Facing the pain: trigeminal neuralgia

Trigeminal neuralgia is severe facial pain that comes on suddenly. Revered London-based consultant neurosurgeon, Mr Jonathan Hyam shares his expertise on the condition, looking at the cause of the pain, how it can be managed with treatment, and when a neurosurgeon may need to step in to relieve the pain. 

What is trigeminal neuralgia?

Trigeminal neuralgia is a facial pain condition affecting the trigeminal nerve, the nerve which is responsible for carrying information about sensations in the face to the brain. There are three divisions of the trigeminal nerve; one along the jaw, one along the cheek below the eye, and one above the eye and into the forehead, and the neuralgia can manifest in one or all three of these divisions.

It's described as one of the most painful pain conditions in existence. The patient can go from being quite comfortable to suddenly having multiple shocks, known as lancinating, and it feels like the face is being pierced or shocked with an electrical current. There can be a run of shocks and then it stops, and then it can repeat. This is called paroxysmal, a term that doctors use for it so it comes really strongly, and then it disappears completely and then comes again.

There are other facial pain conditions that are similar to trigeminal neuralgia and only subtly different. Each condition responds to different treatments so it is vital that they are correctly diagnosed. 

What can trigger trigeminal neuralgia?

For someone who has trigeminal neuralgia, there are multiple different triggers but they tend to be quite classic; touching the face, cold wind against the face, chewing, brushing the teeth, and cold drinks.

We don’t fully know yet why it occurs in some people, however. In approximately 50% of patients, the cause is a blood vessel pushing against the nerve just as it enters the brain. Multiple sclerosis can also produce trigeminal neuralgia and that can be from changes within the nerve but also changes within the brain. In the remaining patients, it isn’t clearly understood why it happens.

In terms of what's happening to manifest this horrible pain, it's thought that there's a jump of electricity along the nerve in an uncontrolled fashion just at the point where it reaches the brain. Here the electric message changes from the wrappings around the peripheral nerves that go into the face to the wrappings around the nerves of the brain. This is the prevailing theory as this interface is a point of potential weakness and of electrical chaos. 

Can it be controlled with treatment? What is involved?

The most important treatment is medication. Carbamazepine, sold as Tegretol, is the most common medication. One of the most diagnostically pure factors of trigeminal neuralgia is how well it responds to Tegretol. Other medications can be added to that if it's insufficient or the patient has adverse effects from the Tegretol. The neurosurgical treatments would be used when the painkillers aren't doing enough and the pain is very intrusive and frequent or if it is not tolerable for the patient to increase the medications. 

How can people manage trigeminal neuralgia alongside treatment?

In terms of neurosurgical options, there are two broad options.

Number one is surgery. This involves drilling a small window into the base of the skull, behind the ear, and teasing the blood vessel away from the base of the brain. This procedure is called microvascular decompression and is performed under a microscope. It takes the pressure off the nerve and has the best results, but it is an open operation and some patients would prefer to avoid open head surgery. Although the risk of surgery is low, there's still a notable risk of stroke or wound healing problems.

Another option is Gamma Knife radiosurgery. This is relatively newer than microvascular decompression surgery and was pioneered in the 1990s and the early 2000s. Gamma Knife is a sophisticated form of radiation; unlike cancer-treating radiotherapy where a whole wave of radiation goes over the brain, Gamma Knife supplies multiple innocuous rays in different directions, and where they cross over is where they provide a noxious dose. This way the brain can receive very little radiation but the targets, in this case, the trigeminal nerves, can receive a big dose of radiation. The aim is to create changes within the nerve, inhibiting the leap of current. It is a day case procedure and entails applying a frame to the head. You won’t feel the gamma radiation, so the actual treatment itself is painless.

The outcomes are not quite as good as surgery but it has a much lower risk profile. Gamma Knife is incisionless and we don't open the head. The patient comes in in the morning and they've gone home by lunchtime, you could call it a day case or even an outpatient procedure. They may have a headache for a couple of days afterward when the frame comes off but that settles down and paracetamol is all they need to get through that. You have to be a little bit patient with the Gamma Knife effect because it is more of a gentle treatment and it takes a bit longer to have its full therapeutic profile reached. After usually about a month, patients notice an improvement. I certainly don't make a judgment on whether the Gamma Knife has worked for at least three to six months so the changes that occur in the nerve are subtle and progressive.

Leading consultant brain and comprehensive spinal neurosurgeon Mr Jonathan Hyam treats patients at the leading National Hospital for Neurology & Neurosurgery, Queen Square, in central London. If you would like to book a consultation with him, you can do so by visiting his Top Doctors profile.