Tarsal Tunnel Syndrome
Tarsal Tunnel Syndrome can be a difficult diagnosis to make and a very difficult problem to treat. Generally, the most reliable diagnostic criteria are evident on clinical exam. Signs and symptoms can include pain in the ankle, pain in the heel, numbness or tingling to the plantar aspect of the foot, and discomfort radiating into the foot. These signs and symptoms may be reproducible by tapping on or increasing pressure over the posterior tibial nerve. Sometimes a nerve conduction/EMG study can be useful in confirming the diagnosis although the study has been reported to be only about 50% reliable.
The cause of tarsal tunnel syndrome is compression of the nerves by the flexor retinaculum and muscle fascia in a constricted area behind the ankle. This process is similar to carpal tunnel syndrome, which affects the median nerve in the wrist. Due to compression, the nerves become diseased and dysfunctional, and will not conduct signals as well. There are many other systemic causes that can contribute to peripheral neuropathy. If there is a possibility of tarsal tunnel syndrome, it is important to also optimize other systemic factors that may be contributing to the neuropathy such as hormone, vitamin, and sugar levels. If tarsal tunnel syndrome continues to be a problem after conservative treatment and modification of other systemic controllable factors, then a release of the tarsal tunnel may be beneficial.
Operative intervention can be attempted if the disease process continues despite other conservative treatments and systemic medical optimization. The aim of operative intervention is to release the tight fascia and flexor retinaculum in order to relieve nerve pressure. This is done through an incision on the inside of the ankle. The tight flexor retinaculum is released and the nerves are exposed and released from any constrictive tissue that may be increasing pressure. Release of the tight structures may allow better blood flow to the nerves and stop progression of the disease process. Sometimes the nerves will recover and the neuropathic symptoms will resolve. However, the recovery can be a lengthy process and incomplete recovery may be experienced if the pathologic process has been severe and long lived. Much of the time immediately after surgery is spent resting and elevating your leg to decrease swelling and scar tissue formation. We generally recommend you keep your leg elevated as much as possible during the first week. You will be discharged from the hospital immediately after surgery with a prescription for pain medicine to help control your pain. A popliteal nerve block is another option you may discuss with the anesthesiologist help with postoperative pain control. Most patients are discharged home in a splint which will be converted to a cast in the office the next week. Stitches are generally removed around 2-3 weeks. Patients are placed in a non-weight bearing cast for the first six weeks postoperatively followed by a walking boot for another six weeks. You will not be able to put weight on your foot during the first six weeks and will need to use crutches, a walker, or a rolling knee walker to mobilize. Patients are generally transitioned from a walking boot into a standard shoe at 12 weeks after the operation.