Abstract:
A surgical tool to assist in handling and implantation of flexible annuloplasty rings. The holder takes the form of an oblate ring to which the annuloplasty ring is mounted. The annuloplasty ring is retained on the holder by means of radially extending fingers and sutures.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to surgical tools and more particularly for surgical tools used in conjunction with annuloplasty rings. 
     Annuloplasty rings are useful in a variety of surgical procedures, including mitral and tricuspid annular reduction. In these procedures, sutures are first placed around the valve annulus at spaced intervals. Sutures passing through the annulus in the intertrigonal area are spaced equidistant from one another, for example, at 2 mm intervals. Sutures passing through the annulus around the remainder of the valve are typically spaced at somewhat wider intervals, for example, 4 mm. The sutures surrounding the valve annulus are then brought through the annuloplasty ring. The sutures passing through the annulus between the trigones are passed through the annuloplasty ring with the same spacing, for example, 2 mm. The remainder of the sutures are passed through the annuloplasty ring more closely spaced than where they pass through the annulus, for example, 11/2 mm. The process of passing the sutures through the ring occurs while the ring is held above the valve annulus. The ring is then moved down into contact with the valve annulus, causing contraction of the annulus with the exception of the intertrigonal area, thus effecting a reduction in valve annulus circumference. This basic procedure is used to correct both mitral and tricuspid annular dilatation. 
     In order for the sutures to be passed through the annuloplasty ring, it is desirable that the ring be held in a fixture or tool of some fashion. One available tool is manufactured by Pilling Instruments, and takes the general form of a cone provided with a circumferential groove near the base. The cone is also provided with longitudinal slits, so that the tool may be contracted to accept the ring around the circumference of the groove. The tool is adapted to be held by means of a threaded handle. 
     SUMMARY OF THE INVENTION 
     The present invention is directed toward an improved holder for use with annuloplasty rings. The holder is specifically configured to assist the surgeon in performing the technique of mitral or tricuspid reduction, and is intended to be provided in conjunction with the annuloplasty ring, ready for use. The ring holder takes the general form of an oblate ring member having an outer circumference equal to the inner circumference of the annuloplasty ring with which it is used. The outer circumference of the holder member comprises two arcuate segments joined at their ends, the radius of curvature of one of the arcuate segments being significantly smaller than the other. 
     Along each of the arcuate segments are a plurality of radially extending fingers which engage the annuloplasty ring, without unduly obstructing access to the ring. A plurality of the fingers are provided with suture bores perpendicular to and peripherally spaced from the ring. Corresponding inwardly placed suture bores in the holder member allow for the use of sutures to retain the annuloplasty ring on the holder. The holder is also provided with a centrally located receiving member having a threaded bore, allowing the holder to be used in conjunction with a threaded handle. 
     The ring is intended to be mounted to the ring holder such that markers placed on the rings, corresponding to the location of the trigones on the valve, are placed along the arcuate segment of the holder having the greater radius of curvature. Radially extending fingers located between the trigone markers are located at first, evenly spaced intervals, while the fingers around the periphery of the rest of the holder are more widely spaced. The spacing of the fingers assists the physician both in assuring that sutures are evenly spaced and that the sutures are at proper intervals around the ring. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a ring holder according to the invention, with the annuloplasty ring mounted thereto. 
     FIG. 2 is a top plan view of the annuloplasty ring holder. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 is a perspective view from above of the annuloplasty ring holder, with the annuloplasty ring attached. This is the configuration in which it is anticipated that the two products will be provided to the physician for use. The outer periphery of the holder member 5 generally comprises two arcuate segments 10 and 12 which define a generally planar oblate ring having upper surface 6 and an opposite, lower surface. The radius of curvature of segment 10 is substantially greater than the radius of curvature of segment 12. Annuloplasty ring 38 is mounted around the external circumferential surface 7 of holder member 5. Spaced around holder member 5 are a plurality of retaining fingers 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34 and 36. Each of the fingers includes a radially extending portion which extends across the annuloplasty ring 38 and a vertically extending portion, located radially outward of ring 38. These fingers, in conjunction with the arcuate segments 10 and 12 serve to retain the ring 38 on the ring holder. 
     Fingers 18, 24, 30 and 36 are provided with suture bores 40, 42, 44 and 46, respectively, which pass through the vertically extending portions of the fingers. The holder member 5 is also provided with a plurality of perpendicular suture bores 48, 50, 52 and 54, located radially inward of ring 38 across from suture bores 40, 42, 44 and 46, respectively. As illustrated, sutures 56, 58, 60 and 62 are passed through the suture bores and around annuloplasty ring 38, and serve to retain annuloplasty ring 38 on the ring holder during the surgical procedure. It should be noted that fingers 18, 24, 30 and 36 are each provided with a portion which extends vertically above the upper surface 6 of the holder member 5. Suture bores 40, 42, 44 and 46 are located in these vertically extending portions of the fingers. Correspondingly, suture bores 48, 50, 52 and 54 are located in portions of the holder member 5 which also extend vertically above the upper surface 6 of holder member 5. This results in the portions of the sutures 56, 58, 60 and 62 which cross the upper surface 6 of the ring member 5 being spaced from the upper surface 6, facilitating the use of a scalpel or other cutting tool to sever the sutures and release the annuloplasty ring 38. Sutures 56, 58, 60 and 62 should be tied to holder member 5 so that after they are cut, they remain attached to the holder member 5. 
