Targeted Reinnervation

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Targeted Reinnervation
Ryan_dolan_at_my.uri.edu

• In Upper-Limb Prostheses

Ryan Dolan, BME 281, Section 02
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Problems with Upper-Limb Prosthetics

• Patients missing an upper-limb struggle everyday
  to overcome the challenges of completing simple
  daily tasks
• Amputees also suffer emotional and social
  disadvantages, and miss out on many things that
  non-amputees take for granted.
• Existing prosthetic options available for
  upper-limb amputees (mainly shoulder
  disarticulation amputees) can not provide
  cutaneous feedback to a prosthetic device to
  provide sensation to the missing limb
• Shoulder disarticulation amputees are limited in
  the choices of prosthetic arms by inadequate
  control methods

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Goals of Targeted Reinnervation

• Targeted Muscular Reinnervation TMR
• To reroute 4 upper-arm nerves to the pectoral
  muscles of the chest in order to provide
  intuitive control of a prosthetic device
• Targeted Sensory Reinnervation TSR
• Reroute sensory nerves along with the upper arm
  nerves of TMR that provide cutaneous sensory
  feedback in order to provide sensation to
  upper-limp amputees using a prosthetic arm
  capable of interpreting the sensory information
  and sending the information back to the sensory
  nerves

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Process of Targeted Muscular Reinnervation

• Phase I Viability Review
• Medical records and examinations to determine
  candidate viability
• Phase II Financial and Medical Clearance
• Insurance approval, then you determine if you go
  forward based on whether or not you can afford it
• Takes 2 weeks to 6 months depending on your
  insurance
• Phase III Surgery and Muscle Reinnervation
• Scheduled 6 weeks after final decision is made
• Two day hospital stay
• Wait 5-6 months for nerves to regrow
• Return for evaluation of nerve growth
• Phase IV Device Fitting and training
• Custom arm built to fit body type/nervous system
  profile (includes several fittings, physical
  therapy, and training sessions
• 2-3 two-week visits spread across a two month
  period on average

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Process of Targeted Muscular Reinnervation

• Phase I Viability Review
• Medical records and examinations to determine
  candidate viability
• Phase II Financial and Medical Clearance
• Insurance approval, then you determine if you go
  forward based on whether or not you can afford it
• Takes 2 weeks to 6 months depending on your
  insurance
• Phase III Surgery and Muscle Reinnervation
• Scheduled 6 weeks after final decision is made
• Two day hospital stay
• Wait 5-6 months for nerves to regrow
• Return for evaluation of nerve growth
• Phase IV Device Fitting and training
• Custom arm built to fit body type/nervous system
  profile (includes several fittings, physical
  therapy, and training sessions
• 2-3 two-week visits spread across a two month
  period on average

6
Qualifications for Procedure

• The ideal candidate
• Will have an (above the elbow) or a (shoulder
  disarticulation) amputation within the last 5
  years (sometimes 10 years can work)
• At least 14 years old
• Meet minimum weight requirement
• Those suffering from nerve degeneration and or
  nerve damage, or those born without an arm are
  not ideal candidates for this procedure

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How It Works

• When you lose your arm neural signals still
  exist, so in theory if you could somehow obtain
  the signal from the brain and send it to a
  prosthetic arm you could intuitively control the
  device
• Obtaining this neural information directly from
  the brain is extremely complex and involves 100s
  of wires and microscopic electrical devices, as
  well as an invasive surgery
• Instead the idea is to reroute the nerves from
  the brachial plexus (4 total) and implant them
  into the pectoral muscles of the chest
• Using surface electrodes you can then obtain the
  neural command to move the arm and apply pattern
  recognition techniques before sending the command
  to the prosthetic
• Targeted Sensory Reinnervation reroutes sensory
  nerves as well in order to provide cutaneous
  sensory feedback in order for the amputee to feel
  the sensations he/she once felt in their arm
• Sensors in the hand of the prosthetic send the
  signal to the rerouted nerves in order to
  simulate the stimulus the prosthetic is sensing

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Jesse Sullivan

• 54 year-old lineman (touched the wrong wire)
• Suffered 7200 volt burns
• Immediate bilateral shoulder disarticulation
• Study Box and Block Test w/ Jesse Sullivan
  (2003)
• Underwent Targeted Muscle Reinervation
• He used his original prosthetic for 20 months,
  and the nerve-transfer prosthetic for about 2
  months (same physical arm, different programming)
• Take a block from one box and place it in the
  other, over and over.
• TMR results were significantly higher than the
  pre-surgery results (by about 72 on average)
• Opened the door to further Targeted Sensory
  Reinnervation research

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Prosthetic Training

• In order to fully utilize all of the technologies
  capabilities a training period is necesarry
• There is a small micro-controller operating the
  prosthetic by both receiving and interpreting
  command signal inputs, and then sending the
  revised or edited signal to the prosthetic to
  carry out its intended command
• Use to take about 4-6 hours to train when
  tethered to a program on a computer
• With the microcontroller included in the
  prosthetic it only takes a few minutes to train
  depending on how much time you want to spend on
  perfecting the control of the arm

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Cost Factors

• Since Targeted Reinnervation, both muscular and
  sensory, are tailored specifically for an
  individuals needs it is almost impossible to
  estimate the cost of the procedure, hospital
  stays, physical therapy, and the prosthetic
  itself.
• 8 hour surgery
• Follow-up examinations and therapy
• Prosthetic Fittings
• Additional expenses e.g. travel expenses,
  training expenses, etc

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Future

• One of the main issues with Targeted
  Reinnervation is that there is not enough real
  estate in the pectoral muscles to provide
  locations where sensors, electrodes, wires, and
  other miscellaneous electronics can do carry out
  their intended functions
• Design very small capsules
• Insert the capsules in the targeted muscle
• Much more room for electronics such as
• motors and electrodes
• The now cleared up real estate of the targeted
  muscle can house many different sensors (EMG,
  etc) that can extract valuable information from
  the nerve signals

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References

• Video Todd Kuiken Prosthetic Arm that Connects
  with the Human Nervous System. July 2011,
  Edinburgh, Scotland. lthhtp//www.ted.com/talks/tod
  d_kuiken_a_prosthetic_arm_that_feelst-5440gt
• Center for Bionic Research RIC Multiple
  Summaries of Research. http//www.ric.org/research
  /centers/bionic-medicine/research/
• Targeted Muscle Reinnervation RIC Phases of
  Procedure. http//www.ric.org/conditions/prostheti
  cs-orthotics/bionic/
• OttoBock Prosthetic Arm through Targeted
  Reinnervation. Vienna, Austria.
  http//www.ottobock.com/cps/rde/xbcr/ob_es_es/646D
  385-GB-03-1006w.pdf
• Control of a six degree of freedom prosthetic arm
  after targeted muscle reinnervation surgery
  Miller, Lipschutz http//www.archives-pmr.org/art
  icle/S0003-9993(08)00795-8/abstract
• Oxford Journals. Robotic touch shifts perception
  of embodiment to a prosthesis in targeted
  reinnervation amputees. http//brain.oxfordjournal
  s.org/content/134/3/747.short
• Redirection of cutaneous sensation from the hand
  to the chest skin of human amputees with targeted
  reinnervation. Todd A. Kuiken. lthttp//www.pnas.or
  g/content/104/50/20061.shortgt