What Is Morton's Neuroma? What Causes Morton's Neuroma?

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What Is Morton's Neuroma? What Causes Morton's Neuroma?

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Morton's neuroma, also called Morton's metatarsalgia, Morton's disease, Morton's

neuralgia, Morton metatarsalgia, Morton nerve entrapment, plantar neuroma, or

intermetatarsal neuroma is a benign (non-cancerous) growth of nerve tissue

(neuroma) that develops in the foot, usually between the third and fourth toes

(an intermetatarsal plantar nerve, most commonly of the third and fourth

intermetatarsal spaces). It is a common, painful condition.

Put simply - Morton's neuroma is a swollen (inflamed) nerve in the ball of the

foot, commonly between the base of the second and third toes.

Patients experience numbness and pain in the affected area, which is relieved by

removing footwear and/or massaging the foot.

A neuroma is a tumor that arises in nerve cells - a benign growth of nerve

tissue that can develop in various parts of the body. In Morton's neuroma the

tissue around one of the nerves leading to the toes thickens, causing a sharp,

burning pain in the ball of the foot. A sharp severe pain, often described as a

red hot needle may come on suddenly while walking. There may also be numbness,

burning and stinging in the toes.

Although it is labeled a neuroma, many say it is not a true tumor, but rather a

perineural fibroma (fibrous tissue formation around nerve tissue).

Morton's neuroma may be the result of irritation, pressure or injury. In some

cases its cause is unknown. In the majority of cases only one nerve is affected.

Having both feet affected is extremely rare. A high percentage of patients with

Morton's neuroma are women who wear high-heeled or narrow shoes.

Patients with Morton's neuroma may need to change their footwear, take

painkillers or steroid injections, while others may require surgery to either

remove the affected nerve or release the pressure on it.

According to Medilexicon's medical dictionary:

Morton neuroma is " a painful, tender focal mass lesion on one of the plantar

interdigital nerves of the foot, most often that which is situated between the

third and fourth metatarsal bones; attributed to either compression of the nerve

between the heads of the adjacent metacarpal bones, or traction being placed on

the nerve as it crosses the anterior edge of the deep transverse metatarsal

ligament. "

What are the signs and symptoms of Morton's neuroma?

A symptom is something the patient feels and reports, while a sign is something

other people, such as the doctor detect. For example, pain may be a symptom

while a rash may be a sign.

Outward signs of Morton's neuroma, such as a lump, are extremely rare.

Morton's neuroma signs and symptoms, which usually occur unexpectedly and tend

to worsen over time, include:

Pain on weight bearing (while walking) - a shooting pain affecting the

contiguous halves of two toes, which may be felt after only a short time (of

weight bearing). Sometimes there may be a dull pain rather than a sharp one.

Most commonly, pain is felt between the third and fourth toes. Typically, a

patient will suddenly experience pain while walking and will have to stop and

remove their shoe.

Burning

Numbness

Parasthesia - tingling, pricking, or numbness with no apparent long-term

physical effect. Commonly known as pins-and-needles.

A sensation that something is inside the ball of the foot.

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.

What are the causes of Morton's neuroma?

Experts are not sure what exactly causes Morton's neuroma. It seems to develop

as a result of irritation, pressure or injury to one of the digital nerves that

lead to the toes, which triggers a body response, resulting in thickened nerve

tissue (neuroma).

Feet conditions/situations that can cause the bones to rub against a nerve

include:

High-heeled shoes - especially those over 2 inches (5cm), or a pointed or tight

toe box which squash the toes together. This is probably why the condition is

much more common in females than in males.

High-arched foot - people whose feet have high arches are much more likely to

suffer from Morton's neuroma than others.

Flat feet - the arch of the foot collapses. The entire sole of the foot comes

into complete or near-complete contact with the ground.

A bunion - a localized painful swelling at the base of the big toe, which

enlarges the joint.

Hammer toe - a deformity of the proximal interphalangeal joint of the second,

third, or fourth toe causing it to be permanently bent.

Some high-impact sporting activities - including running, karate, and court

sports. Any sport that places undue pressure on the feet.

