Department of Oral & Maxillofacial Surgery

NARSINHBHAI PATEL DENTAL COLLEGE AND HOSPITAL VISNAGAR

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THE TRIGEMINAL NERVE

Guided By :Dr. Anil managutti , HOD and Dr. Anil managutti , HOD and ProfessorProfessorDr.shailesh menat , ProfessorDr.shailesh menat , Professor

Presented by: Dr. Nirav Patel1st year PG

TRIGEMINAL NERVEINTRODUCTIONMOTOR FUNCTIONSENSORY FUNCTIONGANGLIONOPTHALMIC NERVEMAXILLARY NERVEMANDIBULAR NERVEEXAMINATION OF TRIGEMINAL NERVEAPPLIED ANATOMY

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INTRODUCTIONThe largestlargest cranial nerveIt is mixed nervemixed nerve ( sensory and motor )Sensory to – Skin of face -Mucosa of cranial viscera -Except base of tongue and pharynxMotor to –Muscles of Mastication -Tensor ville palatini,Tensor tympany -Anterior belly of digastric -Mylohyoid

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NUCLEI

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TRIGEMINAL NUCLEI

o A cranial nerve nucleus is a collection of neurons (gray matter) in the brain stem that is associated with one or more cranial nerves. 

o Axons carrying information to and from the cranial nerves form a synapse first at these nuclei.

o Lesions occurring at these nuclei can lead to effects resembling those seen by the severing of nerve(s) they are associated with.

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SENSORY NUCLEI

1.Mesencephalic nucleus

- Cell body of Pseudounipolar neuron

- Relay proprioception from muscles of mastication,

Extra ocular Muscles, Facial muscles.

Situated in Midbrain just latetral to Aqueduct.

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2.Principal sensory nucleus-

Lies in Pons lateral to Motor nucleus

Relays touch sensation

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3.Spinal nucleus-Extends from caudal end of principal sensory Nucles

in pons to 2nd or 3rd spinal segment It relys Pain and

Temperature

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MOTOR NUCLEUS : Innervates muscles of masticationmuscles of mastication and

tensor tympani tensor tympani andand tensor palatini tensor palatini Derived from first branchial arch. Located in pons medial to principle sensory

nucleus.

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FUNCTIONAL FUNCTIONAL COMPONENTSCOMPONENTS

Sensory Root Sensory Root Motor RootMotor Root

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SENSORY ROOTGENERAL SOMATIC AFFERENTS- Face, Scalp, Teeth, Gingiva, Oral, Nasal,

Cavities, Para nasal sinus, Conjunctiva and Cornea.

Pain, temp, light touch touch, pressure proprioception Trigeminal gang. Bypasses trigem gang. sensory root.

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Spinal nuc. Principal sen nuc. Mesencephalic

CNCNSS

MOTOR NUCLEUS

MOTOR ROOT

MANDIBULAR NERVE

Muscles of mastication Tensor tympani Masseter Tensor palatini Lateral & Medial Pterygoids Temporalis

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CNSCNS

MOTOR ROOTMOTOR ROOT

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COURSE & DISTRIBUTIONCOURSE & DISTRIBUTION

Both motor and sensory root are attached ventrally to

junction of pons and middle cerebellar peduncle with motor

root lying ventromedially to the sensory root.

Pass anteriorly in middle cranial fossa to lie below tentorium

cerebelli in cavum trigeminale, here motor root lies inferior

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Sensory root connected to postromedial concave

border of the trigeminal ganglion.

Convex antrolatateral margin of the ganglion gives

attachment to the 3 div. Of the trigeminal nerve.

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Motor root turns further inferior with sensory component of

V3 to emerge out of foramen Ovale as Mandibular

nerve.

Ophthalmic and Maxillary division emerges through

Superior orbital fissure and foramen Rotundum

respectively.

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GANGLIONGANGLION

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THE THE TRIGEMINALTRIGEMINAL GANGLIONGANGLIONSEMILUNAR OR GASSERIAN GANGLION.

Cresentric in shape with convexity anterolaterally.

Contains cell bodies of pseudounipolar neurons.

LOCATION: lies in a bony fossa at apex of the petrous

temporal bone on floor of middle cranial fossa, just lateral

to posterior part of lateral wall of the cavernous sinus.

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COVERINGS: covered by dural pouch = MECKLES CAVE or CAVUM TRIGEMINALE.

cave lined by pia and arachnoid thus the ganglion is bathed in CSFCSF.

