Morton's neuroma is an enlarged nerve that usually occurs in the third interspace, which is between the third and fourth toes. To understand Morton's neuroma further, it may be helpful to look at the anatomy of the foot. Problems often develop in the third interspace because part of the lateral plantar nerve combines with part of the medial plantar nerve here. When the two nerves combine, they are typically larger in diameter than those going to the other toes. Also, the nerve lies in subcutaneous tissue, just above the fat pad of the foot, close to an artery and vein. Above the nerve is a structure called the deep transverse metatarsal ligament. This ligament is very strong, holds the metatarsal bones together, and 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. This causes compression in a confined space.
The exact cause is as yet unclear. However there are a number of theories. Some expert s believe problems with the design of the foot makes some people more prone to Morton?s neuroma. Having flat feet or a high arch for example encourages the foot to slide forwards which can put excess pressure on the metatarsals. Bunions and hammer toes also increase the likelihood of developing Morton?s. However simply wearing high heels or any form of tight shoes that put pressure on the bones in the feet can also lead to a Morton?s . Typically the condition comes on between the age of 40 and 50. It is far more common in women than men - three out of four sufferers are women.
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.
To confirm the diagnosis, your doctor will examine your feet. He or she will look for areas of tenderness, swelling, calluses, numbness, muscle weakness and limited motion. To check for a Morton's neuroma, your doctor will squeeze the sides of your foot. Squeezing should compress the neuroma and trigger your typical pain. In some cases, your doctor will find numbness in the webbed area between the affected toes. Pain in two or more locations on one foot, such as between both the second and third toes and the third and fourth toes, more likely indicates that the toe joints are inflamed rather than a Morton' neuroma.
Non Surgical Treatment
In most cases, initial treatment for this condition consists of padding and taping to disperse weight away from the neuroma. If the patient has flatfeet, an arch support is incorporated into footwear. The patient is instructed to wear shoes with wide toe boxes and avoid shoes with high heels. An injection of local anesthetic to relieve pain and a corticosteroid to reduce inflammation may be administered. The patient is advised to return in a week or 2 to monitor progress. If the pain has been relieved, the neuroma is probably small and caused by the structure of the patient's foot and the type of shoes the patient wears. It can be relieved by a custom-fitted orthotic that helps maintain the foot in a better position. Another type of therapy that may be used is alcohol sclerosing injections. In this treatment, the doctor injects a small amount of alcohol in the area of the neuroma area to help harden (sclerose) the nerve and relieve the pain. Injections are given every 7-10 days and, in many cases, 4-7 injections are needed for maximum relief. Please ask your physician for more information regarding this type of treatment.
If symptoms do not respond to any of the above measures then surgery may be suggested. This involves a short 30 minute operation to either remove tissue to take pressure off the nerve or to remove the nerve causing the pain. The surgery can be done as a day case but it will be two or three weeks before you can be fully active on your feet. There may be some lingering numbness afterwards if the nerve is removed. But surgery is successful in around 80% of cases. There is a small risk of complications such as infection and thickening of the skin on the soles of the feet.
The best way to prevent a neuroma is by avoiding the things that cause them. Review your risk factors. If relatives have had similar problems, or if you know that you pronate or have any problem with the mechanics of your foot, talk with a podiatric physician about the correct types of shoes and/or orthoses for you. If you are not sure whether you have such a problem, the podiatric professional can analyze your foot, your stride and the wear pattern of your shoes, and give you an honest evaluation. Remember, though, that sometimes neuromas, like other conditions, can develop for no discernible reason. With this in mind, be good to your feet, and be aware of any changes or problems. Don?t wait to report them.