Surgery – Instruments – Surgical mesh – connector – clip – clamp or band
Reexamination Certificate
2000-01-24
2003-12-30
Woo, Julian W. (Department: 3731)
Surgery
Instruments
Surgical mesh, connector, clip, clamp or band
C606S151000, C606S213000, C623S001110
Reexamination Certificate
active
06669707
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and a method for repairing an anatomic vessel wall or the wall of a hollow organ, such as the esophagus, particularly in the human body. In particular, the present invention relates to an attaching or locking element for attaching an implant, such as stent or stent graft, to a vascular or hollow organ wall from the outside of the wall as well as an instrument for positioning and inserting the attaching or locking element into the body. The present invention also encompasses a method for attaching or locking an implant to a vessel or hollow organ wall.
2. Description of the Related Art
An Abdominal Aortic Aneurysm (“AAA”) is a weakening of the wall of the aorta in the abdominal area. AAAs pose a significant health problem and over 160,000 AAAs are diagnosed annually in the United States. A full 25% of AAAs will go on to eventually rupture; in spite of numerous advances in acute medical care, medical transport and resuscitation, ruptured AAAs continue to have a 50% mortality rate.
FIG. 1
shows an infrarenal AAA A′ located in the torso T of a patient P, below the heart H and kidneys K and above the point of bifurcation B of the aorta A into the iliac arteries IA. As may be seen by comparing
FIGS. 2 and 3
, a normal aorta A (
FIG. 2
) exhibits non-bulging walls above the point of bifurcation B, while an aorta A which includes an AAA A′ (
FIG. 3
) bulges outwardly from its normal condition. This bulging is the result of weakening of the aortic vessel walls.
The traditional surgical technique for treating AAAs involved excision of the aneurytic tissue and replacing that tissue with either a synthetic graft or a graft from another section of the patient's body. This approach required a large abdominal incision and total bowel displacement and large disruption of the retroperitoneum, followed by excision of the aneurytic tissue and attachment of the replacement graft to the vessel ends. Disadvantages of this prior art surgical technique include hypothermia, coagulation problems, prolonged ileus, a risk of sexual disfunction and significant pain and disfigurement. As a result of these significant disadvantages attendant to the traditional surgical technique, alternative techniques for AAA repair have been investigated and used.
In 1992, Juan Parodi, a surgeon, first described the placement of a percutaneous vascular prosthesis or stent in the abdominal aorta using interventional radiological techniques in
Transfemoral Intraluminal Graft Implantation for Abdominal Aortic Aneurvsms, Ann. Vasc. Surg
. 1991: 5:491-499. The prosthesis or stent effectively excluded, i.e., provided support for, the aneurysm sac, while avoiding a major access incision in the abdomen. This prior art technique required only a small groin incision, through which the stent was inserted and lead to the aneurysm site with appropriate stent guidance and deployment tools. Upon reaching the aneurysm site, the stent was deployed and grafted to the vascular walls of the aorta at the aneurysm site. A stent S deployed at an aneurysm A′ is shown in dotted lines in FIG.
3
. The use of stent grafts, as in this prior art technique, decreased patient morbidity, and because of the less invasive nature of the technique used to insert and deploy the graft, significantly reduced the problems with the traditional surgical technique for repairing AAAs.
Despite the advantages attendant the stent graft technique, difficulties in passing the stent to the aneurysm site, untimely opening of the stent, and complications, including emboli at the proximal and distal ends of the aneurysm, intimal damage, perforation, and thrombosis, have occurred. In addition, unsatisfactory methods and devices for proximal stent end fixation in order to prevent stent migration, as well as persistent endoleaks, have limited the effectiveness of stent grafts. The proximal stent end is the end of the stent nearest to the heart; this end needs to be fixed to the aorta in order to prevent the stent from migrating from its initial deployed position to a position where it does not fully exclude and support the AAA. This movement or migration can also cause endoleaks (L, FIG.
3
), in which blood passes between the stent S and the aneurysm A′, putting pressure on the aneurysm which can result in rupture.
When inserting implants, such as stents or stent grafts, into vessels or hollow organs, in particular when repairing an aneurysm using a stent graft, it is necessary that the stent introduced into the vessel or hollow organ be attached at both its distal and proximal ends tightly and permanently to the vessel wall surrounding the stent, in order to ensure that the stent does not migrate in the vessel and to ensure that the stent seals off the aneurysm, thus reinforcing the weakness in the vessel. Prior art stents used for repair of AAAs have used a variety of mechanisms for attaching the stent to the vessel wall. One mechanism used to attach a stent to a vessel wall is hook-shaped projections at the proximal and distal ends of the stent, which hook-shaped projections are pressed against the vascular wall from the inside of the vessel. The hook-shaped projections mechanically grip the vessel walls to secure the stent or stent graft to the vessel wall. In a similar attachment method, disclosed in U.S. Pat. No. 5,527,355, the stent or stent graft is secured in position against the vessel wall from the inside using hook-shaped retaining elements; these hook-shaped retaining elements are inserted into bands and surround the vessel externally.
PCT Publication No. WO 97/09008 to Medtronics shows a tubular implant used for repairing aneurysms. In this implant, a sealing layer is disposed at least at the ends of the implant, in order to reduce endoleaks. The implant described in this publication, however, does not include any mechanism for securely fastening the implant to the vessel wall to prevent migration.
U.S. Pat. No. 5,342,393 to Richard Stack of Duke University shows a device for repairing a perforation in a vascular wall. The device of that patent is not disclosed for any use in securing implants into an anatomic vessel or hollow organ. Furthermore, the device of that patent uses a large-diameter catheter or sheath which is inserted through a large perforation in the vessel wall. This device is therefore not suitable for securing an implant to a vessel or hollow organ wall, where large perforations are to be avoided in deploying the implant.
U.S. Pat. No. 4,669,473 to Acufex Microsurgical describes a surgical fastener used for fastening two or more sections of tissue to one another. This fastener is not disclosed or used for fastening of any type of anatomic vessel or organ, in particular any type of hollow anatomic vessel or organ, and the thick bar-like head of that fastener is specifically designed to be embedded within the tissue to be fastened. The head of the fastener also includes at least one pointed end for embedding in tissue. Furthermore, the fastener of that device is not used to clamp two walls together, nor is that fastener used to attach an implant to a vessel or hollow organ.
SUMMARY OF THE INVENTION
Prior art methods for affixing an implant, such as a stent or stent graft, to a vessel or hollow organ wall have not always been reliable. In addition, many of these prior art methods could only be employed using open surgical techniques requiring large incisions. These prior art methods, and the apparatuses used with these methods, have not been amenable to less-invasive techniques.
An object of the present invention is to provide an attachment or locking apparatus which can effectively secure an implant, such as a stent or stent graft, to a vessel or hollow organ wall and which allows less invasive techniques, such as laparotomy with a markedly reduced incision, and minimally-invasive techniques, such as laparoscopy or endoscopy, to be used to attach the implant.
A further object of the invention is to provide a method a
Morales Pedro
Swanstrom Lee L.
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