Presented By:

Dr Akasha Amber

Plastic surgery resident (1st year)BVH BWP

Principals & Techniques Of

Peripheral Nerve Repair

mesoneuriumFascicles of nerve fibers

perineurium

epineurium

endoneurium

Physiology

Nerve Injury Focal contusion (gunshot wounds) Stretch/traction injury Drug injection injury Compression Crush injuries Avulsion Laceration Electrical burns Idiopathic Others(Viral infections, metabolic and neural disorders)

Nerve Regeneration

Changes at proximal and distal site of injury

Classification Of Nerve Injuries

Seddon, Sunderland and lately by Mackinnon 6 degrees

Degrees Of Nerve Injury

1st degree of injury(neuraparaxia)› Segmental demylination› Axons intact› Recovery in 12 to 16 wks

2nd degree injury(axonotmesis)› Axonal injury/ distal wallerian degeneration› Regeneration at rate of 1 inch per month› Complete slow recovery

Degrees Of Nerve Injury

3rd degree injury› Axonal injury & fibrosis of endoneurium› Incomplete recovery

4th degree injury› Axonal injury› Damage to endo and perineurium with dense

scarring› Needs surgical intervention

Degrees Of Nerve Injury

5th degree injury(neurotmesis)› Complete nerve division

6th degree injury› Variable combination of previous five

degrees of nerve injury

normal

1st degree injury

2nd degree injury

3rd degree injury

4th degree injury

6th degree injury

Diagnosis

Motor function

› Movements, muscle atrophy

sensory function

› Tinel sign, Ten test

› Two point discrimination

› Touch, vibration

•History•Examination

Tinel Sign

Tinel sign: -› peripheral tingling or dysaesthesia'

provoked by percussion of the nerve› Positive in axonal injuries

Electrical Stimulation Tests:

EMG NCS Intra operative nerve action potential

Principals Of Nerve Repair

Microsurgical techniques› Adequate magnification› Microsurgical instruments & sutures

Different techniques:› Primary nerve repair› Nerve grafting› Nerve transfer› Nerve conduits› Nerve allografts

Timing Of The Nerve Repair

Sharply transected nerves› Immediate repair

Crushed, avulsed, blast injuries› Nerve ends tacked together› Repair delayed for 3 weeks or until wound bed permits

Re-exploration Neuroma excision, nerve grafts Acute nerve grafting in the 1st sitting Bleeding control ,trimming of fascicles ,loose epineural suturing

Closed injuries treated expectantly for 12 weeks

Primary Nerve Repair

Primary repair› Tension free repair› Mobilization of nerve ends› Discourage

Facilitation by postural position Extreme range of joint movements

Primary Nerve Repair

Primary nerve repair› Epineural repair› Grouped fascicular repair

Epineural Repair

Standard repair

Fascicular Repair

Restore the continuity of fascicles Internal topography Intra-operative nerve stimulation Neurolysis with the eyes Priority to the motor recovery(radial and

peroneal nerve)

e.g. Ulnar Nerve Fascicular Components

Nerve Grafts

Tension at site of repair Need of postural positioning Alignment of sensory & motor components Maximize number of axons Reversal of graft Exclusion of expendable nerve

Options For Nerve Grafts

Sural nerve› 30-40cm› Lateral peroneal communicating br : 10-20cm

Lateral antebrachial cutaneous nerve(LABC)› 8cm

Medial antebrachial cutaneous nerve (MABC)› Anterior & posterior division› 20 cm

Expendable nerves(peroneal and radial) Sensory branches of ulnar and median nerves Distal anterior interosseous nerve and so on…

Disadvantages

Donor site scarring Donor site sensory loss

› Patient education

Neuroma In Continuity

Complete : resection and repair with graft

Neuroma In Continuity

Incomplete neuroma Intra-operative nerve stimulation Black boxing around neuroma

Nerve Transfer

Indications:› Very proximal peripheral nerve injuries› Root avulsions› Excessive scarring› Level of injury unclear

Idiopathic neuritides Radiation induced nerve injury

Nerve Transfer

Motor nerve transfer› Pure motor axons› Close proximity› expendable› Synergistic supply

Sensory nerve transfer› pure sensory axons› Innervates non critical area› Expendable and lying in close proximity

Most Common Uses Of Nerve Transfer

elbow flexion Shoulder abduction Ulnar-innervated intrinsic hand function Forearm pronation Radial nerve function

Transfer of radial nerve to axillary nerve

Nerve Conduits

Veins, pseudo-sheaths, bioabsorbable tubes short nerve gaps ≤ 3cm Low antigenicity , biodegradability Trials to add a nerve graft inside the conduit

› neurotrophic factors

Nerve Allografts

Extensive injuries Limited donor material Immunosuppressive agents

› FK506( tacrolimus )› Prednisone , azathioprine

Processed acellular cadaveric nerve allografts› AxoGen, Inc. ,Alachua, FL.

Thank you