Morton?s Neuroma is a pathological condition of the common digital nerve in the foot, most frequently between the third and fourth metatarsals (third inter-metatarsal space). The nerve sheath becomes abnormally thickened with fibrous (scar) tissue and the nerve fibres eventually deteriorate.This condition is named for the American surgeon, Thomas George Morton (1835-1903), who first recognised the condition in 1876. Incidentally his father was the dentist who discovered the anaesthetics; initially Nitrous oxide, the very gas used today in cryosurgery for the condition his son lent his name to? Morton?s neuroma.
Morton’s neuroma is an inflammation caused by a buildup of fibrous tissue on the outer coating of nerves. This fibrous buildup is a reaction to the irritation resulting from nearby bones and ligaments rubbing against the nerves. Irritation can be caused by Wearing shoes that are too tight. Wearing shoes that place the foot in an awkward position, such as high heels. A foot that is mechanically unstable. Repetitive trauma to the foot such as from sports activities like tennis, basketball, and running. Trauma to the foot caused by an injury such as a sprain or fracture. It is unusual for more than one Morton’s neuroma to occur on one foot at the same time. It is rare for Morton’s neuroma to occur on both feet at the same time.
Many patients describe the sensation as a burning pain in the ball of the foot that often radiates to the toes. Initially, the pain may become much more apparent when the person wears tight, narrow or high-heeled shoes, or engages in activities which place pressure on the foot. Eventually, symptoms may be continuous and last for days, and even weeks. MRI (magnetic resonance imaging) scans have revealed Morton’s neuroma lesions in patients who had no symptoms at all. Symptoms can become so disrupting that many affected individuals become anxious about walking, or even placing their foot on the ground.
The exact cause of Mortons neuroma can often vary between patients. An accurate diagnosis must be carefully made by the podiatrist through thorough history taking and direct questioning to ensure all possible causes are addressed. The podiatrist will also gather further information about the cause through a hands on assessment where they will try to reproduce your symptoms. A biomechanical and gait analysis will also be performed to assess whether poor foot alignment and function has contributed to your neuroma.
Non Surgical Treatment
Simple treatments may be all that are needed for some people with a Morton’s neuroma. They include the following. Footwear adjustments including avoidance of high-heeled and narrow shoes and having special orthotic pads and devices fitted into your shoes. Calf-stretching exercises may also be taught to help relieve the pressure on your foot. Steroid or local anaesthetic injections (or a combination of both) into the affected area of the foot may be needed if the simple footwear changes do not fully relieve symptoms. However, the footwear modification measures should still be continued. Sclerosant injections involve the injection of alcohol and local anaesthetic into the affected nerve under the guidance of an ultrasound scan. Some studies have shown this to be as effective as surgery.
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.