A neuroma is a thickening of nerve tissue that may develop in various parts of the body. The most common neuroma in the foot is a Morton?s neuroma, which occurs between the third and fourth toes. It is sometimes referred to as an intermetatarsal neuroma. ?Intermetatarsal? describes its location in the ball of the foot between the metatarsal bones. Neuromas may also occur in other locations in the foot. MortonThe thickening, or enlargement, of the nerve that defines a neuroma is the result of compression and irritation of the nerve. This compression creates enlargement of the nerve, eventually leading to permanent nerve damage.
The exact cause is unknown. Doctors believe the following may play a role in the development of this condition. Wearing tight shoes and high heels. Abnormal positioning of toes. Flat feet. Forefoot problems, including bunions and hammer toes. High foot arches. Morton neuroma is more common in women than in men.
If you have a Morton's neuroma, you will probably have one or more of these symptoms. Tingling, burning, or numbness. A feeling that something is inside the ball of the foot, or your sock is bunched up. Pain that is relieved by removing your shoes. A Morton's Neuroma often develops gradually. At first the symptoms may occur only occasionally, when wearing narrower shoes or performing certain activities. The symptoms may go away temporarily by massaging the foot or by avoiding aggravating shoes or activities. Over time the symptoms progressively worsen and may persist for several days or weeks. The symptoms become more intense as the neuroma enlarges and the temporary changes in the nerve become permanent.
The physician will make the diagnosis of Morton's neuroma based upon the patient's symptoms as described above in an interview, or history, and a physical examination. The physical examination will reveal exceptional tenderness in the involved interspace when the nerve area is pressed on the bottom of the foot. As the interspace is palpated, and pressure is applied from the top to the bottom of the foot, a click can sometimes be felt which reproduces the patient's pain. This is known as a Mulder's sign. Because of inconsistent results, imaging studies such as MRI or ultrasound scanning are not useful diagnostic tools for Morton's neuroma. Thus the physician must rely exclusively on the patient's history and physical examination in order to make a diagnosis.
Non Surgical Treatment
Wear shoes with plenty of room for the toes to move, low heels, and laces or buckles that allow for width adjustment. Wear shoes with thick, shock-absorbent soles, as well as proper insoles that are designed to keep excessive pressure off of the foot. High-heeled shoes over two inches tall should be avoided whenever possible because they place undue strain on the forefoot. Resting the foot and massaging the affected area can temporarily alleviate neuroma pain. Use an ice pack to help to dull the pain and improve comfort. Use over-the-counter shoe pads. These pads can relieve pressure around the affected area.
Patients are commonly offered surgery known as neurectomy, which involves removing the affected piece of nerve tissue. Postoperative scar tissue formation (known as stump neuroma) can occur in approximately 20%-30% of cases, causing a return of neuroma symptoms. Neurectomy can be performed using one of two general methods. Making the incision from the dorsal side (the top of the foot) is the more common method but requires cutting the deep transverse metatarsal ligament that connects the 3rd and 4th metatarsals in order to access the nerve beneath it. This results in exaggerated postoperative splaying of the 3rd and 4th digits (toes) due to the loss of the supporting ligamentous structure. This has aesthetic concerns for some patients and possible though unquantified long-term implications for foot structure and health. Alternatively, making the incision from the ventral side (the sole of the foot) allows more direct access to the affected nerve without cutting other structures. However, this approach requires a greater post-operative recovery time where the patient must avoid weight bearing on the affected foot because the ventral aspect of the foot is more highly enervated and impacted by pressure when standing. It also has an increased risk that scar tissue will form in a location that causes ongoing pain.