What Causes Mortons Neuroma

Overview

Morton’s neuroma, also called Morton’s metatarsalgia, Morton’s disease, Morton’s neuralgia, Morton metatarsalgia, Morton nerve entrapment, plantar neuroma, or intermetatarsal neuroma is a benign (non-cancerous) growth of nerve tissue (neuroma) that develops in the foot, usually between the third and fourth toes (an intermetatarsal plantar nerve, most commonly of the third and fourth intermetatarsal spaces). It is a common, painful condition.

Causes

Some say that this condition should not be called Morton’s neuroma as, in fact, it is not actually a neuroma. A neuroma is a non-cancerous (benign) tumour that grows from the fibrous coverings of a nerve. There is no tumour formation in Morton’s neuroma. The anatomy of the bones of the foot is also thought to contribute to the development of Morton’s neuroma. For example, the space between the long bones (metatarsals) in the foot is narrower between the second and third, and between the third and fourth metatarsals. This means that the nerves that run between these metatarsals are more likely to be compressed and irritated. Wearing narrow shoes can make this compression worse.

Symptoms

You may initially experience a tingling sensation in the space between your toes, which gets worse over time. This leads to cramp in your toes and a sharp shooting or burning pain on the ball of your foot or at the base of your toes. The pain is often worse when walking or wearing shoes that press on the affected area. This is caused by irritation of the nerve between your toe bones (metatarsal bones). The tingling will eventually lead to pain, which can get worse over time. You may also experience cramping of your toes. The pain is usually felt as a sharp shooting or burning pain on the ball of the foot or at the base of the toes, which is often made worse when you’re walking. Some people with Morton’s neuroma feel anxious about walking or even placing their foot on the ground. The pain is likely to be more intense if you wear tight shoes, so wearing shoes that have more room in the toe area can help. Rubbing your foot may also lessen the pain.

Diagnosis

X-rays of your affected foot will not show a neuroma, as neuromas are made up of soft tissue. X-rays may be helpful, however, in helping rule in osteoarthritis or a stress fracture as the cause of your symptoms. Ultrasonography and MRI are sometimes used to help diagnose neuromas, although they are often ineffective. The clinical diagnosis by a foot care expert with experience treating this health problem is usually the most effective way to diagnose neuromas. Your podiatrist will attempt to duplicate your neuroma symptoms by pressing on the involved nerve at various points, and he or she may try to cause a clicking of your nerve that indicates nerve enlargement.

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.

Surgical Treatment

Interdigital neurectomy (removal of the diseased nerve) in right hands, should give satisfactory results almost all the time. Some of the reasons behind failure is when not enough nerve is dissected, mistakes in initial diagnosis, or bad handling of adjacent nerves, tendons and joint capsules during the operation. It is very common and acceptable to have some numbness in the area where the nerve used to be. This never causes any discomfort and often gets better in few years. It is crucial to address the biomechanical pathologies underlying the impingement of the nerve during and after the surgery.