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.
The pain of Morton’s neuroma occurs when the nerve connecting the toe bones (metatarsal bones) becomes irritated or compressed. The exact cause of the irritation is unknown, but it may be the metatarsal bones pressing against the nerve when the gap between the bones is narrow. This causes the nerve and surrounding tissue to thicken. Some experts believe that a number of other foot problems, including flat feet, high foot arches, bunions and hammer toes, may also play a role in Morton’s neuroma.
Symptoms typically include pain, often with pins and needles on one side of a toe and the adjacent side of the next toe. Pain is made worse by forefoot weight bearing and can also be reproduced by squeezing the forefoot to further compress the nerve. Pressing in between the third and forth metatarsals for example with a pen can also trigger symptoms.
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 high-resolution ultrasound can successfully diagnose Morton’s neuroma. Nerve testing (electromyography) cannot diagnose Morton’s neuroma, but 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
Depending on your overall health, symptoms and severity of the neuroma, the condition may be treated conservatively and/or with surgery. Non-surgical methods for neuroma are aimed at decreasing and/or eliminating symptoms (pain). Wear proper supportive shoes. Use an arch support. Wear shoes with a wide toe box. Modify your activities. Lose weight. Wear shoes with cushion. Prescribe an oral anti-inflammatory medication. Anti-inflammatory medication is useful to significantly reduce pain and inflammation. A physical therapist may perform ultrasound and other techniques to reduce inflammation. You will also be instructed how to stretch your foot and leg properly. Padding and/or cushioning of the ball of the foot is an effective method of preventing physical irritation with shoes. A custom foot orthotic is a doctor prescribed arch support that is made directly from a casting (mold) of your feet, and theoretically should provide superior support compared to shoe insert that you would purchase from a pharmacy. A cortisone injection is a powerful anti-inflammatory medication that is used to rapidly reduce the pain associated with an inflamed nerve. The pain relief that you may experience from the injection(s) is often temporary. Typically injection(s) are administered once every 2 months for a total of 3 injections or until the pain is resolved. A sclerosing alcohol injection is placed around the involved nerve to weaken its capacity to report pain. In other words, the alcohol injection will ?deaden? the affected nerve. The pain relief that you may experience from the injection(s) can be permanent. Typically injection(s) are administered once every week for a few weeks until the pain is resolved.
Surgery for mortons neuroma consists of either a decompression, where more space is created for the nerve or a resection, where this part of the nerve is removed completely. This will result in some permanent minor numbness. Success rates for surgical procedures to treat mortons neuroma have a high success rate.
While Morton?s Neuroma has been an ongoing topic of clinical investigation, the condition is in some cases difficult to either treat or prevent. Experimental efforts involving the injection of muscle or bone with chemicals such as alcohol, as well as suturing, and covering affected areas with silicone caps have been attempted, with varying success.