Trigeminal neuralgia

Speaker: R2 楊芝琳Supervisor: Dr.林嘉祥

1. The clinical journal of pain, 18(1), 20022. Surgical Neurology 66 (2006), 350–3563. JADA, Vol. 135, 2004,1713-17174. 2007;334;201-205 BMJ

IntroductionIntroductionNeuralgia

Unexplained peripheral nerve pain The most common site: head and neck The most frequently diagnosed form: trigeminatrigemina

l neuralgia (TN)l neuralgia (TN) Fothergill’s disease Tic douloureux (painful jerking) Mean age: 50 y/o Female predominance (male : female = 1:2 ~2:3)

Characteristics of trigeminal neuralgiaCharacteristics of trigeminal neuralgia

paroxysms of severe, lancinating, electric shock-like bouts of pain restricted to the distribution of the trigeminal nerve Unilaterally (right side) The mandibular (V3) and/or maxillary (V2) br

anch or, rarely, the ophthalmic (V1) branch

Spontaneously attack or triggered by trigger zone & movement of the face

Seconds to minutes

AnatomyAnatomy

Pathogenesis of trigeminal neuralgiaPathogenesis of trigeminal neuralgia

Uncertain Traumatic compression of the trigeminal nerv

e by neoplastic (cerebellopontine angle tumor) or vascular anomalies

Infectious agentsHuman herpes simplex virus (HSV)

Demyelinating conditionsMultiple sclerosis (MS)

Types of Trigeminal Neuralgia

Typical TNAtypical TNPre-TNMultiple sclerosis-related TNTumor-related TNPost-traumatic TN (trigeminal neuropathy)Failed TN

DiagnosisDiagnosisClassic TNClassic TN

Atypical or mixed TNAtypical or mixed TNA persistent and dull ache between paroxysms or mild sensory loss

TreatmentTreatment Medical treatment

Carbamazepine (Tegretol) – first line Oxcarbazepine Gabapentin (Neurontin) Lamotrigine Baclofen Phenytoin Clonazepam Valproate Mexiletine Topiramate

Second line

Others

Mechanism of medical therapy

Surgical treatment Gasserian ganglion-level procedures

Microvascular decompression (MVD) Ablative treatments

• Radiofrequency thermocoagulation (RFT)

• Glycerol rhizolysis (GR)

• Balloon compression (BC)

• Stereotactic radiosurgery (SRS)

Peripheral procedures Peripheral neurectomy Cryotherapy (cryonanlgesia) Alcohol block

Neuro-destructive procedure

Surgical decompress

Microvascular decompressionMicrovascular decompression(MVD)(MVD)

Mechanism of ablation Mechanism of ablation treatmenttreatment

Radiofrequency thermocoRadiofrequency thermocoagulation (RFT)agulation (RFT)

CSF flow when entry Mechel’s cave 45~90 sec. cycles of 60~90℃ Perceiving a sharp pinprick as a light touch (hypalgesia) Divisional cutaneous facial flushing

Glycerol rhizolysis (GR)Glycerol rhizolysis (GR)

Test dose: 0.1-0.15 ml 0.05~0.1 ml at 3~5 min. intervals Total dose: 0.1~0.4 ml Sensory changes: pain, burning or paresthesia

Balloon compression Balloon compression (BC)(BC)

0.5~1 ml of contrast Pear-shape balloon Compression time:

1~7 min.

Stereotactic radiosurgery Stereotactic radiosurgery (SRS)(SRS)

Peripheral proceduresPeripheral procedures

Peripheral neurectomyAlcohol block

0.5~1.5 ml of 80~100% alcohol

Whole branch & smaller peripheral nerve branches

External approach & intraoral method

Cryotherapy Exposed surgically and dire

ct application of a cryoprobe -50~-140℃ 3 cycles of 2 min. with a 5 m

in. thawing period in between

Ganglion-level proceduresGanglion-level procedures vs. Peripheral proceduresPeripheral proceduresGanglion-level ablative procedures

Similar long-term success rate Varying degrees of sensory loss Balloon compression: least likely to impair

corneal sensation or to cause anesthesia dolorosa

Peripheral procedures High recurrence rates No benefit over ganglion-level procedures Reserved for emergency use

Flow chart of the current practice of surgery for TN at UCLA.

ThanksThanks for your for your attention!!attention!!

(a) Thermal lesion of trigeminal nerve.(a) Thermal lesion of trigeminal nerve. (b) Mislocation of the electrode.(b) Mislocation of the electrode.

(c) Expansion of thermal energy to neighboring neural structures.(c) Expansion of thermal energy to neighboring neural structures.