Trigeminal neuralgia (TN) is often called tic douloureux. It has been described as one of the most painful feelings. The pain usually is in the lower face and jaw area but sometimes it can be near the nose or above the eyes. The trigeminal nerve gets irritated and sends branches of electric, stabbing pain down to the forehead, cheek, or lower jaw. Usually only one side of the face is affected. Pain can be triggered from daily activities or the weather such as eating, going out on a windy day, or brushing teeth. Trigeminal neuralgia can get increasingly more painful if not treated properly.
This condition is not usually cured but treatments can help lower pain. Anticonvulsant medications are typically the first treatments done. Surgery can be an option if a nonsurgical approach does not work.
The Trigeminal Nerve
The trigeminal nerve works to provide sensation to the face and is a set of cranial nerves. One of the trigeminal nerves goes down the right side of the head and the other goes down the left side of the head. There are three main branches to the trigeminal nerve that branch off after the nerve leaves the brain and goes into the skull.
- Ophthalmic Nerve (V1): This is the first branch and will control the feeling in the yes, upper eyelid and forehead
- Maxillary Nerve (V2): This is the second branch of the trigeminal nerve that controls feeling in the lower eyelid, cheek, nostril, upper lip, and the upper gum.
- Mandibular Nerve (V3): The third branch will control feeling in the jaw, lower lip, lower gum and chewing muscles.
PREVALENCE
Every year around 150,000 people get diagnosed with trigeminal neuralgia. The majority of people with TN are over the age of 50. Trigeminal neuralgia is twice as common in females that in males. A type of trigeminal neuralgia is associated with multiple sclerosis.
CAUSES
There is primary and secondary trigeminal neuralgia. There is not a single known cause of trigeminal neuralgia except for nerve irritation in the base of the head at the location where the brain meets with the spinal cord. This can be because of contact between a healthy artery or vein meeting the trigeminal nerve at the bottom of the brain. This causes the pressure to arise on the nerve. Secondary TN happens when the nerve pressure arises from another medical condition such as a tumor, MS, cyst, damage to the myelin sheath, etc.
SYMPTOMS
Typically patients will say that their pain began for no reason and randomly. Sometimes people say their pain can after a traumatic injury or accident or dental work. Dental work usually only triggers the symptoms but does not cause trigeminal neuralgia. Pain is usually first felt near the upper or lower jaw. This leads many patients to believe they have a dental abscess. Some patients may have a root canal performed which does not help this condition. Patient's then realize the pain is not dental related.
There is type 1 (Tn1) and type 2 (TN2) pain for trigeminal neuralgia. TN1 has very sharp, random pains around the eyes, lips, nose, jaw, forehead, and scalp. TN1 can get increasingly worse and pain episodes can lengthen in time. TN2 is usually a constant aching and burning with less intense throbbing.
Trigeminal neuralgia usually happens in cycles of intense pain attacks to periods of no pain for weeks or months or years. The attacks typically get worse as time goes on with less of a pain free time. Sometimes patients can have many attacks each day but others may only experience one or two. An electric shock stabbing pain will usually happen in less than 20 seconds and the patient may have face twitching.
The pain can be localized or spread out but usually pertains to one side of the face. Patients with multiple sclerosis, though, usually feel pain on both sides of their face. The areas that are associated with TN pain include the cheeks, jaws, teeth, gums, eyes, lips, forehead.
Attacks of TN may happen from:
- Light touching of skin
- Washing
- Shaving
- Teeth brushing
- Drinking hot or cold liquids
- Nose blowing
- Wind
- Putting on makeup
- Smiling
- Talking
Many pain disorders have similar symptoms to TN. Trigeminal neuropathic pain is very close to Tn. TNP happens due to a damaged trigeminal nerve. TNP is an ongoing, dull, burning feeling. Sharp pain usually occurs after being touched. Some other conditions similar to TN:
- Temporal tendonitis
- Ernest syndrome
- Occipital neuralgia
- Cluster headaches
- Migraines
- Dental pain
- Post herpetic neuralgia
- Glossopharyngeal neuralgia
- Sinus infection
- Ear infection
- Temporomandibular joint syndrome (TMJ)
DIAGNOSIS
This condition can be difficult to diagnose because there is no test to confirm a diagnosis. Seeking care should be done after experiencing sharp, random pain near the eyes, lips, jaw, forehead, scalp.
