Morton neuromas are focal areas of symptomatic perineural fibrosis around a plantar digital nerve of the foot. The abnormality is non-neoplastic and does not represent a true neuroma. It may more correctly be known as Morton?s metatarsalgia. The condition is thought to be due to chronic entrapment of the nerve by the intermetatarsal ligament. It most often occurs in middle-aged individuals and is many times more common in women than men. Approximately 30% of asymptomatic middle-aged persons have the radiological pathologic findings of a Morton?s neuroma.
Various factors have been implicated in the precipitation of Morton's neuroma. Morton's neuroma is known to develop as a result of chronic nerve stress and irritation, particularly with excessive toe dorsiflexion. Poorly fitting and constricting shoes (ie, small toe box) or shoes with heel lifts often contribute to Morton's neuroma. Women who wear high-heeled shoes for a number of years or men who are required to wear constrictive shoe gear are at risk. A biomechanical theory of causation involves the mechanics of the foot and ankle. For instance, individuals with tight gastrocnemius-soleus muscles or who excessively pronate the foot may compensate by dorsiflexion of the metatarsals subsequently irritating of the interdigital nerve. Certain activities carry increased risk of excessive toe dorsiflexion, such as prolonged walking, running, squatting, and demi-pointe position in ballet.
It usually occurs in between the 3rd and 4th toes (about 65% of cases) as is pictured to the right. It is less commonly found in the 2nd webspace, and rarely at all in the 1st or 4th webspaces. You can also experience pins and needles and/or numbness as a result of the nerve being affected. The condition tends to occur predominantly in middle aged females.
An MRI scan (magnetic resonance imaging) is used to ensure that the compression is not caused by a tumor in the foot. An MRI also determines the size of the neuroma and whether the syndrome should be treated conservatively or aggressively. If surgery is indicated, the podiatrist can determine how much of the nerve must be resected. This is important, because different surgical techniques can be used, depending on the size and the position of the neuroma. Because MRIs are expensive, some insurance companies are reluctant to pay for them. If the podiatrist believes an MRI is necessary, he or she can persuade the insurance company to pay for it by presenting data to support the recommendation.
Non Surgical Treatment
Treatment depends on the severity of your symptoms. Your doctor will likely recommend trying conservative approaches first. Arch supports and foot pads fit inside your shoe and help reduce pressure on the nerve. These can be purchased over-the-counter, or your doctor may prescribe a custom-made, individually designed shoe insert, molded to fit the exact contours of your foot.
If conservative treatments haven't helped, your doctor might suggest injections. Some people are helped by the injection of steroids into the painful area. In some cases, surgeons can relieve the pressure on the nerve by cutting nearby structures, such as the ligament that binds together some of the bones in the front of the foot. Surgical removal of the growth may be necessary if other treatments fail to provide pain relief. Although surgery is usually successful, the procedure can result in permanent numbness in the affected toes.