Morton’s Neuroma

Description

A Neuroma, or Morton’s Neuroma, is a benign soft tissue mass that forms on the nerve that runs between the metatarsals, in the ball of the foot. It is not actually a tumor but a perineural fibrosis. There is a confluence of the medial and lateral plantar nerve between the third and fourth metatarsal heads and often at this junction the nerve is somewhat thicker. An intermetarsal neuroma can affect other spaces; the most common however is the third intermetatarsal space. The deep transverse ligament lies over this area and it is thought to apply some additional pressure. When two metatarsal bones rub together, they pinch the nerve that runs between them. This repeated pinching, or continuous minute trauma to the nerve, will cause the nerve to swell, and eventually a benign mass occurs at the site of the repeated injury. This mass is known as a Morton’s Neuroma (named after the physician who first described this mass, Thomas Morton in 1876).


 Symptoms

The most common symptoms of a neuroma may include:

  1. Pain in the ball of your foot radiating to adjacent toes.
  2. Neuromas can form between all of the metatarsal heads and toes, but the most commonly affected area is between the 3rd and 4th metatarsal heads and toes.
  3. The pain can be sharp, burning, or tingling in nature.
  4. The pain is usually present only when wearing shoes (especially narrow dress shoes), and gradually goes away when the shoes are removed. The removal of the shoe and gentle massage for almost immediate relief is a characteristic symptom.
  5. Numbness in adjacent toes.
  6. When the neuroma is large; patients complain that they can feel a “clicking” between the affected metatarsals. In a clinical examination the doctor can often replicate the “clicking” feeling by lateral compression and application of plantar pressure to the area. This is know as a “Mulders Click”.
  7. Swelling of the area.

Depending on the size and location of the neuroma, patients may experience some, or all of the above symptoms.


Causes

A Morton’s neuroma forms when two adjacent metatarsal heads rub together in the ball of the foot. The nerve that lies between these bones is thus pinched and irritated; and, if this pinching continues, a neuroma (perineural fibrosis) eventually forms. In the normal foot, the five metatarsals are held tightly in place, in a precise relationship to each other, so that they do not rub together. In the Morton’s neuroma foot type, the ligaments and tendons that hold the metatarsals in their normal positions are more flexible (lax) than normal. This abnormal flexibility may be a result of: biomechanical foot defects that we inherit from our parents, the weakening of muscles and ligaments caused by advancing age, or injury. A closer look at these causes of Morton’s Neuroma is necessary if we are to understand how these masses can be prevented and treated: Biomechanical Foot Defects are those defects that we are born with, which predisposes us to Morton’s Neuroma:

  1. Hyper-Flexible Feet: The normal foot is made up of bones and joints that are held firmly together in a precise relationship. When the ligaments and tendons that hold the bones and joints together are more flexible (lax) than normal, the metatarsals are able to drift towards each other. When this occurs, the metatarsals rub together and pinch the nerve that lies between them. This abnormal flexibility is usually a result of the genes we inherit from our parents.
  2. Age-Related Changes of Ligaments Muscles, and Tendons: As people age, the ligaments, muscles, and tendons of the foot begin to lose strength, and become thinner. As the aging process progresses, these structures cannot always hold the metatarsals in their normal positions. If this occurs, the metatarsals may begin to drift towards each other and pinch the nerve that lies between them. Again, if this is allowed to continue, a Morton’s Neuroma may form.
  3. Injury: The two classes of injuries that may contribute to the formation of Morton’s Neuroma are:
    1. Macro-trauma. An example of this type of injury would be a broken metatarsal bone that does not heal straight, and is bent towards the adjacent metatarsal. This situation may allow the metatarsal heads to rub together and pinch the nerve between them.
    2. Micro-trauma. An example of this type of injury would be a woman’s dress shoe with a pointed toe. These shoes are narrow across the ball of the foot and squeeze the metatarsals together. After thousands of steps in this type of shoe, the nerve between the metatarsal heads may become pinched, inflamed, and painful. Eventually a neuroma may form on the nerve.

Custom Treatments

The old adage, “An once of prevention is worth a pound of cure,” is most appropriate when trying to prevent a Morton’s Neuroma from forming, or when treating a neuroma in its earliest stages.

Long Term Treatment/Prevention must be directed towards:

  1. Preventing adjacent metatarsal heads from rubbing together and irritating the nerve that lies between them.
  2. Maintaining the individual bones, joints, muscles, ligaments, and tendons of the Hyper-Flexible Foot and Aging Foot in a normal alignment. This will prevent the metatarsals from drifting towards each other and irritating the nerve between them.
  3. Providing shock absorption to the ball of the foot. This will help to support and protect the metatarsal heads and the nerves between them. As we age, the protective fatty pad on the ball of the foot becomes thinner, and cannot act as a shock absorber for the sensitive nerves and other structures in the ball. Thus, the tremendous forces exerted on the foot with each step we take are passed on to the nerves and bones, rather than being absorbed by the fatty pad. Eventually, these forces could help to irritate the nerves in the balls of the feet, causing a Morton’s neuroma to form.

