Abstract: A composite catheter is formed by the combination of a catheter body and a tubular member insertable or secured inside the catheter body. The tubular member contains a series of relatively rigid segments alternating with flexible, collapsible segments which permit the rigid segments to effectively stack against one another when the tubular member is compressed axially. The shape that results when the rigid segments are forced together differs from that of the shape memory of the catheter body in certain embodiments of the invention, and changing the tubular member from a relaxed condition to the compressed condition inside the catheter body can therefore cause a change in shape of the catheter body.

Abstract: A catheter is provided with steering capability at its distal end by a tubular guiding member which protrudes from an opening at the distal end of the catheter and either changes shape or rotates about its longitudinal axis upon pressurization from the proximal end. In one means of actuation, the tubular member has one or more ports close to its distal end, which form laterally directed jets when the tubular member is pressurized within by fluid, the reaction force of the jets bending the tubular member in the desired direction or causing it to rotate. In another means of actuation, the tubular member either curves upon pressurization from an otherwise straight configuration upon pressurization, or straightens from an otherwise curved configuration. The tubular member can expand upon pressurization to seize the interior of the catheter body, rending both elements movable as a unit. Once the catheter is fully positioned, the tubular member can be withdrawn and replaced by functional devices or guidewires.

Abstract: A catheter is guided by directional control inside a bodily passage by a servo-type system which includes a sensor to transmit position, orientation or velocity information to a microprocessor which is typically programmed with an error detection algorithm, and a motion control system. The motion control system generates a signal representative of the change in position, orientation or velocity needed to guide the catheter along a prescribed course of travel or in general to continuously adjust its position relative to a target, and this signal is transmitted to a directional steering system, a forward drive system or both, to effect the change. The result is a closed-loop servo system capable of automated, preprogrammed advancement and/or positioning of the distal catheter rip through branched and convoluted passages to a site where therapeutic action is needed or from which diagnostic information is sought.

Abstract: A catheter is provided with a directional steering capability by one or more jets ejecting fluid from the distal end of the catheter in a radial direction which causes the catheter tip to bend in the opposite direction by reaction force. Actuation of the jet is controlled by a closure valve at the jet orifice, the closure valve being driven by a signal transmitted from the proximal end of the catheter. Preferred signals are either fluid pressure signals or electrical signals.