What Causes Mortons Neuroma

Overview

MortonAlso known as Morton's Interdigital Neuroma, Morton's Metatarsalgia, Morton's Neuralgia, Plantar Neuroma, Intermetatarsal Neuroma) What is a Morton's neuroma? Morton's neuroma is a condition characterized by localized swelling of the nerve and soft tissue located between two of the long bones of the foot (metatarsals - figure 1), which can result in pain, pins and needles, or numbness in the forefoot or toes.

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

A Morton's neuroma usually causes burning pain, numbness or tingling at the base of the third, fourth or second toes. Pain also can spread from the ball of the foot out to the tips of the toes. In some cases, there also is the sensation of a lump, a fold of sock or a "hot pebble" between the toes. Typically, the pain of a Morton's neuroma is relieved temporarily by taking off your shoes, flexing your toes and rubbing your feet. Symptoms may be aggravated by standing for prolonged periods or by wearing high heels or shoes with a narrow toe box.

Diagnosis

Podiatrists conduct a physical examination and may order imaging tests, such as x-ray or MRI scan to diagnose Morton's neuroma. Conservative treatment options include custom-fitted orthotics, medication, and/or alcohol injections designed to harden the nerve. However, most patients with Morton's neuroma need minor surgery.

Non Surgical Treatment

To help relieve the pain associated with Morton's neuroma and allow the nerve to heal, consider the following self-care tips. Take anti-inflammatory medications. Over-the-counter nonsteroidal anti-inflammatory medications, such as ibuprofen (Advil, Motrin IB, others) and naproxen (Aleve), can reduce swelling and relieve pain. Try ice massage. Regular ice massage may help reduce pain. Freeze a water-filled paper cup or plastic foam cup and roll the ice over the painful site. Change your footwear. Avoid high heels or tight shoes. Choose shoes with a broad toe box and extra depth. Take a break. For a few weeks, reduce activities such as jogging, aerobic exercise or dancing that subject your feet to high impact.interdigital neuroma

Surgical Treatment

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.

Prevention

Always warm-up thoroughly before vigorous athletics. Avoid activities that cause pain. Stretch and strengthen the feet through gradual exercise.
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