Phantom limbs are the human perception of limbs that are absent in the human body. This can occur through the removal of a limb, being born missing limb/s, or through severance of the spinal cord. The perception of pain in phantom limbs is commonly reported (Melzack 1992). Among patients, there is variation in the pain reported in regard to severity and duration (Woodhouse 2005). There have been many forms physiological and psychological intervention in treating phantom pain but there has been little prolonged success in treatment (Melzack 1992). The frequency with which phantom pain is reported is alone enough of a justification for the need in researching for successful, prolonged treatment of phantom limb pain.
The amputation of limbs in human beings is hardly a modern technique in surgery. There have been many well documented cases in history that date back hundreds of years expressing the amputation of limbs in human beings. However, the concept of amputees experiencing sensations and perceptions in phantom limbs is a relatively new and accepted belief. The development of this belief has origins from the Civil War between the United States of America and the Confederate States of America.
There have been many bloody, malicious wars throughout our nation's history. During the time period of the Civil War (1861-1865), medical and surgical techniques were still relatively primitive. In order to minimize the amount of casualties, on either side of the war, field surgeons would use tourniquets and amputations in order to prevent the loss of life. Such surgical intervention was used for soldiers that sustained injuries where their limbs were not reparable or salvageable. Preventing the spread of gangrene provided incentive to resort to such drastic surgical intervention.
Shortly after the Civil War, a physician became aware of many amputees expressing the sensations in their amputated limbs. This physician was Silas Weir Mitchell, who created the term phantom limb (Woodhouse 2005). Amputations were used frequently during the Civil War. Veterans that had received amputations were frequently reporting sensations in their absent limbs through many different manifestations such as itching, burning, and aching (Hicks 2009). Current estimations suggest that as many as 80% of amputation patients have phantom limb experiences (Schneider, Hoffmann, Rost, & Shapiro 2008). What is considerably shocking is that 60-80% of amputee patients experience pain in their phantom limbs (Woodhouse 2005). Before proceeding any further, it is necessary to address what exactly a phantom limb is defined as along with the definition of phantom pain.
For individuals that have a fully intact body, it is hard to grasp what exactly a phantom limb is. A phantom limb is the perception of a missing or paralyzed limb that may be capable of imaginary movement and sensation. Phantom pain can be defined as intense phantom sensations experienced as painful (Borsje, Bosmans, Van der Schans, Geertzen, & Dijkstra 2004). Phantom sensations and phantom pain are common occurrences in these invisible body parts. The pain experienced can range from being occasional and mild to continuous and severe (Melzack 1992). For many years, patients who described these symptoms to doctors were believed to be crazed; suffering from the fact that they had lost, and would never recover a body part (Ramachandran & Blakeslee 1999).
Pressing on, a more abstract concept to grasp is the perception of pain in a phantom limb. How could one possibly perceive pain in a body part that is non-existent? There are three generally accepted explanations for this phenomenon; however, not one explanation can be applied to every phantom pain experience. One explanation is the peripheral theory (Woodhouse 2005). This theory proposes nerves remaining in the stump, at the end of an amputated limb, grow at the point of amputation into nodules that never cease to generate impulses; even in the absence of a limb (Melzack 1992). Another theory, the central theory, renounces the peripheral theory (Woodhouse 2005). The central theory holds that phantom pain is due to excessive, spontaneous firing of nerves in the spinal cord that have lost input from afferent neurons (Melzack 1992). Another theory refutes both the central and peripheral theories. The supraspinal theory maintains that stimulation of the thalamus elicits phantom limb sensations and pain (Woodhouse 2005).
Aside from the three theories that potentially explain the origins of phantom limbs, new studies suggest that there is a far more complex process occurring in the brain. New evidence shows that remapping in the brain takes place following the amputation could very well be the origin of phantom limb pain (Ramachandran & Blakeslee 1999). Several research groups have demonstrated remapping in human upper limb amputees. One group uncovered that afferent signals received from the face activated the hand area (Woodhouse 2005). Melzack proposed a theory regarding the origins of phantom limbs. He proposed that the brain includes a network of neurons that not only respond to afferent signals but also generate continuous neural signals that the body is indeed one's own (Melzack 1992). This is the theory of a neuromatrix. Melzack (1992) goes on further to say that he believes that this matrix is prewired in us prior to birth.
