He explained that, as there are many causes for foot pain, there are many treatments.  Dr. Winfree talked about several common nerve related foot problems and their surgical treatments both in the foot and in the spine.

One of the first problems Dr. Winfree talked about was entrapment neuropathy. Simply put, this is when a nerve gets damaged because it is passing through a space that is too narrow. The specific example he gave was tarsal tunnel syndrome. In this case, a nerve is pinched in the ankle’s tarsal tunnel on on its way to the foot. This tunnel is formed on the inside of the ankle by bones and a large ligament. The surgical treatment is essentially to open the tunnel to take the pressure off the nerve, or to “decompress” it.

Dr. Winfree also talked about sensory neuromas. These are highly sensitive bundles of scar tissue that can form when a nerve is injured. He used the example of, Morton’s neuroma which occurs in the ball of the foot. It is characterized by numbing of the toes and a deep pain made worse by weight bearing. Surgeons can either go through the top or bottom of the foot to remove the neuroma.

Sometimes a painful growth within the nerve is actually a tumor. Tumors that grow within nerves are usually benign and like the neuroma can be surgically removed.

A more baffling problem is called Complex Regional Pain Syndrome (CRPS). Even a minor injury, like a stubbed-toe, can trigger what is, in a sense, an over-reaction by the nerves in the area. The result is exquisite tenderness, swelling, redness, muscle wasting, and even changes in the bones of the foot and lower leg if left untreated. Dr. Winfree says, sometimes these patients benefit from a sympathetic nerve block, which involves injecting a numbing agent into the spine. Also, implanting spinal cord or nerve stimulation devices in the spine can overide pain signals in the foot on their way to the brain (see the blog Turn Up the Static When Back Pain Won’t Stop Calling for a more detailed description of these types of procedures).

Incisional Pain syndrome is another problem Dr. Winfree sees. Patients have described this as a “constant burning pain” along a scar, long after the wound has healed. This can also be treated by implanting nerve stimulation devices at the spine.

At the end of his talk, Dr. Winfree presented two cases of intractable foot pain that were successfully treated with different forms of nerve stimulation. See these two blogs for more about these patients: A New Way to Give an Old Vet Relief and Surgeons Use Ultrasound, Not to Find a Baby, but a Nerve.

Sometimes a patient with back pain has tried everything, pain killers, physical therapy, injections, even surgery, and still has pain. This is where specialists like Dr. Christopher Winfree from our Pain Center come in.  He can surgically implant a spinal nerve root stimulator (SNRS) to block pain signals to the brain.  Dr. Winfree spoke to neurosurgeons at the World Congress of Neurological Surgeons Annual Meeting 2009 about how to do this.  He gave an overview of several placement methods and their best use.

An SNRS is similar to a pacemaker.  It has a small power unit that attaches to electrodes that deliver electrical impulses.  Patients can control their intensity with a remote. When delivered to a nerve the electrical stimulation can override pain signals. Think of nerves as telephone wires to and from our brain.  If pain is a bill collector on the line, then an SNRS offers a way to turn up the static so we canʼt hear him.  These devices can be placed anywhere along a nerveʼs pathway: at the spinal cord, as it exits the spine, as it travels down the arm or leg, or just under the skin.

Placement on the spinal cord is often a surgeonʼs first choice to immediately relieve pain in the arms or legs.  This technique has a long track record but it has limitations.  Pain specific to the low back, hand, foot, groin and buttock can be harder to target with this approach.   Also, over time, pain can stop responding to the spinal cord stimulation.  For these reasons, surgeons may choose another placement point, initially or supplementally.

Nerves become easier to access specifically, once they come off the spinal cord. Pain that lies within the pathway of a certain nerve can be relieved by placing an SNRS electrode anywhere along that nerve between the spine and the painful area. A couple of techniques have been developed to target nerves as they exit the spinal cord (see our blog, A New Way to Give an Old Vet Relief to learn more). Electrodes can also be placed further along the nerve closer to the area of pain. For example, some nerves in the foot can actually be targeted in the back of the knee (see our Peripheral Nerve Center featured article Surgeons Use Ultrasound, Not to Find a Baby, but a Nerve to learn more).

Targeting nerves in this way can provide significant relief but only when pain falls inside a specific nerveʼs pathway. When it doesnʼt, SNRS electrodes can be placed under the skin, right where it hurts.

Each method has its best use and any one may be just what a patient needs. Patients who end up at the Pain Center sometimes have much more complicated pain patterns and need a combination of methods.  In any case, an SNRS can be a powerful tool that provides long suffering patients with a way to turn up the static when pain calls; in fact, they may not even hear the phone ring.

The Pain Center team also has specialized expertise in the treatment and management of a range of other syndromes including anesthesia dolorosa, headache, hemicrania continua, intercostal neuralgia, low back pain, neck pain, occipital neuralgia, pelvic pain, postherpetic neuralgia, and trigeminal neuralgia.

Led by Dr. Christopher Winfree, the Pain Center is a multidisciplinary entity. This allows professionals from diverse fields to bring their abilities to bear upon the needs of each individual patient. For example, many chronic pain conditions are actually caused by peripheral nerve injuries [Peripheral Nerve Center]. Thus, the combination of peripheral nerve and pain neurosurgical techniques allows for the optimal management of these disorders.