MORTON’S NEUROMA ETHANOL ABLATION
A Morton’s neuroma occurs when the nerves in the ball of your foot swell or thicken which can make it painful to walk. This is typically due to repetitive compression of the plantar digital nerve. Toes that are squeezed together too long from wearing tight shoes can cause swelling.
Doctors are able to identify Morton’s neuroma with a physical exam although an x-ray may also be required. Treatment options include the use of orthotics and anti-inflammatory medicine to reduce the swelling. Another treatment method is available if these do not work.
An injection of cortisone and local anaesthetic under ultrasound guidance can provide pain relief for up to 3 months depending on the condition.
Procedure overview
When ethanol is injected around a nerve, it produces chemical neurolysis through dehydration, necrosis, and precipitation of protoplasm. The effect appears in large myelinated fibres which are the nerve fibres that carry pain signals.
Ethanol ablation is a procedure that uses an ultrasound transducer to guide a small needle within the neuroma after a local anaesthetic is injected. A mixture of ethanol with long lasting local anaesthetic is injected in the neuroma under constant ultrasound guidance for high precision.
The injection takes approximately 10 seconds as most of the time is spent on preparations. Patients typically experience mild discomfort during the injection but is only temporary. A small skin plaster will be placed at the injection site but can be removed the next day after the procedure.
After the procedure
Patients are advised to rest and to avoid any heavy physical activity for at least 24 hours. Elevating the foot and applying an ice pack for 20 minutes for 2 hours after the ethanol injection will be beneficial. Medications such as Panadol or Voltaren may be necessary if there is a significant amount of discomfort.
Injections are repeated at 2 weekly intervals for a total of 4 visits. Research has shown an 60-70% chance of significant pain relief following the procedure.
Procedure risks
Ethanol injections for Morton’s neuroma are relatively safe. However, there is a small risk that the pain will worsen or see no significant improvements. Infection and localised bruising in addition to nerve damage are also possible risks.
Some patients report swelling and redness on the injection site for up to 2 weeks but gradually improves. Patients can expect to see an overall improvement within three months from getting the injection.
Ethanol ablation treatment is effective in treating Morton’s neuroma but may be ineffective in up to 30-40% of patients who undergo the procedure. If this is the case, other options include radiofrequency ablation which uses an electrode needle to emit thermal energy. Another treatment option is surgical excision.