Introducing Nerve Transfers for Upper Limb Reanimation

in TetraplegiaNatasha van Zyl MBChB, FRACSPlastic and Reconstructive SurgeonThe Upper Limb ProgramVictorian Spinal Cord ServiceAustin HealthHeidelberg, Victoria, Australia

Co-Authors:Stephen FloodMichael WeymouthCatherine CooperJodie HahnAndrew Nunn

To reconstruct:- Elbow extension Grasp Release

To do it:- By using nerve transfers alone With no/little morbidity from donor nerve harvest While keeping the all the options for standard

tendon transfer reconstruction available

Aim

Background to the conception of this project

Therapeutic & investigational techniques involved

Logistics of delivery & assessment of safe nerve transfer reconstruction in tetraplegia

This presentation describes…

Inspiration: Success of nerve transfers in BPI & PNI

Reanimate the native muscle directly Careful choice of donor nerves can preserve

muscles used for tendon transfers These muscles can be used to reconstruct distal

functions e.g. opposition, intrinsic function No more grafts, tendon tensioning, stretching or

adhesion problems, no long immobilisations Greater than 1:1 functional exchange

Background

Surgical reinnervation of a denervated muscle by transferring an expendable, intact donor nerve to the non-functional nerve of a paralysed muscle in order to reanimate that muscle with axonal ingrowth from the donor nerve

What is a motor nerve transfer?

Donor nerves Use “obscure” muscles – difficult to be sure

they are under voluntary control

Recipient nerves May be LMN or UMN denervated or a

combination of both so time to surgery is an issue

What is different in SCI?

3 Surgeons 2 Specialist Tetraplegia OT’s Spinal Rehabilitation Physicians Spinal Physiotherapists and OT’s Neurologist Neuroscience technician (Histopathologist)

Where to start ?... The Team!

SCI Adults, C5-C7 motor level of injury Complete or incomplete Seeking surgical improvement of upper limb

function No head, BPI or PNI No pre-existing neurological condition Able to comply with therapy pre and post op

Patient Selection

Initial consult - 3/12 Routine motor and sensory examination Upper limb AROM and PROM Upper limb spasticity assessment Examination of all potential donor nerve

muscles FES of recipient nerve’s muscles

Clinical Assessment

Details of operation Hospital stay Immobilisation and upper limb therapy Time till first reinnervation expected Full maturity may take up to 12-18m Expected outcomes nerve vs tendon transfer Specific risks: motor or sensory disturbance,

failure of transfer Opportunity to meet previous patients

Consent

Measurement of pinch and grip strength- Modified pinch meter by Jaymar which allows testing of weak/little

strength

Action Research Arm Test

Grasp Release Test- A timed test of lateral pinch and grasp which records how many

objects can be picked up and released in a given time

Canadian Occupational Performance Measure

Spinal Cord Independence Measure

Baseline Outcome Measures

Donor Muscles Are they under voluntary control? Is there evidence of any denervation?

Recipient muscles Are they UMN or LMN denervated? Or a combination of both?

Electrodiagnostic Testing

Microscope/microsurgery instruments

Nerve stimulator -Biphasic nerve/muscle stimulator with a range of stimulation control (Checkpoint® Stimulator/Locator, Cleveland, OH, USA)

Intraoperative Motor Evoked Potentials -Using trained multi pulse trans-cranial electrical stimulation of the motor cortex

Surgery – Equipment Needs

Elbow Extension Teres Minor Triceps Nerve(s) (Bertelli, J. A., et al. (2011) J Neurosurg 114(5): 1457-1460)

Grasp Brachialis Anterior Interosseous Nerve (Gu, Y., et al. (2004). Microsurgery 24(5): 358-362)

Release Supinator Posterior Interosseous Nerve (Bertelli, J. A., et al. (2010). J Hand Surg Am 35(10): 1647-1651)

The Triple Nerve Transfer

Intra Operative Data Collection

Hospital stay 48hrs Plaster changed to thermoplastic forearm

splint and broad-arm sling Outpatient hand therapy begins

immediately Surgical review 3 monthly for first year,

then 6 monthly for second year Outcome assessments at 12,18 and 24m

Post operative Management

Phase 1 Protect the transferPhase 2 Activate donor & watch for flicker in recipient

musclePhase 3 Strengthen recipient musclePhase 4 Disassociate donor from recipient

Post Operative Rehabilitation

Data Collection

Relatively easy to expand the team & services needed

Learning curve: – Patient selection - Surgical techniques and timing of surgery - Utility of NCS/EMG and MEPs Development of protocols including: - Pre op clinical evaluation - Intra op data collection - Post op nerve transfer therapy - Timing of post op reviews/outcome assessments

Summary

Thank you