One of the more common causes of foot pain occurs in the ball of the foot. Although many conditions can cause pain at that location, one condition in particular stands out as having a rather unique set of symptoms. This common condition is called a neuroma, and has been the scourge of women and men in tight dress shoes alike, as well as runners.
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 second and third toes is often affected as well. Neuromas can occur in the remaining spaces, although this is far less common. The pain of a neuroma generally begins when pressure is placed on the foot after walking for a short while, and can especially be irritated 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 abnormal pressure to the ball of the foot, and the ligament the nerve travels under becomes strained, 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 cause irritation to the nerve tissue and will result in inflammation. Those with normal foot structure can also develop neuromas depending on activity, shoe use, and the 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 and eventual scarring of the covering of the nerve. 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 sensation of clicking when the ball of the foot is moved around, or even a separation of the toes beyond 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 mainstays of treatment are centered around relieving the inflammatory process and restoring normal pressure to the ball of the foot to reverse the fibrosis 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 in this author’s experience the benefit is not very consistent. Some physicians may also inject a diluted alcohol solution into the nerve region to destroy the scar tissue. 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. These control measures are generally required for a lengthy period of time, since one’s foot structure does not generally change.
When all the above treatment attempts fail and the painful neuroma persists, then surgery is required. Many different surgical techniques have been performed to remove or reduce a neuroma. 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. Other techniques are available to treat neuromas, depending on surgeon preference. This can include a minimally invasive surgery using a scope to simply release the ligament over the top of the nerve, resulting in decompression of the region around the neuroma. Freezing therapy is also performed by some surgeons to destroy the irritated nerve tissue.
Neuromas are very common, and can be the source of significant pain when left untreated. Despite the common nature of a neuroma, there are other conditions causing pain in the ball of the foot that can be partially similar to that of a neuroma. A foot specialist can easily identify the actual cause of pain. For relief, simple changes in shoes, as well as basic treatment by a foot specialist can usually result in relief without requiring surgery. When the pain persists despite treatment, surgery is required. Fortunately, surgery does have a high rate of success.