Abstract: This apparatus comprises a rigid half circular headclamp, three fixation pins to firmly secure the clamp to the patient's skull, a connector to firmly secure the clamp to a surgical table on which the patient rests, an articulate arm including clampable joints, secured to the headclamp in one of several possible positions and a double chuck secured to the distal end of the articulated arm. The double chuck has two ball collets arranged in side by side cavities in the chuck body, and two locking screws for each ball collet. A first locking screw releasably locks the ball collet in a selected orientation, a second separate locking screw releasably locks in an adjusted axial position an elongated instrument inserted through said collet. The first and second locking screws are actuated independently of each other. A computer guided probe and a large number of surgical instruments can be slidably inserted within the ball collets and locked in an adjusted axial position and in a selected orientation.

Abstract: This apparatus comprises a rigid half circular headclamp, three fixation pins to firmly secure the clamp to the patient's skull, a connector to firmly secure the clamp to a surgical table on which the patient rests, an articulated arm including clampable joints, secured to the headclamp in one of several possible positions and a double chuck secured to the distal end of the articulated arm. The double chuck has two ball collets arranged in side by side cavities in the chuck body, and two locking screws for each ball collet. A first locking screw releasably locks the ball collet in a selected orientation, a second separate locking screw releasably locks in an adjusted axial position an elongated instrument inserted through said collet. The first and second locking screws are actuated independently of each other. A computer guided probe and a large number of surgical instruments can be slidably inserted within the ball collets and locked in an adjusted axial position and in a selected orientation.