TABLE OF CONTENTS
Chronic pain is defined as pain that persists beyond the normal recovery period or pain that is paired with a chronic health condition. The pathology of chronic pain is extremely varied; the variables involved include, but are not limited to: medical history of injury, infection, disorders, or disease, including arthritis and cancer.
There exists a difficulty in discussing chronic pain because, as mentioned above, there exists an extreme variety of pathologies. A few examples are listed below.
Many times, chronic pain has no apparent cause, or the pain could have originated with a clear physical cause, but over time, the cause transferred basis from physical to psychological.
As of today, DBS has most successfully treated chronic back pain, especially from failed back surgery; it has also been used or can be used to treat leg pain, facial pain, phantom limb pain, stroke pain, or headaches. DBS works by stimulating the area of the brain that has the pain sensors, but it is unknown how it works to decrease the symptoms of pain.
DBS is, as of yet, not approved by the FDA. However, there have been two targets identified that, when stimulated, have decreased pain in chronic pain patients. These two targets are the somatosensory thalamus and the periventricular gray region. There are a myriad of studies available that show DBS’s success in treating chronic pain with these two targets, and those detailed in “Successes and Adverse Events” are a small selection.
Because the pathology of chronic pain is so varied, no one treatment will treat all manifestations of chronic pain. Thus, depending on the pathology of a patient’s chronic pain, one or more of these treatments should be explored.
1. Over-the-counter pharmaceuticals that contain ibuprofen, acetaminophen, or aspirin are generally a safe way to treat pain if no more than the recommended dose is taken.
2. NSAIDs can be used, but if they are used with regularity or on a daily basis, the risk of GI bleeding is significant.
3. Narcotics can be used, but addiction is possible and the side effects are more acute than with over the counter pharmaceuticals. Short acting narcotics should be avoided; long-acting opioids have fewer side effects and control the chronic pain more adequately.
5. Physical therapy can help to reduce pain in certain cases.
6. Spinal cord stimulation can be used to interfere with the pain as it travels up the spinal cord from the abdomen, back, or lower extremities.7. Other treatments that include injections (such as Cortizone) and radiation treatments are available, and some general information about these treatments can be found here.
Many of the treatments for pain will merely decrease the intensity or incidences of pain. DBS offers a more permanent but reversible solution to the problem of chronic pain. The risks associated with brain surgery and DBS in particular must be weighed against the other therapy options, particularly the risks of sustained intake of pain medication, for each individual patient and case.
It is difficult to conduct a therapy analysis of DBS verses other treatments in treating chronic pain because of the highly varied pathologies. DBS should be discussed by each patient with his or her physician, and DBS may be applicable as a form of treatment on a case by case basis.
Evidence exists from many studies that DBS can be used to effectively treat chronic pain, including, but not limited to, the following studies.
In a randomized, double-blind study conducted by Drs. Rasche, Rinaldi, Young, and Tronnier, 56 patients were assigned to DBS of the somatosensory thalamus or DBS of the periventricular gray regionor of DBS of a combination of both regions. “The best long-term results were attained in patients with chronic low-back and leg pain, for example, in so-called failed–back surgery syndrome. Patients with neuropathic pain of peripheral origin (such as complex regional pain syndrome Type II) also responded well to DBS. Disappointing results were documented in patients with central pain syndromes, such as pain due to spinal cord injury and poststroke pain.” (Rasche, et al.)
Another study entitled "Activation of the Anterior Cingulate Cortex by Thalamic Stimulation in Patients With Chronic Pain: A Positron Emission Tomography Study" had success with DBS of the somatosensory thalamus can be found
A third study conducted by scientists at the Australasian Movement Disorder and Pain Surgery (AMPS) Clinic also had positive results in relief of chronic pain by stimulated patients’ periventricular gray region and/or their somatosensory thalamus. “The rate of long-term pain alleviation was highest in those patients undergoing DBS of the periventricular gray region plus sensory thalamus 87 percent. A long-term success rate of more than 80 percent was attained in patients with intractable low back pain and failed back surgery syndrome that underwent successful trial stimulation and proceeded to permanent implantation. Trial stimulation was successful in approximately 50 percent of patients with post-stroke pain, and 58 percent of patients with permanent implantation achieved ongoing pain relief. Moderately higher rates of success were seen in patients with phantom limb pain and radiculopathies.” (www.spineuniverse.com)
Australasian Movement Disorder and Pain Surgery (AMPS) Clinic
Medical Research Council - (UK)
Cleveland Clinic - Center for Neurological Restoration