peripheral nerve injuries - bowen university

DR. ANIPOLE O.A

Lecturer 1/ Consultant Orthopaedic Surgeon

NERVE

INJURY

OUTLINE

Relevant Physio-anatomy

Incidence Of Peripheral N.

Injury

Aetiopathology

Clinical Evaluation

Electrophysiogical Assessment

Imaging Techniques

OUTLINE

Treatments

Complications

Newer Techniques

Relevant Physio-Anatomy

Nerve is composed of neural and connective tissue.

In both myelinated and non myelinated axons, each nerve fiber is surrounded by the endoneurium.

Groups of nerve fibers are surrounded by the perineurium to form fascicles.

Goups of fascicles are surrounded by the internal and external epineurium.

Knowledge of motor and sensory fascicular topography within the nerve is essential to ensure correct alignment of the motor and sensory fascicles.

NERVE TRUNK

PERINEURIUM

BLOOD VESSELS

EPINEURIUM

FASCICLE

NERVE FIBER

MYELIN SHEATH

AXON

ENDONEURIUM

A MOTOR NEURONE

Incidence Of Peripheral

Nerve Injury Limited reported data are available

to determine incidence.

In North America, data taken from

a trauma population in Canada

revealed that approximately 2-3%

of patients had a major nerve

injury.

Incidence Of Peripheral

Nerve Injury

• Ulnar nerve inj: common ass with

# medial humeral epicondyle and

callus around the elbow,

Median nerve inj: common in

elbow dislocation

Incidence Of Peripheral

Nerve Injury

Axillary nerve stretch inj. occur in

~ 5% of shoulder dislocation

Peroneal nerve injury common in

fibular neck # or dislocation of

knee

Aetiopathophysiology

Peripheral nerve injuries may occur due to;

Trauma ( blunt or penetrating wound):

- Stab : from a knife, by a bullet, ragged end of fracture bone.

Vascular Ischaemia as in Volkman’scontracture of the forearm

Compression:

-Acute compression by haemorrhage or oedema: Compartment syndrome

-Chronic compression injuries.

Traction: E.g birth trauma→ Erb’s

palsy

Chemical / Burn injuries; from

injection of drugs, or adjacency of

methylmethacrylate material to the

sciatic nerve during total hip

replacement.

Aetiopathophysiology

Injury → Demyelination or axonal

degeneration

→ disruption of the sensory and/or

motor function

Remyelination /axonal regeneration

→ Reinnervation of the sensory

receptors, motor end plates, or both.

Aetiopathophysiology

Classification

Seddon in 1943 classified nerve injury as neurapraxia, axonotmesis, and neurotmesis.

• Sunderland in 1951 expanded this classification system to 5 degrees of nerve injury.

Mackinnon introduced the sixth degree.

Seddon,1943.

1. Neuropraxia –Minor contusion or compression. Demyelination without axon disruption or degeneration. Conduction block .Transient loss of function

2. Axonotmesis –The axons are disrupted with distal Wallerian degeneration but the endoneurium is intact

3. Neurotmesis –Total division & disruption in continuity of axons, all supporting structures including epineurium.

Classification

CLINICAL EVALUATION

History Taken

Clinical Examination

Inspection

- Lesions of various nerve often

results in a xtic limb attitude.

CLINICAL EVALUATION

Muscle tone

Reduced or abolished

CLINICAL EVALUATION

Muscle Bulk

Progressively atrophy to

approximately 50% - 2 months

Muscle Power

MRC method of grading muscle

power – 0 – 5.

CLINICAL EVALUATION

Sensory Assessment- Dermatones

CLINICAL EVALUATION

Examination of the nerve

Local Tenderness -

- Indicates an in complete

lesion

Tinel sign

- Evidence of axon sprouts

- Sensation of pins & needles

Electrophysiogical

Assessment

(1) Nerve Conduction Studies

(2) Electromyography

Nerve Conduction Studies

Particularly useful in determining

the anatomical site of compression

of a nerve. .

In cases of brachial plexus injury,

can help to determine the

presence of an avulsion injury.

Electromyography

◦ Performed at least 4 weeks following

nerve injury.

◦ Evidence of denervation is indicated

by the presence of fibrillations in the

muscle.

◦ Reinnervation is noted by the

presence of motor unit potentials.

TREATMENT

Conservative

◦ Use of splint or sling for support

◦ Passive mobilization

◦ Maintaining muscle strength in the

unaffected muscles.

No definitive studies have been done to

support the use of electrical muscle

stimulation to prevent muscle

degeneration.

FORMS OF SURGICAL

TREATMENT NERVE REPAIR

NERVE GRAFT

NERVE TRANSFER

TENDON TRANSFER

Types of Nerve Repair

PRIMARY 6 – 8

HOURS

DELAYED PRIMARY 7 – 18 DAYS

SECONDARY >18 DAYS

METHODS OF I ̊ REPAIR

EPINEURIAL

PERINEURIAL {FASCICULAR}

Group Fascicular

Epineurial Repair

Fascicular (funicular) Repair

Nerve Grafting

Sural Nerve

Ant. br. of medial cut. n. of the

forearm

Lat. Cut. n. of the forearm

POST OPT MGT

CARE OF WOUND

SPLINTAGE

PHYSIOTHERAPY/HAND

THERAPIST

FOLLOW-UP CARE

COMPLICATIONS

Injury - Related

PAINFUL NEUROMA

PARALYSIS

JOINT STIFFNESS

MUSCLE WASTING

REFLEX SYMPATHETIC

DYSTROPHY

COMPLICATIONS

Operation - Related:

Infection,

Hematoma,

Seroma, and

injury to surrounding structures,

including vascular structures.

Further injury to the nerve.

THANKSFOR

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