Targeted Nerve Transfers ------- Targeted Muscle Re-innervation

1. Targeted Nerve Transfers -------Targeted Muscle Re-innervation Douglas G. Smith, MD Harborview Medical Center and the University of Washington

2. What are we here to talk about ? • A nerve that currently dead ends • (connects to the brain, but has no distal connection) • Transferred to the motor point of a muscle • (a muscle that had its motor nerve removed) • Hopefully the nerve grows into the muscle • (and finds new connection points and re-innervates) • Creates a Re-Wired Situation • (Muscle now connect to a different part of the brain)

3. What are we here to talk about ? • Why ?

4. Body Powered Prostheses • Refined in WWII • Moving shoulders forward pulls on a bicycle cable • Bicycle cable operates hook or hand and elbow.

5. Myoelectric Prostheses • When muscles contract, they generate electric signals call ‘myoelectric signals’ • Electrodes (or antenna) on the skin over muscles can pick up these signals. The signals are then used to tell a motorized arm what to do.

6. Below-Elbow Amputee • When the Brain says “close hand” the residual volar forearm muscle fires and creates ‘myoelectric signals’ • Electrodes on the skin pick up these muscle signals, close the prosthetic hand • A ‘normal’ interaction between the Brain and the Functional Outcome of Open Hand and Close Hand!

7. Trans-Humeral Amputee • Has Only 2 Normal Signals • Residual Biceps for Elbow Up • Residual Triceps for Elbow Down • When the Brain says ‘close hand’ or ‘open hand’ there are NO NORMAL ‘CLOSE OR OPEN THE HAND’ MUSLCES LEFT TO FIRE!

8. Trans-Humeral Amputee • Currently, We TRICK the System • By co-contracting, we have the arm ‘switch modes’ • Then, to close the hand, the person thinks ‘I have co-contracted to switch modes, now biceps will close the hand, and firing my triceps will open the hand. • This is NOT a normal Brain - Functional result loop.

9. Transhumeral Targeted Muscle Reinnervation • What if we could actually get 4 signals in the upper arm that worked normally with the proper brain thoughts. • Bend elbow • Extend elbow • Close hand • Open hand

10. Seattle Times August 2007

11. Seattle Times August 2007

12. Seattle Times August 2007

13. 4 Signal Prosthesis Control Two Normal Anatomic Signals: • Elbow Up - Musculocutaneous N to lateral biceps • Elbow Down - Proximal Radial N to triceps Two Newly Re-Wired Signals: • Close hand - Median N to medial biceps • Open hand - Distal Radial N to lateral triceps Allows Simultaneous Control of Elbow and Hand with Normal Brain Thoughts !!

14. Targeted Nerve Reinnervation also exists for the Shoulder Disarticulation

15. Nerve-Transfer Surgery Musculocutaneous n. Ulnar n. Median n. P. Minor muscle Radial n. P. Major muscle

16. Who Actually Came up with This Wonderful Idea ? Not Me !

17. Greg Dumanian Todd A. Kuiken, MD, PhD Neural Engineering Center for Artificial Limbs Rehabilitation Institute of Chicago Department of PM&R Who Started Doing the Surgeries: Gregory A. Dumanian, MD The Division of Plastic Surgery Northwestern University - Chicago

18. Jesse Sullivan • 54 yo lineman • May 2001 suffered 7,200 volt burns • Immediate bilateral shoulder disarticulation • Split-thickness skin grafts for closure of lateral chest wall wounds

19. How Did I Get Involved I have known Todd Kuiken for 16 years He started talking to me about this over 10 years ago Every trip to Chicago, he would patiently explain and re-explain. Finally I started to get it: THIS IS A BIG DEAL !

20. Note: This Surgery is not Experimental Nerve Transfers done since 1901 Existing history of putting N into a protected environment either in bone or muscle Difficulty with traditional ‘Dead End’ Nerve Non-physiologic state Neuroma formation There is no implant or internal device - no FDA

21. How did I actually start doing the surgery in Seattle

22. Seattle - September 7th, 2006 18 year old male, car accident and a traumatic right above-elbow amputation The day of injury - I was away in Chicago, and my partner did the initial open amputation I was asked me to do the definitive amputation I had just been explaining to a Madigan Army trauma fellow what the Chicago group has been doing with nerve transfers

