Tarsal tunnel syndrome can cause tingling and numbness in the sole of the foot, although other problems can cause similar symptoms in your feet. It is important to have the correct diagnosis and to identify the level of compression or type of nerve disease so that your symptoms can be treated effectively.
Tarsal tunnel syndrome refers to a condition involving pressure on the tibial nerve in the ankle region, which causes tingling and numbness to the sole of your foot and — in more severe cases — changes to the small muscles in your foot. The tibial nerve comes off the sciatic nerve in the thigh and then continues behind the knee to the inside ankle (medial malleolus), where it goes through a tunnel and then 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. If untreated, over time, your symptoms probably will get worse with increased pressure on the nerve through the tarsal tunnel.
Non-operative treatment of nerve compression involves decreasing the pressure on the posterior tibial nerve. Because you bear weight through your feet when you walk or stand, it is difficult to stop putting pressure on your feet. Shoe orthotics are recommended for some patients, and this often will relieve symptoms. Altering lifestyle habits, including adopting a weight-loss program, may be helpful in relieving symptoms of tarsal tunnel syndrome. Anti-inflammatory medications or nerve-pain medications may be used. Conditions that may increase your symptoms — such as rheumatoid arthritis, hypothyroidism, diabetes and other conditions that may increase swelling to your feet — should be treated to see whether that helps relieve your symptoms. Other causes of tingling or numbness to your feet, such as peripheral neuropathy and lumbar radiculopathy, should be ruled out. Tarsal tunnel syndrome also may be associated with, or confused with, plantar fascitis or heel spurs.
When non-operative treatment fails to relieve your symptoms, surgical release of the tarsal tunnel may be recommended. This surgery requires an incision behind your ankle extending down to the arch of your 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. A long-acting anesthetic is used to help with postoperative pain, and because of this anesthetic, you likely will feel more numbness after surgery. A soft, bulky dressing is applied. Two to three days following surgery, it will be removed. To control swelling, it is important to keep your foot elevated whenever possible, and moving your toes also will help decrease swelling. When you walk, you may put as much weight through your foot as comfort allows. A cane or crutches may be used at first to help decrease weight-bearing through your foot.
After the dressing is removed, you may begin range-of-motion exercises of your ankle, and an Ace wrap may be used to help control swelling in your foot. The stitches are removed two to three weeks after surgery depending on your wound healing. You may progress to full weight bearing as you feel comfortable and may use crutches or a cane for your comfort. In some cases with delayed wound healing, prolonged swelling or decreased ankle strength/range of motion, you may be sent to physical therapy.
Complications from this surgery include bleeding, infection and delayed wound healing. As the feeling comes back to your foot, you may feel more tingling or burning sensations as normal sensation returns. Other surgical complications include injury to the small sensory nerves in the region or to the main nerve.
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More information on treatment of peripheral nerve injuries is available on the Center for Nerve Injury & Paralysis website.