Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Bifurcated
Reexamination Certificate
1998-10-20
2003-04-29
Snow, Bruce (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Bifurcated
C623S001130, C623S901000, C623S001160
Reexamination Certificate
active
06554858
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns an intraluminal prosthesis for a ramification of vessels in the human or animal body. It also relates to a tubular trunk element to be used in such an intraluminal prosthesis and to the method for producing such a tubular trunk element.
2. State of the Art
It has long been attempted to remedy various forms of deterioration which become manifest in the walls of the vessels in the human or animal body, such as the blood vessels, the canals of the gastrointestinal system, the urinary canals, and others. An example of a very common form of deterioration of the type in question involves aneurysms of the blood vessels, in particular aneurysms which affect the infrarenal segments of the abdominal aorta. There, the aorta undergoes dilation, leading to the risk of rupture of the vessel wall and the death of the patient.
Intraluminal prostheses have been used in an attempt to support the defective vessel walls. Various types of intraluminal prostheses with this purpose are described in the literature, and in particular in Patents U.S. Pat No. 4,140,126 and 4,512,332, and in International Patent Applications PCT WO 94/01056 and WO 96/07371. Mention may also be made of PARODI J. C. et al, Transfemoral Intraluminal Graft Implantation for Abdominal Aortic Aneurysms, Annals of Vascular Surgery, Vol. 5, No. 6, 1991, p. 491-499.
These documents describe fixing an intraluminal prosthesis to the distal and proximal necks of the aneurysm, for example an abdominal aortic aneurysm, that is to say to those parts which are the least affected at the onset of the condition. The proximal neck is situated below the renal arteries, and the distal neck is situated just above the aorto-iliac bifurcation. However, no solution is proposed when the aneurysm extends into the branches of this ramification. During the exponential growth of the aneurysm, the necks do in fact also become the site of dilation, particularly the distal neck, and then the iliac arteries. In cases such as this, which are very common, the solutions proposed hereinabove are inadequate.
Attempts have therefore been made to provide intraluminal prostheses for ramifications.
For example, bifurcated intraluminal prostheses are known which have the general appearance of trousers, having, at the three ends, a fastening stent element to be fixed to the proximal neck of the aneurysm and in healthy segments of the iliac arteries (see EP-A-0461791 and EP-A-0539237; T. CHUTER, Bifurcated endovascular graft insertion for abdominal aortic aneurysm, in “Vascular and Endovascular Surgical Techniques”, 3rd ed., Ed. RM Greenhalg Publication WD Saunders Company, 1994, p. 92-99). These intraluminal prostheses have the disadvantage of being difficult to place, after aortic release, for introducing each of the legs of the intraluminal prosthesis into their iliac artery. It is generally necessary to use devices for recovery of a femoral cruciate catheter, which demands a high degree of skill on the part of the surgeon.
Other known bifurcated intraluminal prostheses comprise an aortic segment which is continued via an iliac segment. A branch stump measuring 5 mm in diameter protrudes laterally and has to be placed opposite the mouth of the iliac artery not yet provided with its intraluminal prosthesis. It is then necessary to introduce, via this iliac artery, an additional tube which is to be inserted into this small tubular stump. This necessitates a precise positioning of the latter, which is attempted by arranging radiopaque markers on the intraluminal prosthesis (see BLUM U. et al, Abdominal Aortic Aneurysms . . . , International Radiology, Vol. 198, Jan. 1, 1996, p. 25-31). Just as in the above solution, the surgeon needs to be highly skilful to introduce the additional tube into the tubular stump intended for it, and he must have great expertise in the use of intraluminal catheters.
All these embodiments, whether bifurcated with one trunk and two complete legs, or with one trunk, one complete leg and one leg to be inserted in situ into a stump, have the disadvantage of a complicated design. In addition, they are generally supported in a rigid manner by fastening stent elements, uniquely at the proximal neck and in the iliac arteries, hence the danger of too pronounced a bend in one of the two legs at the site of the bifurcation.
In attempting to overcome this latter disadvantage, expandable and retractable stents have been provided which can support a covering, itself also expandable, along the entire length of the bifurcated intraluminal prosthesis. A model of a bifurcated stent, expandable by balloon, has been provided in U.S. Pat. No. 4,994,071, for example. It is clear, however, that the production of a bifurcated intraluminal prosthesis equipped with a complete bifurcated stent is complex and costly. Its introduction into the patient's body is certainly not easy either.
Finally, intraluminal prostheses are known which are formed by two tubular elements which are to be introduced simultaneously into the aneurysm, the first via one iliac artery, the second via the other iliac artery. The ends of these tubular elements, when they have reached the proximal neck of the aneurysm, are dilated radially in order to be fastened thereto simultaneously, whilst the opposite end of each of these elements is fastened in a similar manner in its corresponding iliac artery. According to one embodiment, a metal stent is dilated in the neck, prior to these operations, so as to receive the two dilatable ends of the aforementioned tubular elements (see EP-A-0551179).
These embodiments have the major disadvantage of not guaranteeing a perfect sealing of the two proximal ends of the tubular elements inside the proximal neck of the aneurysm. This inevitably results in leaks at the periphery of the tubular elements, penetration of blood into the aneurysm and the reestablishment, which is to be avoided, of the blood pressure at this site.
SUMMARY OF THE INVENTION
The object of the present invention is to overcome the problems faced and to provide an intraluminal prosthesis for a ramification of vessels in the human or animal body which is applicable to the majority of the anatomical conditions and which is easy to position without having special experience of catheterization. After it has been put into place, this intraluminal prosthesis cannot present any phenomenon of leakage of blood into the cavity of the aneurysm. Moreover, this intraluminal prosthesis will advantageously be very easy to produce and to store.
This problem is resolved by means of an intraluminal prosthesis for a ramification of vessels in the human or animal body, comprising:
a tubular trunk element which is radially expandable and compressible and which is to be applied in the expansion position in a principal vessel of the said ramification, this tubular trunk element axially having two ends and a cavity which is open at these two ends, and
at least one tubular branch element which is radially expandable and compressible and which axially has two ends and a cavity open at these two ends, each branch element being, in its compression position, independent of the tubular trunk element,
this intraluminal prosthesis being characterized in that the cavity of the trunk element is divided into several axial channels over at least part of its length, and in that each branch element has an end which is to be applied, in the expansion position, within one of the said axial channels of the tubular trunk element, and another end situated outside the tubular trunk element, within a secondary vessel of the said ramification.
This intraluminal prosthesis has the advantage of being made up of independent elements, that is to say elements which are to be introduced successively into the body, and which have an external shape similar to the tubular intraluminal prostheses which are known at present. The trunk element is released between the distal and proximal necks of the aneurysm in a conventional manner, like a non-bifurcated int
Dereume Jean-Pierre Georges Emile
Frid Noureddine
Corvita Europe
Pellegrino Brian E
Snow Bruce
LandOfFree
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