Trigeminal neuralgia

Neurovascular conflicts include syndromes due to compression of cranial nerves, typically at their entry point into the brainstem (root entry zone, REZ). The REZ marks the transition from central myelin (oligodendrocytes) to peripheral myelin (Schwann cells).

Trigeminal neuralgia, or tic douloureux, is a common cause of facial pain affecting areas innervated by the trigeminal nerve, the fifth cranial nerve responsible for facial sensory perception and some motor functions (e.g., chewing). The incidence is 4-5 new cases per 100,000 inhabitants per year, more common in females. The nerve originates from the facial surface, converging through its three branches (ophthalmic V1, maxillary V2, and mandibular V3) into the Gasserian ganglion before terminating in its brainstem nucleus.

Symptoms

Trigeminal neuralgia is characterized by:

  • Stabbing or electric pain in one or more of the three trigeminal nerve territories
  • Trigger points on the face that evoke pain when stimulated (e.g., medial eyebrow, side of the nose, lip)
  • Specific stimuli that induce pain (triggers)
  • Sudden onset of symptoms

Pain is excruciating, lasting from a few seconds to a few minutes, described as “shooting,” “electric shock,” or “stab-like.” It usually affects one side of the face, triggered by daily activities like chewing, brushing teeth, talking, or blowing the nose. Between episodes, there is no pain.

Diagnosis

Diagnosis requires a thorough anamnesis to differentiate typical from atypical forms. It is confirmed by brain MRI targeting the cerebellopontine angle region to visualize the trigeminal nerve and the compressing artery or to exclude tumors. Differential diagnosis includes post-herpetic neuralgia, dental pathology, orbital disease, and temporal arteritis.

Treatment

Includes antiepileptic drugs like carbamazepine, sometimes combined with gabapentin. Carbamazepine may cause side effects such as drowsiness, leukopenia (low white blood cell count), and gastric intolerance. Both drugs may lose effectiveness over time, leading to drug resistance.

Microvascular Decompression (MVD):

A definitive treatment involves microvascular decompression of the trigeminal nerve, separating it from the compressing artery with synthetic material or a foam pad. This is a safe procedure with a success rate exceeding 90%.

Percutaneous Microcompression of the Gasserian Ganglion

Performed under sedation, this involves mechanical compression of the Gasserian ganglion using a Fogarty balloon catheter. Success rates are 80-90%, though recurrences may occur, and the technique is repeatable.