Abstract: A portable stereotactic guidance having coordinated targeting and delivery assemblies. Aligning and orientating a medical instrument in a three-dimensional plane by specific cartesian coordinates or live imaging. The device may operate in conjunction with an X-Ray or CT scanner so as to image a patient allowing the surgeon to accurately introduce a probe such as a needle, cannula, or guide wires into the human body at a preselected angle. The device fits over a patient using and is used in conjunction with an alignment guide to read X, Y and Z coordinates as well as associated angles for precise orientating of a delivery system. Provision is made for aligning of the device can be performed during real time X-Ray or scanning through a target assembly having cross hatching to target an object for use as a reference point. Once a target is set, the delivery system is aligned by sliding the delivery system within a cartesian coordinate system thereby rotating the stir ups along a polar coordinate system.

Abstract: An apparatus for stabilizing a plurality of bone segments, such as vertebrae of a spinal column, comprises one or more fixation devices. Each fixation device comprises an elongated rod having a longitudinal slot through its upper and lower surfaces and having threaded lateral surfaces. Slotted or axially threaded block members are slideably or rotatably movable along each rod into predetermined positions corresponding to locations selected for securing the apparatus to the bone. Posts are provided having have threaded distal ends, such that the distal end of each such post is inserted into the bone. The proximal end of each post is passed through the longitudinal slot in the rod and also through a vertical bore in the block member. The locations at which corrective forces are applied by the posts may be changed relative to the rods in three planes.

Abstract: A method for percutaneously accessing the lumbar region of the spinal column by laterally inserting a cannula through the patient's side above the pelvic crest to contact a predetermined position in the lumbar region and passing objects such as medical instruments through the cannula. This method is useful for performing percutaneous lumbar diskectomies by cutting a portion of the patient's disc capsule and nucleus through the cannula and removing a desired amount of nucleus material. The cannula has a tubular member and anchor means attached to one end of the member for anchoring the cannula in body tissue to prevent shearing movement between it and the tissue. Other instruments for performing a percutaneous lumbar diskectomy are disclosed, including a speculum and trocar for percutaneously inserting the cannula into the patient's body, a diskectomy knife for cutting disc nucleus material and rongeur forceps for removing the disc material. The above instruments may be combined in a surgical apparatus.

Abstract: A tracking radar error signal that is independent of pulse to pulse variations of amplitude of the received signal is derived by combining separately detected sum signal energy and difference signal energy in a manner that provides composite error signal pulses that are one-half sum signal energy and one-half sum plus difference signal energy. The pulse composition is realized by means of an RF switch that interrupts the difference signal during approximately one-half of each pulse period. The composite error signal is detected by an IF logarithmic detector and subsequently processed by two parallel box car generators. One box car generator is gated to process sum signal energy and the other is gated to process sum plus difference signal energy. The tracking error signal is obtained from a single pulse by feeding the outputs of the two box car generators to a differential amplifier and obtaining the difference voltage at its output.