Shiley, Inc.

Other

Perry A Nebergall

Robert C French

A cannula for insertion into a body cavity, duct, or vessel of a patient includes a parent cannula member and an integral radiopaque tip. The tip is configured so as to be distinguishable from internal body parts in an X ray or flouroscopic image, thus serving to precisely locate the position of the cannula within the patient without substantially obstructing the physician's view of such body parts. The cannula tip and parent member are separately pre-formed from a non-toxic polymeric material and can be constructed so as to have different hardnesses. In one embodiment the tip is softer than the parent member in order to prevent internal injury to the patient, while in a second embodiment the tip is harder than the parent member for facilitating certain catheterization applications. The pre-formed tip and parent member are then dielectrically heated and welded securely together to form a unitary, integral cannula. The electrodes of the dielectric heating apparatus are connected to dies whose diametrical dimensions conform closely to those of the tip and parent member to provide the present cannula with completely smooth interior and exterior surfaces. In order to prevent the burning of the cannula during this heating process, air is vented from the junction area by providing the outer die with a convex interior surface and by forming longitudinal grooves in the external surface of the inner die or mandrel. The inner mandrel is formed by encapsulating the inner electrode with a highly insulative material to further inhibit burning of the cannula.

Dielectric heating device for heating cannula members

A cannula for insertion into a body cavity, duct, or vessel of a patient includes a parent cannula member and an integral radiopaque tip. The tip is configured so as to be distinguishable from internal body parts in an X ray or flouroscopic image, thus serving to precisely locate the position of the cannula within the patient without substantially obstructing the physician's view of such body parts. The cannula tip and parent member are separately pre-formed from a non-toxic polymeric material and can be constructed so as to have different hardnesses. In one embodiment, the tip is softer than the parent member in order to prevent internal injury to the patient, while in a second embodiment the tip is harder than the parent member for facilitating certain catheterization applications. The pre-formed tip and parent member are then dielectrically heated and welded securely together to form a unitary, integral cannula. The electrodes of the dielectric heating apparatus are connected to dies whose diametrical dimensions conform closely to those of the tip and parent member to provide the present cannula with completely smooth interior and exterior surfaces. In order to prevent the burning of the cannula during this heating process, air is vented from the junction area by providing the outer die with a convex interior surface and by forming longitudinal grooves in the external surface of the inner die or mandrel. The inner mandrel is formed by encapsulating the inner electrode with a highly insulative material to further inhibit burning of the cannula.

Cannula with radiopaque tip

A method of dielectrically joining the mated ends of tubular members is, specifically, used in the formation of a cannula for insertion into a body cavity, duct, or vessel of a patient. The cannula preferably includes a parent cannula member and an integrally joined tip. The method comprises the steps of joining the mated ends of the tubular members to form a common joint, passing a high frequency electrical current between the electrodes of a dielectric heating device and through the mated ends of the tubular members to heat and fuse them together at said joint, concentrating the heat at the joint to form an integral cannula, permitting the hot air surrounding the joint to escape in order to prevent the burning or scorching of said cannula, pressurizing the joint to facilitate the escape of the hot air and to eliminate dimensional differences in the mated ends, and forming the mated ends of the tubular members while in a heated condition to provide smooth surfaces on the cannula.

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Laguna Hills, CA, United States of America

Perry A Nebergall