nerve injuries.dr.sangram. (nxpowerlite) / orthodontic courses by indian dental academy

INDIAN DENTAL ACADEMY

Leader in continuing dental education www.indiandentalacademy.com

www.indiandentalacademy.com

NERVE INJURIES

NERVE: Nerves are solid white cords made up of bundles of axons

• Each nerve fiber is known as an axon

• Each axon is bound by fibrous tissue into small bundles

The nerve trunk is composed of 4 connective tissue sheaths from

outside inwards are:www.indiandentalacademy.com

1.Mesoneurium: Suspends nerve within soft tissue and provides segmental blood supply to it.2.Epineurium: Protects nerve from mechanical stress3.Perineurium4.Endoneurium• Group of nerve fibers- FASCICULI• Each FASCICULI is surrounded by PERINEURIUM• Group of FASCICULI forms a NERVE TRUNK• FASCICULES are surrounded by EPINEURIUM


Etiology of Nerve injuries:a. LOCAL CAUSES• Facial bone fractures.• Treatment of oral pathological conduction.• Maxillofical reconstructive surgery.• Removal of impacted lower third molar.b. CENTRAL DISEASES

- Syringomyelia - Multiple Sclerosis - Bulbar Paralysis


Classification of Injuries:In 1943 SEDDON introduced a classification of nerve injury based on three types of nerve fiber injury. 1. Physiologic Disruption NEUROPRAXIA, 2. Axonal disruption AXONOTEMESIS, 3. Division of the nerve NEURONOTEMESIS.


Neuropraxia:

1. Least severe form of peripheral nerve injury, 2. Result of contusion of the nerve ( continuity of

epineurial sheath and axons maintained.3. Blunt trauma, traction stretching of nerve,

inflammation or local ischemia 4. Full recovery of the nerve function within few

days or weeks.


Axonotmesis:

Blunt trauma, nerve crushing, extreme traction of nerve. • Afferent fibers degenerate but nerve trunk intact, no disruption of endo/peri/Epineurium• Recovery is good but incomplete (2, 4-12month)


Tinnel’s sign:

Painful, electric shock like sensation elicited by tapping directly over the cutaneous distribution of injured nerve


Neurotmesis:

Severe disruption of connective tissue component of nerve trunk. ( Loss of nerve continuity) Prognosis for recovery poor

Sensory recovery is not expected when nerve in soft tissue, but if within canal minimal recovery expected www.indiandentalacademy.com

SUNDERLAND (based on degree of tissue injury)Five degrees based on increasing anatomic severity of injury.Classification DescriptionGrade I Loss of axonal conductionGrade II Loss of axonal ContinuityGrade III Loss of axonal and endoneurial

continuity Grade IV Loss of perineurial continuity with

fascicular disruptionGrade V Loss of continuity of entire nerve

trunkwww.indiandentalacademy.com

COMPARTMENT SYNDROME:

• Local increase in pressure (edema/venous stasis) causing decreased oxygenation.

• Abnormal vibration and touch perception


TESTING FOR NERVE INJURY:

1. Light touch: cotton wisp2. Two-point discrimination: >10mm abnormal3. Localization4. Sharp blunt differentiation5. Thermal stimuli: 150c to 500c


BASIC PRINCIPLES OF NERVE REPAIR:1. Decompression:2. Neurorraphy: (Gap of 10mm only)

a. Preparation of nerve stumpsb. Approximationc. Cooptatione. Maintaining the cooptation

3. Nerve Grafts:- Sural nerve- Greater auricular nerve


TRIGEMINAL NEURALGIA

Synonyms:· Tic douloureux- spasmodic contraction of facial muscles · Fother gill’s disease

· Trifacial neuralgia


Definition:

‘A painful unilateral affliction of the face, characterized by brief electric shock like (lancinating) pain limited to the distribution of one or more divisions of the trigeminal nerve’


PREVIOUSLY CLASSIFIED AS:

1. Classical trigeminal neuralgia or Idiopathic trigeminal neuralgia

2. Specific trigeminal neuralgia (known etiology) Pre- trigeminal neuralgia (PTN


INCIDENCE: Female affected more than males (3:2) Right > left Middle age and elderly 4% Bilateral 95% Maxilla + Mandibular nerve involved 5% Ophthalmic nerve involved


CLINICAL FEATURES:

“WHITE AND SWEETS CRITERIA”1. PAIN: Paroxysmal (lasts from few seconds to few minutes)

Extremely intense (stabbing/ lightening/ pricking/ knife like)

Pain free episodes/ intervalswww.indiandentalacademy.com

2. TRIGGER ZONES:

Vermilion/ alae/ cheeks/ periorbital area Cutaneous in distribution Stimuli includes- touch/ breeze/ talk/ chew/brush/shave

3. PRE-TRIGEMINAL NEURALGIA(PTN): Mild, lancinating/pricking type Months to years before chronic type of trigeminal neuralgia

4. HYPERESTHESIA/ HEPERALGESIA On routine clinical examination


5. ALWAYS UNILATERAL:If bilateral, then only one side affected at a time

Unshaven and unclean face (frozen face) Spontaneous remission is unusual Attacks do not occur during sleep(characteristic) Secondary radiation of pain to adjacent division

HYPOTHESIS:1. Neural back talk theory – secondary to nerve injury2. Deafferentation of central processes due to peripheral injury


CLINICAL FEATURES: Male = female Middle age or late life Pain: lancinating pain of oropharynx or neck, lasts for week-months Triggered by swallowing/ cough/ talk Unilateral & radiates to ear & or mouth Syncope is a feature Rarely causes xerostomia/excess salivation Disturbs sleep


ETIOLOGY:

1. C-P angle tumors: Acoustic Neuroma/ Cholesteotoma/ Meningioma/ Osteoma/ Angioma2. Anatomical variation of Petrous bone/ridge3. Aneurysms and Adhesions4. Multiple Sclerosis

INVESTIGATIONS: Nerve functions- sensory and motor (trigger zones)Diagnostic nerve blocksSpecial tests for tumors and systemic diseases


Treatment modalities:Medical:(A)1. Phenytoin sodium (dilantin) 200-600mg/day in divided doses2. Carbamazepine (tegretol/ carbital) Initially – 100mg BID Increase to 200mg TID 3. Max. Dose is 1200mg/day in divided doses Baclofen or l-baclofen (lioresal) 10-80-mg/ day in divided doses4. Valproic acid (depakote) 125-250 mg/day5. Clonazepam (klonopin) 0.5 - 8mg/day6. Pimiozide (orap) 2-12 mg/day7. Lamotragine (lamicital) 50-100mg/day


(B) PERCUTANEOUS injections:(2days -1-week interval)

Chemicals used: local anesthesia/ absolute alcohol/ phenol-

glycerin mixture

Injection site: peripheral nerves/trigger zones/gasserian ganglion

(C) percutaneous electro-coagulation

(D) cryosurgery (-900 to –1600 c)

(E) ratners procedure/ osseous curettage

Bone decortication+curettage+triple antibiotic pack

(chloromphenicol+tetracycline+iodoform)www.indiandentalacademy.com

TREATMENT:

▪ Medical: - Carbamazepine/ Phenytoin/ Baclofen▪ Local: - Cryotherapy/ Alcohol Injection▪ Surgery: - Section GPN & Upper Rootlets Of Vagus▪ Central: - Micro vascular Decompression


Thank you

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nerve injuries.dr.sangram. (nxpowerlite) / orthodontic courses by indian dental academy

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