natasha van zyl mbchb, fracs plastic and reconstructive surgeon the upper limb program victorian...
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Introducing Nerve Transfers
for Upper Limb Reanimation in Tetraplegia
Natasha 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
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