Patients can present to a dentist with pain in their face or teeth but it is of non-dental origin and can lead to unnecessary dental treatments such as extractions, fillings and root canal treatment. Trigeminal neuralgia is a severe unilateral facial pain which is paroxysmal i.e sudden severe but short lived attacks of excruciating pain. Analgesics will not work.
It is described by patients as the “the worst pain they have ever had” and some even feel suicidal or at least anxious in anticipation and depressed.
The paroxysmal attacks of pain last from a fraction of a second to two minutes that affect one or more divisions of the trigeminal nerve. 35% affect the maxillary branch and 30% affect the mandibular branch of the TGN.
The pain is described as “intense and stabbing”.
Treatments that work are available but disagreements remain about how and which is best of the available treatments.
It occurs in 10 per 100,000 people each year so it is fairly common. Almost twice as many women are affected as men and it is rare to be below 40.
Trigeminal neuralgia is a clinical diagnosis based on symptoms and eliminating other causes.
The history is an important feature and typically the patient will say that there is a sudden and severe lancinating/knife stabbing/needle-like pain which usually lasts from a few seconds to two minutes and within the trigeminal nerve distribution which is normally the maxillary or mandibular branches. The pain is also often elicited by trivial stimulation of certain trigger zone areas such as shaving or rubbing.
The nerves/areas affected for a particular patient are constant and lie within the sensory distribution of the trigeminal nerve.
Most patients respond well to drugs with carbamazepine the first line treatment. Adverse effects are high but patients would rather have this than the pain. Gabapentin has been used as the second line for trigeminal neuralgia. Lamotrigine and baclofen have been suggested as an alternative also if the above 2 don’t work. If drug treatment with carbamazepine fails or is not tolerated, surgical treatments are considered.
Causes Of Trigeminal Neuralgia?
Increasing evidence suggests that 80-90% of cases are caused by compression of the trigeminal nerve close to its exit from the brainstem by an aberrant loop of an artery or vein.
Post-mortems show that an aberrant loop of artery, or less commonly vein, is found to be compressing the root entry zone of the trigeminal nerve in 80-90% of patients. The trigeminal nerve is found to be demyelinated next to the compressing vessel. Eliminating the compression by surgery provides long term relief in most patients and complications are few.
With recent improvements in magnetic resonance imaging techniques, vascular compression is being picked up radiologically in increasing numbers of patients with trigeminal neuralgia.
Common conditions that are usually easy to distinguish from trigeminal neuralgia include:
- Dental infection such as pulpitis, periapical periodontitis, periodontal problems or cracked tooth syndrome.
- Temporomandibular joint dysfunction pain which has painful jaw opening which may be limited and can produce an audible click.
- Persistent idiopathic facial pain (previously called “atypical facial pain”). The pain will be often continuous, mild to moderate in severity, and aching or throbbing.
- Migraine is usually preceded by aura. There is a severe unilateral headache often associated with nausea, photophobia, phonophobia, and neck stiffness.
- Temporal arteritis commonly in elderly people who have a temporal pain constant and often associated with jaw claudication, fever, and weight loss plus the temporal arteries may be firm, tender, and non-pulsatile.
Surgical Treatment Of Trigeminal Neuralgia
The two types of surgical procedure are;
- Microvascular decompression, where the posterior fossa is explored and the compressing vessel and trigeminal nerve root are separated.
- Ablative treatments that stop signals along the trigeminal nerve in different ways such as Gamma knife surgery. Gamma Knife Surgery is a non-invasive radiosurgical technique that fires a focused beam of radiation to target the root of the trigeminal nerve so the nerve stops sending sensory signals back to the brain.