Historically, the first attempts to explain the pain mechanism in trigeminal neuralgia are linked to the work of Walter Dandy in 1929.
While transecting the trigeminal nerve root during a treatment procedure, Dandy noticed that the root was irregular due to contact with an arterial vessel. Since then, numerous studies have confirmed that the pain symptoms of trigeminal neuralgia are closely related to vascular compression of the nerve.
This anatomical situation has been recognized as a factor strongly correlated with neuralgia. As many as 80–90% of symptomatic individuals demonstrate neurovascular conflict.
Most commonly, the trigeminal nerve is compressed by the anterior inferior cerebellar artery, less frequently by the basilar artery. In approximately 25% of cases, the conflict involves a venous vessel.
The most common site of compression is the root entry zone of the trigeminal nerve into the brainstem. During surgery, various types of vessel-nerve contact are observed: from simple contact, through indentation, to atrophy or deformation of the nerve.
Evolution of Views on Pain Pathogenesis
Jannetta's research drew attention to focal demyelination at the entry point of the trigeminal nerve into the pons.
At the site of compression, fiber atrophy is observed, and sometimes even pathological nerve enlargement caused by an increased number of collagen fibers. Changes in oligodendrocytes and Schwann cells have also been documented.
Simultaneously, a process of remyelination occurs, a repair mechanism in which a single myelin sheath envelops several axons.
An attempt to integrate all these changes led Devor and colleagues to develop the so-called ignition theory.
This theory proposes that damaged sensory neurons become hyperexcitable and susceptible to cross-excitation by neighboring fibers. A single stimulus can trigger an explosion of neuronal activity that spreads to other neurons, leading to a pain paroxysm.
This phenomenon can be interrupted by neuronal hyperpolarization, which explains why pain-free intervals occur between attacks.
Current Understanding
Today we know that no single theory explains all mechanisms of trigeminal neuralgia.
The most widely accepted hypothesis holds that pain, the cardinal symptom of neuralgia, results from focal demyelination of the trigeminal nerve.
A particularly vulnerable site is the so-called locus minoris resistentiae, the zone where the myelin sheath produced by Schwann cells meets the myelin sheath formed by oligodendrocytes. This is where damage most commonly occurs.
As a result of demyelination, ectopic discharges arise, and sodium channels (Nav1.3, Nav1.6, Nav1.7, Nav1.8) become overactive, leading to neuronal hyperexcitability.
Even a minor stimulus, such as a pulsating vessel, can trigger severe pain.
Animal studies also confirm the possibility of ephaptic transmission, contact points between damaged nerve fibers that can initiate pain excitation.
Another theory suggests that damage to Aβ fibers (responsible for touch sensation) leads to deafferentation, loss of sensory input. As a result, pain pathways (Aδ and C fibers) become continuously stimulated, producing constant pain.
Yet another concept proposes that trigeminal nerve hyperactivity can lead to sensitization within the spinal nucleus or higher centers, at which point even an innocuous stimulus becomes a source of pain.
All these theories share one common element: the critical role of nerve fiber demyelination and the resulting neuronal hyperexcitability.
The degree of damage and individual response explain why symptoms, disease course, and treatment effectiveness vary so greatly between patients.
Neuralgia vs. Neuropathy
It is important to remember that the pathogenesis of trigeminal neuralgia differs from that of painful trigeminal neuropathy.
In classical neuralgia, there is no extensive nerve damage but rather focal demyelination at the site of compression. In painful trigeminal neuropathy, actual structural nerve damage occurs, which changes the character of pain and sensory symptoms.
Natalia — since 2014 I've been living with trigeminal nerve pain. I write in plain language, based on reliable sources and personal experience. Read my story →
Frequently Asked Questions
What is trigeminal neuralgia?
Trigeminal neuralgia is a chronic facial pain condition. It manifests as sudden, severe, usually one-sided pain attacks — often described as an electric shock. A single attack typically lasts from a few seconds to about two minutes.
What is the difference between neuralgia and neuropathy?
In simple terms: neuralgia primarily involves paroxysmal pain along a nerve, usually without loss of sensation. Neuropathy involves nerve damage that more often causes constant pain along with numbness and sensory loss.
What is neurovascular conflict (vascular compression)?
This is the most common cause of classical trigeminal neuralgia — a blood vessel compresses the nerve root at the base of the brain, damaging its myelin sheath and triggering pain.
Can trigeminal neuralgia be cured?
In many people, pain can be effectively controlled with medications or procedures, and MVD provides the most durable results in eligible patients. The course varies — with periods of remission and relapse. Decisions are made together with your doctor.
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