Tarsal tunnel syndrome is a painful condition that is caused by the entrapment of the posterior tibial nerve on the inside of the ankle.
There are some very tight structures in this area, so there is very little room for expansion if any of these structures becomes inflamed or enlarged. This inflammation or enlargement of the nerve in this area causes the entrapment.
The tarsal bones are the short bones that form the bridge between the forefoot (metatarsals) and the ankle. Just below the bony prominence on the inside of the ankle (medial malleolus) is a passage called the tarsal tunnel through which the posterior tibial nerve passes.
Tarsal tunnel syndrome is caused by anything that produces compression on the posterior tibial nerve, such as:
Biomechanical factors: The most common cause of tarsal tunnel syndrome relates to faulty structure of the foot. Over-pronation (flat feet) is the leading cause of tarsal tunnel syndrome. The flattened arches force the nerves and muscles surrounding the ankle to veer away from their normal route, squeezing the tibial nerve.
Systemic Diseases: Diabetes, osteoarthritis at the ankle joint and rheumatoid arthritis may contribute to the development of tarsal tunnel syndrome. These conditions can cause swelling in joints that may compress the nerve.
Trauma: Ankle fractures and other similar traumas causing a misalignment , or the development of scar tissue can affect how the nerve functions and the pressures on it.
Talonavicular coalition: Fusing of two of the tarsal bones.
Footwear: Non-supportive footwear puts abnormal strain on foot structures. Improper footwear can exacerbate the problem caused by the original genetic structure.
An enlarged or abnormal structure that occupies space within the tunnel can compress the nerve. Some examples include a varicose vein, swollen tendon, ganglion, lipoma, and arthritic bone spur.
Pain (often described as burning) radiating into the arch of the foot, heel and sometimes the toes.
Numbness including pins and needles may be felt in the affected area of the foot.
Pain when running or when standing for long periods of time. Usually relieved by rest and often worst at night.
Tenderness to the touch of the area under the medial malleolus.
Physical exam: Diagnosis is made by the history of the pain or numbness in the area of the distribution of the nerves on the bottom of the foot. The structure and biomechanics of the patient’s entire foot is examined. Diagnosis is aided by tapping or palpating the posterior tibial nerve at a site of compression or injury. This will often produce Tinel’s sign. Tinel’s sign is a tingling electric shock sensation that occurs when you tap over an affected nerve.
|Examining for Tinel’s sign||Typical distribution of symptomatology|
The sensation usually travels into the foot but can also travel up the inner leg as well. Tenderness may be noted over the nerve just behind the ankle joint.
X-rays: X-rays help determine the cause for specific cases of tarsal tunnel syndrome. X-rays can be useful to determine the presence of any other structures such as cysts, arthritis, exostosis or a tarsal coalition.
Treatment of tarsal tunnel syndrome usually begins with strategies you can accomplish at home.
Immobilize the area: Wrap the ankle and arch of the foot with an elastic bandage or ankle brace, especially when the pain is more severe or the condition has become recurrent. These devices often lessen pressure within this area of the body. Immobilization of the foot and ankle in a splint, cast or cast boot may be prescribed by the doctor.
Appropriate Footwear: Walking without shoes can put undue strain and stress on your ankle and foot. Wearing supportive shoes that have good arch support can reduce pressure and minimize the degree of over-pronation.
Ice: Using an ice pack on the inside of the ankle for 15 minutes several times a day helps reduce inflammation. Place a thin towel between the ice and your skin; do not apply ice directly to the skin.
Limit activities: Reduce extended physical activities to give your foot and ankle a rest.
Medications: Oral non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may be recommended to reduce pain and inflammation.
Orthotic devices: Custom orthotic devices that fit into your shoe may be prescribed for correcting biomechanical imbalance, controlling excessive pronation. Orthotic support has been shown to decrease strain on many of the structures (nerve and tendon) that pass from the leg to the foot through the tarsal canal.
Injection therapy: In some cases, corticosteroid injections are used to help reduce the inflammation and relieve pain.
Physical therapy: Ultrasound treatments or stretching exercises may provide some pain relief.
Although most patients with Tarsal Tunnel Syndrome respond to non-surgical treatment, a small percentage of patients may require surgery. If you do not respond to non-surgical treatment,and continue to have pain, surgery will be considered.
Both the traditional and minimally invasive surgical correction techniques are performed at the Coeur d’Alene Foot and Ankle Surgery Center. Both techniques involve a release of ligament and exploration of the tarsal canal with decompression of the posterior tibial nerve.
Because the minimally invasive techniques are less traumatic, and the recovery time shorter, most patients prefer this method of correction. Each patient is unique, however, and the doctor will discuss which technique he feels best suits the patient for optimal outcome.
Traditional Tarsal Tunnel Syndrome Correction
Open or traditional surgical correction techniques require a large incision, several centimeters in length, which is made on the inside of the ankle, allowing the surgeon access to the structures for release and decompression. The incision is closed with stitches, and you are placed in a bulky bandage to protect the foot while it heals. You may be placed in a splint for certain open technique corrections. The large incision into the ankle may preclude the patient from bearing any weight on the foot immediately.
Minimally Invasive Tarsal Tunnel Syndrome Correction
The technique used in minimally invasive or minimal incision percutaneous surgery involves a much smaller incision on the inside of the ankle with minimal suturing necessary. For this technique, surgeons use specially designed instruments which are very fine to make tiny, precise cuts, to stretch the retinaculum(a ligament in the medial part of the ankle). There is less trauma to the tissue and surgical times are lessened with this technique, reducing pain and recovery time. Postoperative patients ambulate immediately and are sometimes placed in a surgical shoe or boot to aid ambulation.
The most commonly performed MIS procedure for correction of Tarsal Tunnel Syndrome is the tarsal tunnel release, stretching the flexor retinaculum. On rare occasions if there is a growth pressing the nerve then the surgeon may need to use a larger incision to remove this growth.
Minimally Invasive Tarsal Tunnel Surgery – Image Gallery
Surgical Day Visit
Surgeries are performed at the CDA Foot and Ankle Surgery Center and are done with local anesthesia where in the foot usually stays asleep 4 to 6 hours. A small surgical incision is used which enables the surgeon to use fine specially designed instruments to obtain the best long term pain free, functional and cosmetic results. Only a few stitches are required due to the small incision size. Dr. Nunez also uses a fluoroscope during surgery, enabling him to visualize foot anatomy during surgery in spite of the small incisions. The entire surgery takes approximately 1- 2 hours. This includes viewing a preoperative video and procedure explanation, anesthetic administration, setting up the sterile field, the surgical procedure and post operative dressing and instructions.
Patients are not required to discontinue their prescription medication unless specifically instructed. There are no restrictions on diet or fluid intake the night before surgery. As recommended by the CDC (Centers for Disease Control), an antibiotic is usually administered at the time of surgery. The patient is given a postoperative pain medication prescription and if appropriate one dose of antibiotic to be taken that evening. Occasionally an RX is also given to the patient for continued antibiotic therapy if necessary according to their medical history.
The dressing must stay dry, clean and intact and is not changed until the first post-operative office visit.
The patient leaves the facility walking with a special surgical boot or shoe. This will be provided for the patient. Crutches or walkers are usually NOT needed.
All minimally invasive surgical techniques are performed in compliance with the Standards of Care published by the Academy of Ambulatory Foot and Ankle Surgery and can be viewed on the U.S Department of Health & Human Services National Guideline Clearinghouse: www.guideline.gov
The Coeur d’Alene Foot and Ankle Surgery Center is Medicare Certified and an Accredited surgical facility with the Academy of Ambulatory Foot and Ankle Surgery.