relieve pain, which may lead to adverse drug reactions. Many of these drugs can have a toxic effect in some patients, especially those with a history of bone marrow suppression and kidney and liver toxicity. To ensure the safety of these patients, their blood values are examined.

Trigeminal Neuralgia Surgery

When medications are ineffective in treating TN, several surgical procedures can help control pain. Surgical treatment falls into two categories: 1) Open Cranial Surgery or 2) Lesion Formation Procedures.

Generally, open surgery is performed in patients who are found to be pressing on the trigeminal nerve from a nearby blood vessel, which can be diagnosed by imaging the brain, such as with a specialized MRI. This surgery is thought to remove the underlying problem causing TN. In contrast, lesion-making procedures involve interventions that intentionally injure the trigeminal nerve to prevent the nerve from causing facial pain. The effects of the lesion may be of shorter duration and may result in facial numbness on some keys.

Open Surgery

Microvascular decompression involves microsurgery exposing the trigeminal nerve root, identifying a blood vessel pressing on the nerve, and gently moving the blood vessel away from the pressure point. Decompression can reduce sensitivity and allow the trigeminal nerve to heal and return to a more normal, pain-free state. While this is generally the most effective surgery, it is also an invasive procedure because it requires the skull to be opened through a craniotomy. There is a slight risk of hearing loss, facial weakness, facial numbness, double vision, stroke or death.

Lesion Procedures

• Percutaneous radiofrequency rhizotomy: treats TN using electrocoagulation (heat). It can relieve nerve pain by destroying the part of the nerve that is causing the pain and suppressing the pain signal to the brain. The surgeon inserts a hollow needle from the cheek into the trigeminal nerve. A heating current passed through an electrode destroys some nerve fibers.
• Percutaneous balloon compression: It uses a needle that goes through the cheek into the trigeminal nerve. Your neurosurgeon places a balloon through a catheter into the trigeminal nerve. The balloon is inflated where the fibers produce pain. The balloon compresses the nerve and injures the fibers causing the pain and is then removed.
• Percutaneous glycerol rhizotomy: It utilizes glycerol injected through a needle into the area where the nerve divides into three main branches. The goal is to selectively damage the nerve to interfere with the transmission of pain signals to the brain.
• Stereotactic radiosurgery (Gamma Knife, Cyberknife, Linear Accelerator (LINAC): These procedures deliver a high concentration of ionizing radiation to a small, precise target at the trigeminal nerve root. This treatment is noninvasive and avoids most of the risks and complications of open surgery and other treatments for a while During and as a result of radiation exposure, the gradual formation of a lesion in the nerve interrupts the transmission of pain signals to the brain.

In general, the benefits of surgery or lesion-creation techniques should always be carefully weighed against the risks. Although a large percentage of TN patients report pain relief after the procedures, there is no guarantee that they will help every individual.

Neuromodulation

For patients with TNP, another surgical procedure may be performed that involves placing one or more electrodes in the soft tissue near the brain nerves responsible for sensing facial sensation, under the skull in the lining of the brain, and sometimes deeper into the brain. In peripheral nerve stimulation, the leads are placed subcutaneously on the branches of the trigeminal nerve. In motor cortex stimulation (MCS), the region innervating the face is stimulated. In deep brain stimulation (DBS), regions that affect the sensory pathways to the face can be stimulated.

How Do You Prepare for a Neurosurgery Appointment?

Write down the symptoms. This should include: what the pain feels like (for example, is it sharp, pounding, aching, burning or something else), where exactly the pain is (lower jaw, cheek, eye/forehead), if accompanied by other symptoms (headache, numbness, facial spasms), duration of pain (weeks, months, years), pain-free intervals (longest pain-free period or between attacks), severity of pain (0 = no pain, 10 = most severe pain).

Pay attention to any pain triggers (e.g. tooth brushing, face touching, cold weather)

Make a list of medications and surgeries related to facial pain (previous medications, did they work, did they have side effects), current medications (duration and dosage).

Follow-up

Patients should be followed up regularly by their doctors to continue their treatment. Typically, neuromodulation surgery patients are asked to return to the clinic every few months during the year following surgery. During these visits, they can adjust the stimulation settings and assess the patient’s post-operative recovery. A routine doctor’s follow-up ensures that care is accurate and effective. Patients undergoing any neurostimulation surgery will be followed up with their physician as well as a device representative who will adjust device settings and parameters as needed.