GB818711A - Stereotaxic device - Google Patents

Abstract

818,711. Brain centres localizing and treating. MINISTER OF SUPPLY. Jan. 9, 1957 [Dec. 6, 1955], No. 34979/55. Class 81 (2). A sterotoxic device comprises a rigid frame for securing to a patient, mounting members adjustable on the frame, X-ray grids mountable on the mounting members for locating in three dimensions the target area to be treated, a pivotal semi-circular bridge mountable on the mounting members in place of the X-ray grids and having an adjustable holder for a piercing instrument and means for adjusting the bridge or the instrument holder according to the location of the target by the X-ray grids so that when the bridge is mounted the instrument tip may be brought to the target area. A frame 10 having limbs formed by double parallel bars 10a, 10b which are secured together by corner blocks 11, is temporarily fixed on the head by auxiliary studs. The studs 16 are mounted on clamps secured to the frame 10 and engage the head at the back, the ears and the nose. Mountings 14, vertically adjustable on the blocks 11 carry pointed studs 13 which engage with holes made in the skull by a countersink cutter which is mounted for use on each stud 13 in turn. The auxiliary studs are removed from the frame 10 when the pointed studs 13 engage the head. X-ray grid screens 20 suitable for teleradiography are then mounted on carriers 19a, 19b, 19c secured to the frame at the sides and front of the head and X-ray pictures are taken. The position of the target area to be treated about three major axes is noted from the pictures on the screens 20. The X-ray grid screens are removed and laterally slidable brackets 22a, 22b are arranged on the two side carriers 19a, 19b. These brackets 22a, 22b carry quadrants 23a, 23b which are vertically adjustable by set screens 24 slidable in slots 25a. The set screens 24 have extensions 24b which serve as diametral pivots for a semi-circular bridge 26 which is supported clear of the head. A housing 30, supporting slidable electrodes 31 or other operating instrument, is slidable on the bridge 26. The housing 30 provides a stop which limits the movement of the instrument beyond the centre of the diameter of the bridge 26. Set-screws 24 are adjusted so that the diameter of the bridge 26 is at the same vertical height as the target area as determined by the X-ray pictures, carriers 19a, 19b, are adjusted along the frame 10 so that the diameter of the bridge 26 passes through the target area and finally, brackets 22a, 22b are moved laterally so that the centre of the diameter of the bridge 26 coincides with the target area. The bridge 26 is angularly adjustable on the quadrants 23a, 23b and the housing 30 is adjusted on the bridge 26 so that it overlies the best point of entry into the skull. The operating instrument is then used to penetrate the brain as far as the target area. The operating instrument may be directed at a point other than the centre of the diameter of the bridge 26.