Deep Brain Stimulation for Pediatric Dystonia

Abstract

Dystonia is defined as a movement disorder in which “involuntary sustained or intermittent muscle contractions cause twisting and repetitive movements, abnormal postures, or both.” Dystonia may be classified as primary or secondary. Primary dystonia is characterized by isolated dystonia and is the result of a number of hereditary mutations. Secondary or symptomatic dystonia is acquired from any number of insults to the brain, most commonly cerebral palsy, kernicterus, or other toxic/metabolic insults to the brain. Secondary dystonias present earlier in life and are associated with other neurologic symptoms including epilepsy, developmental delay, spasticity, and hypertonia. Any child presenting with a clinical exam concerning for dystonia should be referred to a neurologist specializing in movement disorders as dystonia is associated with the development of skeletal abnormalities in the growing child. Initial management is medical; however, some patients are refractory to medical management and may be candidates for surgical evaluation. Deep brain stimulation (DBS) is the treatment of choice for dystonia and involves stereotactic placement of neurostimulators powered by an implantable pulse generator into the basal ganglia. Although patients with primary dystonia may have marked improvements with stimulation, patients with secondary or progressive dystonias characteristically have more variable responses and on average show more modest improvements on clinical measures of dystonia. Despite its invasive nature, this procedure is relatively safe with low mortality although reduction in the rate of surgical site infections, the most common complication, remains an active area of research.