Abstract: System for stereotaxic lateral extradural disc puncture has a frame fitting over the patient which provides for proper location of the cannula of the needle. The frame has a pair of right-angle members. A lower bridge frame extends horizontally and is clipped to the vertical legs of the right angle members by magnetic clips. A bridge clip fits onto the lower bridge frame and is longitudinally slidable thereon. The stem of the cannula guide slides vertically in the bridge clip. A half-channel on the top of the stem comprises the cannula guide and a bead chain fixed near the half-channel insures that the stem is vertical. Forward and rear heading guide supports are magnetically attached to the horizontal legs of the right-angle members. These supports hold magnetic strips by which a transverse disc overlay strip is held in place. A second bead chain depends from the forward end of the disc overlay strip to locate the proper alignment of the point of the cannula.

Abstract: For pre-operative radiography preparatory to stereotaxic lateral extradural disc puncture (e.g. as disclosed in U.S. Pat. No. 3,941,127) the patient is placed on his side and a radiographic film is exposed from which the surgeon calculates position and angle of needle approach to the disc before the actual operation begins. An X-ray opaque marker device similar to a ruler is located parallel and adjacent to the patient at the level of the midsaggital plane. Markings and numbers on the marker device show on the exposed film. With prolonged X-ray exposure, the image of the marker may be "burned". The present device provides a series of radiopaque shields which may be interposed between the marker and the film to reduce burn-out of the image of the marker on the film. A convenient stand supports and stores the marker and one or more shields so that they may be individually and selectively raised and turned into operative position.

Abstract: A cannula has a hub formed with a hollow upward projection on its top which communicates with a lumen having a bore in the hub and the cannula itself. On one side of the hub is a vane having converging sides and a rounded end. The vane has a horizontal opening extending inward and the portion above the opening is cut away so that it is about half the thickness of the portion below the opening. A stylet or an obturator fits through the hollow projection, bore and cannula, extending to the tip of the cannula. A hub on the stylet or obturator has a socket to receive the cannula hub projection and a vane formed with a cutout to receive the portion above the opening of the cannula hub, the portion of the stylet or obturator vane below the cutout locking in the opening in the cannula hub. A hollow needle also fits through the hollow projection, bore and cannula and has a hub formed with a socket to receive the hollow projection and a fitting for attachment to a syringe.