What Causes Mortons Neuroma

Overview

intermetatarsal neuromaA neuroma is a thickening of nerve tissue that may develop in various parts of the body. The most common neuroma in the foot is a Morton?s neuroma, which occurs between the third and fourth toes. It is sometimes referred to as an intermetatarsal neuroma. ?Intermetatarsal? describes its location in the ball of the foot between the metatarsal bones. Neuromas may also occur in other locations in the foot. MortonThe thickening, or enlargement, of the nerve that defines a neuroma is the result of compression and irritation of the nerve. This compression creates enlargement of the nerve, eventually leading to permanent nerve damage.

Causes

Some say that this condition should not be called Morton’s neuroma as, in fact, it is not actually a neuroma. A neuroma is a non-cancerous (benign) tumour that grows from the fibrous coverings of a nerve. There is no tumour formation in Morton’s neuroma. The anatomy of the bones of the foot is also thought to contribute to the development of Morton’s neuroma. For example, the space between the long bones (metatarsals) in the foot is narrower between the second and third, and between the third and fourth metatarsals. This means that the nerves that run between these metatarsals are more likely to be compressed and irritated. Wearing narrow shoes can make this compression worse.

Symptoms

The most common symptom of Morton’s neuroma is localized pain in the interspace between the third and fourth toes. It can be sharp or dull, and is worsened by wearing shoes and by walking. Pain usually is less severe when the foot is not bearing weight.

Diagnosis

During the examination, your physician will feel for a palpable mass or a “click” between the bones. He or she will put pressure on the spaces between the toe bones to try to replicate the pain and look for calluses or evidence of stress fractures in the bones that might be the cause of the pain. Range of motion tests will rule out arthritis or joint inflammations. X-rays may be required to rule out a stress fracture or arthritis of the joints that join the toes to the foot.

Non Surgical Treatment

Sclerosing alcohol injections are an increasingly available treatment alternative if the above management approaches fail. Dilute alcohol (4%) is injected directly into the area of the neuroma, causing toxicity to the fibrous nerve tissue. Frequently, treatment must be performed 2-4 times, with 1-3 weeks between interventions. An 60-80% success rate has been achieved in clinical studies, equal to or exceeding the success rate for surgical neurectomy with fewer risks and less significant recovery. If done with more concentrated alcohol under ultrasound guidance, the success rate is considerably higher and fewer repeat procedures are needed. Radio Frequency Ablation is also used in the treatment of Morton’s Neuroma The outcomes appear to be equally or more reliable than alcohol injections especially if the procedure is done under ultrasound guidance.intermetatarsal neuroma

Surgical Treatment

Surgery to remove the neuroma may be recommended if more conservative treatment does not solve the problem. While surgery usually relieves or completely removes the symptoms, it often leaves a permanent numb feeling at the site of the neuroma.

Prevention

It is not always possible to prevent a Morton’s neuroma. However, you probably can reduce your risk by wearing comfortable shoes that have low heels, plenty of toe space and good arch support.

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