Evolution of basal ganglia surgery for movement disorders.

In 1942, it was thought that basal ganglia surgery would cause permanent unconsciousness and significant impairment of motor control. By 1947, when human stereotactic surgery was introduced, the first target was the globus pallidus in a patient with chorea. What happened during those 5 years to set the stage for stereotactic surgery? During the last half of the 19th century, it was first noted that motor disorders were often accompanied by atrophy of various parts of the basal ganglia, and when histopathology became part of necropsy, that relationship between movement disorders and the basal ganglia was strengthened. The impairment of fine motor control was noted in experiments that involved lesioning the basal ganglia, which led to the conclusion that disease of the basal ganglia might cause motor impairment. Finally, in 1939, Russel Meyers took the bold move of surgically resecting the head of the caudate nucleus at craniotomy in a patient with Parkinson's disease, demonstrating that Dandy was wrong in the view that the basal ganglia were the center of consciousness, and that symptoms and motor control might be improved by caudate lesions without motor impairment. He reported his first patient in a meeting in 1940, which was published in 1942, and was encouraged to investigate basal ganglia surgery further. Although results were encouraging, the mortality rate was prohibitive. Since the introduction of pallidoansotomy in 1947, basal ganglia surgery has become both safe and effective and has been expanded and refined.