2012 CRN - Acute Nerve Injury and Repair - Part 1- 010613

Sensory ETS Nerve Transfers

Ulnar Nerve Stimulation

Interfascicular Anatomy

Nerve Repair

Internal Topography

Interneural Plexus

Zone of Injury

Fascicular Pattern

Courtesy of A. Van Beek, MD

Nerve Injury

Nerve Axons

Scar Tissue

Poor Repair - Too Tight

Nerve Injury

Distance Time

Time Muscle

Muscle Function

Nerve Injury and Recovery

Neuron Cell Body (Gateway Arch)

Muscle

Anchorage, AK

St. Louis, MO

Classification of Nerve Injury

Correct Repair - Alignment

Classification of Nerve Injuries

IV

Microsurgical Technique

I

III

V

II

VI

Nerve Grafting

Credits

Andrew Yee, BS

Kawamura DH, et al. Regeneration through nerve isografts is independent of nerve geometry. J Reconstr Microsurg, 24:243-49, 2005.

Avoid Nerve Graft Tension

Good Example

Goal: Redundancy with No Tension

Peripherial Nerve Surgery Education

nervesurgery.wustl.edu

Surgical Video Library

https://vimeo.com/user6062882

Prezi Presentation

http://prezi.com/user/yeeandrew/

Bad Example

MABC Nerve Graft

Neuroma

A.

Nerve Grafting

Sural Cable Crafting

Deep Motor Branch of Ulnar Nerve

Reconstruction

B.

Obturator Motor Nerve Graft

Strategies for

Nerve Reconstruction

Histomorphometry

Graft Phenotype (Motor vs Sensory)

Sensory

Motor

Motor Cable Grafts

Sensory Cable Grafts

Non-critical Proximal Nerve Graft

Graft Material

C.

Distal End-to-side

Sensory Nerve Transfer

3rd Webspace Fascicle - Donor Nerve Graft

Median Nerve Reconstruction

Ross D, et al. Intraneural anatomy of the median nerve provides "third web space" donor nerve graft. J Reconstr Microsurg, 8:255-32, 1992.

Medial Antebrachial Cutaneous Nerve Graft

Distal End-to-side

Sensory Nerve Transfer

Part I - Peripheral Nerve Surgery

Alternatives to Sural Nerve Grafts

• Non-critical Proximal Injured Nerves
• 3rd webspace fascicle of median nerve
• dorsal cutaneous branch of ulnar nerve

• Medial Antebrachial Cutaneous Nerve

Acute Nerve Injury and Repair

Recovery of Donor Deficit

• Distal End-to-side Sensory Nerve Transfer

I, Susan E. Mackinnon, MD, am the co-inventor of the PGA Neurotube and have received research funding from AxoGen Inc.

NIH - 5R01 NS 033406-17

Nerve Allotransplantation for Traumatic Nerve Injury

Susan E. Mackinnon, MD

Plastic and Reconstructive Surgery

Washington University School of Medicine

St. Louis, MO

Comprehensive Review of Neurosurgery

Extender

Nerve Allograft

Nerve Allografts

Equals to autograft with immunosupression

Disadvantages

• requires systemic immunosuppression (~18 mths)
• vulnerable to opportunistic infections and tumors

Advantages

• temorary scaffold
• no donor site morbidity
• limitless donor nerve grafts
• significant segmental injuries
• FK506 promotes nerve regeneration

Nerve Allografts and Neuropathic Pain

Surgical Management of Neuropathic Pain

Nerve Allografts

Intercostal Neuropathy Post-Thoracotomy

Summary

Schwann Cell Migration

Allograft Loops

Reserved for patients with otherwise irreparable extensive peripheral nerve injuries

T8

Neuroma Pain

Proximal Transection

T5

T7

T6

T7 Allograft T8

T6

T5

T7

Coaptation Ends:

T8

T5 Allograft T6

Regenerative Fronts

Nerve Autograft

Proximal Transection of Intercostel Nerves

Nerve Allograft

T8

T7

A

Nerve Allografts

Spine

T6

T5

Proximal Ends:

B

Equals to autograft with immunosupression

C

Immunosuppression

D

Immunosuppression Withdrawal

E

Midha R, et al. Comparison of regeneration across nerve allografts with temporary or continuous cyclosporin A immunosupression. J Neurosurg, 78:90-100, 1993.

