Medications For Post-Amputation Pain

April 23, 2013
1:45 pm

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Medications For Post-Amputation Pain

04/16/2013 // Concord, CA, USA // LifeCare123 // Greg A. Vigna, M.D., J.D. // (press release)

Medical Perspective:

Chronic pain following an amputation is very common, occurring in nearly seventy-eighty percent of patients. This can be devastating to a patient who is faced with the physical, mental, social, and vocational loss following an upper or lower extremity amputation. Management of chronic pain in an amputation patient requires a knowledgeable physician who utilizes a multidisciplinary approach to the patient’s treatment, which may include anesthesia injections, implantable pain devices, physical therapy, psychological services, and pharmacologic management.

There are several medications that are useful in the management of post-amputation pain. Best practice pain management usually requires knowledge of the mechanism that generates the pain sensation; this allows clinicians to intervene with either local medications delivered by way of injections or oral medications that systemically act on the mechanism to decrease the generation of the pain. Unfortunately, post-amputation pain is poorly understood and is believed to have contribution from the peripheral nervous system, the spinal cord, and the brain. Because of this, from a clinical standpoint from my experience from providing amputee post-operative care for over 15 years, I do not break down the medications by how they affect the nervous system; I employ medications in a framework of acute, sub-acute versus chronic medication management.

Acute management of post-amputation pain involves the period from 24 hours pre-operative to fourteen days post-operative. During this time, I believe regional anesthesia versus epidural anesthesia is most important for adequate pain control. There is a suggestion in the literature that providing this type of care may decrease the risk and severity of post-operative chronic pain. During the 72 hours post-operatively, physical therapy must mobilize the patient, work on range of motion of residual joints, and promote early weight bearing with a total contact cast application on the stump. The physical therapy post-operatively is similar to treatment that is required following sympathetic blocks in the treatment of Reflex Sympathetic Dystrophy and this rapid mobilization may decrease the sympathetic component of pain. Mirror therapy is useful with essentially no downside and can be done both in the therapy gym as well as in the hospital room. Acutely, adequate narcotic pain management is essential. From my experience I believe it is best to utilize long acting narcotics such as Oxycontin or a duragesic patch, which should provide a baseline level of pain control. I don’t like my patients having significant peaks and valleys of severe pain from the use of short acting drugs. By providing longer acting agents, with an understanding that they will be weaned in the future, there is a significant increase in their activity tolerance in therapy and a decrease in levels of anxiety related to their anticipation of pain. Any significant anxiety regarding pain may increase the sympathetic component of pain which needs to be avoided. Side effects of narcotics include sedation, impaired cognition, urinary retention, and constipation. Patients should be prescribed a stool softener during this acute period. During this acute period, if a patient is having phantom pain at night which is preventing sleep, I like to prescribe Neurontin, a seizure drug that is used in neuropathic pain with a side effect of some sedation that is helpful in this context.

During the sub-acute period, two to eight weeks post-operation, the patient should be progressing in therapy while tapering the longer acting narcotics. Shorter acting narcotics or non-narcotic pain medicines such are Tylenol or Ultram should be considered. In patients who are having symptoms and signs of depression, antidepressants should be considered with an understanding that they will be continued for approximately three months post-operation. There are antidepressants that are used in pain management such as Effexor and Cymbalta that I will prescribe during this period. If phantom pain is a significant component of their pain, Neurontin or it close relative Lyrica, should be utilized on a scheduled basis. If despite the use of Neurontin and Lyrica a patient continues to have pain interfering with sleep, the patient may be placed on Elavil or Doxepin at night, which are effective in neuropathic pain with a useful side effect of sedation. During this time a patient needs to be fitted for a prosthetic and be proceeding with prosthetic training with continuing mirror therapy at home. In patients where there is a concern that there is a component of reflex sympathetic dystrophy, the clinician should consider sympathetic blocks with aggressive physical therapy.

After eight weeks it becomes pretty apparent which patients will have problematic pain that potentially limits their functional outcome. In these patients, it is important to refer them to a psychologist who is experienced in pain management and who can work on biofeedback and cognitive behavioral therapy used in the treatment chronic pain. Antidepressants that are effective in chronic pain should be considered. Lyrica or Neurontin should be considered since they are effective in both management of neuropathic pain and myofascial pain. The issue of chronic narcotic pain management will need to be formalized with the treating physician and the patient by way of a narcotic pain contract where the optimum dose of narcotic medicine should be titrated with a goal of optimizing function and decreasing side effects. In patients who have symptoms consistent with RSD, sympathetic blocks with aggressive physical therapy should be considered.

Life Care Planner Perspective:

A life care planner must consider all future care necessary and appropriate that is related to an amputation. Failure to provide for all future care will lead to an inadequate award and would not provide for all the necessary care. This would lead to depression, maladapted behaviors, complications, and poor functional outcomes. Included in this would be all necessary future care related to post-amputation pain. A life care planner must know all options, including physical therapy, exercise equipment, injection therapy, implantable devices, medications, laboratory tests, imaging studies, psychological services, physician needs, as well as the potential need for inpatient chronic pain management in the future. A life care planner should be familiar with all of the services required and anticipated in the future both by experience and by collaboration with the treating physicians.

Attorney Perspective:

A catastrophic injury attorney must prove to the jury all past and future medical costs that are directly related to the amputation. Future management of chronic pain related to post-amputation pain over the projected lifetime of the injured patient is typically a significant amount. Independent to these costs are pain and suffering which will be contained in any award for damages. Future planned treatment of a patient’s pain, as well as testimony by the patient, family members, friends and loved ones are the types of evidence that a jury would consider when awarding a significant pain and suffering award.