Kristin Slaugenhaupt

Feet Disorders Explained

What Causes Mortons Neuroma

Overview

plantar neuromaMorton's neuroma is an inflammation of the nerves in the foot that go to the toes. Although the name includes the word ?neuroma,? it is not really a tumor. It can affect any of the toes in the foot. However, it most often affects the nerves that run between the third and fourth, or second and third toes.

Causes

There are a number of common causes for Morton?s Neuroma, (though the condition can arise spontaneously for reasons still unknown). The Neuroma often occurs in response to irritation, pressure or traumatic injury to one of the digital nerves leading to the toes. A thickening of nerve tissue results as part of the body?s response to the irritation or injury. Abnormal foot movement used to compensate for bunions, hammertoes, flatfeet and other conditions can lead to irritation and development of Morton?s Neuroma. Pronation of the foot may cause the heads of the metatarsal bones to rotate slightly, thereby pinching the nerve running between the metatarsal heads. Chronic pressure or pinching causes the nerve sheath to enlarge, becoming increasingly squeezed, producing worsening pain over time, if not addressed. Morton?s Neuroma can be exacerbated when tight shoes providing little room for the forefoot are worn. Activities which over-pronate the foot (such as walking barefoot in sand) may increase the pain associated with Morton?s Neuroma, as will any high-impact activity, such as jogging.

Symptoms

Symptoms include tingling in the space between the third and fourth toes, toe cramping, a sharp, shooting, or burning pain in the ball of the foot and sometimes toes, pain that increases when wearing shoes or pressing on the area, pain that gets worse over time. In rare cases, nerve pain occurs in the space between the second and third toes. This is not a common form of Morton neuroma, but treatment is similar.

Diagnosis

The clinical symptoms should quickly lead your doctor to suspect a neuroma. When examined, the doctor may feel a "click" which is known as Mulder's sign. There may be tenderness in the interspace. The metatarsal bones will also be examined both clinically (and often with an xray). Tenderness at one of the metatarsal bones can suggest an overstress reaction (pre-stress fracture or stress fracture) in the bone. An ultrasound scan can confirm the diagnosis and is a less expensive and at this time, at least as sensitive a test as an MRI. An x-ray does not show neuromas, but can be useful to "rule out" other causes of the pain.

Non Surgical Treatment

Treatment options vary with the severity of each neuroma, and identifying the neuroma early in its development is important to avoid surgical correction. For simple, undeveloped neuromas, a pair of thick-soled shoes with a wide toe box is often adequate treatment to relieve symptoms, allowing the condition to diminish on its own. For more severe conditions, however, additional treatment or surgery may be necessary to remove the tumor. The primary goal of most early treatment regimens is to relieve pressure on areas where a neuroma develops. Your podiatric physician will examine and likely X-ray the affected area and suggest a treatment plan that best suits your individual case. Padding and Taping. Special padding at the ball of the foot may change the abnormal foot function and relieve the symptoms caused by the neuroma. Medication. Anti-inflammatory drugs and cortisone injections can be prescribed to ease acute pain and inflammation caused by the neuroma. Orthotics. Custom shoe inserts made by your podiatrist may be useful in controlling foot function. Orthotics may reduce symptoms and prevent the worsening of the condition.intermetatarsal neuroma

Surgical Treatment

When conservative measures are unsuccessful, surgery can be a good choice in the treatment of Morton's neuroma. The operation for Morton's neuroma does not require an overnight hospital stay. The anesthetic used is an ankle block, which completely numbs the foot during the surgery. The physician removes the neuroma from an incision made on the top of the foot between the involved metatarsal heads. The nerve to the interspace is exposed and cut next to the metatarsal heads.

Prevention

Always warm-up thoroughly before vigorous athletics. Avoid activities that cause pain. Stretch and strengthen the feet through gradual exercise.
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