Morton's neuroma is an enlarged nerve that usually occurs in the third interspace, which is between the third and fourth toes. To understand Morton's neuroma further, it may be helpful to look at the anatomy of the foot. Problems often develop in the third interspace because part of the lateral plantar nerve combines with part of the medial plantar nerve here. When the two nerves combine, they are typically larger in diameter than those going to the other toes. Also, the nerve lies in subcutaneous tissue, just above the fat pad of the foot, close to an artery and vein. Above the nerve is a structure called the deep transverse metatarsal ligament. This ligament is very strong, holds the metatarsal bones together, and creates the ceiling of the nerve compartment. With each step, the ground pushes up on the enlarged nerve and the deep transverse metatarsal ligament pushes down. This causes compression in a confined space.
A Morton's Neuroma is not a true neuroma, which is a tumor that is generally benign. Rather, it is an enlargement of the nerve where it goes between the metatarsal bones of the foot. Because the nerve no longer fits between the gap, the pressure causes pain and sometimes numbness. This enlargement of the nerve is often an inflammation due to irritation. If the forefoot becomes compressed due to shoes that are too narrow, the nerve becomes damaged and inflamed. This inflammation means the nerve no longer fits in the space between the bones, creating further irritation and more inflammation. If this vicious circle can be broken, the problem may be resolved. However, in some situations the nerve can have fibrous tissues formed around it, which may require the destruction of the nerve or surgical removal.
Patients will complain of numbness, a ?pins and needles? type of tingling and loss of sensation in the toes. Burning pain in the ball of the foot that may radiate into the toes. The pain generally intensifies with activity or wearing shoes. Night pain is rare. There may also be numbness in the toes, or an unpleasant feeling in the toes. Runners may feel pain as they push off from the starting block. High-heeled shoes, which put the foot in a similar position to the push-off, can also aggravate the condition. Tight, narrow shoes also aggravate this condition by compressing the toe bones and pinching the nerve.
To confirm the diagnosis, your doctor will examine your feet. He or she will look for areas of tenderness, swelling, calluses, numbness, muscle weakness and limited motion. To check for a Morton's neuroma, your doctor will squeeze the sides of your foot. Squeezing should compress the neuroma and trigger your typical pain. In some cases, your doctor will find numbness in the webbed area between the affected toes. Pain in two or more locations on one foot, such as between both the second and third toes and the third and fourth toes, more likely indicates that the toe joints are inflamed rather than a Morton' neuroma.
Non Surgical Treatment
If you have Morton's neuroma, shoes with a wider toe area may be recommended. You can also take painkillers to help ease the pain. Steroid injections may also be given to treat the affected nerve. If these treatments don't work, surgery may be needed. This involves removing the thickened tissue around the nerve (and sometimes the nerve itself) to release the pressure.
Surgery for Morton's neuroma is usually a treatment of last resort. It may be recommended if you have severe pain in your foot or if non-surgical treatments haven't worked. Surgery is usually carried out under local anaesthetic, on an outpatient basis, which means you won't need to stay in hospital overnight. The operation can take up to 30 minutes. The surgeon will make a small incision, either on the top of your foot or on the sole. They may try to increase the space around the nerve (nerve decompression) by removing some of the surrounding tissue, or they may remove the nerve completely (nerve resection). If the nerve is removed, the area between your toes may be permanently numb. After the procedure you'll need to wear a special protective shoe until the affected area has healed sufficiently to wear normal footwear. It can take up to four weeks to make a full recovery. Most people (about 75%) who have surgery to treat Morton's neuroma have positive results and their painful symptoms are relieved.