Abstract: Apparatus and methods for advancing and retracting a medical instrument within an introducer device, wherein the instrument includes a distal tip, a distal linear portion, a first distal curve, a substantially linear inter-curve portion, and a second proximal curve. The length of the distal linear portion and the angle of the first curve determine the position of the distal tip within a lumen of the introducer device, such that the distal tip occupies a substantially central transverse location within the lumen and the distal tip avoids contact with the introducer device. The length of the inter-curve portion and the angle of the second curve determine deflection of the distal tip from a longitudinal axis of the shaft when the second curve is extended distally beyond a distal end of the introducer device. Also, methods and apparatus for treating an intervertebral disc by ablation of disc tissue.

Abstract: A double-layer medical catheter with an integral soft tip is made by the coextrusion of a relatively rigid inner layer and a relatively soft outer layer, where the extrusion equipment is configured and so controlled to interrupt the supply of the material for the inner layer to form a periodic void in the inner wall. The act of interrupting the supply causes a ramp down in the inner wall thickness at the leading edge of each void and the ramp up of the thickness at the trailing edge. The void is cut to produce two ideal integral soft-tipped catheters.

Abstract: Plastic replacements for glass capillary tubes for drawing samples of blood or other body fluids are achieved by texturing the inside surface of the tube with uniform fine features and by extruding the tube over a suitably textured tapered pin with a (gradual) ratio of at least 6:1 during extrusion to ensure the transfer of the pin's surface texture to the inside diameter of the tube.

Abstract: A splittable tube, useful in medical applications as a cannula for insertion into the body, comprises an inner and an outer layer. The inner layer defines a central lumen for accepting catheters and probes. The inner layer also includes a longitudinal slot through its wall for defining a stress line in the outer layer. The outer layer is very thin, membrane-like, and tears along the longitudinal stress line when the cannula is pulled to the side of a catheter occupying the central lumen. The tube may be made of electrically insulating material and used, for example, as strippable insulation as telephone or house wire, and strippable without the use of tools.