Chronic pain conditions caused by medical conditions such as cancer, chronic reflex sympathetic dystrophy, complex regional pain syndrome, and failed back syndrome impact your life. This impact takes you to the point where maintaining function becomes difficult. Traditional pain relief methods – surgical, psychological, physical, or pharmacological – have not helped to reduce the level of pain you have been living with.
What is Spinal Cord Stimulation and How Does it Work?
If you are an appropriate candidate, you undergo surgical implantation of a power source. A lead is attached via an extension wire. Depending on the complexity of the chronic pain, four to eight leads can be attached to extension wires and the power source. This is typically a battery or a radio frequency receiver. Chronic pain conditions usually require more complex stimulation.
Spinal cord stimulation is used to treat various types of chronic pain conditions. It is also used to manage critical limb ischemia and refractory chest pain. Medical professionals do not yet understand the neurophysiology of pain relief after you have begun using spinal cord stimulation. Two theories suggest that pain relief may come from the “activation of an inhibitory system” or through the blockage of facilitative circuits or nerves that transmit and facilitate chronic pain, according to the Blue Cross Blue Shield of Montana website.
Spinal Cord Stimulator Testing
When you undergo testing to determine if you are a suitable candidate for spinal cord stimulation, your doctor closely studies your pattern of pain distribution. This helps him decide where the stimulation lead should be placed. Once you have been found to be a suitable candidate for this type of pain therapy, you undergo two surgical procedures. The first is the implantation of an electrode into the epidural space. At this point, you go through a trial period of spinal cord stimulation to determine whether treatment will be effective. For this type of therapy to be considered effective, you must experience at least a 50 percent reduction in pain. Once this has been determined, you then proceed to the second stage of surgery. This involves the permanent implantation of the electrodes and the radio-receiver/transducer.
This type of therapy is considered a “therapy of last resort,” used only after other treatment methods have failed or if those methods are contraindicated for any reason. For you to be considered an appropriate candidate for spinal cord stimulation, your pain must be neuropathic. That is, you have suffered physical damage to the peripheral nerves in your body. Some of these types of pain can include phantom pain or stump pain, radiculopathies, or peripheral neuropathy. The types of pain this therapy will not affect include nerve irritation or nociceptive pain. Also, pain that is related to central nervous system damage or the result of a spinal cord injury or stroke.
Study Results
A pain relief study using spinal cord stimulation was conducted at the Maastricht University Hospital in Maastricht, the Netherlands. Dr. Marius A. Kemler et al. conducted the study with patients aged 18 to 65 years. These patients all met the diagnostic criteria for reflex sympathetic dystrophy as established by the International Association for the Study of Pain. Each patient suffered from impaired function, and symptoms ranged beyond the area of injury. Other requirements for enrollment in the study included disease and pain clinically restricted to one foot or hand. The pain lasted for at least six months. It did not respond well to standard therapy, including six months of physical therapy, transcutaneous electrical nerve stimulation, sympathetic blockade, or pain medications, according to Kemler et al.
Conditions that excluded patients from the study included a current or previous neurologic abnormality that was unrelated to the sympathetic dystrophy, Raynaud’s disease, a blood-clotting disorder or use of anticoagulant medication, a condition affecting the function of the diseased extremity, or the use of a cardiac pacemaker.
The Symptom Checklist
Each patient responded to a 90-item symptom checklist measuring levels of psychological distress. Scores nearing or reaching 450 showed the patient was in severe psychological distress. Those scoring 200 or higher undergo a full psychological examination. This is meant to rule out a major psychiatric disorder or substance abuse. As well as to look at any issues of a possible secondary gain from the treatment of an illness.
Patients who were selected underwent a test to determine if they would have a positive response to spinal cord stimulation. For those who had no response, no implant was scheduled. The patients selected for implantation received a prophylactic, intravenous dose of an antibiotic and were then placed in a prone position. Using direct fluoroscopy, the epidural space of the spinal cord was entered using a Tuohy needle. Depending on the limb affected, a temporary electrode was passed through the needle and implanted at the appropriate level for the limb. Generally, this meant the C4 epidural space was used for the electrode if the hand was involved.
Involvement of the Foot
If the foot was involved, the T12 epidural space was used. An external stimulator was connected to the electrode and then positioned so that the patient could stimulate it. Ideally, the patient would report pain relief over the entire area where he experienced his pain. When implantation was successful, the needle was removed and the electrode was stitched to the patient’s skin, then connected to the stimulator. The patient was required to undergo a seven-day home testing process while continuing their normal daily activities. After the seven-day trial period, surgeons removed the temporary lead. If the patient indicated a score of “at least” 6, indicating a “much improved” status on a seven-point scale, he underwent implantation of the spinal cord stimulator. In addition to spinal cord stimulation, each patient was also required to undergo standardized physical therapy twice per week for six months.
Blue Cross Blue Shield of Montana also reported that the American Society of Pain Physicians did an evidence-based review. They found that the evidence was strong for short-term pain relief. It was also found to be moderate for long-term pain relief in relation to complex regional pain syndrome (CRPS) or reflex sympathetic dystrophy (RSD).
Blue Cross Blue Shield of Montana: Spinal Cord Stimulation; The New England Journal of Medicine: Spinal Cord Stimulation in Patients with Chronic Reflex Sympathetic Dystrophy.