Introduction:
The term tarsal in Latin means pertaining to the ankle. A narrow passage found between the bones and the soft tissue inside the ankle is called the tarsal tunnel. This tunnel is present near the bony bump on the inner side of the ankle. Few tendons, blood vessels, and tibial nerves pass through this tunnel to reach the foot. Damage to the tibial nerves is rare and is often caused by the entrapment or compression caused inside the tunnel.
What Is Tarsal Tunnel Syndrome?
The tarsal tunnel syndrome is a painful foot condition caused by compressive neuropathy of the tibial nerve. The syndrome is common in the active adults, with a higher incidence in women. Sports activities involving more of the lower limb like playing football, skating, snowboarding, and track and field events have a higher risk of developing tarsal tunnel syndrome. This syndrome can occur in one foot or both feet.
What Causes Tarsal Tunnel Syndrome?
Tarsal tunnel syndrome can be idiopathic (without any underlying diseases) or secondary to any factor that compresses the tibial nerve. The common causes are
-
Injury: Trauma to the foot or ankle causes bone fractures or sprains that can put pressure on the tibial nerve.
-
Tumor: A lesion or a mass occupying the space can compress the tibial nerve.
-
Bony Growth: The bony lumps or bone spurs formed inside the tarsal tunnel following an injury can stress the tibial nerve.
-
Varicose Veins: The twisted and enlarged veins of the leg often pressurize the tibial nerve and surrounding structures during an action.
-
Inflammation: Inflammation of the tendons or the membranes create pressure in the tarsal tunnel.
-
Debilitating Diseases: Common conditions like diabetes and arthritis can cause inflammation, swelling, and nerve compression.
-
Postural Disorders: Flat feet are a postural disorder where one or both feet have little to no arch. Typically, the upper tilt of the heel with fallen arches produces pressure over the tibial nerve.
-
Disc Hernia: The bulging of the disc in the lower back can pinch the nerve leading to the double crush phenomenon (the nerve is pinched first in the lower back, and the same nerve is pinched in the tarsal tunnel).
What Are the Symptoms of Tarsal Tunnel Syndrome?
-
Pain that occurs spontaneously or aggravated during movements.
-
Tingling or numbness around the ankle, toes, and sometimes the leg.
-
Sharp shooting pain along the tibial nerve path.
-
Burning or electric shock-like sensation over the feet.
-
Pins and a needle prick type of feeling.
-
Rarely the pain may radiate up to the calf muscles.
-
Muscle damage or weakness in the bottom of the feet.
-
Severe tarsal tunnel syndrome causes a partial or complete loss of sensation and movement in the feet.
How to Diagnose Tarsal Tunnel Syndrome?
1. Physical Examination: Evaluating the patient’s history and physical examination are the first steps in the diagnosis of tarsal tunnel syndrome. Physicians may perform a simple, non-invasive test to check for nerve problems which are called the Tinel’s sign.
-
Tinel’s Sign: This test involves tapping over the nerve, which will produce a tingling or pain sensation. The sensation is a positive sign of nerve damage or irritation. Tinel’s sign is a potential indication of tarsal tunnel syndrome.
2. Imaging Techniques:
-
X-rays are used to rule out fractures or any other medical conditions.
-
MRI (magnetic resonance imaging) can visualize soft tissue lesions and tumor masses.
-
Ultrasound can evaluate inflammation around the ankle.
3. Nerve Conduction Test:
The nerve conduction test is the gold standard in diagnosing secondary tarsal tunnel syndrome.
4. Electromyography (EMG):
Electromyography records and evaluates the electrical activity of skeletal muscles and the nerve cells that control them. Any abnormal result may indicate a suspected tarsal tunnel syndrome.
How to Treat Tarsal Tunnel Syndrome?
The treatment of the tarsal tunnel syndrome depends on the severity of the condition and the intensity of pain elicited during activities.
Non-Surgical:
-
Rest, manipulation, physical therapy, muscle strengthening exercises, steroid shots, immobilization using a cast, alternative ice packs, and heating pads during sports are the conservative treatment for tarsal tunnel syndrome.
-
Over-the-counter medications like painkillers and anti-inflammatory drugs are used to relieve pain and swelling temporarily. Injection of local anesthetic may also provide pain relief.
-
Orthotics are specially designed shoes or soles used to improve the functional ability of the skeleton. An orthotic can reduce the pressure on the tibial nerve. Binders, braces, straps, and stents are also available for decompressing the tibial nerve.
-
In the case of cysts, aspiration of the fluid under the guidance of ultrasonography can be done.
Surgical:
-
Surgery is recommended when conservative management does not improve the condition. In the case of a tumor, surgical resection is the best choice of treatment to debride the tunnel and relieve the nerve.
-
An incision is made at the back of the ankle, and the nerve is traced and followed into the tunnel. The ligaments, fibrous band, and septum are the important structures in the tunnel that may compress the tibial nerve. Hence these structures are released to relieve the tibial nerve.
-
Researchers devised a rating scale for the severity of tarsal tunnel syndrome to evaluate the treatment outcome, especially before and after surgery.
A result with a total score of ten points was judged as excellent, eight to nine points as good, six to seven points as fair, and below five as poor.
Conclusion:
Tarsal tunnel syndrome is similar to carpal tunnel syndrome. However, the prevalence of tarsal tunnel syndrome is rare. Tarsal tunnel syndrome is a chronic condition of foot pain that may progress and result in nerve damage. It is very important to treat the symptoms at the earliest. Many patients have good treatment outcomes. If left untreated, tarsal tunnel syndrome can greatly impact the patient’s quality of life. Depending on the severity, proper pain management, counseling, and even surgery are considered.
