Morton's neuroma is a thickened nerve between the 3rd and 4th toes. Such digital nerves can also become thickened between other toes in which case the condition is called an interdigital neuroma. (Mr Morton only described the nerve between the 3rd and 4th toe only). The term neuroma is slightly incorrect as the condition should be called a peri-neural fibroma i.e. a nerve that becomes abnormally thickened with fibrous tissue.
Generally speaking, neuromas tend to form together with a fluid filled bag called a bursa. This "neuroma bursa complex" occurs to protect the nerve. However, rather than proving to be a solution the reaction causes more pain. Crysurgery targets the neuroma and also reduces the bursa.
Why does it occur? It is believed that the nerve becomes thickened because of shearing stress from the adjacent tissues and bones. This occurs because of an abnormality in foot function whereby the foot is unstable or excessively compressed. Footwear appears to play a role and the condition is therefore more common in woman. Patients with foot deformity such as bunions and corns or flat feet appear more susceptible although the conditions sometimes also seen in patients with fairly normal looking feet. Here there may be an abnormality in the anatomy of the nerve to begin with. Patients who are hypermobile (double jointed) can be more susceptible to the condition as can patients with a history of nerve tension / abnormality such as sciatica. The Centre has treated patients with neurological conditions such as MS and diabetes and these patients may be more susceptible because of the underlying disease process.
The Centre always investigates the source and possible underlying causes for a neuroma (peri neural fibroma). This may involve in-depth in our gait analysis facility or specialist referral (for example to a neurologist). In cases where we are satisfied that such investigations have taken place and where appropriate conservative care has been tried we are happy to proceed with cryosurgery.