ARTERIAL SUPPLY: Ganglionic branches of Internal Carotid Artery, middle meningeal artery and accessory meningeal artery.

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RELATIONS: SUPERIORLY: *superior petrosal sinus *free margin of tentorium cerebelliINFERIORLY: *motor root *greater petrosal nerve *petrous apex *foramen lacerumMEDIALLY: *posterior part of lateral wall of cavernous sinus *Internal Carotid Artery with its sympathetic plexusLATERALLY: *uncus of temporal lobe *middle meningeal artery and vein *nervous spinosum

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DIVISIONS OF DIVISIONS OF TRIGEMINAL NERVETRIGEMINAL NERVE

1. Ophthalmic nerve 2. Maxillary nerve 3. Mandibular nerve

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OPHTHALMIC BRANCH OF TN

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OPHTHALMIC NERVE BRANCHES

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A.InfratrochlearB. Anterior EthmoidC. Posterior EthmoidD. LacrimalE. SupraorbitalF. SupratrochlearG. Nasociliary

First division of the trigeminal.Is a sensory nerve.Smallest of the three divisions of the trigeminal.Arises - upper part of the semi lunar ganglion as a

short, flattened band, about 2.5 cm. Long - passes forward along the lateral wall of the cavernous sinus - below the oculomotor and trochlear nerves.

Before entering the orbit through superior orbital fissure, it divides into three branches,

Lacrimal. Frontal. Nasociliary.

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1)LACRIMAL NERVE:Smallest of the three branches. Derived – possibly from branch which goes from the

ophthalmic to the trochlear nerve. Enters orbit through the lateral angle of the superior

orbital fissure.In orbit - runs along the upper border of the lateral

rectus with the lacrimal artery - communicates with the zygomatic branch of the maxillary nerve.

Enters the lacrimal gland - gives off several filaments, which supply the gland and the conjunctiva.

Finally - pierces the orbital septum - ends in the skin of the upper eyelid, joining with filaments of the facial nerve.

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2) FRONTAL NERVE: Largest branch of ophthalmic. Enters the orbit - superior orbital fissure and runs forward

between the Levator palpebræ superioris and the periosteum.

Midway between the apex and base of the orbit it divides into two branches

A) Supratrochlear B) Supraorbital

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A) SUPRATROCHLEAR NERVE: Smaller of the two - passes above the superior Oblique and

gives off a descending filament - to join the infratrochlear branch of the nasociliary nerve.

Escapes from the orbit between the superior oblique and the supraorbital foramen.

Supplies - skin of the lower part of the forehead close to the midline

- sends filaments to the conjunctiva and skin of the upper

eyelid.

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B) SUPRAORBITAL NERVE:Passes - supraorbital foramen - gives off palpebral

filaments to the upper eyelid.Then ascends upon the forehead and ends in two

branches Medial Lateral which supply the anterior scalp region to the

vertex of skull, the forehead and skin of upper eyelid.

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3) Nasocillary nerve. Third main branch of ophthalmic division. Enters the orbit through superior orbital

fissure. Divide into: those arising in the orbit, in the

nasal, and on the face.

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1) Branches in the orbita) Long root of the ciliary ganglion b) Long ciliary nerves.

c) Posterior ethmoid nerve.d) Anterior Ethmoidal nerves.

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a) LONG ROOT OF CILIARY GANGLION:Arises – from nasociliary b/W the two heads of the

lateral Rectus. It contains sensory fibers-pass through the

ganglion without synapsing and continue on to the eyeball.

b) LONG CILIARY NERVE:Two or three in number - given off from the

nasociliary, as it crosses the optic nerve.Distributed to the Irish and cornea.

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c) POSTERIOR ETHMOIDAL BRANCH:Posterior branch leaves the orbital cavity through

the posterior ethmoidal foramen and gives some filaments to the sphenoidal sinus.

d) ANTERIOR ETHMOID NERVE :

Nerve continues anteriorly along the medial wall of the orbit.

In its course, the nerve gives of fillament -supply the ant.ethmoid cell & frontal sinus.

Upper part of nasal cavity divide into 2 set of nasal branch :

1) internal nasal branch. 2) external nasal branch.

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1) Internal nasal branches: - 2 branches : Medial or septal branches – travel downward to

supply sensory innervation to the mucous membrane of that area.

: lateral branches- supply to the mucous membrane of the anterior ends of the superior and middle nasal conchae.

2) external nasal branches: -At the border b/w the lower edge of the nasal bone

and the upper edge of the lateral nasal cartiladge. -Supply- skin over the tip of the nose & ala of the

nose.