     It should be noted that the trigonal markers 64 and 66 are located along arcuate segment 10, between fingers 16 and 18 and between fingers 30 and 32. Fingers 32, 34, 36, 14 and 16, located between trigonal markers 64 and 66 are evenly spaced from one another at their radial extremities. Similarly, fingers 16, 18, 20, 22, 24, 26, 28 and 32 are evenly spaced from one another at their radial extremities. However, the spacing between fingers 26 and 28, for example, is significantly greater than the spacing between fingers 14 and 16. 
     As noted above, during mitral or tricuspid annular reduction, the spacing of the sutures between the trigonal markers 64 and 66 is intended to be different from that between sutures surrounding the rest of the annuloplasty ring. The fact that the fingers are evenly spaced within each of these regions of the ring facilitates even spacing of the sutures by the physician. The fact that the fingers are differentially spaced along these two regions assists in reminding the physician that the spacing of the sutures should be spaced differently between the trigonal markers than around the rest of the ring. 
     Located centrally to the holder member is a receiving member 68 which includes a central, cylindrical portion 70, provided with a threaded bore 72. A threaded handle may thus be inserted into bore 72 to facilitate use of the ring holder. The cylindrical portion 70 extends vertically above the portions of the ring member 5 in which the suture bores are located so that a locking nut may be used in conjunction with the threaded handle without interfering with access to the sutures 56, 58, 60 and 62. Threaded bore 72 is dead-ended, so that a threaded handle may be inserted only from one direction. 
     As illustrated in FIG. 1, adjacent arcuate segment 10, the holder member 5 bears the marking &#34;MITRAL 29 mm&#34;, while adjacent arcuate segment 12 is the marking &#34;TRICUSPID 29 mm&#34;. These markings are intended as an aid to the physician. These markings presume that access to the mitral valve will be made by means of an atrial left atriotomy. In this case, the labeling &#34;MITRAL 29 mm&#34; will be generally upright in the physician&#39;s field of vision when the trigone markers 64 and 62 are properly oriented with respect to the trigones of the valve. Similarly, assuming that access to the tricuspid valve is made by means of a longitudinal right atriotomy, the trigone markers 64 and 66 will be generally in their proper locations with respect to the trigones of the valve when the label &#34;TRICUSPID 29 mm&#34; is upright in the physician&#39;s field of vision. This feature is believed to assist in initial proper orientation of the ring and holder during the surgical procedure. 
     FIG. 2 is a top, plan view of the holder illustrated in FIG. 1. In this view, the spacing between the radially extending fingers and the different arcs of curvature of the two arcuate segments are more clearly visible. As can be seen, arcuate segment 10 has a substantially greater radius of curvature than arcuate segment 12. In this view, it is also apparent that the spacing between the radial extremities of fingers 32, 34, 36, 14 and 16 is relatively even, and less than the spacing between the radial extremities of fingers 18, 20, 22, 24, 26, 28 and 30. In use, marks on the annuloplasty ring signifying the location of the trigones will fall between fingers 30 and 32 and between fingers 16 and 18. All other structures marked in FIG. 2 correspond to identically marked structures in FIG. 1. 
     The annuloplasty ring 38 illustrated in FIGS. 1 and 2 is a Duran™ flexible annuloplasty ring, marketed by Medtronic, Inc. While the specific configuration illustrated is optimized for use with the Duran™ annuloplasty ring, the holder of the present invention is believed also adaptable for use in conjunction with other flexible and rigid annuloplasty rings, including those disclosed in Carpentier et al U.S. Pat. No. 4,055,861, Reed U.S. Pat. No. 4,489,446, Angel U.S. Pat. No. 4,042,979 and Bex et al U.S. Pat. No. 4,217,665. While the configuration of the external periphery of the holder may have to be varied in order to adapt the holder for use with some of these other rings, it is believed within the scope of the invention to do so. 
     The Duran™ annuloplasty ring is a ring which is both flexible and slightly elastic. Typically, the ring may be circumferentially elongated up to about 10% of its circumference. The ring is also resilient. For rings of this type, it is desirable that the annuloplasty ring fit snuggly around the circumference of the ring holder member 5 without substantial elongation. A snug fit is desirable to prevent looping or pulling away of the ring from the holder member during the suturing procedure as the sutures are pulled through the ring. While the fit should be snug, it should not result in any significant circumferential elongation of the ring, as this may encourage the ring to take a permanent set. 
     The holder illustrated in FIGS. 1 and 2 is intended to be an example of one of a family of products, covering a range of sizes. Each annuloplasty ring of the type illustrated is provided with three equidistantly spaced markers, two of which correspond to markers 52 and 64 (FIG. 1) and are intended to correspond to the location of the trigones of the patient&#39;s valve. The distance between two adjacent markers on the annuloplasty ring is the size designation. For example, in the annuloplasty ring illustrated in FIG. 1, the lineal distance along the ring 38 between marker 52 and marker 64 is 29 mm. Flexible annuloplasty rings of this type are generally available in sizes from 25 mm to 35 mm. As such, the spacing between the fingers on the variously sized ring holders will vary somewhat. It is also anticipated that the number of fingers and the number of fingers which carry suture bores may also be varied, although the configuration illustrated in FIG. 2, in which the four suture bores are located in fingers displaced approximately 90° from one another, is believed to be the preferred configuration. The illustrated embodiment of the ring holder is intended to be merely exemplary, and not limiting with regard to the following claims.