TESTING
MRI can show if a tumor or multiple sclerosis is having an effect on the trigeminal nerve. It can also show if there is a blood vessel causing compression. Compression that is caused by veins is hard to see on a scan. TN is often diagnosed based on the patient's description of pain. This refers to the type of pain, location of pain, and trigger of pain. Physical and neurological examinations may also be done.
TREATMENT
Nonsurgical treatment
Medications are one way to reduce pain. The medicine is usually started on a low dose and increases based on how the patient responds.
- Carbamazepine: This is an anticonvulsant drug and is very common for TN. This can control pain early on in TN. If this medication does not help reduce pain, this might be a sign that the patient does not have TN. This medication is not as effective over time. Some side effects can include becoming dizzy, having double vision, drowsiness, or nausea.
- Gabapentin: This is an anticonvulsant drug that is often used to treat epilepsy or migraines. This drug has minimal side effects that include drowsiness and dizziness.
- Oxcarbazepine: This is similar to carbamazepine but has less side effects. Some side effects include dizziness and double vision.
Other helpful medications may include: baclofen, amitriptyline, nortriptyline, pregabalin, phenytoin, valproic acid,clonazepam, sodium valproate, lamotrigine, topiramate, phenytoin and opioids.
These medications can usually cause side effects and many patients need very high doses of medication. Anticonvulsant medications can become less effective as time goes on. Adverse drug reactions may occur from high doses of medications and they may have a toxic effect on certain patients. If a patient has bone marrow suppression and kidney and liver toxicity, then they should have their blood be monitored.
Surgery
If nonsurgical approaches have not worked, then surgery may be an option. TN surgical treatment is divided into open cranial surgery or lesioning procedures. Open surgery is done on patients that have pressure on the trigeminal nerve from a blood vessel. This surgery may take away the underlying problem. Lesion procedures injure the trigeminal nerve on purpose to stop the nerve from sending pain to the face. Sometimes lesion procedures are short lasting and can make the face numb.
Open surgery
Microvascular decompression involves microsurgical exposure of the trigeminal nerve root to find a blood vessel that is squeezing the trigeminal nerve and carefully removing the pressure. Decompression may let the nerve recover and stop the pain. This is a more effective surgery but it is also more invasive. The surgery requires a craniotomy. There is a small risk from surgery of hearing loss, facial weakness and numbness, double vision, stroke or death.
Lesioning Procedures
Percutaneous radiofrequency rhizotomy treats TN through heat or electrocoagulation. This stops the brain from receiving pain signals from the nerve. A hollow needle is passed through the cheek to the trigeminal nerve. A heat current can damage nerve fibers.
Percutaneous balloon compression uses a needle that gets put through the cheek to reach the trigeminal nerve. A balloon is placed in the trigeminal nerve through a catheter. The balloon is inflated at the areas where the fibers are creating pain. The fibers are damaged as the balloon compresses to take away pain. The balloon is removed.
A percutaneous glycerol rhizotomy injects glycerol into the area where the nerve splits into branches. This causes nerve damage and can block pain signals.
Stereotactic radiosurgery is when a high concentrated dose of ionizing radiation is delivered at the trigeminal nerve root. This is a noninvasive procedure and has less risks than open surgery. The radiation over time will slow the formation of a lesion in the nerve and interrupt the pain signals.
There are benefits and cons to each surgical option. There is also no promise surgery will alleviate pain for every individual.
Neuromodulation
This is for patients who have TNP. This surgery places one or multiple electrodes in the soft tissue beneath the skull near the nerves on the covering of the brain and sometimes deeper into the brain. It brings electrical stimulation to the part of the brain that causes sensations. In peripheral nerve stimulation, the leads or put beneath the skin on the branches of the trigeminal nerve. In motor cortex stimulation the area which innervates the face is stimulated. In deep brain stimulation the areas that deal with sensation to the face area are stimulated.
PREPARING FOR A NEUROSURGICAL APPOINTMENT
- Write down symptoms experienced including where, what, when. Rank severity of the pain, how long pain free intervals are, pain duration, what triggers pain, etc.
- List medications and surgeries related to the pain and the effects and effectiveness of them
- Questions
FOLLOW UP
Patients should continue to follow up with a physical or care provider. Neuromodulation surgical patients should visit the neurosurgeon to check up every couple of months. The stimulation may be adjusted and the patient’s recovery will be assessed.
