Causes

Tibial nerve dysfunction is an unusual form of peripheral neuropathy. It occurs when there is damage to the tibial nerve, one of the lower branches of the sciatic nerve of the leg. The tibial nerve supplies movement and sensation to the calf and foot muscles.

A problem in function with a single nerve group, such as the tibial nerve, is called mononeuropathy. The usual causes are:

• Direct trauma
• Pressure on the nerve for a long period of time
• Pressure on the nerve from nearby body structures

Entrapment createes pressure on the nerve where it passes through a narrow structure.

The damage may destroy the myelin sheath that protects and insulates the nerve, or part of the nerve cell (the axon). This damage reduces or prevents the movement of impulses through the nerve.

The tibial nerve is often injured by pressure from a ligament on the inner part of the ankle. Injury or disease of structures near the knee may also damage the tibial nerve. The tibial nerve may also be affected by diseases that damage many nerves, such as diabetes.

In some cases, no cause can be found.

Symptoms

• Sensation changes in the bottom of the foot and toes
  • Burning sensation
  • Numbness, tingling, or other abnormal sensations
  • Pain
• Weakness of foot muscles
• Weakness of the toes or ankle

Exams and Tests

An examination of the legs will be done to diagnose tibial nerve dysfunction. The health care provider will also take a medical history.

Signs include:

• Inability to curl the toes, push the foot down, or twist the ankle inward
• Weakness

In severe cases, the foot muscles may become very weak and the foot may be deformed.

Tests for tibial nerve dysfunction may include:

• EMG (a recording of electrical activity in muscles)
• Nerve biopsy
• Nerve conduction tests (recording of electrical activity along the nerve)

Tests may also include blood tests, x-rays, or scans.

Treatment

Treatment is aimed at restoring feeling and strength to the foot and toes. In some cases, no treatment is needed, and patients will recover on their own. Severe loss of sensation may lead to toe or foot sores (ulcers) and infections.

Surgery to enlarge the tarsal tunnel will reduce pressure on the tibial nerve and may benefit some people.

Over-the-counter analgesics may be helpful for mild pain (neuralgia). Other medicines include:

• Phenytoin, carbamazepine, gabapentin, pregabalin, duloxetine, or tricyclic antidepressants such as nortriptyline may reduce the stabbing pains that some people experience.
• Opiate pain relievers, such as morphine or fentanyl, may be needed to control severe pain.

Whenever possible, medication should be avoided or reduced to lessen the risk of side effects.

Physical therapy exercises may help some people maintain muscle strength.

Job counseling, therapy, changes, or retraining may be recommended.

Outlook (Prognosis)

If the cause of the tibial nerve dysfunction can be found and successfully treated, patients can recover fully. Some people may have a partial or complete loss of movement or sensation. Nerve pain may be uncomfortable and last for a long period of time.

Possible Complications

• Deformity of the foot (mild to severe)
• Movement loss in the toes (partial or complete)
• Repeated or unnoticed injury to the leg
• Sensation loss in the toes or foot (partial or complete)

When to Contact a Medical Professional

Call for an appointment with your health care provider if symptoms of tibial nerve dysfunction are present. Early diagnosis and treatment increases the likelihood that symptoms can be controlled.

Prevention

Prevention is variable depending on the cause of the nerve damage.

Alternative Names

Neuropathy - posterior tibial nerve; Tarsal tunnel syndrome

References

Harati Y, Bosch EP. Disorders of peripheral nerves. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Bradley: Neurology in Clinical Practice. 5th ed. Philadelphia, Pa: Butterworth-Heinemann Elsevier; 2008:chap 80.

Update Date: 2/5/2012

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by Josh V. Campellone, MD, Division of Neurology, Cooper University Hospital, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.