Phantom Limb Pain
What is phantom limb pain?
Phantom limb pain is the sensation that a person has when a body part or limb has been amputated, but it still feels as if it is attached. Many amputees have phantom sensations that are not painful. It is estimated that 85% of people experience phantom limb sensations in the first several weeks following amputation; however, a smaller population of people will continue to feel these sensation for prolonged periods of time. It is reported that 60% of people will continue to experience sensations one year after surgery.
What causes phantom limb pain?
A number of other factors are believed to contribute to phantom limb pain, including damaged nerve endings, scar tissue at the amputation site, and the physical memory of pre-amputation pain in the affected area.
While the exact cause of phantom pain is unclear, it appears to originate in the spinal cord and brain. Many experts believe phantom pain may be at least partially explained as a response to mixed signals from the brain.
Some patients have severe, painful debilitating phantom limb sensations. Some of the sensations a patient may feel include tingling, numbness, hot or cold, cramping, stabbing, and burning. The most common sensation that patients continue to feel is pain in the missing limb. These painful sensations can often diminish over time, but some people suffer from long-term pain that can be difficult to treat.
Some treatments for phantom limb pain include the following:
Studies have shown that tricyclic antidepressants, sodium channel blockers, and anticonvulsant medications can be useful in neuropathic pain conditions like phantom limb pain. Currently, gabapentin is the most commonly used medication for phantom limb pain.
Many studies have shown that oral opioid medications are not effective at treating neuropathic pain. However, a study by Omote, et al (1995) showed that intrathecal administration of buprenorphine was very effective in many patients and provided them with a prolonged resolution of their phantom limb symptoms.
Desensitization therapies along with sympathetic nerve blocks may provide relief for patients who have sympathetically mediated pain. Proper fit of any prosthetic is also important in decreasing pain for many who suffer from phantom limb pain.
One of the more promising treatments for phantom limb pain is mirror therapy. Mirror therapy involves the use of a mirrored box with two openings: one for the amputated limb and one for the other limb. The patient then performs isometric exercises with the non-amputated limb, so it appears as though the amputated limb is moving as well. In a randomized controlled study by Chan, et al. (2007), it was found that the patients who had the mirror therapy for four weeks experienced a significant reduction in pain.
Injection therapy such as interscalene blocks or stellate ganglion blocks for upper extremity phantom limb pain or lumbar sympathetic blocks for lower extremity phantom limb pain can also be beneficial. Neuroma injections can also be beneficial for those who suffer from extremity neuromas. These blocks are often combined with physical therapy.
Neuromodulation by way of transcutaneous electrical nerve stimulation (TENS) or spinal cord stimulation offers significant relief to many patients who have not had success with other treatment options.
Spinal cord stimulation (SCS) is often described as a “pacemaker for pain” and uses groundbreaking technology that works by introducing an electrical current into the epidural space near the source of chronic pain impulses. Under a local anesthetic and minimal sedation, your doctor will first place the trial SCS leads into the epidural space. The SCS lead is a soft, thin wire with electrical leads on its tip that is placed through a needle in the back into the epidural space. The trial stimulator is typically worn for five to seven days as the lead is taped to your back and connected to a stimulating device. If the trial successfully relieves your pain, you can decide to undergo a permanent SCS if desired.
Various treatments are available for phantom limb pain.