A neuroma is a thickening of nerve tissue. This problem may develop in various parts of the body. The most common neuroma in the foot is a Morton%26rsquo;s neuroma. It occurs at the base of the third and fourth toe. It is sometimes referred to as an inter-metatarsal neuroma, where inter-metatarsal describes its location (in the ball of the foot between the metatarsal bones, extending from the toes to mid-foot). Neuromas may also occur in other locations in the foot. The thickening or enlargement of the nerve that defines a neuroma is the result of nerve compression and irritation. This compression creates a swelling, eventually leading to permanent nerve damage as a serious consequence of Morton%26rsquo;s neuroma.
Morton's neuroma is an enlarged nerve that usually occurs in the third inter-space. This inter-space is between the third and fourth toe. Problems often develop in this area because a part of the lateral plantar nerve combines with a part of the medial plantar nerve here. When the two nerves combine, they are typically larger in diameter than nerves going to the other toes. Moreover, the nerve lies in subcutaneous tissue, just above the fat pad of the foot, close to arteries and veins. Above the nerve, there is a structure called the deep transverse metatarsal ligament. This ligament is very strong, holding the metatarsal bones together. This ligament also creates the ceiling of the nerve compartment. With each step, the ground pushes up on the enlarged nerve and the deep transverse metatarsal ligament pushes down, which causes compression in a confined space. The reason the nerve enlarges has not been determined yet. Flat feet can cause the nerve to be pulled toward the middle more than normal. This could lead to irritation and possibly enlargement of the nerve. The syndrome is more common in women than men, possibly because women wear confining shoes more often.
High heels cause more weight to be transferred to the front of the foot, and tight toe boxes create lateral compression.
Because of this, more force is being applied in the area and the nerve compartment is squeezed from all sides. Under such conditions, even a minimal enlargement in the nerve can elicit pain as one of the symptoms.
Signs and symptoms of Morton%26rsquo;s neuroma
The most common symptom of Morton's neuroma is a localized pain in the inter-space between the third and fourth toe. The pain could be sharp or dull, and is worsened by wearing shoes and by walking. However, the pain is usually less severe when the foot is not bearing weight. Patient diagnosed with Morton%26rsquo;s neuroma will probably have one or more of these symptoms where the nerve damage occurs. These symptoms are tingling, burning, or numbness, pain, and a feeling that something is inside the ball of the foot, or that there is a rise in the shoe or a sock is bunched up. The progression of a Morton%26rsquo;s neuroma often follows the same pattern. The symptoms begin gradually, and at first they occur only occasionally, when wearing narrow-toed shoes or performing certain aggravating activities. Symptoms may be suppressed temporarily by massaging the foot or by avoiding aggravating shoes or activities. Over time the symptoms progressively worsen and may persist for several days or weeks even when you avoid walking. The symptoms become more intense as the neuroma enlarges and the temporary changes in nerve become permanent.
What causes Morton%26rsquo;s neuroma?
Anything that causes compression or irritation of the nerve can lead to neuroma. One of the most common offenders is wearing shoes that have a tapered toe box. High-heeled shoes that cause the toes to be forced into the toe box could also cause Morton%26rsquo;s neuroma. People with certain foot deformities, such as bunions, hammertoes, flatfeet, or more flexible feet are at higher risk for developing Morton%26rsquo;s neuroma. Other potential causes are activities that involve repetitive irritation to the ball of the foot, such as running or racquet sports. An injury or other type of trauma to the area may also lead to Morton%26rsquo;s neuroma.
Diagnosing Morton%26rsquo;s neuroma
To diagnose Morton%26rsquo;s neuroma the podiatrist commonly palpates the area to elicit pain. He will try to diagnose you by squeezing the toes from the side. Next he or she may try to feel the neuroma by pressing a thumb into the third interspace of the foot. The podiatrist then tries to elicit Mulder%26rsquo;s sign. He or she will do this by holding the patient%26rsquo;s first, second, and third metatarsal heads with one hand and the fourth and fifth metatarsal heads in the other and pushing half the foot up and half the foot down slightly, where in many cases of Morton%26rsquo;s neuroma, this causes an audible click. This click is known as Mulder%26rsquo;s sign, which can help with Morton%26rsquo;s neuroma diagnosis. An x-ray should be taken to ensure that there is not a fracture of the foot. X-rays also can be used to examine the joints and bone density, ruling out arthritis and osteoarthritis. An MRI scan or magnetic resonance imaging is used to ensure that the compression is not caused by a tumor. An MRI also determines the size of the neuroma and how the syndrome should be treated - whether conservatively or aggressively. If surgery is indicated, the podiatrist can determine how much of nerve must be resected. This is important because there are different surgical techniques available, depending on the size and the position of the neuroma. However, MRIs are expensive, which is why 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. To establish a diagnosis, the foot and ankle surgeon will also need to obtain a thorough history of your symptoms and examine your foot. The best time to see a foot and ankle surgeon is early in the development of symptoms. This is because early diagnosis of a Morton%26rsquo;s neuroma greatly lessens the need for more invasive treatments and may avoid surgery.
Treatment of Morton%26rsquo;s neuroma
There are two surgical procedures available in Morton%26rsquo;s neuroma treatment. The dorsal approach involves making an incision on the top of the foot, which permits the patient to walk soon after surgery. This is because the stitches are not on the weight-bearing side of the foot. The podiatrist maneuvers the instruments carefully through many structures and cuts the deep transverse metatarsal ligament. This ligament typically causes most of the nerve compression. This procedure can lead to instability in the forefoot that may require attention after treatment. The second procedure involves a plantar approach. In this procedure the incision is made on the sole of the foot. The patient must use crutches for about three weeks and the scar that forms can make walking uncomfortable as a side effect of this approach.
The advantage of the plantar approach is that the neuroma can be reached easily and resected without cutting any structures in the foot. However, before surgery, while developing a treatment plan, the foot and ankle surgeon will first determine how long the patient has had the neuroma. He will also need to evaluate its stage of development, because treatment approaches vary according to the severity of the problem. For mild to moderate cases of neuroma, treatment options include padding, which are techniques that provide support for the metatarsal arch, thereby lessening the pressure on the nerve and decreasing the compression when walking. Icing mean placing an icepack on the affected area helps reduce swelling. Orthotic devices issued by a foot and ankle surgeon provide the support needed to reduce pressure and compression on the nerve. Activity modifications are important to reduce especially those that put repetitive pressure on the neuroma. You should avoid these activities until the condition improves.
Changes in shoe wear could help, because it is important to wear shoes with a wide toe box and avoid narrow-toed shoes or shoes with high heels. Non-steroidal anti-inflammatory drugs such as Ibuprofen help reduce the pain and inflammation. If there is no significant improvement after the initial treatment, injection therapy may be tried as a treatment option for Morton%26rsquo;s neuroma. Surgery may be considered in patients who have not received adequate relief from other treatment options. The foot and ankle surgeon will determine which approach is optimal for your condition. The length of the recovery period after surgery will vary depending on the procedure or procedures performed. Regardless of whether you've undergone surgical or non-surgical treatment, your foot and ankle surgeon will recommend long-term measures, since it is important to help keep your symptoms from returning.
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