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B) Branches arising in the nasal cavity:o Supply – mucous membrane lining the

cavity. C) Terminal branches of the ophthalmic

division on the face: o Supply – medial part of the both eyelids,

lacrimal sac.

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MAXILLARY BRANCH OF TNSecond division of the trigeminalIs a sensory nerve. It is intermediate - both in position and size b/w the

ophthalmic and mandibular. It begins - middle of semilunar ganglion as a flattened

plexiform band - passing horizontally forward - leaves the skull - foramen rotundum - becomes more cylindrical in form and firmer in texture.

Then crosses - pterygopalatine fossa - enters the orbit through the inferior orbital fissure - it traverses the infraorbital groove and canal in the floor of the orbit and appears on the face - infraorbital foramen

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At its termination - the nerve lies beneath the Quadratus labii superioris & divides into branches which spread out upon the

side of the nosethe lower eyelidthe upper lip

joining with filaments of the facial nerve.

BRANCHES OF MAXILLARY NERVE:May be divided into four groups, according as

they are given off In the cranium

In the pterygopalatine fossaIn the infraorbital canalOn the face.

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In the cranium Middle Meningeal Nerve

In the Pterygopalatine fossa

ZygomaticSphenopalatine

Posterior Superior Alveolar

In the Infraorbital Canal

Anterior Superior Alveolar

Middle Superior Alveolar

On the Face Inferior PalpebralExternal NasalSuperior Labial40

MAXILLARY NERVE BRANCHES

A. ZygoticaticotemporalB. ZygomaticofacialC. Post. Sup. Alveolar BrsD. NasopalatineE. Greater PalatineF. Lesser PalatineG. Mid. & Ant. Alveolar BrsH. Infraorbital

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(Branches given off in the middle cranial foss) MIDDLE MENINGEAL NERVE:

Given off from the maxillary nerve directly after its origin from the semilunar ganglion.

It accompanies the middle meningeal artery and supplies the dura mater.

(Branches in the pterygopaltine fossa) A) ZYGOMATIC NERVE:Arises - pterygopalatine fossa.Enters the orbit - inferior orbital fissure - into two

branches, Zygomaticotemporal Zygomaticofacial

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ZYGOMATICO-TEMPORAL BRANCH:Runs along - lateral wall of the orbit in a groove in

the Zygomatic bone.Receives - communication from the lacrimal and

passing through a foramen in the Zygomatic bone - enters the temporal fossa.

Ascends b/w the bone and substance of the Temporalis muscle - pierces the temporal fascia about 2.5 cm. above the Zygomatic arch - distributed to the skin of the side of the forehead - communicates with the facial nerve.

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ZYGOMATICO-FACIAL BRANCH:Passes along the infero-lateral angle of the orbit.Emerges - face through a foramen in the Zygomatic bone. Perforating the Orbicularis oculi - supplies the skin on the

prominence of the cheek.B) SPHENOPALATINE NERVE (PTERYGOPALATINE

NERVE):Two short nerve trunk unite the pterygopalatine ganglion.Descend to the sphenopalatine ganglion. Branches of distribution of ptery.pal. Nerve divide in 3 group: 1)orbital branch 2)nasal branch 3)palatine branch

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1) ORBITAL BRANCH:Two or three delicate filaments - enter the orbit by

the inferior orbital fissure - supply the periosteum.

2) PALATINE NERVES:Distributed to the roof of the mouth, soft palate,

tonsil, and lining membrane of the nasal cavity. Most of their fibers are derived - sphenopalatine

branches of the maxillary nerve. They are three in number:

Anterior MiddlePosterior.

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ANTERIOR PALATINE NERVE:Descends - pterygopalatine canal - emerges upon

the hard palate - greater palatine foramen.Supplies the gums, the mucous membrane and

glands of the hard palate In the pterygopalatine canal - gives off posterior

inferior nasal branches - enter the nasal cavity through openings in the palatine bone.

MIDDLE PALATINE NERVE: emerge from lesser palatine foramen.Emerges through one of the minor palatine canals

and distributes branches to the uvula, tonsil, and soft palate.

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POSTERIOR PALATINE NERVES:Descends - pterygopalatine canal – emerges –

lesser palatine formen.Supplies the tonsil.

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3) NASAL BRANCHES : • 2 branches divided:• a) posterior superior latral nasal branch:

Transmit sensory impulses from the mucous membrane of the nasal septum and posterior ethmoid cell.

b) Medial or septal branch:

Transmit sensory impulses from the mocous membrane over the vomer.

