Tarsal Tunnel
Tarsal Tunnel
Tarsal tunnel syndrome (TTS), also known as posterior tibial neuralgia, is a compression neuropathy and painful foot condition in which the tibial nerve is compressed as it travels through the tarsal tunnel. This tunnel is found along the inner leg behind the medial malleolus (bump on the inside of the ankle). The posterior tibial artery, tibial nerve, and tendons of the tibialis posterior, flexor digitorum longus, and flexor hallucis longus muscles travel in a bundle through the tarsal tunnel. Inside the tunnel, the nerve splits into three different segments. One nerve (calcaneal) continues to the heel, the other two (medial and lateral plantar nerves) continue on to the bottom of the foot. The tarsal tunnel is delineated by bone on the inside and the flexor retinaculum on the outside.
Symptoms
Some of the symptoms are:
- Pain and tingling in and around ankles and sometimes the toes
- Swelling of the feet
- Painful burning, tingling, or numb sensations in the lower legs. Pain worsens and spreads after standing for long periods; pain is worse with activity and is relieved by rest.
- Electric shock sensations
- Pain radiating up into the leg, and down into the arch, heel, and toes
- Hot and cold sensations in the feet
- A feeling as though the feet do not have enough padding
- Pain while operating automobiles
- Pain along the Posterior Tibial nerve path
- Burning sensation on the bottom of foot that radiates upward reaching the knee
- “Pins and needles”-type feeling and increased sensation on the feet
- A positive Tinel’s sign
Tinel’s sign is a tingling electric shock sensation that occurs when you tap over an affected nerve. The sensation usually travels into the foot but can also travel up the inner leg as well.
Diagnosis
Diagnosis is based upon physical examination findings. Patients’ pain history and a positive Tinel’s sign are the first steps in evaluating the possibility of tarsal tunnel syndrome. X-ray can rule out fracture. MRI can assess for space occupying lesions or other causes of nerve compression. Ultrasound can assess for synovitis or ganglia. Nerve conduction studies alone are not, but they may be used to confirm the suspected clinical diagnosis. Common causes include trauma, varicose veins, neuropathy and space occupying anomalies within the tarsal tunnel. Tarsal tunnel syndrome is also known to affect both athletes and individuals that stand a lot.[1]
Cause
It is difficult to determine the exact cause of Tarsal Tunnel Syndrome. It is important to attempt to determine the source of the problem. Treatment and the potential outcome of the treatment may depend on the cause. Anything that creates pressure in the Tarsal Tunnel can cause TTS. This would include benign tumors or cysts, bone spurs, inflammation of the tendon sheath, nerve ganglions, or swelling from a broken or sprained ankle. Varicose veins (that may or may not be visible) can also cause compression of the nerve. TTS is more common in athletes and other active people. These people put more stress on the tarsal tunnel area. Flat feet may cause an increase in pressure in the tunnel region and this can cause nerve compression. Those with lower back problems may have symptoms. Back problems with the L4, L5 and S1 regions are suspect and might suggest a “Double Crush” issue: one “crush” (nerve pinch or entrapment) in the lower back, and the second in the tunnel area. In some cases, TTS can simply be idiopathic
Diabetes makes the peripheral nerve susceptible to nerve compression, as part of the double crush hypothesis. In contrast to carpal tunnel syndrome due to one tunnel at the wrist for the median nerve, there are four tunnels in the medial ankle for tarsal tunnels syndrome. If there is a positive Tinel sign when you tap over the inside of the ankle, such that tingling is felt into the foot, then there is an 80% chance that decompressing the tarsal tunnel will relieve the symptoms of pain and numbness in a diabetic with tarsal tunnels syndrome.
Treatment
Treatments typically include rest, manipulation, strengthening of tibialis anterior, tibialis posterior, peroneus and short toe flexors, casting with a walker boot, corticosteroid and anesthetic injections, hot wax baths, wrapping, compression hose, and orthotics. Medications may include various anti-inflammatories such as Anaprox, or other medications such as Ultracet, Neurontin and Lyrica. Lidocaine patches are also a treatment that helps some patients.
Many patients report good results. Some, however, experience no improvement or a worsening of symptoms. In the Pfeiffer article (Los Angeles, 1996), fewer than 50% of the patients reported improvement, and there was a 13% complication rate. This is a staggering percentage of complications for what is a fairly superficial and minor surgical procedure.
