Put simply - Morton's neuroma is a swollen (inflamed) nerve in the ball of the foot, commonly between the base of the second and third toes. Patients experience numbness and pain in the affected area, which is relieved by removing footwear and/or massaging the foot. A neuroma is a tumor that arises in nerve cells, a benign growth of nerve tissue that can develop in various parts of the body. In Morton's neuroma the tissue around one of the nerves leading to the toes thickens, causing a sharp, burning pain in the ball of the foot. A sharp severe pain, often described as a red hot needle may come on suddenly while walking. There may also be numbness, burning and stinging in the toes. Although it is labeled a neuroma, many say it is not a true tumor, but rather a perineural fibroma (fibrous tissue formation around nerve tissue).
When a nerve is pinched between bones, the result is swelling of the nerve. It is this swelling which is referred to as a Neuroma. When the condition occurs in the foot, it is known as a Morton?s Neuroma. Morton?s Neuroma is technically not a tumor. Rather, it is a thickening of the tissue that surrounds the digital nerves leading to the toes. These nerves allow for physical sensation on the skin of the toes. The region of inflammation is found where the digital nerve passes under the ligament connecting the toe bones (metatarsals) in the forefoot. Morton?s Neuroma commonly develops between the third and fourth toes, generally as a result of ongoing irritation, trauma or excessive pressure. In some cases, the second and third toes are involved. Morton?s Neuroma is confined to one foot in most cases, though it can occur in both, particularly in athletes such as runners.
Pain is usually increased by forefoot weight bearing activities (such as running), with narrow-fitting footwear, or with high heeled shoes. It is usually painful to firmly touch the affected region and, in chronic cases, pain and sometimes an audible click, may be heard when squeezing the foot and toes together with the hand. Often a localized area of swelling may be evident at the site of injury.
Plain x-rays of the foot may demonstrate that one or more of the metatarsals are long (Figure #5). Not uncommonly, the second and/or third metatarsal may be long relative to the third or fourth. This can create a situation where excessive load is occurring in and around the vicinity of the interdigital nerve.
Non Surgical Treatment
Most non-operative treatment is usually successful, although it can take a while to figure out what combination of non-operative treatment works best for each individual patient. Non-operative treatment may include the use of comfort shoe wear. The use of a metatarsal pad to decrease the load through the involved area of the plantar forefoot. A period of activity modification to decrease or eliminate activities, which maybe exacerbating the patient?s symptoms. For example, avoiding long periods of standing or other activities that result in significant repetitive loading to the forefoot can be very helpful. Wearing high heels should be avoided. Local corticosteroid injections can help decrease inflammation associated with the nerve. However, this does not necessarily address the underlying loading forces that maybe causing the injury to the nerve in the first place. It has been proposed that an alcohol injection in and around the nerve will cause a controlled death to the nerve and subsequently eliminate symptoms from the nerve. In theory, this may be helpful. In practice, adequate prospective studies have not demonstrated the benefit of this procedure above and beyond the other standard non-operative treatments available. In addition there is the concern that the alcohol will cause excessive scarring and death of other important structures in the area.
Operative treatment of Morton?s neuroma should be entertained only after failure of non-operative management. Standard operative treatment involves identifying the nerve and cutting (resecting) it proximal to the point where it is irritated/injured. This is usually done through an incision on the top (dorsal) aspect of the foot, although an incision on the sole (plantar) aspect of the foot can be used. Some physicians will attempt to treat Morton?s neuroma by releasing the intermetatarsal ligament, and freeing the nerve of local scar tissue. This may also be beneficial.