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POSTERIOR SUPERIOR ALVEOLAR NERVE:Arise - trunk of the nerve just before it enters the

infraorbital groove.Descend - tuberosity of the maxilla - give off

several twigs to the gums and mucous membrane of the cheek.

Then enter - posterior alveolar canals on the infratemporal surface of the maxilla - communicate with the middle superior alveolar nerve - give off branches to the lining membrane of the maxillary sinus and three twigs to each molar tooth.

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(In the infraorbital groove and canal)

MIDDLE SUPERIOR ALVEOLAR NERVE:Given off from the nerve in the posterior part of the

infraorbital canal.Runs and forward in a canal - lateral wall of the maxillary

sinus to supply - two premolar teeth. It forms - superior dental plexus with the anterior and

posterior superior alveolar branches.

ANTERIOR SUPERIOR ALVEOLAR NERVE:Given off from the nerve just before its exit from the

infraorbital foramen.It descends in a canal in the anterior wall of the maxillary

sinus - divides into branches - supply the incisor and canine teeth.

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(Terminal branches of the maxillary division on the face)

INFERIOR PALPEBRAL BRANCH:Ascend behind the Orbicularis oculi. Supply - skin and conjunctiva of the lower eyelid.Join at the lateral angle of the orbit with the facial

and zygomaticofacial nerves.

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EXTERNAL NASAL BRANCHES: Supply - skin of the side of the nose and of the septum

mobile nasi - join with the terminal twigs of the nasociliary nerve.

SUPERIOR LABIAL BRANCHES: The largest and most numerous - descend behind the

Quadratus labii superioris. Distributed - skin of the upper lip, the mucous membrane of

the mouth and labial glands. They are joined - immediately beneath the orbit, by filaments

from the facial nerve - forming with them the infraorbital plexus.

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MANDIBULAR BRANCH OF TN

Largest of the three divisions of the fifth nerve.Made up of two roots:

A large - sensory root proceeding from the inferior angle of the semilunar ganglion.

A small motor root which passes beneath the ganglion - unites with the sensory root - just

after -its exit - foramen ovale. Branches divided into 2 group: 1)undivided nerve. 2)divided nerve.

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Supplies - Teeth and gums of the mandible - The skin of the temporal

- The lower lip - The lower part of the face

- The muscles of mastication - It also supplies the mucous membrane

of the anterior two-thirds of the tongue.

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(Branches from the undivided nerve) NERVOUS SPINOSUS:

Enters the skull through the foramen spinosum with the middle meningeal artery. It divides into two branches, anterior and posterior

Supply the dura mater. The posterior branch - supplies the mucous lining of the mastoid cells. The anterior communicates with the meningeal branch of the maxillary

nerve.

INTERNAL PTERYGOID NERVE: Nerve to the Pterygoideus internus - slender branch - enters the deep

surface of the muscle. It gives off one or two filaments to the otic ganglion.

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(Branches from the divided nerve)

Below –leval-undivided-trunk seprates into 2 part. a) Anterior division. External pterygoid. Masseteric.

nerve to temporal. Buccinator .

b) Posterior division. Auriculotemporal nerve. Lingual nerve. Inferior alveolar nerve.

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o Branch to External pterygoid muscle: Enter the medial side of external pterygoid muscle to

provide motor supply.

o Massetter nerve: Passes above –external pterygoid to transverse mandibular

notch-enter-deepside-masster muscle.

o Nerve to temporal muscle: 1) anterior deep temporal nerve : passes upward

and crosses the infratemporal crest of the sphenoid bone and it end into anterior part of deep temporal muscle.

2)posterior deep temporal nerve: passes upward to the deep temporal nerve.

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o Buccal nerve: passes downward ,anteriorly and laterally b/w

2 head – external pterygoid muscle. At the level of occlusion plane of the

mandibular 2 & 3 molars, it divide into several branches that ramify on the buccinator muscle.

Supply-buccal gingivae about the mandibular molars nd mucous membrane of the lower part of buccal vestibule.

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b)Posterior division: AURICULOTEMPORAL NERVE:Arises by two roots – b/w which the middle meningeal

artery ascends. Runs backward beneath to the medial side of the neck

of the mandible. Than it passes with superfacial temporal artery in its

upward courses and divide into numerous branches,to the tragus of the pinna of the external ear,to the scalp above the ear,and far upward as vertex of the skull.

