A common cause of tingling, numbness and pain in the sole of the foot is tarsal tunnel syndrome. Tarsal tunnel syndrome refers to a condition involving pressure on the tibial nerve in the ankle region. In severe cases it can even result in changes to the small muscles in the foot.
The tibial nerve comes off the sciatic nerve in the thigh and continues behind the knee to the inside ankle, where it goes through a tunnel and divides into the calcaneal nerve and the medial and lateral plantar nerves. The medial and lateral plantar nerves go through separate tunnels in the foot, and each tunnel can put more pressure on the nerve.
At first, the symptoms of tingling and/or numbness may come and go. Then, as the pressure on the nerve increases, these feelings may last for longer periods of time.
Non-operative treatment of nerve compression involves decreasing the pressure on the posterior tibial nerve. Because the feet bear weight during walking or standing, it is difficult to stop putting pressure on them. Shoe orthotics are recommended for some patients, and this often will relieve symptoms. Making lifestyle changes or taking anti-inflammatory or nerve-pain medication also may be helpful in relieving symptoms.
Tarsal tunnel syndrome may be associated with â€” or confused with â€” plantar fascitis or heel spurs.
When non-operative treatment fails to relieve symptoms, surgical release of the tarsal tunnel may be recommended. This surgery requires an incision behind the ankle extending down to the arch of the foot. The ligament over the tibial nerve in the region of the tarsal tunnel is released. The nerve is followed in the foot, and the tunnels for the medial and lateral plantar nerves also are released. The calcaneal branch frequently has its own tunnel, which also is released.