23. September 7th, 2006 In the OR - the nerves had been left long I was explaining how the transfer would work - using the low bovie setting to test the distal muscle to find the point of maximal contraction, finding the distal motor point. Army doc - says so…., and then I said so… So …. we did our first transfers: Median N to distal biceps, and Radial N to brachialis Patient got Hand Open and Hand Close Signals

24. Current Seattle Experience Discuss with Patients and Families - when appropriate - talk about traditional nerve management - talk about evolving understanding of nerve transfers Discussed with my dean - this is not experimental - standard pre-op discussion and consent I have no formal research funding or protocol

25. Current Seattle Experience Which patients do I consider it reasonable: All new trans humeral patients All new shoulder disarticulation patients All major painful neuroma resection pts Established TH or SD to obtain new signals For a unique group of lower limb amputees

26. Seattle Experience 32 Patients have had Nerve Transfer Surgery to Muscle Motor Points 16 Upper Limb Amputees 15 Lower Limb Amputees 1 Non-Amputee

27. Seattle Experience: 16 Upper Limb 9 Patients: TMR done at time of initial definitive amputation 1 Elbow Disarticulation 6 Trans Humeral Amputations 2 Shoulder Disarticulation 5 Patients: TMR done as secondary procedure 2 Shoulder Disarticulation 3 Trans Humeral Amputation 2 Patents: Trans Radial with neuroma pain - surgery done to resect neuroma and implant N into muscle motor point

28. Seattle Experience: 14 Cases of Nerve Transfer for New Myoelectric Signals • 9/7/06 Traumatic AE • 12/21/06 Traumatic AE 1.5 years out • 12/29/06 Elbow Disarticulation for Infection • 1/19/07 Traumatic Modified Shoulder Disarticulation • 3/12/07 Traumatic AE • 5/31/07 Traumatic Shoulder Disarticulation 1 year out • 6/7/07 Traumatic AE • 2/4/08 Traumatic SD • 2/4/08 Definitive AE after necrotizing fasciitis open amp • 4/17/08 Traumatic SD • 7/24/08 Traumatic AE 1 yr out, Vancouver BC • 7/31/08 Traumatic SD 1.5 yr out, severe pain • 8/21/08 Traumatic SD • 5/21/09 Traumatic AE, 3 ys out, 80 yo, primarily for pain relief

29. Seattle Experience: 14 Cases of Nerve Transfer for New Myoelectric Signals 6 Using a Electronic arm and taking advantage of the TMR function to varying degrees. 2 Have signals - no approval for any prosthetic arm 1 Has signals - using body power, no approval for myo arm 1 Has signals learned to use loaner myo arm but -- jail, EtOH, no follow up 1 Has signals, IVDA, jail -- never got an arm 1 Necrotizing fasciitis, sepsis, severe brain ischemia • Revision SD with some pain relief, getting signals but died 3 months post-op from aspiration and cardiac arrest 1 Four months out, has pain relief, no signals yet

30. Clinical Reality What do I Think ? How do I explain this evolving management of nerve to patients and families ?

31. Thoughts I have been frustrated with traditional nerve management for quite some time. I feel bad for many of our patients with nerve pain.

32. Traditional Nerve Management Gently distract nerve, transect and allow it to retract to a more protected area. However: This leaves very abnormal physiology Dead end situation Axons sprouting to nowhere Scar formation Neuromas Has been standard of care for 100 years

33. Targeted Nerve Transfers • Transfer nerve to the motor point of a remaining muscle • Nerve grows into denervated muscle • Arborizes into the muscle (TMR) • Finds end organs • Reconnects to the brain • Remains physiologic

34. Thoughts I think this works ! Nerves remain physiologic New signals do develop Sensory and motor ingrowth I believe there is less pain

35. Thoughts BUT: It is Not Magic Patients still have some pain Some patients still have severe pain

36. Thoughts If patient having revision for neuroma: It makes sense Think of nerve management options Can we regain nerve physiology If arborizes into muscle, no neuroma

37. Thoughts If Done at Time of Definitive UL Amp: Nerve transfer done distally Signal location distal close to each other Co-contraction a much bigger problem Getting myo-prosthesis funded is not easy

38. My Conclusions It works It is primarily about Nerves Connects functional thoughts to new muscle signals Potential to restore upper limb function and improve prosthetic use

39. Robert Lipschutz Greg Dumanian Todd Kuiken Laura Miller Kathy Stubblefield Neural Engineering Center for Artificial Limbs RIC NWU Jon Sensinger Jesse Sullivan Richard Weir Ping Zhou

40. Thank You