Sufficient evidence has shown that amputee individuals can experience pain in their phantom limbs. Thus far only individuals that have had amputations are discussed as experiencing phantom limbs. In spite of this, one does not have to be an amputee in order to have phantom limbs and phantom limb pain. Some paraplegics have experience phantom pain in limbs or body parts that are present, but paralyzed (Melzack 1992). Many physicians have had patients who were born without limbs, yet still experienced phantom sensations (Melzack 1992). How is this possible? To experience phantom sensations in limbs that never existed. This fortifies Melzack's theory in that some neural circuitry of the brain is developed independent of motor or tactile experience; that is, our body image is prewired (Melzack 1992).
The phenomenon of experiencing pain in a non-existent limb is a difficult concept to grasp. Regardless of this, the pain is clearly being perceived by many individuals with phantom limbs; approximately 60-80% (Woodhouse 2005). One research study suggests that several predispositions for phantom pain exist. Several of these predispositions are gender, location of the phantom limb, reason for amputation, and the level of amputation (Borsje et al. 2004). Such a great proportion of individuals reporting phantom limb pain had led to numerous treatments, many of which were and are trial-based.
Treatments have varied in practice from psychological to physiological. Both approaches in treatment have yielded mixed results. Several physiological techniques that have been implemented are the use of local anesthesia, dorsal root lesions, cordotomy, the removal of neuromas, and the use of pharmaceuticals (Schneider et al. 2008). In spite of this, the complete elimination of phantom pain is only moderate at best (Schneider et al. 2008). Only half of individuals that have received treatment for long-term phantom pain respond to any approach of therapy. Similar results have been collected in placebo studies (Schneider et al. 2008). Several psychological treatments have been used. They are hypnosis, relaxation, the use of mirror boxes, and more. Results using psychological intervention have also yielded mixed results (Melzack 1992). Recently, one new form of psychological treatment has, thus far, yielded promising results. This treatment is called eye movement desensitization and reprocessing (EMDR) (Schneider et al. 2008). In five different patients, Schneider (et al. 2008) report that the use of EMDR led to the complete elimination of pain in two individuals and the diminishing of pain in three individuals.
There is substantial evidence to confirm that individuals experiencing phantom limbs may very well experience pain in their phantom limb(s). If there is any distinction to note here it is that the pain that an individual experiences in a phantom limb may vary from minor to severe and in duration ranging from seconds to hours (Woodhouse 2005). Borsje (et al. 2004) noted that it is common for phantom limb pain to occur after amputation; however amputation is not necessary for one to experience phantom limb pain. Phantom limb pain can occur in individuals that are born missing limbs and in paraplegics (Melzack 1992). The fact that individuals can have phantom limb pain in limbs that never existed fortifies Melzack's theory of the neuromatrix.
Phantom limb pain is often reported by individuals with phantom limbs; upwards of 70% (Melzack 1992). Many physiological and psychological methods have been implemented in the treatment of phantom limb pain. In spite of this, few methods have shown prolonged success in treatment. In fact, many physiological methods of intervention only show alleviation in pain for only months and years (Melzack 1992). The treatment of those experiencing phantom pain is imperative but so is the initiation of research for new methods to treat phantom limb pain. The lack of success in the treatment of phantom limb pain is a calling for the undertaking of further research in the treatment of phantom pain. Which theory or method of pain management do you think is best? Why?
Jake, So far everything looks very good. The only thing I would add in would be your opinion on which theory or pain management method is best at this point in time.
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Borsje, S., Bosmans, J.C., Van der Schans, C.P., Geertzen, J.H.B., Dijkstra, P.U. Phantom pain: A sensitivity analysis. (2004). Disability and Rehabilitation. 26 (14). 905-910.
Schneider, J., Hoffmann, A., Rost, C., Shapiro, F. EMDR in the treatment of chronic phantom limb pain. (2008). Pain Medicine. 9 (1). 76-82.
Hicks, J. On phantom nations. (2009). Massachusetts Review. 50 (4). 479-495.
Melzack, R. Phantom limbs. (1992). Scientific American. 266 (4). 84-91.
Ramachandran, V.S., & Blakeslee, S. (1999). Phantoms in the brain: probing the mysteries of the human mind. New York: Harper Perennial.