Tarsal tunnel syndrome
Tarsal tunnel syndrome causes numbness, pain or tingling in the feet. It happens when a nerve in the leg called the posterior tibial nerve passes through a narrow tunnel inside the ankle and gets compressed. This tunnel is called the tarsal tunnel.
The posterior tibial nerve supplies most of the feeling to the bottom of the foot. When pressure is placed on the nerve, it creates burning or numbness on the bottom of the foot, usually along the outside of the foot. It can also affect the toes.
Conditions that cause similar symptoms are diabetic neuropathy, alcoholic neuropathy or nerve compression above the ankle. Poor blood flow can also cause burning of the feet. If you have any of these symptoms, see your doctor as soon as possible.
Tarsal tunnel syndrome usually starts when people reach their 30s or 40s and gets worse with age. It’s caused by anything that puts pressure on the posterior tibial nerve, including:
- A flat foot or a foot in which the arch flattens a lot while walking
- Soft tissue masses that may develop in the tarsal tunnel and compress the nerve
- Small varicose veins that may form around the nerve
Diagnosis is made by physical exam, which often reveals a flat foot or collapsed arch. A history of burning on the bottom of the foot should alert the doctor to possible causes. X-rays, MRIs and nerve conduction studies may also be done.
Treatment focuses on correcting the abnormal pronation of the foot. This involves wearing custom shoe inserts (functional orthotics).
Other treatments include:
- Anti-inflammatory medications
- Vitamin B supplements
- Certain exercises, including calf muscle stretching, can ease tension on the ankle joint
- Surgery if there is a soft tissue mass
If damage to the nerve is significant, there might be permanent nerve damage. In this case, treatment often focuses on easing symptoms. Certain prescription medications may ease the burning pain that can happen at night.
Alternative treatments include magnetic insole therapy and non-invasive electrical stimulation. Your doctor may also urge you to see a pain medicine specialist.