presentation- trigeminal nurelgia latest final

8/3/2019 Presentation- Trigeminal Nurelgia Latest Final

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Trigeminal Neuralgiaand its Latest Treatment

OptionsPresentation by:

Dr. Sundus WahidDr. Xainab Rasheed


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Trigeminal Neuralgia and it'streatment options 2

Introduction

Trigeminal neuralgia, also referred to as tic douloureux,is a distinct, painful disorder of the face that is easilyevoked by trivial stimuli.

The International Association for the Study of Pain

defines classical idiopathic trigeminal neuralgia (TN) asa sudden, usually unilateral, severe, brief, stabbing,

recurrent pain in the distribution of one or more branches

of the fifth cranial nerve.


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Pathway of Trigeminal Nerve


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Types of Trigeminal Neuralgia

Typical Trigeminal Neuralgia (Tic Douloureux) This is the most common form of TN, that has previously been

termed Classical, Idiopathic and Essential TN. Nearly all casesof typical TN are caused by blood vessels compressing thetrigeminal nerve root as it enters the brain stem


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Atypical Trigeminal Neuralgia Atypical TN is characterized by a

unilateral, prominent constant andsevere aching, boring or burning pain

superimposed upon otherwise typicalTN symptoms.


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Pre-Trigeminal Neuralgia Days to years before the first attack of TN pain, some sufferers

experience odd sensations in the trigeminal distributionsdestined to become affected by TN. These odd sensations ofpain, (such as a toothache) or discomfort (like "pins and

needles", parasthesia), may be symptoms of pre-trigeminalneuralgia
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Multiple Sclerosis-Related TrigeminalNeuralgia The symptoms and

characteristics of multiplesclerosis (MS)-related TNare identical to those fortypical TN. Two to fourpercent of patients with TNhave evidence of multiplesclerosis and about 1% ofpatients suffering frommultiple sclerosis developTN.


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Secondary or Tumor Related Trigeminal Neuralgia Trigeminal neuralgia pain caused by a lesion, such as a tumor, is

referred to as secondary trigeminal neuralgia. A tumor thatseverely compresses or distorts the trigeminal nerve may causefacial numbness, weakness of chewing muscles, and/or constant

aching pain


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Trigeminal Neuropathy or Post-

Traumatic Trigeminal Neuralgia Injury to the trigeminal nerve

may cause this severe paincondition. TrigeminalNeuropathy or Post-TraumaticTN may develop following

cranio-facial trauma (such asfrom a car accident), dentaltrauma, sinus trauma (such asfollowing Caldwell Lucprocedures) but mostcommonly following destructive

procedures (rhizotomies) usedfor treatment of TN. These painconditions are caused byirreparable damage to thetrigeminal nerve and secondaryhyperactivity of the trigeminal

nerve nucleus.


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Aetiology of Trigeminal Neuralgia

Tumors:

Acoustic neurinoma

Chondroma at the level of clivus Pontine glioma

Epidermoid

Metastasis

Lymphoma

Vascular defects: Pontine infarct

Aerteriovenous malformation in the vicinity

Persistence of primitive trigeminal artery

Vascular decompression by superiorcerebellar artery

Inflammatory:

Multiple sclerosis

Sarcoidosis

Lyme disease neuropathy


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Pathophysiology of Trigeminal Neuralgia

Increased refractory period of pain threshold: The true cause of TN is unknown. A common hypothesis

is that chronic irritation of the nerve by an artery leads toa greater than normal excitability of the nerve. This

hyperexcitability then causes the brain to interpretnormal sensory stimuli as exceedingly painful. Otherexperts hold that the painful stimuli are a result of anabnormality within the central nervous system.

Demyelination of nerve fibers: Demyelination of nerve,primary or secondary ,leads to

uncontrolled firing of unmyelinated nerve fibressuggesting a partly central mechanism.


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Pathophysiology of Trigeminal Neuralgia(continued)

Vascular decompression:

Arterial decompression is reported among 85% of the patients goingunder mitral valve disease and about 68% of venous decompressionhas been reported among such patients.

Viral agents: Herpes simplex reactivation has been reported among 27-94%

patients going under surgical procedures for treatment of trigeminalneuralgia. HSV is associated with altered trigeminal ganglionicfunction


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Diagnosis of Trigeminal Neuralgia

History of the patient

Imaging studies

CT scan

MRI

MRA

Conventional angiogram

Enlarged views on the pontine area

Clinical neurophysiology testing (blink reflex study). It

indicates the bilateral delay in response to thestimulation on the pathological side.

