Apparatus and method for surgical fastening

#The present invention relates generally to surgical fastening tools for fixating tissue and/or—surgical materials during minimally invasive surgery, and particularly to a surgical fastening tool having a space-efficient, simplified fastening mechanism that permits deployment of the tool through a minimal opening but which also maximizes the gripping area of the applied surgical fastener. More particularly, the invention relates to a reduced diameter (5 mm) surgical fastening tool for use in hernia repair. The tool is deployed through a reduced diameter access port in the body to fasten a piece of surgical mesh to body tissue using a specially formed fastener having a maximized gripping area. The tool also has a simplified, jam-free fastening mechanism. The present invention also relates to methods for repairing a patient's hernia through a minimized diameter access port while maximizing the gripping area of the surgical fastener as well as methods for applying surgical fasteners from a miniatured device with reduced risk of jamming.

#During some surgical procedures, most notably hernia repair procedures, it is considered desirable by many practitioners to reinforce the muscle tear or other defect with a piece of surgically implantable mesh. Physicians most often use an open-weave, sintered mesh made of polypropylene and hold it in place by a type of permanent fixation method. One common method of fixation uses metallic fasteners, such as staples, which remain in the body permanently after the hernia repair. Medical device designers have created a number of larger-size devices to fasten tissue and/or surgical materials to tissue during minimally invasive surgery. According to these designs, the devices typically contemplate a 10-mm or wider application tool used to deploy a fastener. For example, Green et al., U.S. Pat. No. 5,356,064, col. 21, II. 34-53, describes a device for deployment through a 12 mm trocar guide tube wherein the device stacks a set of staples at roughly a forty-five degree angle to the axis of the device to provide greater visibility. See Green et al. FIG. 18.

#However, these tools are being judged too large for deployment according to the current minimally invasive techniques which are bringing the size of the surgical instruments and access ports down to a 5 mm diameter. Moreover, Green et al. cannot be readily scaled down because of physical limitations caused by the generally transverse stacking of fasteners. See Green et al., FIG. 18. In, addition, the design of Green et al. cannot be effectively scaled down because the fastener discharged by the application tool must be of sufficient scale to securely span across the defect and/or strands of surgical mesh and efficaciously engage sufficient tissue area for adequate gripping strength. Green et al. employs a fastener forming system which unduly reduces the finished span or width of the fastener relative to its initial width. See Green et al., FIG. 20-21, col. 22, II. 38-48. Thus, reduction in Green et al.'s tool diameter would result in an unsatisfactory gripping area for the finished fastener.

#Reference is made to a brief description of the drawings, which are intended to illustrate surgical fastening tools for use herein. The drawings and detailed description which follow are intended to be merely illustrative and are not intended to limit the scope of the invention as set forth in the appended claims.

#FIG. 1 is a schematic front view of an embodiment of the preferred fastener, space-efficient shaping slide and anvil of the present invention.

#FIG. 2 is a schematic front view of a traditional staple with its shape-forming slide about to form the staple on a rectangular anvil.

#Referring more particularly to the drawings, FIG. 6 shows one embodiment of the surgical fastening tool. The surgical fastening tool comprises a handle portion 10 an applicator 20 and a trigger portion 30. FIG. 7 shows a cut-away cross-section—of a preferred embodiment of the applicator portion of the device. According to the preferred embodiment, the applicator comprises a tubular housing 40 having an insert contained within. Although the insert could be made as a single unit or even be manufactured out of a single piece that forms the tubular housing, the insert is preferably made from two cooperating half-shells which are inserted into the tubular housing. The half-shells preferably have a beveled outer edge which permits crimping of the distal most end of the tubular housing to secure the insert. In the preferred embodiment, the first half-shell 50 has a rounded side 52 which abuts the tubular housing 40 and a flat side 54 that has recessed region 70 whose surface forms one the walls of the fastener storage channel containing fasteners 80. Above the fasteners 80 sits a pusher 82, which rides in the fastener storage channel. The pusher 82 continuously exerts a downward pressure on the vertically stacked fasteners 80 by virtue of a biased pusher spring 84.

#Recessed region 70 gradually rises to the diametrical plane of flat side 54 (diametrical relative to the tube circumference on flat side 54) by virtue of a slanted ramp 72. A fastener positioning spring 60 attached to and flush with the recessed portion 70 of flat side 54 of the first half shell 50 is biased to extend beyond both the recessed region 70 of the flat side 54 and the most prominent plane of the flat side 54. The spring 60 is capable of being completely contained within a slot 90 in the first half-shell. Finally, the first half-shell 50 has a cut-away region 92 at the distal end of the applicator to permit ejection of the fastener.

#A perspective view of the first half-shell 50 is shown in FIG. 9. The diametrical plane of flat side 54 appears uppermost in the drawing. This view shows that in a preferred embodiment the cut-away region 92 has two further recessed regions 94a and 94b.