Phantom Limb Pain

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Phantom Limb Pain

• Jake, Nikki, Jacob Ryan

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Overview

• Following traumatic amputation of a limb, many
  patients report feeling tingling,
  pins-and-needles, burning, and stabbing pain
  where their limb used to be
• A common description of the pain is of a limb
  being in a hyperextended or unnatural posture
• Phantom pain often resembles the type of pain
  experienced before amputation
• 4 out of 5 people who lose limbs suffer from
  Phantom Limb Pain
• Anesthetic blocks applied to the nerves at the
  stump have failed to eliminate this pain in some
  individuals
• Physical Therapy techniques rarely help
• Many resort to morphine-like drugs

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Causes of Phantom Limb Pain

• Unknown
• Origin in brain or spinal cord?
• Peripheral Nervous System Theory
• Severed nerves send occasional pain messages back
  to the brain
• Neuromas non-cancerous tumors that grow out of
  injured nerve fibers that continue to give off
  pain impulses
• Central Nervous System Theory
• Non-functional sensory cortex becomes overpowered
  by functional areas of the brain

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Peripheral Theory
When the neurolemmal tube is destroyed, the
nerve begins to branch back out into the
injured area resulting in random firing in the
sensory neuron.
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Central Nervous System Theory

• Following loss of a limb, the brain tries to
  makeup for the loss of sensory input by rewiring
  its circuitry.
• Cortical remapping
• Example phantom pain sufferers feel an increase
  in their phantom arm pain by touching part of
  their face on the same side of the body.

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Current Treatment Options

• Anesthetic applied prior to surgical amputation
  and for an extended period after surgery
• reduce incidence of phantom pain
• helps with the psychological effects of pain
• Antidepressants
• increase descending pre-synaptic inhibition of
  the pain pathway
• Morphine (opiates) used to relieve pain
• Massage, Acupuncture, Heat Therapies
• Surgeries to remove scar tissue and neuromas
• The best results are from combined treatments

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Experimental Treatments

• Calcitonin
• Calcitonin (Miacalcin). Intravenous infusions of
  calcitonin during the week after amputation can
  reduce phantom limb pain.
• Researchers aren't certain why it provides pain
  relief.
• Evidence shows increased serotonin activity in
  the brain
• Calcitonin binding sites found in areas of the
  brain rich in serotonin such as the hypothalamus
  and limbic system

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Experimental Treatments, cont.

• Controlling Dorsal Horn Sensitization
• Hours after an injury, changes take place in the
  dorsal horn of the spinal cord that alter the way
  sensory impulses are processed. Now sensory and
  painful signals are more likely to be transmitted
  up the spinal cord to the brain instead of being
  blocked in the spinal cord.
• Sensitization is dependent on an NMDA receptor
  activation. Antagonist blockers like Ketamine (a
  dissociative) prevent sensitization from
  occurring.

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Analogy
The Peripheral Theory The Neurolemmal tube acts
like a maze because the nerve is trying to find
its original pathway but gets lost and begins to
spread out in all directions

• The Central Theory
• A plant dies and the surrounding plants grow
  over that area and take in the nutrients that the
  dead plant once received.