Medicine is evolving as electronic technology invades all aspects of medical care, and pain management is no exception. The areas that have changed the most are imaging technology and implantable devices. What is interesting to patients is how imaging can improve care and implantable devices may help when nothing else is working. The improved imaging makes diagnostic and treatment decisions easier and also makes interventions more precise when tied to management by an astute clinician. No matter how good the technology is, without the skill of a good clinician to understand the medical problem, no solution would be helpful.
The new implantable technology available is peripheral nerve stimulation. This is designed for treatment of pain that is related to damage to a peripheral nerve, such as in the arm or leg. Pain can often be traced to an isolated nerve and preventing that nerve from propagating the pain signals helps to control the problem. These pain issues arise sometimes after amputations with phantom pains, and can be seen after trauma when nerves are damaged. These problems can also occur with surgeries like joint replacements, orthopedic interventions, spinal operations and some fractures. When the pain is not resolving and an isolated set of nerves can be found and successfully blocked with local anesthetic, then nerve stimulation may be appropriate. This is a treatment to consider when simpler interventions like medications, physical therapy, and injections have not been successful.
Nerve Stimulation For Pain Management
The idea of peripheral stimulation has been around for a long time. In the distant past, traditional spinal cord stimulators were used for peripheral nerve stimulation. Unfortunately, at some point this began being abused and since those systems were extremely expensive, this process stopped. In the last two years, new systems have been designed specifically for peripheral nerve stimulation that are very technologically advanced and effective.
One example is electrode stimulation. The electrode is a very thin wire coated in silicone that can be delivered to the right place along the specific nerve with a needle guided by ultrasound imaging. The wire contains a special signal receiver that can be used to help stimulate the nerve and drown out pain signals. Most importantly, the signal generator is now a very small rechargeable unit that is placed on the skin over the end of the electrode. In the near future the electrode may connect even further from the generator such that it may be able to be carried in a pocket or other safe place.
The new technology is FDA approved for peripheral nerve pain from any type of nerve injury. The easiest insurance approval is Medicare, but other providers are starting to approve of such treatments when proven simpler treatments have failed. There currently are at least two manufacturers of equipment, the difference appears to be mainly in the generator’s ability to deliver a variety of signals that may effectively block pain signals and not be uncomfortable to the patient. From experience developed in spinal cord stimulation, the electrical signals can be varied such that the nerve pain is blocked but the patient does not feel any other odd sensations. The net effect is that one can perform activities that were once painful without the ongoing sense of pain.
For pain patients, this new technology is nice since the only thing implanted into the body is a thin wire to the appropriate location. Testing prior to implant is first by a local nerve block with a long lasting anesthetic. If that is successful, than a trial implant can be done for a week or longer to determine if a final implant would be indicated. The permanent implant is a brief outpatient procedure and can be easily removed in the future if necessary.
Pain patients who may benefit from peripheral nerve stimulators include those where pain symptoms have a definite peripheral nerve origin and the pain can be extinguished by blocking just one or possibly two nerves that are nearby each other in the body. The first problems that have been treated have been pain related to shoulder injuries that do not resolve with surgery. Other common orthopedic problems include knee and foot pain after trauma or other surgery with nerve damage or nerve pain afterwards. Amputation phantom limb pain and complex regional pain syndrome are other pain problems that may benefit from this technology. An interventional pain specialist who does implants should be able to help determine if the pain problem may be helped with such treatment. Not all pain problems can be helped and if the pain is coming from multiple pain generators or is centrally generated in the brain, this treatment is less likely to be helpful.