72 Tic Douloureux

Burak Sade and Joung H. Lee

Clinical Presentation

An 83-year-old right-handed man presents with a 2-year history of neuralgia-like pain on the right side of his face involving the ophthalmic (V1) and maxillary (V2) divisions of the trigeminal nerve.

He has been taking carbamazepine and topiramate, which provided minimal relief, and says he no longer wishes to use these medications.

His neurologic evaluation is within normal limits.

Magnetic resonance imaging (MRI) of the brain is shown in Fig. 72.1.
The patient underwent a microvascular decompression (MVD) procedure. At the time of surgery, the trigeminal nerve was found to be in severe compression by a redundant vertebrobasilar complex ventrally and inferiorly and by the anterior inferior cerebellar artery superiorly. Decompression was achieved using small pieces of Teflon paddies.
He experienced immediate and complete recovery of his pain following surgery.

Fig. 72.1 Magnetic resonance imaging scan of the brain. Three-dimensional axial image of the Circle of Willis demonstrating a prominent vascular loop ventral to the trigeminal nerve root entry zone on the right side.

Questions

What are the different types of facial pain syndromes?
What are the characteristics of the pain in trigeminal neuralgia?
What are the main nuclei of the trigeminal nerve, and what functions do they serve?
What is the initial management of a patient with trigeminal neuralgia?
What are the surgical indications?
What are the other treatment options?
Which vessel is the most common culprit of the compression?
What are the efficacies of MVD and other treatment options in trigeminal neuralgia?

Answers

What are the different types of facial pain syndromes?

According to the classification proposed by Burchiel 1:

Trigeminal neuralgia (type 1 – predominant episodic and type 2 – predominant constant) or symptomatic trigeminal neuralgia (in multiple sclerosis)

Trigeminal neuropathic pain

Trigeminal deafferentation pain

Postherpetic neuralgia

Atypical facial pain
What are the characteristics of the pain in trigeminal neuralgia?
- Characteristics of pain in trigeminal neuralgia¹:
  - Sharp, shooting, electric shocklike pain
  - Momentary or lasting only a few seconds
  - Very intense
  - Common provoking factors include touching, washing the face, teeth brushing, make-up, chewing, talking, eating, a cold breeze.
  - May involve one or more branches of the trigeminal nerve
What are the main nuclei of the trigeminal nerve, and what functions do they serve?
- The principal sensory or main nucleus: Located in the upper pons, it conveys tactile and pressure senses from the face.
- The mesencephalic nucleus: Located near the central gray matter of the upper 4 th ventricle, it conveys pressure and kinesthetic senses from the teeth, hard palate, and jaw.
- The spinal trigeminal tract and nucleus: Extends from the upper cervical spine to the midpons, it is divided into three parts (pars caudalis, pars interpolaris, and pars oralis), which convey sensation of pain and temperature from different parts of the face (Fig. 72.2).
- The motor nucleus relays fibers to the muscles of mastication and plays part in the jaw jerk reflex.
- The ventral and dorsal trigeminothalamic tracts relay sensory information to the ventroposterior medial nucleus of the thalamus.²
What is the initial management of a patient with trigeminal neuralgia?
- Initial management in trigeminal neuralgia is medical.
- Medications that are most commonly used include carbamazepine, gabapentin, lamotrigine, and Trileptal (Novartis, East Hanover, NJ).
- Among these, carbamazepine is the most widely used.
- In addition, antidepressants or narcotic analgesics and steroids during severe pain episodes may provide temporary relief.
What are the surgical indications?
- Indication for surgical treatment include failure of medical therapy, intolerance to the medications, and patients who do not like to take medications for a long time.
What are the other treatment options?
- Other treatment options^3–5:
  - MVD
  - Percutaneous techniques: glycerol rhizotomy (GR), balloon compression (BC), radiofrequency rhizotomy (RF)
  - Gamma knife radiosurgery (GKRS)
Which vessel is the most common culprit of the compression?
- Superior cerebellar artery (75%)³
What are the efficacies of MVD and other treatment options in trigeminal neuralgia?
- In a review by Taha and Tew,⁴ the initial pain relief was 98% in MVD and RF, 93% in BC, and 91% in GR.
- Ten years after surgery, excellent results were seen in 70% of cases who underwent MVD.³
- Pain recurrence was seen in 15% of MVD, 21% in BC, 23% in RF, and 54% in GR.⁴
- Postoperative facial numbness and corneal anesthesia incidences were 2% and none in MVD, 60% and 4% in GR, 72% and 2% in BC, 98% and 7% in RF, respectively.⁴
- Therefore, when V1 or multiple divisions including V1 are involved, MVD is the preferred option to minimize the risk of corneal anesthesia.
- GKRS has been reported to be effective in 50–80% of the patients, with ~25% pain recurrence.⁵
  - The risk of facial numbness and dysesthesias increase with higher radiation dose in this technique.