A large nerve called the tibial nerve crosses behind your ankle on the inside of your foot and around your heel pad and into your arch, to supply sensation to the bottom of your foot and toes. Where the nerve passes behind the ankle, there is a tunnel between the tibia and a ligament band. The tunnel houses the tibial nerve as it branches into two nerve that goes into the arch and forefoot. There is also a smaller branch that supplies sensation to the bottom of the heel.
Sometimes this area on the inside of the ankle can become swollen, congested or scarred from overuse and injury.
Sprained or broken ankles or arthritis, cysts or ganglions of the tendons in the ankle can result in swelling and prolonged compression on the nerves. Some medical conditions are known to affect the nerves. These include rheumatoid arthritis and Lupus, alcoholism, thyroid disorders, kidney and heart conditions that cause leg swelling. Diabetes and chemotherapy can also factor in with swelling of the nerves themselves.
What does compression do to the nerves? When the nerve receives increased pressure, then blood flow to the nerve decreases. The nerve responds with altered sensations such as tingling and numbness. It may become so severe that it feels as if the foot is asleep. Often the symptoms are worse after standing or walking when mild swelling can occur within the tarsal tunnel. The small muscles cramp as they lose their nerve supply. The heel will hurt just as in bone spurs or plantar fasciitis.
Treatments of compression neuropathy, including tarsal tunnel syndrome, are aimed at removing the pressure off the tibial nerve and its branches. Orthoses and arch supports and some ankle splints may help position the foot to relieve pressure on the nerves. You may need to alter your work or sports activities. Support stockings or ank elastic ankle brace will control swelling and this often helps to provide relief.
Anti-inflammatory medications may help if the tendons are inflamed and swollen. A careful injection of a small amount of cortisone may be given. There are oral medications, useful for treating neuropathic pain. These are Elavil, Dilantin, Neurontin, Tegretol, and Lyrica. New prescription B vitamins called Metanx has also helped with painful neuropathy and without the side effects of some of the above-mentioned drugs.
When all that can be done by either medication, physical therapy, changing your activities or by orthoses proves to be ineffective in relieving the symptoms, there is an operation to relieve the pressure on the tibial nerve and its branches. Decompression neurolysis is also performed on other nerves of the leg if they are also affected by compression neuropathy. The nerve is identified and uncovered as they follow in their tunnels. The areas of compression are opened and the nerves are decompressed. Cysts, spurs are removed, as well as scar tissue from injuries. A bulky dressing is applied for one week. Smaller dressings are then applied once a week until the incisions are healed. After surgery, as the sensation returns to normal, there will be varying sensations. If the compression as exited for many years and the nerves have degenerated or died, regeneration of the nerve fibers may take a long time. The recovery phase actually occurs in two stages. The operation releases the pressure on the nerves and blood flow to the nerves improves. This relieves the original pain and numbness. Long-term compression may have caused scarring within the nerve. This will result in slower healing and recovery. The nerves must regenerate and grow into muscles and into the tips of the toes. The nerves regenerate about an inch per month and thus recovery can take several months.
Surgery: This surgical approach to nerve pain is delicate and should be performed only by foot surgeons who are specially trained, experienced, and comfortable with the procedure. Before surgery is considered, a full understanding of the cause of the nerve pain is important.
As with all problems, the best advice is to see a foot specialist when symptoms develop. Many treatments are available and most work best when the problem is new. Why wait until the pain and numbness stop you? Physical therapy, shoe inserts, and other simple treatments can keep you going.