Peripheral Nerve Injury Basar Atalay M.D. - PowerPoint Presentation

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Peripheral Nerve Injury

Basar Atalay M.D.

Yeditepe University

FACULTY OF MEDICINE

Department of Neurosurgery

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Anatomy

Connective tissue

- major tissue component

- epineurium, perineurium, endoneurium

Nerve tissue

- axon, schwann cell

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Peripheral Nerve Injury

Acute injury

Chronic injury

(entrapment neuropathy)

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Neuropraxia

The mildest form, reversible conduction

block

Loss of function, which persists for hours

or days

Direct mechanical compression, ischemia, mild burn trauma or stretch

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Axonotmetic

Axon continuity is disrupted

Fascicular integrity is maintained

Wallerian degeneration occurs

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Neurotmesis

Laceration from sharp or blunt forces

The only important consideration is

the timing of repair

Acute repair or more bluntly lacerated

nerves are repaired 3-4 weeks

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Classification

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Factors for Decision Making

Age

Segment between injury and end organ

Gap of injury

Mechanism of injury

Severity of injury

Presence of pain

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Axonal Regeneration

Initial delay

to the distal stump : 1-2 week delay

Growth rate

1mm/day, 1 inch/month

Terminal delay

several weeks-several months

Recovery within 6 weeks



good prognosis

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Clinical Signs

Motor function

Tinel’s sign

positive-sensory function

negative(after 4-6weeks)-total interruption

Sweating-sympathetic fiber

Sensory function

Diagnosis

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Electrophysiological Tests

EMG

SNAP

SSEP

Intraoperative NAP

Diagnosis

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Muscle Atrophy

24 month rule

- muscle scar tissue

Muscle atrophy

start : post-injury 1 month

peak : 3

rd

- 4

th

month

Segment between injury and end organ

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Time of Operation

Open injury

Early intervention

Delayed intervention

Closed injury

Delayed intervention

Treatment

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Early Intervention

Enlarging hematoma/aneurysmal sac

Predisposing to Volkmann’s ischemic contracture

Severe noncausalsic pain

Injury to N. in areas of potential entrapment

Simple, clean lacerating injury

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Delayed Intervention

2-3 months after injury

No clinical or substantial recovery

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Operations

Neurolysis :

internal/external

Nerve repair

end-to-end repair : epineural/fascicular

autologous graft : sural N.

Neurotization

intercostal N./accessory N./cervical plexus

within 1 year

Muscle and tendon transfer

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Epineural Repair

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Fascicular Repair

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Nerve Graft

# leading cause of failure of nerve graft

Inadequate resection

Distraction of repair site

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Conclusions

1. Immediate primary repair in sharp injuries

Immediate repair is especially important for brachial plexus and sciatic nerve transsections because delay leads not only to retraction but also to severe scaring

Bluntly transsected nerve best repaired after a delay of several weeks.

2. A focally injured nerve should be explored if no functional return within 8-10 weeks

3. Decision - making as to whether neurolysis or resection & repair in a lesion in gross continuity is based on intraoperative electrophysiological evaluation

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4. Nerve anastomosis failure

① inadequate resection of scarred nerve ends

② nerve suture distraction

5. A good end result requires rehabilitation.

Conclusions

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Chronic Injuries of Peripheral Nerves by Entrapment

Pain

Paresthesia

Loss of function

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Pathophysiology of Entrapment

Direct compression

segmental demyelination

wallerian degeneration(distal)

Ischemia

swelling of nerve

microcompartment SD

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Conservative Treatment

Indications

not long history

mild-moderate, intermittent

reversible cause

pregnancy, oral contraceptive, endocrine abnormalities(DM…)

Method

nonsteroidal anti-inflammatory drugs

splint

Treatment

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Surgical Indications

Failed conservative tx

Typical clinical finding

with electrodiagnostic data

Severe

sensory loss

muscle atrophy

motor weakness

Treatment

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Entrapment of Thoracic Outlet

Cervical

rib or anomalous transverse process of C7

Fibromuscular bands or scalene muscle abnomality

- X-ray

- NCV & EMG

- Angiography – vascular anomaly

Treatment

:

Supraclavicular approach

- Best op. management

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scalene anterior

and medius M.

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Carpal Tunnel Syndrome

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thenal atrophy

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Entrapment of Radial Nerve

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Entrapment of Ulnar Nerve

- Cubital tunnel

- Guyon’s canal

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Meralgia Paresthesia

Lateral

femoral cutaneous nerve injury (L1-2)

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Tarsal Tunnel Syndrome

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Intraoperative NAP