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					TARGETED MUSCLE
REINNERVATION
Nicholas Mulhern
10/9/12
BME 281
What is TMR
• Surgical Method for patients with upper extremity
  amputations
• Reassigns nerves that once controlled the hand and arm
• Enables patients the ability to control motorized
  prosthetics and regain sensory feedback
Historical Background
• First proposed in 1980 by Dr. Hoffer and Dr. Leob
  – Nerve-Muscle Grafting
• Developed in 1995 by Dr. Todd Kuiken and DR. Gregory
 Dumanian NWU
  – Hyper-reinnevation on animals
• TMR for artificial limb control
  – First Human work 2002
  – Bilateral shoulder disarticulation amputee
Nerves
Use the Brachial Plexus Nerve bundle


                               Allow EMG Signals to be
                               generated naturally by
                               transferred residual nerves

                                Allows for sensory feedback
                                to the brain (natural
                                connection)

                               Brachial Plexus nerves drive
                               all joint degrees of freedom
Surgical Procedure
• Pectoral Muscles chosen for innervation
  • Close to Shoulder
  • Biologically unused due to amputation
• First Muscles are denervation
  • Ligated Proximal end to prevent reinnervation
Musculocutaneous nerve  Clavicular head of the
Pectoralis major

Radial Nerve  Lower sternal end of the Pectoralis Major

Median Nerve  Upper Sternal of the Pectoralis Major
Surgical Procedure
• The pectoralis minor is translocated
  • From under the major to the chest wall
• Connect the Ulnar nerve
• Removal of subcutaneous fat
  • From over pectoral muscles to allow electrodes to be close to the
    muscles
Post Surgical Rehabilitation
Post Surgery
• 3 months  First muscle Twitches
   • Bending Phantom Elbow
• 5 Months Could contract all 4 pectoralis positions
  separately
• Placed in training for all 27 motions
• Use 128 monopolar electrodes to detect signal impulse
 Proportional Control
• Proportional EMG Control
  • 4 EMG signal controls for 4 motions
  • Elbow (Flexion/extension)
  • Hand(open/ close)
  • Allows 2 degrees of freedom
EMG recording and Proccesing
• Prosthetic control based on EMG from TMR muscles
  • EMG: Electromyography




Purple: Direct control site
Green: Electrode Placement



Most electrodes placed over
muscles reinnervated by the
median and radial nerves
Future Innovation
• Enhance the Signals recorded
  • Eliminate Crosstalk from other muscles
    • Create a more distinct signal during multiple contractions

• Incorporate a 6 motor prosthesis
   • TouchEMAS shoulder
   • a humeral rotator
   • Hand (Flex/ Exten)
• Improve TMR based NMI
   • Using more neural information
   • TMR uses nerves capable of controlling many muscles
Future Innovation




 Thumb abduction   Thumb Adduction   Wrist Supination
Advantages
• Attempt at Advanced motorized neural prosthetic control
    using natural EMG signals
•   Doesn’t require any implants, Biocompatible
•   Targeted muscle acts as a natural amplifier
•   Multiple EMG signals produced allowing separate
    functions controlled all at once
•   Intuitive to patients, based on nerves used
Sources
• http://en.wikipedia.org/wiki/Targeted_reinnervation
• http://informahealthcare.com/doi/abs/10.3109/030936404
  09167756
• http://jama.jamanetwork.com/article.aspx?articleid=18337
  1
• Department of BME URI, BME 468 Slideshow 11

				
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