Branches of nerve: Parotid branches. Articular branches. Auricular branches. Meatal branches.

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LINGUAL NERVE:

Supplies - mucous membrane of the anterior two-thirds of the tongue.

First it passes to medially to the external pterygoid muscle.Than descends,lies b/w the internal pterygoid muscle and

ramus in pterygoid space.Finally runs across the duct of the submaxillary gland and

along the tongue to its tip.

BRANCHES OF DISTRIBUTION: Supply - sublingual gland

- mucous membrane of the mouth, the gums, and the anterior two-thirds of the tongue.

The terminal filaments communicate - at the tip of the tongue with the hypoglossal nerve.

Communications of the lingual nerve with the corda tympani.

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INFERIOR ALVEOLAR NERVE:Largest branch of the mandibular nerve. Descends with the inferior alveolar artery - at first

beneath the External pterygoid muscle – medial side of the ramus in pterygomandibular space, it enters the mandibular foramen.

Then passes forward in the mandibular canal - beneath the teeth as far as the mental foramen - where it divides into two terminal branches - incisive and mental.

Branches of the inferior alveolar nerve are the mylohyoid

Incisive Mental.

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MYLOHYOID NERVE:Derived - inferior alveolar just before it enters the

mandibular foramen. It descends - groove on the deep surface of the

ramus of the mandible - reaching the under surface of the Mylohyoid - supplies this muscle and the anterior belly of the Digastric.

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INCISIVE BRANCH:Continued onward within the bone and supplies the

1st premolar, canine and incisor teeth.

MENTAL NERVE:Emerges at the mental foramen - divides beneath

the Triangularis muscle into three branches.One descends to the skin of the chin.Two ascend to the skin and mucous

membrane of the lower lip.

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Examination of trigeminal nerve

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Examination of trigeminal nerve1- Sensation Function2- Motor Function3- Corneal reflex4- Test jaw jerk

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Sensation functionuse sterile sharp item on forehead, cheek, and jaw

If any abnormality present we test the thermal sensation and light touch

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Corneal reflexa clean piece of cotton wool and ask the patient

to look away gently touch the cornea with the cotton wool and the patient will blink.

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Test jaw jerkDoctor finger on tip of jaw, grip patellar hammer

halfway up shaft and tap finger lightly usually nothing happens, or just a slight closure.

APPLIED ANATOMYSensory distribution of the trigeminal

nerve explains why headache is a common symptom in involvements of the nose, paranasal air sinuses, the teeth & gums, the eyes & the meninges

Trigeminal neuralgia may involve one or more of the three divisions of the V nerve

Congenital cutaneous naevi on the face (port wine stains) map out accurately the areas supplied by one or more divisions of the V nerve

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APPLIED ANATOMY OF TRIGEMINAL NERVE

The sensory distribution of the trigeminal nerve explains why headache is a uniformly common symptom in involvements of the nose (common cold,boils), the paranasal air sinuses(sinusitis),the teeth and gums, the eyes, the meninges and so on.

Trigeminal neuralgia. – it causes attacks of very severe , burning and scalding pain along the distribution of the affected nerve.

TRIGEMINAL

NEURALGIA

DEFINATIONTrigeminal neuralgia (TN) is defined as sudden, usually unilateral,

severe, brief, stabbing, lancinating, recurring pain in the distribution of one or more branches of 5th cranial nerve.

John Locke in 1677 gave the first full description with its treatment.Nicholaus Andre in 1756 coined the term ‘Tic Doloureux.’John Fothergill in 1773 published detailed description of TN, since

then, it has been referred to as ‘Fothergill’s disease’.In spite of the condition being known since centuries, it still

continues to baffle the clinician and its pathogenesis remains as enigma to the medical profession. Multiple views have been hypothecated regarding its etiology generating nothing, but confusion and simultaneously opting for many different therapies in an effort to treat this ongoing condition.

Types of Trigeminal Neuralgia and Their

Causes

We define seven forms of TN: typical TN, atypical TN, pre-TN, multiple-sclerosis-related TN, secondary TN, post-traumatic TN (trigeminal neuropathy), and failed TN. These forms of TN should be distinguished from idiopathic (atypical) facial pain, as well as other disorders causing cranio-facial pain.

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 cases of typical TN are caused by blood vessels compressing the trigeminal nerve root as it enters the brain stem. This neurovascular or microvascular compression at the trigeminal nerve root entry zone may be caused by arteries of veins, large or small, that may simply contact or indent the trigeminal nerve. In people without TN, blood vessels are usually not in contact with the trigeminal nerve root entry zone. 