Selective blocking with local anesthetic at the nerveending is helpful in determination of effected periphery


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Trigeminal Neuralgia : Epidermoid tumour

45 yr male with 3 yr of classic Trigeminal neuralgia

MRI


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Characteristics of Trigeminal Neuralgia (TICDOULOUREUX)

Confined to one or two divisions of the trigeminal nerve,most often within the lower two thirds of the face

Sudden, lacerating, severe, brief pain (Not constant,burning pain) lasting for not more than two seconds

Repetitious, but with significant pain-free intervals Usually unilateral

Almost exclusively a disorder of adults

Most common sights are mandibular or maxillary division

of trigeminal nerve, opthalmic is rare.


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Trigger Zones

Can be triggered by a nonpainful stimulus. Stimuli canbe:

Touching

Applying heat or cold to the

cheek or gum Yawning, talking, chewing

Wind blowing on the face

Gustatory stimuli or/andvibration


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Treatment Options

Medical treatment options Conventional drugs

Surgical treatment options Microvascular Decompression Surgery

Percutaneous Rhizotomies1. Percutaneous Glycerol Injection2. Percutaneous Balloon Compression Rhizotomy3. Radiofrequency Rhizotomy

Gamma Knife Radiosurgery Peripheral Trigeminal Nerve Blocks, Sectioning and Avulsions

including cryosurgery and neurectomy Microsurgical Rhizotomy Stereotactic Radiosurgery

Medullary tractotomy


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Medical Treatment Options

Carbamazepine(Tegretol):

Dose: ranges from 600 to

1600 mg divided in threeor four doses per day


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Trileptal(Oxycarbazepine)

The dose usually begins

at 300 mg twice a dayand is graduallyincreased to achieve paincontrol. The maximumdose is 2400-3000 mg

per day.


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Phenytoin (Dilantin)

Phenytoin relieves ticpain in over half of TNsufferers at doses of 300to 500 mg, divided intothree doses per day.


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Baclophen (Lioresal)

The usual dosage takenfor complete pain relief isbetween 50 and 60 mgper day. Baclophen has ashort duration of functionso sufferers with severeTN may need to take

doses every 3 to 4 hours.


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Gabapentin(Neurontin)

The starting dose is

usually 300mg threetimes a day and this isincreased to a maximal

dose.


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Latest Surgical Treatment Options

Mi l D i A i l


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Microvascular Decompression AnatomicalApproach


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Surgical Treatment Options Microvascular Decompression Surgery alleviates

neurovascular compression by placing inert shredded

Teflon felt implants between offending vessels and thetrigeminal nerve root.

Prior to MVD. During MVD, the

vessel is mobilizedaway from the nerve

root entry zone.

The decompression

is maintained withshredded Teflon

felt implants.

MVD has

resulted inpermanent

alleviation of theneurovascularcompression.


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Surgical Treatment Options Percutaneous Rhizotomies involve inserting a needle

through the cheek and into an opening at skull base(foramen ovale). There, a controlled injury to thetrigeminal nerve and Gasserion ganglion may beproduced in one of three ways:

1) Percutaneous GlycerolInjection - glycerol is injectedinto the space around theGasserion ganglion, andchemically damages the nervous

tissue.


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Surgical Treatment Options

3) Radiofrequency Rhizotomy -an electrode is advanced into the

Gasserion ganglion, and heatedto thermally damage the nervoustissue.

2) Percutaneous BalloonCompression Rhizotomy - aballoon is inflated next to theGasserion ganglion, compressingand mechanically damaging thenervous tissue.


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Gamma Knife Radiosurgery focuses cobalt radiation upon thetrigeminal nerve root, producing a delayed injury to nervous tissuethat is similar to that produced by other percutaneous rhizotomytechniques.

Radio Frequency Thermocoagulation: The needle used here is areusable radio frequency electrode. It is passed through foramenovale into the trigeminal ganglion at the site of the defect.


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Peripheral Trigeminal Nerve Blocks, Sectioning andAvulsions including cryotherapy involve injuring theperipheral portions of the trigeminal nerve external to theskull.


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Microsurgical Rhizotomy involves surgical exposureand cutting of the trigeminal nerve root near its entry intothe brain stem.


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Stereotactic Radiosurgery isused for the treatment ofidiopathic TN. Gamma unit isused primarily

4mm single isocenter targeted2 -4mm anterior to junction ofpons and trigeminal nerve30% isodose is delivered tobrain stem

Dosage 70 - 80Gy.


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Thank You!

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