DR. FAKHRUL IMAMFCPS PART I I TRAINEE

ORAL & MAXILLOFACIAL SURGERY DEPARTMENT,

DHAKA DENTAL COLLEGE HOSPITAL

to CME Presentation on Trigeminal Neuralgia,

What is TN

Recurrent attacks of lancinating pain in the distribution of a trigeminal nerve division.

It is considered to be “the worst pain known to man”. In severe cases in gives rise to suicidal tendency to the sufferers.

Some Facts about TN

Prevalence (approximate): 1 per 15,000.Age mainly affected: 50–70 year age group.Gender mainly affected: F > M

Types of TN

According to TNA :1) Classical TN or Primary TN 0r ITN2) Symptomatic TN or secondary TN

Etiopathogenesis

Of TN

FIGURE : Transverse sections of a peripheral nerve (A) showing the outermost epineurium, the inner perineurium that collects nerve axons in fascicles, and the endoneurium that surrounds each myeli-nated fiber. Each myelinated axon (B) is encased in the multiple membranous wrappings of myelin formed by one Schwann cell, each of which stretches longitudinally over approximately 100 times the diameter of the axon. The narrow span of axon between these myelinated segments, the node of Ranvier, contains the ion channels that support action potentials. Nonmyelinated fibers (C) are enclosed in bundles of 5 to 10 axons by a chain of Schwann cells that tightly embrace each axon with but one layer of membrane.

Etiopathogenesis

Trigeminal neuralgia (TN) appears to result from demyelination causing abnormal nerve signal transmission. In 90–95% of cases, no neurological lesion is identified, and the condition is then labeled ITN. The cause of ITN may be the superior cerebellar artery becoming atherosclerotic and less flexible, pressing on the trigeminal nerve roots in the posterior cranial fossa, damaging the myelin sheath.Demyelination may also be caused by multiple sclerosis (MS), cerebrovascular disease with pontine or medullary infarcts, neoplasms, aneurysms, cysts, trauma, infections, deposits such as amyloidosis or other causes (secondary TN). Some 2% of patients with MS develop TN. Hypertension is increased in patients with TN.

Clinical Features

International Headache Society (IHS) defines the characteristics of TN as paroxysmal attacks of pain which last a few seconds to < 2 minutes, especially in the morning, rarely at night, as the disease progress pain becomes more severe & prolonged in duration.

Right side is commonly affected with involvement of Infraorbital nerve & Mental nerves.

Typical TN pain has thefollowing features:• intermittent• unilateral or Bilateral (10-12% cases)• distribution along one or more trigeminal division • a sudden severely intense, sharp superficial, stabbing or

burning quality or constant, dull burning or aching pain, sometimes with occasional electric-shock-like stabs

• absence of no sensory or motor deficiency• definative trigger areas or daily activities affecting the

trigeminal area such as eating, swallowing, talking, smiling, washing the face, shaving, cleaning the teeth. Emotional or physical stress can increase the frequency and severity of TN attacks.

Differential Diagnosis

Cluster headaches, Causalgia,Post-herpetic neuralgia,glossopharyngeal neuralgia, Mixed connective tissue disease (MCTD),idiopathic facial pain,dental problems,MS,Lyme Disease,HIV,

Investigations

Imaging: Most physicians recommend elective MRI (gives better of brain stem and cranial nerves than CT) of the entire

trigeminal nerve for all patients and it is certainly mandatory if atypical features are present.

Blood tests: Erythrocyte sedimentation rate (ESR) to exclude vasculitides,Anti-RNP antibodies for MCTD, and serology for Lymedisease or, rarely, HIV.Only if all imaging and blood investigations prove negative can

adiagnosis of ITN be made

Management

Noninvasive treatment:- carbamazepine, Oxcarbamazepine, clonazepam, phenytoin,

gabapentin,topiramet, lamotrigine, pregabaline, valproic acid, Capsaicin.

- Drug therapy should be slowly withdrawn if a patient remains pain free for 3 months.

- low intensity low frequency surface acoustic wave ultrasound (painshield)

Invasive Treatment:Injections: absolute Alcohol, Glycerol, streptomycin with or without

LA.Surgical Options- Peripheral nerve surgery- cryosurgery, peripheral rhizotomy,

radiofrequency thermocoagulation.

Percutaneous approaches inserting a needle through the face into the

skull for trigeminal gangliolysis, percutaneous radiofrequency trigeminal gangliolysis (PRTG), Fogarty balloon microcompression (FBM), and retrogasserian glycerol rhizotomy (PRGR). Gamma knife stereotactic radiosurgery, however, is the least invasive procedure,with a high rate of pain control.

Open surgical procedures include posterior cranial fossa procedures -microvascular decompression of the

trigeminal root (MVD) -retrogasserian rhizotomy

Thank you