Phantom Limb Pain

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Phantom Limb Pain

• Vicky Sanderson, Katherine Stuth, Tony Nguyen

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Question

• Following traumatic amputation of a limb, within
  weeks or months many patients begin to report
  tingling, pins-and-needles, burning and stabbing
  pain that may never go away. Anesthetic blocks
  applied to the nerves that serve the stump do not
  eliminate the pain in most cases. Physical
  therapy techniques also rarely serve to
  significantly improve the pain, and therefore
  morphine-like drugs are often used in treatment-
  but these drugs aren't without side-effects.
  Recently, pain researchers have used calcitonin
  to modulate the transmission of pain impulses in
  the brain. Describe the current understanding of
  phantom limb pain (why it occurs), and how
  calcitonin may work to alleviate pain in these
  patients.

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What Is Phantom Limb Pain?

• Phantom limb pain (PLP) describes a wide range of
  sensations felt by amputees in what is perceived
  as the missing limb.
• Pins-and-needles, tingling, pressure, stabbing,
  and cramping among others.
• Pain is often localized and specific
• Pain almost always felt in distal part of missing
  limb
• Affects 50-80 amputees

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PLP contd

• Phantom limb is often shorter than the real limb.
  
• Amputees may feel as if they are able to wiggle
  their toes or count on their fingers.
• New amputees suffer from PLP as frequently as
  every day for multiple hours, however it
  generally becomes less frequent and intense over
  time.
• In most cases PLP will never fully go away.
• Usually the onset of PLP will occur in the first
  few days. (75)

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What Causes PLP?

• Peripheral N.S.
• Ectopic discharges perceived as pain below level
  of amputation
• Neuromas?
• Central N.S.
• Increased excitability of neurons in dorsal horn
  and decreased inhibitory process
• Changes in brainstem, thalamus, and cortex

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Other PLP Influences

• Use of prosthetic limb
• Weather changes
• Fatigue
• Sleeplessness
• Anxiety
• Pain or stimulation from other body parts

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Treatments

• Farabloc
• Electrodes in thalamus
• or spinal cord
• Acupuncture
• Physical Therapy
• Antiseizure and antidepressant drugs
• Local anesthetics
• Other substances such as calcitonin, baclofen,
  and Opioids

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Calcitonin

• In the 1980s there was a double blind study on 21
  patients with severe PLP after lower limb
  amputation, in which the use of salmon calcitonin
  (s-Ct) versus saline as treatment was examined.
• 76 of patients reported no pain after one week.
• After 2 years, 71 had no reports of PLP, however
  this did include the 38 who had died during that
  time.
• Possible side effects include nausea (28),
  vomiting (24) and temporary enhancement of PLP
  (20).

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How s-Ct Works

• Calcitonin is used in the early post-operative
  period when patients have experienced immediate
  severe PLP.
• The exact mechanism of how s-Ct works is unknown
  however one theory is that it amplifies serotonin
  activity.
• Evidence comes from s-Ct binding sites in
  serotonin rich regions of the brain including the
  hypothalamus and limbic system. Also, serotonin
  antagonists have been found to reverse the
  analgesic effects of s-Ct.

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Analogy

• Ants
• PLP works similarly to a line of ants, as the
  ants continue marching it signifies transduction
  of the nerves. But when a rock blocks the path of
  the ants (the severing of a limb), the ants find
  a detour to get back on path (nerves firing
  without a limb).

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References

• Doctors Guide. 1998. New Piece to Puzzle In
  Phantom Pain Mystery. http//www.pslgroup.com/dg/5
  1982.htm
• Durham, Janelle. 2004. Phantom Pain.
  http//www.dallasamputeenetwork.org
• Farabloc Development Corporation. Amputees.
  http//www.farabloc.com/amputee.html
• Sidebotham, Payne, Shug. 1996. Calcitonin and
  Ketamine. Australian Anesthesia.
• King, Steven A. M.D. M.S. 2006. Exploring Phantom
  Limb Pain
• http//www.psychiatrictimes.com/
• And a special thanks to Janice for letting us go
  today and not Wednesday, sorry group 3.