In people without TN, there is usually no vascular compression upon the trigeminal nerve root.

In most sufferers of typical trigeminal neuralgia, vessels compress the trigeminal nerve root.

Pulsation of vessels upon the trigeminal nerve root do not visibly damage the nerve. However, irritation from repeated pulsations may lead to changes of nerve function, and delivery of abnormal signals to the trigeminal nerve nucleus. Over time, this is thought to cause hyperactivity of the trigeminal nerve nucleus, resulting in the generation of TN pain.

The generation of TN pain is thought to result from peripheral pathology (i.e. neurovascular compression) and central pathophysiology (i.e. hyperactivity of the trigeminal nerve nucleus).

The superior cerebellar artery is the vessel most often responsible for neurovascular compression upon the trigeminal nerve root, although other arteries or veins may be the culprit vessels. TN may be cured by an operation that effectively relieves the neurovascular compression upon the trigeminal nerve root.  This operation is called microvascular decompression, and is described in Part Two: Treatment of Trigeminal Neuralgia.

Atypical Trigeminal Neuralgia

     Atypical TN is characterized by a unilateral, prominent constant and severe aching, boring or burning pain superimposed upon otherwise typical TN symptoms. This should be differentiated from cases of typical TN that develop a minor aching or burning pain within the affected distribution of the trigeminal nerve.

     Vascular compression, as described above in typical TN, is thought to be the cause of many cases of atypical TN. Some believe atypical TN is due to vascular compression upon a specific part of the trigeminal nerve (the portio minor), while others theorize that atypical TN represents a more severe form or progression of typical TN.

  

Atypical TN pain can be at least partially relieved with medications used for typical TN, such as carbamazepine (Tegretol®). MVD surgery is curative for many patients with atypical TN, but not as reliably as for those with typical TN. It is also important to note that rhizotomy procedures may be effective in treating atypical TN, but are more likely to be complicated by annoying or even painful numbness (i.e. deafferentation pain).

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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 distributions destined to become affected by TN. These odd sensations of pain, (such as a toothache) or discomfort (like "pins and needles", parasthesia), may be symptoms of pre-trigeminal neuralgia. Pre-TN is most effectively treated with medical therapy used for typical TN. When the first attack of true TN occurs, it is very distinct from pre-TN symptoms.

MULTIPLE SCLEROSIS REALATED TRIGEMINAL NEURALGIA

     The symptoms and characteristics of multiple sclerosis (MS)-related TN are identical to those for typical TN.  Two to four percent of patients with TN have evidence of multiple sclerosis and about 1% of patients suffering from multiple sclerosis develop TN.  Those with MS-related TN tend to be younger when they experience their first attack of pain, and the pain progresses over a shorter amount of time than in those with typical TN. Furthermore, bilateral TN is more commonly seen in people with multiple sclerosis.

     MS involves the formation of demyelinating plaques within the brain. When these areas of injury involve the trigeminal nerve system, TN may develop. MS-related TN is treated with the same medications used for typical TN (see Medications). Trigeminal rhizotomies are employed when medications fail to control the pain. For some individuals with MS and TN, neurovascular compression of the trigeminal nerve root may be a rare cause and demonstrated with special MRI or CT scans. In such cases, microvascular decompression surgery may be considered for treating the MS-related TN.

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 that severely compresses or distorts the trigeminal nerve may cause facial numbness, weakness of chewing muscles, and/or constant aching pain (also see Trigeminal Neuropathy or Post-Traumatic Trigeminal Neuralgia ). Medications usually help control secondary TN pain when first tried, although often become. Surgically removing the tumor usually alleviates pain and trigeminal function may return. At the time of surgery, after the removal of the tumor, the trigeminal nerve may be found to also be compressed by an artery or vein that causes the typical features of TN. This vessel must then be moved away from the nerve by microvascular decompression techniques to cure TN.

In these MRI images, a tumor responsible for compressing the trigeminal nerve is highlighted in red.

