Surgery – Instruments – Sutureless closure
Reexamination Certificate
2001-09-07
2004-03-09
Milano, Michael J. (Department: 3731)
Surgery
Instruments
Sutureless closure
C606S216000, C606S224000, C606S139000
Reexamination Certificate
active
06702835
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to apparatus and methods for treating septal defects, and more particularly to apparatus and methods for closing a patent foramen ovale or other septal defect that include a flap of tissue using a needle device.
BACKGROUND
During development of a fetus in utero, blood is generally oxygenated by the mother's placenta, not the fetus' developing lungs. Most of the fetus' circulation is shunted away from the lungs through specialized vessels or foramens that are open during fetal life, but generally close shortly after birth. Occasionally, however, these foramen fail to close and create hemodynamic problems, which may ultimately prove fatal unless treated.
One defect that may occur is a patent foramen ovale (“PFO”) or patent ductus arteriosus (“PDA”), which may occur between the left and right atria of the heart. During fetal life, an opening called the foramen ovale allows blood to pass directly from the right atrium to the left atrium (bypassing the lungs). Thus, oxygenated blood from the placenta may travel through the vena cava into the right atrium, through the foramen ovale into the left atrium, and from there into the left ventricle for delivery via the aorta to the fetus' body. After birth, the foramen ovale is replaced with a membrane called the fossa ovalis, and over time, a solid mass of tissue may form.
Occasionally, this membrane and tissue mass fail to form or completely close the foramen ovale, which may be fatal if untreated. Similar defects may occur in other regions within a septum between chambers of the heart, such as atrial septal defects, ventricular septal defects, and the like.
To close such defects, open surgery may be performed to ligate and close the defect. Such procedures are obviously highly invasive and pose substantial morbidity and mortality risks.
Alternatively, catheter-based procedures have been suggested. These may involve introducing umbrella-like structures into the heart that include opposing expandable structures connected by a hub. One of the expandable structures is inserted through the defect, and both are expanded to secure the tissue surrounding the defect between the structures in an attempt to seal and close the defect. Such structures, however, involve frame structures that support membranes, both of which may fail during the life of the patient being treated, opening the defect, and/or releasing segments of the structure within the patient's heart.
Accordingly, apparatus and methods for closing patent foramen ovale, patent ductus arteriosus, or other septal defects would be considered useful.
SUMMARY OF THE INVENTION
The present invention is directed to apparatus and methods for closing patent foramen ovale (“PFO”), patent ductus arteriosus (“PDA”), or other septal defects.
In accordance with a first aspect of the present invention, an apparatus for closing a septal defect is provided that includes an elongate needle including a first end defining a tissue-penetrating tip, and a second end defining a substantially blunt tip. A filament extends from an intermediate portion of the needle between the first and second ends, and a locking element, such as a clip, clamp, cross-brace, and the like, may be securable to the filament, thereby preventing the locking element from moving along the filament away from the needle.
Preferably, the needle has a tapered cross-section such that the second end is substantially larger than the first end. A slot may be provided in the needle that extends from the intermediate portion to the second end, the slot having a size for receiving a portion of the filament therein. The second end of the needle may include a flared outer edge and/or a rounded inner edge.
In one embodiment, the locking element may be a clip that is slidable along the filament towards the needle, the clip including opposing arms having teeth or other engaging elements for preventing the clip from being moved along the filament away from the needle. Alternatively, the clip may be plastically deformable such that the clip may received around the filament and then crimped or otherwise secured to the filament during closure of a septal defect, as explained further below.
In accordance with another aspect of the present invention, a delivery apparatus for delivering a needle apparatus, such as that described above, is provided that includes an outer catheter and a pusher member that are slidably coupled to one another. The catheter may be a tubular member including proximal and distal ends and a lumen therebetween, the distal end having a size for insertion into a blood vessel or other body lumen. The needle may be carried within the lumen such that the first end is disposed distally to the second end.
The pusher member may be an inner catheter or other elongate member that is disposed within the lumen of the outer catheter. The pusher member may include a distal end that may be disposed proximate the second end of the needle, the pusher member being movable axially relative to the tubular member for ejecting the needle distally from the lumen. The pusher member may include a lumen extending proximally from the distal end of the pusher member such that the filament extending from the needle may be received through the lumen.
An actuator may be provided on the proximal end of the tubular member and/or the pusher member for advancing the pusher member relative to the tubular member. Preferably, the actuator may limit advancement of the pusher member such that the distal end of the pusher member extends only a predetermined distance beyond the distal end of the tubular member when activated. The actuator may also be coupled to the filament received through the lumen in the pusher member for applying proximal tension to the filament during use, as described further below.
The lumen of the catheter may include an enlarged distal region proximate the distal end for receiving the needle therein. For example, the second end of the needle may have a cross-section that is substantially larger than a cross-section of the distal end of the pusher member. In addition, the second end of the needle may have a flared outer edge such that the second end extends laterally from the distal end of the pusher member. Alternatively, the second end of the needle may simply be larger in cross-section than the distal end of the pusher member, In addition, the second end of the needle may include a rounded edge for facilitating pivoting of the needle about the intermediate region when the filament is pulled proximally.
In addition, the delivery apparatus may include a clip carrier having a proximal end and a distal end having a size for introduction into a body lumen. A clip or other locking element may be releasably carried by the distal end of the clip carrier, the clip including opposing arms defining a slot therebetween for receiving a filament therein. The clip carrier may include a hammer/anvil arrangement for plastically deforming at least one of the opposing arms to engage a filament received within the slot. The clip carrier may be completely separate from the catheter and pusher member or may be carried by the catheter and/or pusher member. For example, the catheter may include an additional lumen through which the clip carrier may be advanced.
In a further alternative, the delivery apparatus may include an imaging device including an imaging element associated with the distal end of the tubular member for imaging beyond the distal end of the tubular member. For example, the imaging device may be an endoscope or ultrasound device that may be received within a lumen of the tubular member or may be a separate device that may introduced independently into the patient but used in conjunction with the delivery apparatus during a procedure.
In accordance with yet another aspect of the present invention, a method is provided for closing a PFO or other septal defect within a patient's heart. Generally, the septal defect includes a flap of tissue partially detached from
Core Medical, Inc.
Milano Michael J.
Orrick Herrington & Sutcliffe LLP
Roberts P
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