More often than not, Tarsal Tunnel Syndrome is overlooked, misunderstood, and neglected by physicians. This complex disorder may present itself to the patient as heel pain, an arch strain, a burning sole, toe numbness, or as a variety of other complaints. During examination, the astute practitioner will include focus of the tibial nerve as means of ruling this disorder in or out of the list of potential causes of the patient’s complaint. Such an examination may lead to faster recovery, as it properly considers all possible diagnoses.

The tibial canal resides behind the medial (inside) ankle on the inside region of the rear-foot. The roof of the tarsal canal (tunnel) is a ligament (Laciniate or flexor retinaculum). The contents of the tunnel include three tendons, one artery, two vena comitantes (veins), and the tibial nerve and its branches. As the tibial nerve travels from the upper to the lower limits of the canal, it forms the medial and lateral calcaneal branch, and the medial and lateral plantar nerves. These nerves are susceptible to entrapment and compression, which causes neurological irritation and dysfunction.

During the sequence of the gait cycle, the foot strikes at heel contact on the lateral (outside) aspect. The arch then collapses (pronates) to absorb the shock force. As the arch rises (supinates), the heel lifts prior to toe off. This causes the nerves to roll or shift slightly to accommodate the changing foot posture. Trouble occurs when the nerve is not allowed to move. Thus, entrapment of the nerves occur. This entrapment can be caused by space occupying lesions, such as a cyst or rheumatoid nodule, scar tissue from a previous injury, or tightness of the soft tissue around the nerve. As the demands on the foot occur, the nerve becomes strangulated. With time, the nerve will break down (demyelinate), eventually slowing nerve function. Evidence of this can be represented on EMG (Electromyography) and NCV (nerve conduction velocity) studies.

EMG and NCV study results can be used in support of the diagnosis of Tarsal Tunnel Syndrome, yet they cannot be used in ruling out the disorder’s existence. This is due to the possibility of the nerve being entrapped although not yet demyelinated. The nerve at this point is entrapped but not malfunctioning. Given time, the nerve will dysfunction. Therefore, the diagnosis of Tarsal Tunnel Syndrome is not based solely on signs (physical findings), but on symptoms (patient complaints) as well.

As previously mentioned, some of the symptoms of Tarsal Tunnel Syndrome are dull ache, numbness, burning, itching, tingling, stinging, and lightening bolt (electrical) sensations on the bottom of the foot or at the tarsal tunnel area. Many other pathologies (diseases) may mimic a Tarsal Tunnel Syndrome. Therefore, the astute examiner must eliminate these from the differential diagnoses (list of possible causes). The examiner will correlate the symptoms to the signs (findings) of the physical examination.

There are distinct maneuvers that must be utilized to determine the signs of a Tarsal Tunnel Syndrome. The first is a positive Tinel’s sign, which is elicited by compressing the nerve at the point of entrapment, causing radiation of pain into the tarsal canal and possibly into the foot. The second is a positive Valleix’s sign. This sign is positive upon percussing the point of entrapment with a neurological hammer, causing migration of electrical activity (lightning bolt) sensation up the leg and into the foot. The third sign helps to eliminate the diagnosis of sciatica from the differential diagnosis. A positive Laseque’s sign (straight leg raises) indicates the sciatic nerve is involved. This is elicited when the patient feels pain upon raising the leg due to tension placed on the sciatic nerve. With the symptoms and signs the physician should be able to determine if a Tarsal Tunnel Syndrome exists.

Treatment of the Tarsal Tunnel Syndrome is accomplished by resisting the forces on the tibial nerve. This is accomplished by taping or strapping the foot to eliminate or reduce these forces. An orthotic, if successful, should be prescribed for long term control. To reduce the inflamed nerve, nonsteroidal and steroidal anti-inflammatory medications are supplemented. Should these fail, a steroid injection at the point of entrapment is implemented. If the patient responds minimally to all of the above mentioned conservative measures, then decompression of the nerve is indicated.

The surgical management begins with the patient anesthetized by a spinal or general anesthetic. Attention is directed to two centimeters above the posterior (behind) aspect of the ankle joint. The incision is made in a curvi-linear fashion to terminate inferior to the medial malleolus, any bleeding vessels are tied off or cauterized at this point. Blunt dissection to the lacineate ligament is performed. The surgeon must appreciate the anatomy and texture of the ligament. Any abnormal appearance must be documented with careful transection of the ligament. The contents of the canal are appreciated. Starting at the top of the canal, moving inferiorly or distally, the nerve and the branches are identified and isolated gently. Each must be freed from any and all entrapment so that they move freely. Inspection of the abductor hallucis muscle belly must be done. Commonly, this muscle is attached to the fascia which is causing the entrapment of nerves. The fascia will be released if this is the case. Once the tibial nerve, medial calcaneal nerve, lateral calcaneal nerve, lateral plantar nerve, and medial plantar nerve can be moved with vessel loops and not be restricted, the decompression is complete. Inspection for any bleeding is performed. If a tourniquet is used, it must be deflated now. Once hemostasis is achieved, then closure of the subcutaneous and skin layers are performed. The ligament is not repaired. The patient will be placed in a non-weight bearing cast for three weeks to minimize scarring.

A majority of patients do well. A minority of patients will have re-entrapment of the nerve or other complications. If successful, the patient may see immediate relief or a nine to twelve month period of time before full or partial relief.

Dr. Graham has been in private practice in Effingham since 1989 and is on staff at St. Anthony's Memorial Hospital and Effingham Ambulatory Surgical Treatment Center. He is Board Certified by the American Board of Podiatric Surgery and American Board of Podiatric Orthopaedics and Primary Podiatric Medicine. Dr. Graham is a Fellow of the American College of Foot and Ankle Surgeons, the American College of Foot and Ankle Orthopaedics and Medicine, and American Professional Wound Care Association. He is also a member of the American Podiatric Medical Association and the Illinois Podiatric Medical Association.

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