Trigeminal Neuropathy or Post-Traumatic Trigeminal Neuralgia

 Injury to the trigeminal nerve may cause this severe pain condition. Trigeminal Neuropathy or Post-Traumatic TN may develop following cranio-facial trauma (such as from a car accident), dental trauma, sinus trauma (such as following Caldwell Luc procedures) but most commonly following destructive procedures (rhizotomies) used for treatment of TN. Following TN injury, numbness may become associated with bothersome sensations or pain, sometimes called phantom pain or deafferentation pain. These pain conditions are caused by irreparable damage to the trigeminal nerve and secondary hyperactivity of the trigeminal nerve nucleus

The pain of trigeminal neuropathy or post-traumatic TN is usually constant, aching or burning, but may be worsened by exposure to triggers such as wind and cold. Such deafferentation pain can start immediately or days to years following injury to the trigeminal nerve. In the most extreme form, called anesthesia dolorosa, there is continuous severe pain in areas of complete numbness.

    Unfortunately, treatment of post-traumatic TN is often ineffective and pain may not be controlled with medications. There are some reports of pain relief associated with the use of trigeminal nerve stimulation procedures. More invasive procedures such as brain surface (pre-motor cortex) stimulation, or focused injuries in the brain stem (tractotomy) have also been tried.

"Failed" Trigeminal Neuralgia

 Not all cases of TN may be effectively controlled with any one form of medications or surgical interventions. When medications are no longer effective, surgical interventions are considered. If pain recurs or persists following surgery, medications are tried again and may then work more effectively. Rarely, additional or repeated surgical interventions are necessary. Unfortunately, in a very small proportion of sufferers, all medications, microvascular decompression and destructive rhizotomy procedures prove ineffective in controlling TN pain. This condition is called "failed" trigeminal neuralgia. Such individuals also often suffer from additional trigeminal neuropathy or post-traumatic TN as a result of the destructive interventions they underwent. Investigational treatments may be considered including stimulation of the brain surface (pre-motor cortex stimulation), controlled lesioning of the brain stem (tractotomy), or stimulation of the trigeminal nerve or Gasserion ganglion (trigeminal nerve stimulation).

Treatment of Trigeminal Neuralgia

Medications are the first line of treatment for TN and include carbamazepine (Tegretol®), phenytoin (Dilantin®), gabapentin (Neurontin®) and baclophen (Lioresal®).

As the disease progresses and pain becomes more frequent and severe, increased doses of medications are required which may lead to intolerable side effects and/or inadequate pain control.

Each sufferer has differing tolerance to these medications and pain, but at least half will eventually find that medications do not adequately control their progressively worsening TN.

The surgical procedures then considered are either microvascular decompression surgery or some form of nerve injury procedure (rhizotomies).

MEDICINAL TREATMENT OF TRIGEMINAL

NEURALGIA

 

Carbamazepine (Tegretol®)

     Almost all typical TN sufferers experience significant pain relief with carbamazepine. The starting daily dose is low, (one to two pills a day), which is gradually increased until the pain is completely alleviated or side effects occur. Good relief of pain may be achieved at low doses, but the usual effective dose ranges from 200 to 1200 mg divided in three or four doses per day. Even higher doses may be required during severe attacks of pain.  Once relief of the pain has been achieved, the same dose is usually continued for at least two weeks before trying to reduce to a minimal dosage that provides pain relief.  As with

Carbamazepine (Tegretol®)

As with all TN medications, Tegretol® may gradually be decreased during periods of remission.

     Several dose-related side effects are often experienced including drowsiness, mental confusion, dizziness, nystagmus (rapid movements of the eye), ataxia (decreased coordination), diplopia (double vision), nausea, and anorexia (loss of appetite). If side effects are severe, the daily dose of carbamazepine may be decreased for 1 to 3 days, before trying to increase the daily dose again. 

     

Trileptal (Oxycarbazepine) Trileptal, or oxycarbemazepine, is a form of Tegretol®

that is becoming more widely prescribed for a variety of conditions. Like Tegretol®, it is an anti-seizure drug, but the side effects are less severe and less frequently experienced.

The dose ::begins at 300 mg twice a day gradually increased to achieve pain control.

The maximum dose is 2400-3000 mg per day. Common side effects are nausea, vomiting, dizziness,

fatigue and tremors. Less frequent symptoms are rash, respiratory infections, double vision, and changes in electrolytes in blood. If you have had an allergic reaction to Tegretol® (carbemazepine), then you should not try Trileptal. As with other anti-seizure medications, increasing and decreasing the dose should be gradual.

Phenytoin (Dilantin®)  Phenytoin relieves

tic pain in over half of TN sufferers at doses of 300 to 500 mg, divided into three doses per day.

 Phenytoin may also be administered intravenously to treat severe exacerbations of TN.

Baclophen (Lioresal®)

not as effective as carbamazepine or phenytoin for TN, but may be used in combination with these medications.

The starting dose is 5 mg two or three times a day, and may be gradually increased.

