Neuroma or neuromata is a benigntumor composed chiefly of neurons and nerve fibers, usually arising from a nerve tissue. In the foot, it is usually located in the web between the third and fourth toes.
A neuroma is a tumor and can occur anywhere there is a nerve. The offended nerve is being pinched or impinged upon for a number of reasons. It is not uncommon for a tight shoe to result in an impinged nerve in the foot.
Aside from the toes, the most common neuroma is under a metatarsal head (bone) in the middle of the foot. It is also possible to develop a similar inflammation on the side of the big toe.
The interdigital nerve to the third and fourth toes is formed by a third digital branch of the medial plantar nerve and a connecting branch from the lateral plantar nerve. In 1876, Morton described a painful condition of the forefoot that he attributed to neuritis of this digital nerve.
The symptoms includ pain centered around the fourth metatarsophalangeal joint and in the third intermetatarsal space. Pain is exacerbated by weight bearing and in some cases is steadily progressive. Structural metatarsalgia is experienced almost exclusively during weight bearing and is relieved by rest.
The symptoms are a burning, tingling, numbing, and/or pins-and-needles sensation.
Neuroma pain is distinguishable from simple structural foot pain by the fact that it is constant and not relieved by rest.
Diagnosis is based on the history and physical examination. The complaint of unremitting pain in the interspaces of the foot is highly suggestive. Palpation of the space reproduces, sharp, stabbing pain, as does compression of the interspaces produced by squeezing the forefoot circumferentially.
Simple metatarsalgia can be ruled out by a trial of shoe inserts to pad the metatarsals. Neuroma pain will rarely respond to those orthotics alone.
Intractable neuroma pain in the intermetatarsal space unresponsive to shoe pads requires surgical treatment. Treatment consists of excision of the nerve through a longitudinal incision in the dorsal web space. Many patients describe dramatic relief of symptoms immediately after surgery.