Surgery – Instruments – Sutureless closure
Reexamination Certificate
1998-12-16
2002-03-12
Chaudhuri, Olik (Department: 2814)
Surgery
Instruments
Sutureless closure
Reexamination Certificate
active
06355052
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a device for closure of defect openings in the human or animal body. It can be employed, for example, in the treatment of congenital heart defects with left-to-right shunt, for instance an atrial septal defect, by means of catheter techniques.
In the case of vessels to which surgical access is difficult, attempts have for many years been made to close these vessels with the aid of catheter techniques by way of the vessel pathway. A catheter intervention is less onerous on the patient than an operation, and in some cases sedation is sufficient.
Septal defects of the heart can also be closed by means of catheter techniques. The first transcatheter closures of atrial septal defects were performed in 1976 by King and Mills (Kills N. L., King T. D.: Nonoperative Closure of Left-to-right Shunts; J. Thorac. Cardiovasc. Surg. 72: 371-378, 1976) in animal experiments and on humans. The closure device used, and a subsequent device which was developed by Rashkind (Rashkind W. J., Mullins C. E., Hellenbrand W. E., et al: Nonsurgical Closure of Patent Ductus Arteriosus: Clinical Application of the Rashkind PDA Occluder System; Circulation 75: 583-592, 1987), never gained wide-spread clinical application, on account of the size of the introducing sheath of at first 23 F in the case of the first-mentioned device, and on account of the fixing hooks in the insertion device according to Rashkind. The hooks made correct centring and implantation difficult.
Two further closure devices are the so-called “clamshell device” according to Lock (Lock J. E., Rome J. J., Davis R., et al: Transcatheter Closure of Atrial Septal Defects, Experimental Studies, Circulation 79: 1091-1099, 1989) and the “buttoned device” according to Sideris (Sideris E. B., Sideris S. E., Fowlkes J. P., et al: Transvenous Atrial Septal Defect Occlusion in Piglets with a “Buttoned” Double-disk Device; Circulation 81: 312-318, 1990) which essentially have an umbrella-like form with metal struts extending outwards from the centre and acting as a support for a material covering. The left atrial umbrella and a counter-support in the right atrium are connected to one another at a central node or “button”. Problems with the “clamshell device” include spontaneous embolization of the device, residual shunts and wire breaks. The disadvantages of the “buttoned devices” are an uncomfortable implantation technique, residual defects and embolizations.
D. Pavcnik et al. describe, in Cardiovasc. Intervent. Radiol. (1993) 16:308-312, an insertion device consisting of a spring-like wire coil made of special steel and covered with two layers of nylon mesh. Three sections of a hollow spiral coil are sewn as an anchoring means on the rear of the disc. Three strands of nylon monofilament yarn are looped through the anchor wires and guided through the catheter lumen. In this way the device is fixed in a reversible manner on the advance catheter. For implantation, the device is compressed and is transported through a catheter to the septal defect. The self-expanding disc opens out in the left atrium when it leaves the sheath. The anchor wires on the rear are brought into position on the right side of the atrial septum, the nylon filaments are cut through, whereupon the flexible wires spring back and press against the septal wall, so that the disc is anchored in the defect. A disadvantage of this insertion device is that the disc leaves the implantation catheter laterally and has to be turned, only with some difficulty, through 90° in the left atrium.
In Circulation Volume 88, No. 4, Part 1, October 1993, G. S. Das describes a further device for closure of atrial septal defects of the heart. It consists of two square frames of superelastic nitinol wire which are offset through 45° in relation to each other. The wire stretching across one square frame is shaped into flexible eyelets at the corners of the frame and at the midpoints of the sides. The eight eyelets in each frame make it possible for the frame to be folded up in order to introduce it into the implantation catheter. Both wire frames are covered with an elastic Dacron (polyester) fabric in each case, and these fabrics are sewn together and so form two connected discs. Each square frame can be collapsed by being folded such that the four corner eyelets are moved towards one another. The radial tensioning of the superelastic nitinol wire frames and the taut fabric have the effect that the discs lie closely opposite one another. A disadvantage of this double umbrella is that it requires a catheter diameter of at least 12 F, and, at the same time, in each case eight wire sections of the frame of a folded individual umbrella have to be transported through the catheter. Moreover, in the case of this double umbrella, a repositioning mechanism can only be attached laterally on the outside, and not in the centre, which would be more favourable for exact implantation. In addition, the umbrella shape is restricted to the square configuration, which can lead to disturbances with valve structures. In addition, after it has left the implantation catheter, the second umbrella opens out so suddenly that damage to the septum is possible.
U.S. Pat. No. Specification 5,108,420 discloses a device for closure of defect openings which, in a first state, when it is located in an insertion catheter, assumes an elongate shape and, after implantation, opens out into a second shape on account of the resiliency of the material. The device consists of a wire framework which, in a preferred embodiment, in made up of three point-symmetrical individual elements which form a common axis which, in the implanted state, extends through the opening which is to be closed. On both sides of the opening which is to be closed, these individual elements form circular arc segments which complement each other to give approximately a full circle and can be covered with a fabric. The individual elements are in this case prestressed in such a way that, in the implanted state of the device, the tissue surrounding the opening is clamped between opposite circular arc segments and the covering bears on the tissue surrounding the opening. The device is hold in position as a result of this clamping action. However, the common axis of the individual elements, and thus the device, remains movable within the opening which is to be closed. This has a number of disadvantages. On the one hand, after implantation has been performed, the device can be displaced in the radial direction in relation to the opening. For safety reasons, in order to preclude the possibility of a residual shunt, a large radius of the circular arc segments therefore has to be chosen. However, this device can then only be used on defects in which there in a sufficiently large residual tissue surface surrounding the opening. In addition, the device has to be adapted very exactly to the shape and size of the defect which is to be closed. Finally, the device has to be positioned very precisely by the operating surgeon upon implantation, which makes the intervention more difficult and also much longer.
A prosthesis for closure of an atrial or a ventricular septal defect is known from DE-A 4,222,291, which prosthesis has two units made of a resilient material and comprising six arms which extend in a radial direction, are arranged at uniform angular spacings from one another, and are connected to one another via a tension spring. In the transport state of the prosthesis, i.e. when the latter is located in the inside of a catheter, the prosthesis is stretched in the axial direction counter to the action of the tension spring, the arms of the two units being curved in the direction of the longitudinal axis. In the implanted state, the prosthesis opens out, with the two units moving towards one another on account of the spring action, and the arms being spread. The tissue surrounding the defect opening is thus clamped between the arms of the two units, as a result of which the prosthesis is held in position. This prosthesis t
Freudenthal Franz
Neuss Malte
Chaudhuri Olik
Paul A. Beck & Associates
pfm Produkte fur die Medizin Aktiengesellschaft
Trinh (Vikki) Hoa B.
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