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1. INDIAN DENTAL ACADEMY
Leader in continuing dental education
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2. 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:
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3.
1.Mesoneurium: Suspends nerve within soft tissue
and
provides segmental blood supply
to it.
2.Epineurium: Protects nerve from mechanical
stress
3.Perineurium
4.Endoneurium
• Group of nerve fibers- FASCICULI
• Each FASCICULI is surrounded by
PERINEURIUM
• Group of FASCICULI forms a NERVE TRUNKwww.indiandentalacademy.com

4. 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
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5. 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.
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6. 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.
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7. 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)
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8. Tinnel’s sign:
Painful, electric shock like sensation elicited
by tapping directly over the cutaneous
distribution of injured nerve
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9. 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
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10. SUNDERLAND (based on degree of tissue injury)
Five degrees based on increasing anatomic severity
of injury.
Classification Description
Grade I Loss of axonal conduction
Grade II Loss of axonal Continuity
Grade III Loss of axonal and endoneurial
continuity
Grade IV Loss of perineurial continuity with
fascicular disruption
Grade V Loss of continuity of entire nerve
trunk
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11. COMPARTMENT SYNDROME:
• Local increase in pressure
(edema/venous stasis) causing decreased
oxygenation.
• Abnormal vibration and touch perception
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12. TESTING FOR NERVE INJURY:
1. Light touch: cotton wisp
2. Two-point discrimination: >10mm abnormal
3. Localization
4. Sharp blunt differentiation
5. Thermal stimuli: 150
c to 500
c
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13. BASIC PRINCIPLES OF NERVE REPAIR:
1. Decompression:
2. Neurorraphy: (Gap of 10mm only)
a. Preparation of nerve stumps
b. Approximation
c. Cooptation
e. Maintaining the cooptation
3. Nerve Grafts:
- Sural nerve
- Greater auricular nerve
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14. TRIGEMINAL NEURALGIA
Synonyms:
· Tic douloureux- spasmodic contraction of facial
muscles
· Fother gill’s disease
· Trifacial neuralgia
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15. 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’
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16. PREVIOUSLY CLASSIFIED AS:
1. Classical trigeminal neuralgia or Idiopathic
trigeminal neuralgia
2. Specific trigeminal neuralgia (known etiology)
Pre- trigeminal neuralgia (PTN
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17. 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
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18. 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/ intervals
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19. 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
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20. 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 injury
2. Deafferentation of central processes due to peripheral injury
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21. 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
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22. ETIOLOGY:
1. C-P angle tumors: Acoustic Neuroma/ Cholesteotoma/
Meningioma/ Osteoma/ Angioma
2. Anatomical variation of Petrous bone/ridge
3. Aneurysms and Adhesions
4. Multiple Sclerosis
INVESTIGATIONS:
Nerve functions- sensory and motor (trigger zones)
Diagnostic nerve blocks
Special tests for tumors and systemic diseases
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23. Treatment modalities:
Medical:
(A)
1. Phenytoin sodium (dilantin)
200-600mg/day in divided doses
2. 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 doses
4. Valproic acid (depakote) 125-250 mg/day
5. Clonazepam (klonopin) 0.5 - 8mg/day
6. Pimiozide (orap) 2-12 mg/day
7. Lamotragine (lamicital) 50-100mg/day
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24. (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)
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25. TREATMENT:
▪ Medical: - Carbamazepine/ Phenytoin/ Baclofen
▪ Local: - Cryotherapy/ Alcohol Injection
▪ Surgery: - Section GPN & Upper Rootlets Of Vagus
▪ Central: - Micro vascular Decompression
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26. Thank you
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