Six ways that podiatrists can assist your patients that may surprise you.
Part 2: Nocturnal Paraesthesia / Tarsal Tunnel Syndrome (TTS)
As we all are aware, there are many causes of neuropathy and paraesthesia. These run the gamut from idiopathic to endocrine to exposure to toxic substances and, for the most part, treatment outcomes are poor. An under-appreciated cause is nerve compression within the tarsal tunnel which generally responds very well to conservative treatment.
Symptoms of TTS include:
- Burning / tingling / buzzing feet, particularly at night or at rest
- More activity during a day means worse trouble that night
- Paraesthesia is usually not present while active
- Almost always subjectively described as affecting “the whole foot” but on closer questioning, doesn’t usually include the heel.
- Is often described as “numbness” though, on examination, sensation is intact.
What Is the Tarsal Tunnel?
The tarsal tunnel is a narrow space below the medial malleolus that runs in an inferior/anterior orientation as shown in the diagram. In the hand, the carpal tunnel is formed by two bone canals and as the canal becomes stenotic with age, surgical intervention may become necessary to drill out the osteophytic spurring. In the foot, the tunnel is bordered on one side by the tissue of the flexor retinaculum. The space contains blood vessels and the flexor tendons in addition to the posterior tibial nerve which is compressed in TTS.
Causes of Tarsal Tunnel Syndrome.
TTS is caused by excessive pressure on the posterior tibial nerve that produces neurological pain in the efferent area that the nerve supplies. The most common cause (by far) is flat feet / pronation / fallen arches. In this foot position, the tunnel changes from being a short, squat, relatively straight aperture to being a longer, narrower, curving space. This stretches and compresses the nerve and causes pain.
Other, rarer causes can include anything that invades the space of the tarsal tunnel, such as swelling in the tendons, a ganglion or invasion by another mass.
Diagnosis and Treatment of Tarsal Tunnel Syndrome.
Early treatment is important to avoid permanent nerve damage. Diagnosis is generally made from the history and physical examination of the foot. It is possible to use strapping tape to alter the foot position and reorientate the tunnel back into an ‘open’ position for a few days. When the diagnosis is correct, the pain will be significantly reduced the following night. This being the case, the next step is to make in-shoe orthotics to keep the foot in its best position going forward. This has an excellent success rate.
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Further patient-directed information can be found here: Patient Info Sheet.
Part 1: Trochanteric Bursitis – A simple cure
Part 2: Nocturnal Paraesthesia
Part 4: Sever’s Disease
Part 5: Patello-femoral Pain
Part 6: Do Podiatrists still do Chiropody ?