• zone of injury
• topography

• donor morbidity
• expendability

• antigenicity / immunosuppression

• length limitation <3cm
• no Schwann cells

• no extracellular matrix (ECM)
• $

Nerve Repair

Nerve Grafting

Nerve Allografts

Conduits

Acellularized Allografts

Nerve Transfers

End-to-side Nerve Transfers

Supercharge Nerve Transfers

• length limitation <5cm
• no Schwann cells

• ECM (superior regeneration)
• $$$

Conduit and Acellularized Allograft

• topography
• motor (sensory) re-education

Conduit

Matrix

Conduit

Schwann Cells and Matrix

Conduit

• sensory collateral sprouting
• motor requires neurectomy

Clinical

Research

Acellularized Allograft

Research

Acellularized Allograft

Schwann Cells

Autograft

Acellularized Allograft

Gold Standard

• enhances 2nd / 3rd degree injuries

Clinical

Research

Conduits < Allografts < Grafts

Good Results with Nerve Conduits

Clinical

Nerve Conduit Marketing

226 Digital Nerve Cases

18 Median / Ulnar Nerve Cases

Ulnar Nerve with Collagen Conduits (2x 6mm x 2cm)

Failed Case #4

Ulnar Nerve with Collagen Nerve Wrap (7mm x 2cm)

Failed Case #3

Acellularized Allografts

Failed Results with Nerve Conduits

Proximal

Clinical Utility - Small Diameter Non-critical Nerves

Ulnar Nerve with PGA Conduit (4mm x 2cm)

Failed Case #2

ANA Marketing

Distal

Conduit Volume

14mm Length Study

Median Nerve with Collagen Conduit (7mm x 2cm)

Failed Case #1

Collagen Conduit vs Acellularized Nerve Allograft (ANA)

FDA/CE Approved Nerve Conduits

• graft for non-critical sensation

• extender graft
• for proximal neuroma transposition
• for sensory ETS transfer to provide rudimentary sensation
• for sensory ETS transfer to recover donor nerve graft deficits

Time and Regenerative ANA Distance

28mm Length Study

Comparison of Grafts and Conduits

Moore AM, et al. Limitations of conduits in peripheral nerve repairs. Hand (NY). 4(2):180-6, 2009.

Histomorphometery

Meek MF, Coert JH. US food and drug adminstration/conformit Europe-approved absorbable nerve conduits for clinical repair of peripheral and cranial nerves. Ann Plast Surg. 60(1):110-6, 2008.

Regeneration Distance

Functional - Muscle Force

Architecture

6cm - 10weeks

Long Isograft Model

6 Weeks

Architecture

Graft

Whitlock EL, et al. Processed allografts and type 1 collagen conduits for repair of peripheral nerve gaps. Muscle and Nerve. 39:787-99, 2009.

22 Weeks

Non-critical Sensation

Long Acellularized Allograft

Extender

Moore AM, et al. Acellular nerve allografts in peripheral nerve regeneration: A comparative study. Muscle and Nerve. 44:221-34, 2011.

Proximal Neuroma Transposition

Extender Graft

ETS Sensory Transfer

End-to-end

Nerve Transfers

End-to-side

Supercharge

End-to-side

Regenerative Sprouting

Spontaneous Collateral Sprouting

C5,6 Nerve Palsy - 1st and 2nd Webspace Deficit

Rudimentary Sensation

3rd to 1st Sensory Nerve Transfer

Pain Management

Dorsi MJ, et al. The tibial neuroma transposition (TNT) model of neuroma pain and hyperalgesia. Pain. 138:320-334, 2009.

1. Neuroma Pain

Bridging the Gap

2. Hyperalgesia Pain

Surgical Management

Donor Deficit

Proximal Transposition

Proximal Transposition and ETS Nerve Transfer

Backfilling Donor Muscle

Motor ETS Nerve Transfers

Requirements: Proximal Crush and Neurectomy

Motor End-to-side Neurectomy

Anterior Approach - Spinal Accessory to Suprascapular ETS Nerve Transfer

Proximal Crush

2nd Degree Nerve Injury

Reinnervation - Backfilling

Post-operative Outcome

Ray WZ, et al. Functional recovery following an end to side neurorrhaphy of the accessory nerve to the suprascapular nerve: case report. Hand (NY). 5(3):313-7, 2010.