The early clinical presentation of Tarsal Tunnel Syndrome may start with a mild tingling (like an electrical charge) and burning sensation in the sole of the foot. Symptoms are aggravated by prolonged standing and walking but relieved by rest. Paresthesia or “pins and needles pricking sensation” occurs in the distribution of the tibial nerve and its branches.
The affected foot may feel weak and numb in chronic cases. The area under the medial malleolus (inner bone bit of the ankle) may feel pain to palpation and resonate paresthesia if gently tapping by a neurologic hammer, otherwise known as the “Tinel’s sign” which is pathognomonic for Tarsal Tunnel Syndrome. Soft tissue masses like retention cysts, ganglioma or lipoma may directly be palpable below the medial malleolus. Chronic disease may show muscle wasting and loss of bone density in the affected foot.
A good detailed clinical history revealing the characteristic early tingling and pain in the foot may point in the direction of an early nerve compression disease. History of injury and inflammation of the ankle will also be a mitigating clue in the diagnosis of Tarsal Tunnel Syndrome.
A comprehensive neurologic exam may elicit a positive Tinel’s sign which is positive in 67% of all cases . Radiographic X-ray may not be of value for it does not show signs of a damaged nerve but could be helpful in determining the extent of over-pronation while weight is applied.
Sonogram imaging, Computed Tomography Scan and Magnetic Resonance Imaging may elucidate masses and cysts that impedes the tunnel space. Nerve conduction studies may only be positive distally during the late course of the disease.
The goal of the treatment of Tarsal Tunnel Syndrome is to relieve the impending stress that compresses the tunnel. Corrective shoes or the use of orthotic appliances to restore the normal arch of the foot may alleviate the symptoms. Custom orthotics have been found to alleviate symptoms of Tarsal Tunnel Syndrome and restore functionality in a study group of factory workers . Inflammation of the ankle and the persistent irritation of the nerve may be allayed by oral anti-inflammatory agents.
Refractory cases may benefit from corticosteroid injection to the tunnel to control swelling. Physical therapy using the Graston’s manual technique or the active decompression release techniques have shown promising results in alleviating pain with professional hands . On the average, surgical intervention ensues at the sixteenth (16th) month of unsatisfactory non-surgical approach .
The surgical approach to the decompression is to release the flexor retinaculum by resecting the tendon along the line of the tibial nerve. When the fibrous sheath is released, the tarsal tunnel will loosen up relieve the compression symptoms. Physical therapy post-surgically is also required to properly position the tibial nerve during the healing process and the scar tissue formation of the retinaculum.
When the tibial nerves are not aligned, the scarring tissue may impinge it again and cause a relapse in symptomatology; thus requiring a scar tissue or fascial stripping operation . A Gondring scoring system to determine the intensity of the pain during follow-up visits could help quantify the pain symptoms and predict patient’s recovery outcome .
The compression signs and symptoms of Tarsal Tunnel Syndrome like gnawing pain and numbness may remain the only fleeting remnant of a mild disease if left untreated.
However, complications from severe and long standing nerve compression may present with muscle atrophy and loss of tactile and temperature sensation of the affected distal digits. Neuro-arthropathy may result from the chronic compression of the proximal afferent nerve. Trophic signs of hair loss and ulcerations may be eminent in with irreversible nerve damage.
There are a number of health conditions that results to Tarsal Tunnel Syndrome, all of these compress the small space of the tarsal tunnel through which the tibial nerve, nerve branches, and vessels pass. Most common of which occurs among middle aged adults with flat foot.
Soft tissue masses may causes compression to the tunnel like ganglioma, ranula, varicosities, neuroma, schwannoma, tendon sheath ganglia and lipoma . Bony spurs like exostoses may also compress this space. A valgus deformity of the rear foot was also demonstrated to have caused these symptoms as well . Ankle injuries and systemic diseases like Diabetes Mellitus and Rheumatoid Arthritis can cause localized swelling impinges the tarsal nerve in this tunnel.
Tarsal Tunnel Disease is a slow and progressive disease that is most commonly seen in patients with ages 30 to 40 years old. People who tend to roll their foot inward or “overpronate” tend to develop compression signs in time.
Obese people with recent foot and ankle injury may have a higher risk for Tarsal Tunnel Syndrome. Studies have shown that people who often run or jog notices the signs and symptoms the earliest. In a significant percentage of these patients Tarsal Tunnel Syndrome has no particular cause and thus labelled idiopathic in origin.
The pathophysiology of Tarsal Tunnel Syndrome stems as a compression neuropathy of the tibial nerve and its branches. Current studies of podiatry and neurosciences have demonstrated that compression injuries to the foot can cause both tension and compression symptoms.
Tension is caused by the direct pulling of the nerve causing a local effect like those exemplified in nerve injuries. Nerve compression injuries dwell with the premise that the axoplasm (nerve endoplasm) transmits and receives nerve impulse, thus any compression may damage the whole segment distally.
Nutrient flow is usually towards the distal axoplasm making the distal nerves more susceptible to injury than the compressed segment proximal nerve segment .
Patients born with flat foot or Pes planus deformity should submit to early physical therapy or the use of othotics to mimic the planar arch of the foot to prevent the occurrence of Tarsal Tunnel Syndrome before they reach the age of 30 – 40 years old.
Diabetics who are more prone to Tarsal Tunnel Syndrome must make regular visits to their podiatrists for a regular foot assessment. Arthritic patients must medically control foot inflammation to prevent nerve compression in the Tarsal tunnel.
Tarsal Tunnel Syndrome is a clinical disease caused by the compression of the posterior tibial nerve in the tarsal tunnel of the foot. The tarsal tunnel is just a small and narrow space inside the ankle which lies directly under the bony protrusion in the medial side of the foot. The tibial nerve and its branches are compressed at the level of the flexor retinaculum (thick fibrous band in the ankle) of the foot .
Mechanical pressure on the tibial nerve causes numbness and a burning sensation at the plantar (bottom) aspect of the foot. Tarsal Tunnel Syndrome is very common in people with flat foot (Pes Planus) that are devoid of the natural arch in the foot causing the weight of the body to compress the tarsal tunnel.
The early identification of the risk factors for the Tarsal Tunnel Syndrome and the early detection of its primary signs is as important as its treatment. Patients should continually be conscious of any unusual sensation or deformity in their foot and should seek medical consult. One must also remember that compression in the tarsal tunnel is governed by many modifiable factors like weight control, proper walking and running gait, and correct use of footwear.