Injuries - an injury or other type of trauma to the foot may lead to a neuroma.

Diagnosing Morton's neuroma

A GP (general practitioner, primary care physician) or a podiatrist (foot

specialist doctor) will ask the patient to describe the pain as well as its

intensity, when symptoms started, what types of shoes are worn, as well as some

questions about their job, lifestyle and hobbies.

The doctor will then examine the foot and try to locate the affected nerve. This

may involve attempting to reproduce symptoms by manipulating the foot.

In order to get a detailed image of the inside of the food, one of the following

scans may be ordered:

X-ray - this is a type of high-energy radiation. In low doses they are used to

diagnose diseases and condition by making pictures of the inside of the body. In

higher doses they are used to treat cancer. This procedure is non-invasive and

painless.

Ultrasound scan - high frequency sound waves are pointed at a specific part of

the body, which in this case is the foot. The ultrasound waves bounce of

tissues; their echoes are then converted into a picture, called a sonogram. This

allows the doctor to get an inside view of the foot. This procedure is

non-invasive and painless.

MRI (magnetic resonance imagining) - a device that uses a magnetic field and

radio waves to create detailed images of the body. Unlike CT scanning or general

x-ray studies, no ionizing radiation is involved with an MRI. This procedure is

non-invasive and painless.

The doctor will have to rule out other conditions which may have similar

symptoms, including capsulitis, bursitis, or Freiberg's disease.

What are the treatment options for Morton's neuroma?

Treatment for Morton's neuroma may depend on several factors, including the

severity of symptoms and how long they have been present. The earlier on the

condition is diagnosed, the less likely surgery is required.

Doctors will usually recommend self-help measures first. These may include:

Resting the foot

Massaging the foot and affected toes

Using an ice pack on the affected area (skin should not be directly exposed to

ice, the ice should be in a container or wrapped in something)

Changing footwear - wearing wide-toed shoes, or flat (non high-heeled) shoes

Trying arch supports (orthotic devices). A type of padding that supports the

arch of the foot, removing pressure from the nerve. The doctor may recommend a

custom-made, individually designed shoe-insert, molded to fit the contours of

the patient's foot. There are several OTC (over the counter, non-prescription)

metatarsal pads or bars available which can be placed over the neuroma.

Taking OTC (over-the-counter, non-prescription) painkilling medications

Modifying activities - avoiding activities which put repetitive pressure on the

neuroma until the condition improves.

Bodyweight management - if the patient is obese the doctor may advise him/her to

lose weight. A significant number of obese patients with foot problems, such as

flat feet, who successfully lose weight experience considerable improvement of

symptoms.

If symptoms are severe or persistent and self-help measures did not help, the

doctor may recommend:

Corticosteroid injections - a steroid medication that reduces inflammation and

pain is injected into the area of the neuroma. Only a limited number of

injections are advised, otherwise the risk of undesirable side effects

increases, including hypertension (high blood pressure) and weight gain.

Alcohol sclerosing injections - studies have shown that alcohol injections

reduce the size of Morton's neuromas as well as alleviating pain. This is a

fairly new therapy and may not be available everywhere. The doctor injects

alcohol in the area of the neuroma to help sclerose (harden) the nerve and

relieve pain. Injections are typically administered every 7 to 10 days. For

maximum relief 4 to 7 injections are usually needed.

Surgery - if other therapies have not worked it may be necessary to perform

surgery. As surgery may result in permanent numbness in the affected toe,

doctors ten to use this procedure as a last resort. However, in most cases

surgery is extremely effective.

The patient usually receives a local anesthetic.

Surgery involves either removing the nerve, or removing the pressure on the

nerve. Two surgical approaches are possible:

The dorsal approach - the surgeon makes an incision on the top of the foot,

allowing the patient to walk soon after surgery, because the stitches are not on

the weight-bearing side of the foot.

The plantar approach - the surgeon makes an incision on the sole of the foot. In

most cases the patient will be in crutches for about three weeks. The resulting

scar may make walking uncomfortable. However, with this approach the neuroma can

be reached easily and resected without cutting any structures.

There is a small risk of infection around the toes after surgery.