The usual dosage taken for complete pain relief is between 50 and 60 mg per day. Baclophen has a short duration of function so sufferers with severe TN may need to take doses every 3 to 4 hours.

Gabapentin (Neurontin®) Gabapentin is an anti-epileptic drug that is

structurally related to the neurotransmitter GABA.

This drug is almost as effective as carbamazepine but involves fewer side effects. 

The starting dose is usually 300mg three times a day and this is increased to a maximal dose.  The most common adverse reactions include somnolence (sleepiness), ataxia (decreased coordination), fatigue, and nystagmus (rapid movements of the eye).  There is no known interaction with Tegretol® or Dilantin®, permitting usage of these drugs in combination with Neurontin®. As with all of these drugs, rapid discontinuation should be avoided as severe withdrawal reactions may occur.

SURGICAL TREATMENT OF TRIGEMINAL NEURALGIA

1. PERIPHERAL NERVE SURGICAL TREATMENT

A. PERIPHERAL INJECTIONSa) LONG ACTING ANAESTHETIC AGENTSb) ALCHOHOL INJECTIONS

B. PERIPHERAL NEURECTOMYa) INFRAORBITALb) INFERIOR ALVEOLAR NERVEc) LINGUAL NERVEC. CRYOTHERAPY OR CRYONEUROLYSISD. PERIPHERAL RADIOFREQUENCY

NEUROLYSIS OR THERMOCOAGULATION

2. GASSERIAN GANGLION PROCEDURES

A. TECHNIQUES FOR PERCUTANEOUS APPROACH

a) INJECTION METHOHEXITONEb) INJECTION GLYCEROL

c) CONTROLLED RADIOFREQUENCY THERMOCOAGULATION

d) BALLOON COMPRESSION RHIZOTOMY

The introduced cannula positioned

and balloon catheter advanced.

The balloon is then inflated, injuring

the nerve.

B. OPEN PROCEDURES

a) MICROVASCULAR DECOMPRESSION OF THE SENSORY ROOT OR POSTERIOR FOSSA DECOMPRESSION

During MVD, the vessel is mobilized away from the nerve root entry zone.

b) TRIGEMINAL ROOT SECTION

i. EXTRADURAL ROOT SECTION

ii. INTRADURAL ROOT SECTION

iii. TRIGEMINAL TRACTOTOMY

Stereotactic Radiosurgery (Gamma Knife)

Recently, a new technique allows for focused radiation to be delivered to the trigeminal nerve root and produces injury and results similar to the other percutaneous rhizotomy procedures. 

Gamma Knife Radiosurgery is performed by applying a frame to the patient’s head and then obtaining a MRI.  The patient is then positioned in the Gamma Knife, where up to 201 focused beams of cobalt radiation are directed at the trigeminal nerve root. 

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2. TRIGEMINAL NEUROPATHY

• sensory loss of face or weakness of the jaw muscles

• causes- sjogren syndrome

• herpes zoster, leprosy

• meningioma,schwanomma

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3. HERPES ZOSTER OPHTHALMICUS:

Recurrent neurocutaneous inf. In opth. Div. of trigeminal

dermatome, most freq. affecting nasociliary branch

HHV3 / vericella zoster

Gasserian ganglion

ophthalmic nerve

Supraorbital N. Infraorbital N.Supratrochlear N.Infratrochlear N.Nasal N.

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4. Cavernous sinus syndrome

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• Cavernous sinus syndrome• Multiple cranial neuropathies• Exophthalmos, ocular motor defects, sensory

loss in V1 and / or V2.• Pupils may be spared or involved. causes: bacterial thrombophlebitis actinomycosis rhinocerebellar mucormycosis aspergillosis tolosa hunt syndrome neoplasms vascular lesions

5.Gradenigos syndrome

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Petrous bone osteitis due to otitis media

Characterized by I/L trigeminal N palsy (Va,

Vb)

retro orbital pain

I/L sixth N palsy.

Conclusion

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Since Trigeminal nerve is mixed nerve, suplies mainly head and neck region. Hence as a Oral and Maxillofacial surgeon one should know throughly about intracranial and extracranial course and distribution of Trigeminal nerve,to diagnose the pathologies associated with Trigeminal nerve and for appropriate treatment.

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Refrences: Greys anatomy Snells anatomy Head and Neck Anatomy-BD

Chourasia Textbook of Local Anesthesia-

Stenly F Malamed Dr najeeb lacture on trigeminal

nerve.

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