The term neuroma refers to a painful inflammation that can occur in one of the nerves in the bottom of the foot.
The space (interspace) between the third and fourth toes is most commonly affected with the space between the second and third toes the next most commonly involved.
Why neuromas form is not entirely clear. The most likely cause seems to be an irritation of the plantar digital nerve branches over a long period of time. Irritating factors such as faulty footwear, walking on hard floors, standing for long periods of time, and previous injuries may be a source of irritation. Prolonged irritation of the tissue in the region of the nerve can cause thickening of the nerve.
The most common symptoms of an interdigital neuroma is pain localized to the bottom of the foot between the metatarsal heads. The pain often increases with walking and is relieved by resting the foot. The pain is usually well localized to the bottom of the foot, but will often radiate to the tips of the toes of the involved interspace. Occasionally there is a feeling of numbness in the distribution of the nerve itself. Also, occasionally patients complain of having the feeling of a marble or stone underneath the forefoot region or the feeling that there is something moving around on the bottom of the foot which when caught in the right position causes acute, sharp pain.
Treatment with pads can give temporary relief as well as an injection into the involved interspace with cortisone and local anesthetic. Sometimes an injection is useful in determining which interspace is involved.
Surgical treatment for a neuroma is an excision of the nerve. A foot block is used to numb the foot and a small incision is made on the top of the foot. This is an outpatient procedure and usually a patient is at the hospital for approximately two hours. A small bulky dressing is used right after surgery and then a smaller dressing used and changed on a weekly basis for 3 weeks. Patients do note decreased sensation in the area where the nerve formerly traveled.