Overview
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.
Causes
A Morton’s Neuroma is not a true neuroma, which is a tumor that is generally benign. Rather, it is an enlargement of the nerve where it goes between the metatarsal bones of the foot. Because the nerve no longer fits between the gap, the pressure causes pain and sometimes numbness. This enlargement of the nerve is often an inflammation due to irritation. If the forefoot becomes compressed due to shoes that are too narrow, the nerve becomes damaged and inflamed. This inflammation means the nerve no longer fits in the space between the bones, creating further irritation and more inflammation. If this vicious circle can be broken, the problem may be resolved. However, in some situations the nerve can have fibrous tissues formed around it, which may require the destruction of the nerve or surgical removal.
Symptoms
Many patients describe the sensation as a burning pain in the ball of the foot that often radiates to the toes. Initially, the pain may become much more apparent when the person wears tight, narrow or high-heeled shoes, or engages in activities which place pressure on the foot. Eventually, symptoms may be continuous and last for days, and even weeks. MRI (magnetic resonance imaging) scans have revealed Morton’s neuroma lesions in patients who had no symptoms at all. Symptoms can become so disrupting that many affected individuals become anxious about walking, or even placing their foot on the ground.
Diagnosis
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
Depending on your overall health, symptoms and severity of the neuroma, the condition may be treated conservatively and/or with surgery. Non-surgical methods for neuroma are aimed at decreasing and/or eliminating symptoms (pain). Wear proper supportive shoes. Use an arch support. Wear shoes with a wide toe box. Modify your activities. Lose weight. Wear shoes with cushion. Prescribe an oral anti-inflammatory medication. Anti-inflammatory medication is useful to significantly reduce pain and inflammation. A physical therapist may perform ultrasound and other techniques to reduce inflammation. You will also be instructed how to stretch your foot and leg properly. Padding and/or cushioning of the ball of the foot is an effective method of preventing physical irritation with shoes. A custom foot orthotic is a doctor prescribed arch support that is made directly from a casting (mold) of your feet, and theoretically should provide superior support compared to shoe insert that you would purchase from a pharmacy. A cortisone injection is a powerful anti-inflammatory medication that is used to rapidly reduce the pain associated with an inflamed nerve. The pain relief that you may experience from the injection(s) is often temporary. Typically injection(s) are administered once every 2 months for a total of 3 injections or until the pain is resolved. A sclerosing alcohol injection is placed around the involved nerve to weaken its capacity to report pain. In other words, the alcohol injection will ?deaden? the affected nerve. The pain relief that you may experience from the injection(s) can be permanent. Typically injection(s) are administered once every week for a few weeks until the pain is resolved.
Surgical Treatment
Operative treatment of Morton?s neuroma should be entertained only after failure of non-operative management. Standard operative treatment involves identifying the nerve and cutting (resecting) it proximal to the point where it is irritated/injured. This is usually done through an incision on the top (dorsal) aspect of the foot, although an incision on the sole (plantar) aspect of the foot can be used. Some physicians will attempt to treat Morton?s neuroma by releasing the intermetatarsal ligament, and freeing the nerve of local scar tissue. This may also be beneficial.
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.
georgiedorvillier 