Morton neuroma (interdigital neuroma), first described in 1876, is a perineural fibrosis and nerve degeneration of the common digital nerve. Morton neuroma, or Morton's neuroma, is not a true neuroma, although it results in neuropathic pain in the distribution of the interdigital nerve secondary to repetitive irritation of the nerve. The most frequent location is between the third and fourth metatarsals (third webspace). Other, less common locations are between the second and third metatarsals (second webspace) and, rarely, between the first and second (first webspace) or fourth and fifth (fourth webspace) metatarsals.
There are many reasons to develop a neuroma. Improper shoe gear is probably the most likely cause. Repetitive activity and excessive pressure on the ball of the foot are common. Heredity and genetic factors may also be involved. In many cases the structure of the foot may predispose the condition. Associated conditions that may cause neuroma include: bunion, hammer toes, ligament laxity, and/or a tight calf muscle. Some patients may have thinning of the fat pad on the ball of the foot, which may result in increased pressure of the nerves. Tight pointy shoes (and high heels) without padding may induce pain in the ball of the foot. Neuroma may occur suddenly, or develop over time.
The most common presenting complaints include pain and dysesthesias in the forefoot and corresponding toes adjacent to the neuroma. Pain is described as sharp and burning, and it may be associated with cramping. Numbness often is observed in the toes adjacent to the neuroma and seems to occur along with episodes of pain. Pain typically is intermittent, as episodes often occur for minutes to hours at a time and have long intervals (ie, weeks to months) between a single or small group of multiple attacks. Some patients describe the sensation as "walking on a marble." Massage of the affected area offers significant relief. Narrow tight high-heeled shoes aggravate the symptoms. Night pain is reported but is rare.
Your health care provider can usually diagnose this problem by examining your foot. A foot x-ray may be done to rule out bone problems. MRI or ultrasound can successfully diagnose the condition. Nerve testing (electromyography) cannot diagnose Morton neuroma. But it may be used to rule out conditions that cause similar symptoms. Blood tests may be done to check for inflammation-related conditions, including certain forms of arthritis.
Non Surgical Treatment
In developing a treatment plan, your foot and ankle surgeon will first determine how long you?ve had the neuroma and evaluate its stage of development. Treatment approaches vary according to the severity of the problem. For mild to moderate neuromas, treatment options may include Padding techniques provide support for the metatarsal arch, thereby lessening the pressure on the nerve and decreasing the compression when walking. Placing an icepack on the affected area helps reduce swelling. Custom orthotic devices provided by your foot and ankle surgeon provide the support needed to reduce pressure and compression on the nerve. Activities that put repetitive pressure on the neuroma should be avoided until the condition improves. Wear shoes with a wide toe box and avoid narrow-toed shoes or shoes with high heels. Oral nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may be recommended to reduce pain and inflammation. Treatment may include injections of cortisone, local anesthetics or other agents.
For severe or persistent pain, you may need surgery to remove the neuroma. Once the nerve is gone, you permanently lose feeling in the affected area. One alternative to surgery is to undergo neurolysis injections. These use chemical agents to block pain signals. Another alternative is to take a prescription pain reliever that alleviates nerve pain.