Electrical Exploration of the Internal Capsule and Neighbouring Structures During Stereotaxic Procedures

Abstract

T He. var iabi l i ty in position, shape and size of deep cerebral s t ructures in relat ion to radiologically visible landmarks hard ly needs to be stressed again and even the mos t careful p lot t ing of a t a rge t point and the mos t precise ins t rumenta t ion leave a margin of error which becomes more impor t an t as the t a rge t is s i tuated fa r the r away f rom the l andmarks used to plot its position. I n an effort to compensate for or minimize this error in localization because of unpredictable ana tomica l variat ions, workers in the field of stereotaxic surgery have used various physiological methods to obta in a more precise identification of the deep structures involved in the projected lesion or of other neighbouring s tructures which it is desirable to avoid. In our modes t series of stereotaxic operations for the t r e a t m e n t of involuntary movements a t the Mont rea l Neurological Inst i tute, we have found such physiological explorat ion of the area in which we planned to make our lesions an ext remely useful if not indispensable tool. In this presentat ion, we shall repor t on the results of this explorat ion in s procedures carried out on ~ pat ients .