A neuroma is an inflammation of the tissue that surrounds a nerve located in the ball of the foot near where the toes begin. Symptoms of this condition can include the sensation of a hard or hot pebble in the ball of the foot, as well as burning, tingling, and numbness in the toes immediately beyond the area of pain in the ball of the foot. The part of the foot most commonly involved is the area between the third and fourth toes (with the count starting at the big toe), although the area between the other toes can be affected as well. The pain of a neuroma generally begins when pressure is placed on the foot after walking for a short while, and can especially worsened when tight shoes are worn that squeeze the ball of the foot together. The pain generally worsens as activity increases, such as during running or when one is walking for awhile. Certain shoes can make this pain worse. Given this, many people with a neuroma will find that removing one's shoes and rubbing often relieves some of the symptoms.
A neuroma is technically inflammation of the tissue that surrounds the nerves that travel between the long bones of the foot towards the toes. These long bones travel from the middle of the arch to the base of the toes. As they near the toes at the front of the long bones, they course under a tight ligament that binds the metatarsal bones to each other. The nerve then splits into two branches, with each branch going to one of the adjacent toes. Several factors can cause nerve inflammation to occur. Many people with a neuroma have either flat feet or high arches. When one has flat feet, the flattening and high flexibility of the feet creates increased pressure to the ball of the foot, and the ligament the nerve travels under becomes tented, causing it to gradually irritate the nerve tissue lying below it. When one has high arches, the ball of the foot sustains an unusual amount of pressure and shock for the opposite reason, since the foot does not have enough flexibility. This pressure will eventually irritate the nerve tissue and will result in inflammation. Those with normal foot structure can also develop neuromas depending on activity, shoe use, and the surface/terrain that the activity takes place on.Technically, a neuroma is not so much an inflammation of the nerve itself but rather the tissue (or sheath) that surrounds the nerve. Also called 'perineural fibrosis', it represents a thickening of the covering of the nerve. Eventually this becomes scarring. The mechanical forces that act on the nerve as described above allow the scarring and inflammation to gradually increase, until the section of the nerve covering that is irritated begins to resemble a small onion wrapped around the nerve. This bulging of the nerve tissue can cause other changes in the foot, such as the feeling there is 'clicking' when the ball of the foot is moved around. Sometimes even a separation of the toes occurs beyond the location of the neuroma as the mass takes shape and displaces the tissue around it. When shoes are worn that are tighter at the ball of the foot, the side-to-side pressure on the nerve can worsen the pain and cause increased scarring.
Treatment is vital to relieving this condition, as persistent irritation can lead to long term nerve problems. The components of treatment are centered around relieving the inflammatory process and restoring normal pressure to the ball of the foot to reverse the swelling and scarring around the nerve. Anti-inflammatory measures are often effective and can consist of steroid (cortisone-like) injections directly at the irritated area, as well as oral anti-inflammatory medications to reduce the body's capability to create inflammation and the old standby technique of icing. Physical therapy can sometimes be helpful if these measures fail, although the benefit is not very consistent. In very severe cases, the foot may have to be immobilized in a walking boot to help decrease inflammation. To relieve the mechanical pressure causing this condition, prescriptions foot inserts (orthotics) are required, as over-the-counter inserts have too little control over the foot structure. Wider shoes to reduce squeezing on the nerve are absolutely necessary.
When all the above treatment attempts fail and the painful neuroma persists, then surgery is required. The most common technique involves an actual removal of the inflamed nerve and the branches that split towards the involved toes. Although this results in permanent light numbness at the ball of the foot where the nerve is located as well as the inner sides of the toes the nerve serves, most sufferers of a neuroma will gladly trade the pain for numbness. Healing is usually uneventful, the only major complications being painful fluid temporarily filling the space the nerve occupied, or partial regrowth of the cut ends of the nerve that can cause neuroma-like pain if they are not buried deep enough in the foot to prevent this regrowth from occurring. This condition is called a stump neuroma, and surgeons always take extra steps to prevent this from occurring, resulting usually in a low occurrence rate.