Morton neuromas are focal areas of symptomatic perineural fibrosis around a plantar digital nerve of the foot. The abnormality is non-neoplastic and does not represent a true neuroma. It may more correctly be known as Morton?s metatarsalgia. The condition is thought to be due to chronic entrapment of the nerve by the intermetatarsal ligament. It most often occurs in middle-aged individuals and is many times more common in women than men. Approximately 30% of asymptomatic middle-aged persons have the radiological pathologic findings of a Morton?s neuroma.
The cause of this problem is often due to impingement of the plantar nerve fibres between the metatarsal heads and the intermetatarsal ligament. It is entirely a biomechanical phenomenon. Differential diagnoses include stress fracture, capsulitis, bursitis or ligament injury at the metatarsal-phalangeal joint, a tendon sheath ganglion, foreign-body reaction and nerve-sheath tumour.
What are the symptoms of Morton?s neuroma? A sharp or stinging pain between the toes when standing or walking. Pain in the forefoot between the toes. Swelling between the toes. Tingling (?pins and needles?) and numbness. Feeling like there is a ?bunched up sock? or a pebble or marble under the ball of the foot.
A GP (general practitioner, primary care physician) or a podiatrist (foot specialist doctor) will ask the patient to describe the pain as well as its intensity, when symptoms started, what types of shoes are worn, as well as some questions about their job, lifestyle and hobbies. The doctor will then examine the foot and try to locate the affected nerve. This may involve attempting to reproduce symptoms by manipulating the foot. In order to get a detailed image of the inside of the food, one of the following scans may be ordered. X-ray, this is a type of high-energy radiation. In low doses they are used to diagnose diseases and condition by making pictures of the inside of the body. In higher doses they are used to treat cancer. This procedure is non-invasive and painless. Ultrasound scan, high frequency sound waves are pointed at a specific part of the body, which in this case is the foot. The ultrasound waves bounce of tissues; their echoes are then converted into a picture, called a sonogram. This allows the doctor to get an inside view of the foot. This procedure is non-invasive and painless. MRI (magnetic resonance imagining) a device that uses a magnetic field and radio waves to create detailed images of the body. Unlike CT scanning or general x-ray studies, no ionizing radiation is involved with an MRI. This procedure is non-invasive and painless. The doctor will have to rule out other conditions which may have similar symptoms, including capsulitis, bursitis, or Freiberg’s disease.
Non Surgical Treatment
If symptoms are severe or persistent and self-help measures did not help, the doctor may recommend corticosteroid injections, a steroid medication that reduces inflammation and pain is injected into the area of the neuroma. Only a limited number of injections are advised, otherwise the risk of undesirable side effects increases, including hypertension (high blood pressure) and weight gain. Alcohol sclerosing injections, studies have shown that alcohol injections reduce the size of Morton’s neuromas as well as alleviating pain. This is a fairly new therapy and may not be available everywhere. The doctor injects alcohol in the area of the neuroma to help sclerose (harden) the nerve and relieve pain. Injections are typically administered every 7 to 10 days. For maximum relief 4 to 7 injections are usually needed.
Operative treatment of Morton?s neuroma should be entertained only after failure of nonoperative management. Standard operative treatment involves identifying the nerve and cutting (resecting) it proximal to the point where it is irritate/injured. This is usually done through an incision on the top (dorsal) aspect of the foot, although in rare instances, an incision on the sole (plantar) aspect of the foot maybe used. An incision on the sole of the foot works very well, unless an excessive scar forms in which case it can be problematic. Some physicians will attempt to treat Morton?s neuroma by releasing the intermetatarsal ligament and freeing the nerve of local scar tissue. This may also be beneficial.
Wearing shoes that fit properly and that have plenty of room in the toe area may help prevent Morton’s neuroma.