Method of anchoring pullwire directly articulatable region in catheter

Abstract

A catheter comprises a flexible polymer catheter body including a proximal shaft section and a distal working section, a wire support structure embedded within the distal working section of the catheter body, a proximal adapter mounted to the proximal shaft section of the catheter body, and a wire disposed within the catheter body. The wire has a proximal end and a distal end. The proximal end of the wire being operably connected to the proximal adapter, and the distal end of the wire is anchored to the wire support structure.

Description

FIELD OF INVENTION[0001]The invention relates generally to minimally-invasive instruments and systems, such as manually or robotically steerable catheter systems, and more particularly to steerable catheter systems for performing minimally invasive diagnostic and therapeutic procedures.BACKGROUND[0002]Minimally invasive procedures are preferred over conventional techniques wherein the patient's body cavity is open to permit the surgeon's hands access to internal organs. Thus, there is a need for a highly controllable yet minimally sized system to facilitate imaging, diagnosis, and treatment of tissues which may lie deep within a patient, and which may be accessed via naturally-occurring pathways, such as blood vessels, other lumens, via surgically-created wounds of minimized size, or combinations thereof.[0003]Currently known minimally invasive procedures for the treatment of cardiac, vascular, and other disease conditions use manually or robotically actuated instruments, which may ...

AI Technical Summary

Benefits of technology

The present invention relates to a catheter with a flexible polymer body and a wire support structure embedded within the distal working section of the catheter body. The wire support structure can be a braided tubular structure or a coiled structure, and it is optionally mounted to the catheter body using a proximal adapter. The wire can be a pullwire, an electrical wire, or a combination of both. The catheter can also have a lumen extending through it with the wire embedded within the lumen. The wire support structure can be exposed and used to anchor the wire to the catheter body. The technical effects of the invention include improved flexibility, better maneuverability, and better bending performance of the catheter body.

Problems solved by technology

Increasing the lateral flexibility of the sheath and catheter, however, introduces catheter navigation problems that may not otherwise occur when the sheath and catheter are laterally stiff.

However, the compressive forces on the relatively flexible catheter shaft also cause undesired effects.

For example, the axial compression on the catheter shaft during a steering maneuver that bends the distal end of the catheter may cause undesired lateral deflection in the catheter shaft, thereby rendering the catheter mechanically unstable.

As another example, the curvature of the catheter shaft may make the articulation performance of the catheter unrepeatable and inconsistent.

This un-intentional rotation of the shaft causes instability of the catheter tip and prevents the physician from being able to articulate the catheter tip in the direction shown in FIG. 1A.

However, this will placed the tensioned inside pullwire to the outside of the proximal bend causing further tensioning of the pullwire, and possibly causing the distal end of the catheter to whip around.

All of these mechanical challenges contribute to the instability and poor control of the catheter tip, as well as increased catheter tracking forces.

But these changes will also laterally stiffen the catheter shaft, thereby causing further difficulties in tracking the catheter through the vasculature of the patient.

Therefore, the catheter designer is faced with having to make a compromise between articulation performance and shaft tracking performance.

However, the use of coil pipes adds to the cost of the catheter and takes up more space in the result, resulting in a thicker catheter wall.

Furthermore, because the relatively stiff coil pipes are spaced away from the neutral axis of the catheter, its lateral stiffness may be unduly increased.

However, in the case where it is desirable to access the ostium of the left coronary artery, the proximal curve of the catheter locates the distal end of the catheter too far from the left coronary artery, which therefore cannot be easily accessed via manipulation of the distal end of the catheter, as shown in FIG. 2B.

However, in the case where it is desirable to access the ostium of the left coronary artery, the proximal curve of the catheter locates the distal end of the catheter too close to the right coronary artery, such that the distal end would be seated too deeply within the ostium of the right coronary artery, as shown in FIG. 2D.

Thus, it can be appreciated that multiple catheters may have to be used to treat both the left coronary artery and right coronary artery, thereby increasing the cost and time for the procedure.

However, when manufacturing a catheter that has two regions of articulation, this task can be difficult and usually requires the lamination of an outer polymer jacket extrusion up to the proximal articulation region, then the installation of the most proximal control ring with attached pullwires, and then the lamination of an outer polymer jacket for the remaining portion of the catheter.

Another issue with respect to the use of control rings is that the laminated polymer extrusion or extrusions need to be carefully sized at the control ring, since the ring itself consumes volume in the wall that not only requires thinner extrusions so as to not have a bulge in the catheter at the control ring, but also creates a significantly stiffer region the length of the control ring, which causes a “knuckle” where there should be a gradual stiffness change required to achieve good catheter performance during tracking through the vasculature.

However, guide wires longer than 300 cm are not readily available in sterile catheter laboratories.

Furthermore, such a configuration disadvantageously increases the length of the robot required to axially displace the guide wire within the inner catheter to the fullest extent.

The increased size of the robot may be impractical and too big and heavy to be mounted on a table in a catheter lab environment.

Additionally, because the inner catheter passes entirely “over-the-wire,” the inner catheter cannot be robotically removed while holding the guide wire in place.

The procedure time for removing the inner catheter from the outer guide sheath is increased for an over-the wire configuration (typically greater than one minute), thereby increasing fluoroscopic time and radiation exposure to the physician and staff.

However, no known designs exist for rapid exchange steerable catheters due to the challenge of navigating the pullwires proximal of the exit port.

In addition, no known designs exist for the robotic interface for rapid exchange catheters.

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