Surgery – Diagnostic testing – Flexible catheter guide
Reexamination Certificate
1998-06-23
2001-06-26
O'Connor, Cary (Department: 3736)
Surgery
Diagnostic testing
Flexible catheter guide
C600S433000, C604S095030, C604S286000
Reexamination Certificate
active
06251085
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a guidewire for guiding a medical device having a hollow structure such as a catheter or the like, which is introduced into a human body directly or through an endoscope in a medical treatment or inspection.
In recent years, medical treatments have come to introduce positively a technique which makes less incision damages to a human body. Specifically, in place of an incision operation, such as abdominal section, thoracotomy or the like, which provides a heavy physical burden to a patient, an inspection and a treatment carried out by inserting various catheters into a human cavity have come to be used. In case of practicing such a technique, it is general that a guidewire is inserted through a catheter which is to be inserted into a human body and a device such as the catheter or the like is guided to an aimed body cavity portion along the guidewire. Many guidewires of this kind are used in an inspection or a treatment on a stomach, duodenum, bile duct, cholecyst, liver, pancreatic duct, pancreas, or the like, as a digestive organ.
Conventional guidewires for digestive organs, used with the technique of such a low incision damage, are suggested in Japanese Patent Application KOKAI Publication No. 2-180277 and U.S. Pat. No. 5,111,829, for example. Each of these guidewires has an inner core made of a superelastic metal and an X-ray contrast portion provided at the top end, and the entire of the inner core and the X-ray contrast portion is coated with a synthetic resin. The coating has a substantially uniform outer diameter and has an outer circumferential surface which is shaped into a smooth and even cylindrical surface without roughness.
However, in the guidewires described above, the outer circumferential surface of synthetic resin coating the inner core has a smooth cylindrical shape without roughness. Therefore, in case of actually guiding a catheter by the guidewire described above, the inner circumferential surface of the catheter is closely contacted on and intensively sticks to the smooth and even outer circumferential surface of the guidewire. The friction resistance when the guidewire slides is large and makes worce an operability in inserting and/or pulling out a catheter.
In this respect, Japanese Utility Model Application KOKOKU Publication No. 2-40992, Japanese Patent Application KOKAI Publication No. 62-231675, Japanese Utility Model KOKOKU Publication No. 61-7735, and U.S. Pat. No. 4,579,127 have proposed guidewires each of which has an outer circumferential surface formed in an uneven shape in order to decrease the friction resistance to a catheter or the like.
In the guidewire suggested in Japanese Utility Model Application KOKOKU Publication No. 2-40992, a tube-like member freely engaged on the inner core is formed of a net-like member or the outer circumferential surface of the tube-like member is processed by a lacquer ware with a flecked effect, so that the outer circumferential surface of the tube-like member is formed to have an uneven surface.
In the guidewire according to Japanese Patent Application KOKAI Publication No. 62-231675, a thin wire-like inner core is coated with a relatively thick coating layer, and the outer circumferential surface portion of the coating layer is formed to be uneven.
In the guidewire according to Japanese Utility Model Application KOKOKU Publication No. 61-7735, a relatively thin coating film is applied to the outer circumference of the coil-like spring composing the guidewire, such that the coating film has an uneven shape.
U.S. Pat. No. 4,579,127 suggests a catheter and a probe-mandrel, which are comprised of a wire core and an external wire wound like a coil on the wire core, and a thin resin-made coating layer of a uniform thickness is formed on the semicircular circumferential surface.
The guidewire according to Japanese Utility Model Application KOKOKU Publication No. 2-40992 is made of a tube-like member freely engaged on an inner core and has a drawback that the structure is complicated and thick. Although its thickness, its rigidity is rather low, and further, the guidewire lacks a force transmission ability when it is twisted.
In the guidewire according to Japanese Patent Application KOKAI Publication No. 62-231675, its narrow wire-like inner core is coated with a relatively thick coating layer, so that the guidewire tends to be thickened with ease. The rigidity of the guidewire is rather low in spite of its thickness. Further, the guidewire lacks a force transmission ability when it is twisted. In the guidewire according to Japanese Utility Model Application KOKOKU Publication No. 61-7735, it comprises a coil-like spring as a core member, so that the guidewire lacks rigidity and a force transmission ability when it is twisted. Further and the follow-up ability of its top end portion is low.
Further, the mandrel according to U.S. Pat. No. 4,579,127 has a structure in which an external wire is wound like a coil on the wire core, so that the guidewire has low rigidity although it has flexibility, and the guidewire lacks force transmission ability when it is twisted. In this structure, the function of guiding a catheter or the like easily tends to be affected. Also, the entire guidewire must be thickened to improve the rigidity and the transmission ability. However, such a guidewire is not preferable as a guidewire.
BRIEF SUMMARY OF THE INVENTION
The present invention has been made in view of the problems described above and has an object of providing a guidewire having a reduced diameter, which ensures rigidity and excellent guidance ability in spite of its reduced diameter, and which achieves an excellent slide ability and insertion ability with respect to a catheter or the like.
According to the present invention, there is provided a guidewire for using with a medical device having a hollow structure, comprising: an inner core formed of one of a strand formed of a plurality of wire elements without a core member and a single wire, the inner core having an outer circumferential surface having at least a part formed of an uneven surface; and a high-polymer coating having an outer circumferential surface and covering the outer circumferential surface of the inner core, the outer circumferential surface of the high-polymer coating having an uneven surface formed by the uneven surface of the outer circumferential surface of the inner core.
According to the guidewire, an uneven surface is formed on the outer circumferential surface of the coating by an influence from the unevenness of the outer circumferential surface of the inner core, and as a result, the contact portion of the guidewire with respect to a catheter or an endoscope channel is dispersed into several points. Since the contact area is thus reduced, the guidewire is prevented from sticking to the catheter or the endoscope channel. The uneven surface of the outer circumferential surface of the inner core forms the outer circumferential surface of the coating into an uneven surface, so that the shape of the unevenness of the outer circumferential surface of the coating can be controlled finely and easily by appropriately selecting the shape of the unevenness of the outer circumferential surface of the inner core.
Therefore, the inner core of the guidewire according to the present invention is formed of a single wire or a strand without a core member. The inner core is coated with a coating and the uneven shape formed on the outer circumference of the inner core appears on the outer circumference of the coating. Accordingly, regardless of a coating having an uneven outer circumferential surface, the thickness of the coating is thinned in comparison with the thickness of the inner core, and the guidewire is very thin and attains high rigidity. At the same time, the ability of transmitting a force required for operation is excellent when the guidewire is twisted, and the follow-up ability of the distal end of the guidewire is also excellent.
As has been described above, according to the present inven
Frishauf, Holtz Goodman, Langer & Chick, P.C.
O'Connor Cary
Olympus Optical Co,. Ltd.
Wingood Pamela L.
LandOfFree
Medical guidewire does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Medical guidewire, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Medical guidewire will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2540440