Custom-Made Orthotics are considered to be the most effective conservative treatment for Morton’s neuroma, especially in is early stages. Our custom-made orthotics for this condition are constructed of comfortable, shock absorbent materials, which gently and effectively:

  1. Prevent the metatarsals from pinching the nerves, which run between them. Our custom-made orthotics may use a Morton’s Neuroma Pad that is strategically placed so that it can help to keep themetatarsals apart. In so doing, the metatarsals do not rub on the nerve. This greatly reduces the chances of nerve irritation and the formation of a Morton’s neuroma. The Pad is made of a soft and comfortable material and is built into the forefoot of the orthotic (that part of the orthotic that lies under the ball of the foot).
  2. Replace the protective fatty pad in the balls of the feet. In the construction of our custom-made orthotics, we protect the balls of the feet with materials that will absorb friction and excessive pressure, rather then passing these forces on to the nerves and bones in the balls of the feet. The “space-age” materials that we use act as though more fat and padding were added to the feet, without adding excessive bulk.
  3. Support the arch of the foot so that it can aid in shock absorption. The primary shock absorber of our feet is the arch. To aid this structure so that it can properly support the foot and absorb shock, we construct our custom-made orthotics so that they provide semi-flexible support to the arch to absorb the shock of each step, rather than our foot absorbing the shock.
  4. Adjust and accommodate for any abnormal walking patterns you have, such as pronation (a rolling out of the foot, forcing you to walk with more pressure on the inner aspect of the foot), in toeing, out toeing, etc. This will insure proper weight distribution across the balls of our feet when we walk. Thus, our custom-made orthotics will allow the feet to function in a normal position when they strike the ground, rather than in a twisted position, thus removing excessive weight and pressure from the balls of the feet. This will reduce the chances of nerve irritation in the balls of the feet.

Self-Help Treatments

Immediate Self-Treatment:

  1. Wear a wider shoe with a padded innersole. Women should wear flat shoes. This removes lateral compression on the neuroma.
  2. Use a gel pad to cushion the ball of the foot.  Dr. Jill’s Pads protect the tender neuroma and offer temporary pain relief.  These re-usable gel pads will fit in all shoe styles, including most dress shoes
  3. Apply ice to the painful area in the ball of the foot (avoid ice directly on the toes). The ice should give a soothing coolness to the area…do not freeze the area). Apply the ice for 10 minutes at a time, about every 3 or 4 hours. If the ice makes the pain worse, stop immediately.
  4. Gentle massage with a topical pain reliever can help to provide comfort. By combining the pain relieving properties of Corganics Relief Topic Analgesic Cream with gentle massage, pain, swelling, and inflammation can be reduced or eliminated.
  5. If the pain is intense or present all the time, see a doctor for treatment. Also, if you are a diabetic, have poor circulation, or have other serious medical problems, discuss your foot symptoms with your physician. Lastly, if you can feel a mass, or the area is discolored or inflamed, or an open wound is present, see your doctor immediately.

If Conservative Care Fails

If your pain is severe or persistent, and conservative approaches aren’t working, your doctor may recommend:

  1. Injections of Corticosteroids (Cortisone Injections). Cortisone, or corticosteroids, is medication that reduce inflammation. Injections of cortisone into the area of the neuroma may reduce pain and inflammation of the nerve. Recurrence of symptoms may be lessened by combining cortisone injections with other forms of treatment such as orthotics, changes in shoe gear, shoe pads, and rest. Overuse of these injections may lead to a number of side effects, including rupture of tendons and ligaments, thinning of the fatty pad in the ball of the foot, and other tissue changes.
  2. Alcohol injections (Chemical Neurolysis). According to recent studies, diluted alcohol injections have been shown to improve pain and decrease the size of Morton’s neuroma.The intent of chemical neurolysis is to destroy the internal contents while preserving the external sheath of the nerve. With the nerve sheath intact, regeneration of the nerve without a neuroma is possible in a controlled manner utilizing the existing sheath. By contrast, removal of the nerve by surgery sometimes results in the nerve regenerating and the formation of a mass of scar tissue called a stump neuroma. Stump neuromas in time may become painful.
  3. Surgical Removal Of The Neuroma may be necessary if other treatments fail to provide pain relief. Although surgery is usually successful, doctors often turn to surgery as a last resort, because the procedure removes both the neuroma and the nerve, which can leave permanent numbness in the affected toes as well as the formation of a painful stump neuroma.
  4. Nerve Decompression: It is thought that, in many cases, the nerve is pinched by the overlying ligament that connects the metatarsal heads together. A Morton’s neuroma results from this continuous pinching of the nerve. A simple surgery allows the release of this ligament allowing for increased space for the nerve and relief of pain. This surgery leaves the nerve intact and allows continued sensation to the toes.

Because of the possible complications involved with any surgery, one should be sure to understand the risks that may be involved with Morton’s neuroma surgery.