A statisticl outline of the subthalamic target for the arrest of tremor

In 60 cases operated on for the treatment of tremor, the insertion of an electrode that measured 1 mm in diameter produced complete arrest (40 cases) or significant decrease (20 cases) of the tremor on the contralateral side. The area where such effect was obtained was studied in AP and lateral radiograms. Using a method of standardization of the size of the thalamus and subthalamus, based on a proportional reucction of the length of the AC-PC line, the cases were found to cover a small area in the subthalamus. A statistical analysis of the position of the electrode tips at the moment the tremor was arrested was carried out in order to determine, with a high degree of probability, the area that includes the mean value of the target for the general population. This work allowed us to outline a small zone in the subthalamus as the target to be destroyed in future cases. The practical implications of the method are discussed and the possibility of reducing the size of the lesion is pointed out.