Dystonia is a form of movement disorder in which a patient usually starts to develop difficulty in controlling movements in their limbs, not due to weakness, but due to inability to coordinate contraction and relaxation of the muscles around limbs and their trunk. Although there are some known causes of dystonia – other diseases, poisons or injuries to the deep structures of the brain – the most common form develops without any known causes or with a genetic cause. For this reason dystonia mostly develops in young people and children.
Patients will develop slow onset of worsening abnormal movements in their limbs or trunk and neck. In some patients the muscular contractions become so violent and persistent that they develop kidney failure and can die from it. Dystonia is progressive in nature and follows a relentless progression with time. Medication remains the first-line therapy for patients with dystonia, but in about a third of patients, the disease will not respond to medication. This is where Deep Brain Stimulation (DBS) comes in.
DBS is a surgical procedure in which small electrodes are placed deep into the brain of a patient to deliver a very small current at a predetermined frequency into the part of the brain that controls movements. The procedure is done under anaesthesia and a battery is implanted under the skin to deliver the current.
DBS is a life-changing therapy for patients with dystonia. It is not curative (once the battery is switched off – the dystonia returns), but it can add great independence and improvement in quality of life to the patient with dystonia, especially children. The implant is very expensive and the procedure requires a specific skill-set from the neurosurgeon.
Red Cross Children’s Hospital in Cape Town is the only hospital that offers this therapy to children on a regular basis. It is also the only state-hospital that regularly performs this procedure in South Africa.
Written by: Dr. Nico Enslin, neurosurgeon at the Red Cross Memorial Children’s Hospital, Cape Town