A tarsal tunnel syndrome is much like a carpal tunnel syndrome where a nerve is trapped and causing compression of the nerve. In the case of tarsal tunnel the nerve involved is the posterior tibial tendon in the ankle region. Heel pain may also result from an entrapment of a branch of this nerve.
Symptoms of tarsal tunnel syndrome primarily are sharp, burning pain from the lower leg on the inside aspect extending through the arch into the bottom of the foot. This may also result in numbness along the same course of the nerve and even extending to the toes. Usually this is aggravated by shoes and aggressive activities and is usually relieved by rest. Usually the symptoms come on slowly but occasionally this can be due to a traumatic incident.
Causes for tarsal tunnel syndrome can be anything that causes compression of the nerve in its compartment. The posterior tibial nerve runs in a small canal along with the a major artery and vein to the foot. If any of these structures is enlarged, it takes up more room in the canal and compresses the nerve. Sometimes the nerve itself is enlarged or has been damaged from trauma taking up space within the canal. Pronation allows for more pressure to be applied to the inside aspect of the ankle and arch which may place tension within the canal and compress the nerve excessively.
Prevention of tarsal tunnel is usually aimed at controlling the foot structure of your foot if you have excessive pronation. The best prevention may be to get advice from your orthotic to try and control the foot structure especially if you have excessive pronation. Sometimes other examinations are needed to better understand the problem including an MRI, Electromygraphy (EMG), or a Nerve Conduction Study. Your podiatrist may send you to a neurologist to do these studies or evaluate you for conditions within your back. With these results and without relief using conservative care your podiatric physician may also recommend a surgical procedure to release the tarsal tunnel and decompress the nerve.
Surgery for release of a tarsal tunnel is basically explorative. The tarsal tunnel is explored to release any compression from surrounding the nerve. If a definite problem is seen other than a tight compartment it may be corrected as well as a decompression of the nerve.
Post-operative Care and Risks with a decompression of the tarsal tunnel is usually with a soft bandage with a post-operative shoe for protection. Weight bearing is usually allowed if tolerated. You should expect some pain following surgery as well as swelling. Especially for the first 48 hours you should keep your leg elevated and occasional ice placed over the area of surgery (about 20 minutes per hour). Surgical cuts are made through the skin so a scar is expected. If you are a keloid former, let your surgeon know. Surgical cuts are not only made through skin, but through other layers of tissue as well, a scar may form within your foot and lead to adhesions. Typically you can get back into a supportive tennis shoe in 3-5 weeks following healing of the wound and stitches are removed. You may use crutches, a walker, or wheelchair to help you keep weight off of this foot if needed for post-operative pain. Healing time is influenced by many factors including your nutrition, circulation, and other medical conditions. If you are a smoker you can expect to take longer to heal. If you are required to keep pressure off of your foot your leg muscles are not being used as they were before surgery. This allows for slower movement of the blood through the leg vessels. Occasionally this can lead to a blood clot in the leg which can become life threatening. Hip and knee flexion and extension exercises as well as wiggling your toes gently can help prevent this from occurring. If you have a history of blood clots you should let your surgeon know. Any time surgery is done around a nerve the patient may experience a variety of feelings following surgery for several months, including some tingling, burning, and phantom pains. Some small nerve fibers maybe released causing permanent numbness after surgery.