By definition, the medical term “neuroma” means “swollen nerve” as derived from “neuro-” (referring to nerve tissue) and “-oma” (referring to tumor). In the simplest of terms a neuroma is a swollen and irritated nerve. A “Morton’s neuroma” refers specifically to a swollen nerve on the bottom of the foot between the third and fourth toes. There are other neuromas in the foot, but most occur on the bottom of the foot where they pass under a ligament before continue their course out into the toes.
When one of the nerves on the bottom of the foot (plantar nerves) becomes irritated, they start to produce new nerve endings in response to the irritation. At first a neuroma may cause the sensation of a lump in your shoe. Many people will say that they feel like there is a wrinkle or seam in their sock that is bunched up. They will often even remove the shoe, but don’t see any bunched up material or source of the lumpy feeling. In one of the earliest description of the neuroma, Dr. Morton described patients complaining of a “sensation of wet leather stuck to the bottom of the foot” as the first sign of a neuroma.
One of the early signs and symptoms of a Morton’s neuroma is numbness. The numbness is typically in the middle toes, but sometimes in the ball of the foot.
With continued irritation of the nerve, these strange sensations can become more pronounced and uncomfortable. Tingling sensations in the middle toes or ball of the foot indicate an irritated response in the nerve. It is often times worse when bending the toes. Aggravation activities can include elliptical trainers, stair climbing, cycling while standing on the pedals, or kneeling down when gardening. When wearing tight shoes, such as climbing shoes, ski boots or cycling shoes, the tingling may become worse or more persistent.
With continued mechanical irritation of the nerve, the numbness and tingling becomes worse and often will become gradually more painful. The pain from a Morton’s neuroma is most often described as brief shooting or burning pains that shoot out into the middle toes or along the bottom of the foot toward the arch. It is often times worse when bending the toes or wearing tight shoes.
A neuroma in the foot is generally caused by mechanical irritation or compression of the nerve. Because the nerve course from the arch, divides and travels between the metatarsal bones on the bottom of the foot, before the turn and head upward in to the toes, there are many ways the nerves can become irritated.
Some people have a foot type where the metatarsal bones are spaced close together and can bump into the nerve. Other people engage in activities where tight footwear squeezes these bones together and can irritate the nerves. Examples include rock climbing, horse-back riding, bowling, skiiing, and cycling.
Still others might have activities where the stand up on the toes, stretching and irritating the nerves. Common activities that have been related to neuromas include ballet, rock climbing, running, cycling and exercising on elliptical trainers or stair-climbers.
Fortunately not everyone who has a neuroma needs surgery. If treated early, it is often a simple matter of letting the nerve calm down. Treatments can include padding to take pressure away from the injured nerve, modifying activities and changing shoes. Other treatments aim to decrease inflammation of the neuroma with icing, cortisone injections, or NSAIDs (non-steroidal anti-inflammatory drugs like ibuprofen). If these treatments fail, physical therapy and custom orthotics might be used to decrease the inflammation and prevent further irritation to the nerve.
Custom orthotics are often effective at relieving the pressure on the neuroma. When properly casted and created, custom functional foot orthotics (a specialized insert you wear in your shoe) can reposition the metatarsal bones in the foot to alleviate neuroma pain and decrease irritation of the nerve. If orthotics therapy is started early enough, this may be all the treatment that is needed to allow the nerve to heal and cure the neuroma.
In addition, there is a controversial treatment called alcohol schlerosing injections. This involves a series of weekly injections (usually 5-7) that attempt to destroy the painful nerve in order to decrease the pain. This treatment is often times a last resort in those who are not surgical candidates. This is often a better option than surgery for very active individuals like runners, triathlete and climbers. Surgery requires that you decrease your activity for several weeks. But with schlerosing injections you can stay active and there is no concern for losing all of your strength and fitness.
Surgery is reserved for those who simply cannot improve with other treatments. Surgery should only be considered when other treatments have failed and the patient is experiencing pain that interferes with activities.
There are essentially two different surgical procedures to relieve the pain from a neuroma: surgical excision and surgical release.
Surgical release of the neuroma involves releasing the ligament on the bottom of the foot in order to give the nerve more space and decrease irritation. The benefit of this surgery is that (if successful) there is no loss of sensation in the foot or toes. When successful, patients typically experience a gradual reduction in symptoms over time after the surgery.
Surgical excision of the neuroma is simply the removal of the painful nerve. The Y-shaped portion of nerve where it divides between the toes is dissected away from the surrounding tissue. The swollen part of the nerve is then removed. The benefit of this surgery is that (if successful) there is no more pain. Surgical excision also has a high success rate in reducing the pain from the neuroma. The trade-off is that there is always numbness in the toes supplied by the nerve that is removed. In essence, you trade pain for permanent numbness. In most cases, this is a fare trade. It allows the patient to return to the activities that they enjoy.
A neuroma is a localized swelling in a nerve in the bottom of the foot that can cause numbness, tingling or pain. Early treatments should focus on decreasing the irritation to the nerve as well as reducing inflammation. By seeking treatment with an orthopedic or podiatric foot surgeon early, there is hope that the neuroma can be successfully treated without surgery.
Dr. Christopher Segler is a foot surgeon and sports medicine podiatrist in San Francisco. His practice caters to busy professionals and athletes who have restrictive schedules. To accommodate his clientele, he offers house calls at homes and his clients offices in the San Francisco Bay Area. As a runner and triathlete himself, he always seeks to find the best treatment that will allow his patients to recover and remain active. If you have a question about a foot problem that you think is a neuroma, you can reach him directly at (415) 308-0833.