Bi-directionally expandable sternal clamp device

[0001] This patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/001,628, filed Nov. 2, 2007.

[0002] This invention generally relates to devices used to rejoin a human sternum that has been severed longitudinally, and more particularly relates to such devices that function in a clamping manner to retain the severed sternum portions in a closed and abutting relationship post-operatively.

[0003] It is often necessary in surgical operations to longitudinally sever the patient's sternum so that the ribs may be spread to provide access to internal organs such as the heart. It is then necessary to secure the sternum halves together for post-operative recovery. Various closure techniques are used to accomplish this task. For example, holes may be drilled into the sternum halves and suture material passed through and tightened to cinch the sternum halves together. Apertured plates may be added to further rigidify the sternum post-operatively, with the suture material being passed through the apertures in the plate and the sternum. Encircling members may be wrapped around the sternum and tightened. Toothed bridging members extending across the cut line may be pressed into the sternum surfaces and/or secured with threaded rods extending between the sternal halves.

[0004] Another sternal closure technique involves the use of clamps having hook-like projections or engagement members on both ends, the clamp being positioned laterally relative to the sternal incision with the projections being disposed between adjoining rib pairs. The clamp is then linearly contracted or compressed to shorten the device and force the sternal halves together, the clamp typically comprising two members joined in a linear telescoping manner. Locking or securing means, either permanent or releasable, maintain the clamp in the contracted configuration.

[0005] Often the sternum may be in a weakened state, in which case the sternal clamps having a pairs of engagement members on each side are utilized in order to spread the compressive forces, with the engagement members on a given side of the sternum being disposed to either side of a rib. A problem with this design is that size of the rib the distance between adjacent ribs will vary, and thus the separation distance between the two engagement members may not be correct to properly locate the sternal clamp.

[0006] Examples of such techniques and sternal clamp devices are described in U.S. Pat. No. 3,473,528 to Mishkin et al., U.S. Pat. No. 4,201,215 to Crossett et al., U.S. Pat. No. 4,279,248 to Gabbay, U.S. Pat. No. 4,583,541 to Barry, U.S. Pat. No. 5,139,498 to Astudillo Ley, U.S. Pat. No. 6,051,007 to Hogendijk et al., U.S. Pat. No. 6,217,580 to Levin, U.S. Pat. No. 6,302,899 to Johnson et al., U.S. Pat. No. 6,540,769 to Miller, III, and U.S. Pat. No. 6,712,821 to Gabbay.

[0007] It is an object of this invention to provide a bi-directionally expandable sternal closure clamp device having the functionality of a contractible sternal clamp, such that the sternal halves may be quickly and easily pressed or drawn together in a sliding or telescoping manner and retained in position, but which also is extendible in the direction parallel to the sternal incision, such that the engagement members on each side of the sternum can be properly spaced to surround single or multiple ribs.

[0008] The invention is in general a sternal closure clamp device for post-operatively closing, securing and supporting a patient's sternum that has been longitudinally severed into two sternal halves. The sternal clamp generally comprises four interconnected body members that together form a unified, bi-directionally expandable clamp, with four engagement members that extend generally from the area of the corners of the unified clamp, such that two engagement members are disposed on one side and two engagement members are disposed on the other side. The engagement members are means to engage, secure or otherwise retain the sternal halves in an abutting relationship, with the engagement members comprising hooks, projections, fingers or the like, whereby the engagement members can be disposed against the outer edges of the sternal halves and between adjoining ribs, with the two engagement members located on a given side being positioned in the inter-rib spaces to either side of a single rib or multiple ribs when the clamp is extended. The clamp is also extendable in the sternal longitudinal direction, such that the spacing between engagement members on each side can be adjusted to account for variations in rib size.

[0009] The body members interconnect in a sliding or telescopic manner and are relatively adjustable, such that the distance between the engagement members can be lengthened in the longitudinal direction relative to the sternum to properly locate the engagement members in to the inter-rib spaces, then shortened in the transverse direction to press or draw the sternal halves together. The sternal clamp further comprises locking means to secure and retain the body members in the contracted position, with the locking means preferably being releasable.

[0013] With reference to the drawings, the invention will now be described in detail with regard for the best mode and the preferred embodiment. The invention is a sternal closure clamp device used to close, secure and support a sternum post-operatively, the sternum having been severed longitudinally into left and right lateral sternal halves to provide access to the interior of the chest, wherein the clamp may be extended both laterally and longitudinally relative to the sternal incision.

[0014] In general, the invention is a sternal clamp 10 having means to expand and contract the clamp 10 in a first direction longitudinally relative to the sternum, means to expand and contract the clamp 10 in a second direction orthogonal to the first direction and transverse relative to the sternum, and means to engage the sides of the sternum and alternatively the sides of ribs such that halves of a longitudinally divided sternum can be compressed together and held in place during healing and such that the halves of a transversely divided sternum can be compressed and held together during healing.

[0015] In one embodiment of the device, as shown in FIG. 1, the sternal clamp 10 comprises four, generally L-shaped, telescopically interconnected body members 11, 12, 13 and 14 that in combination form a bi-directionally expandable clamp 10, with four engagement members 15, 16, 17 and 18 that extend generally from the area of the corners of the assembled clamp 10, with two engagement members 15 and 16 disposed on one side of the clamp 10 and two engagement members 17 and 18 disposed on the other side of the clamp 10. The engagement members 15, 16, 17 and 18 are means to engage, secure or otherwise retain the sternal halves or the ribs in an abutting relationship, with the engagement members 15, 16, 17 and 18 having hooks, projections, fingers or the like disposed on their ends, whereby the engagement members 15, 16, 17 and 18 are disposed against the outer edges of the sternal halves and between adjoining ribs, with the two paired engagement members 15/16 and 17/18 on a given side being positioned in the inter-rib spaces to either side of a single rib or multiple ribs when the clamp 10 is extended. Prior to positioning of the engagement members 15, 16, 17 and 18, the clamp 10 is contracted or extended in the sternal longitudinal direction in order to decrease or increase the distance between engagement members 15 and 16 and engagement members 17 and 18 to account for variations in rib spacing. The engagement members 15, 16, 17 and 18 are mounted to the body members 11, 12, 13 and 14 in a manner that allows each to be rotated such that the engagement members on a given side may be pointed towards each other in order to abut the sides of ribs or pointed across the clamp toward the engagement members on the other side in order to engage the sternal halves.

[0016] The body members 11, 12, 13 and 14 interconnect in a sliding or telescopic manner and are relatively adjustable, such that the distance between the engagement members 15, 16, 17 and 18 can be lengthened in two orthogonal directions to properly locate the engagement members 15, 16, 17 and 18 relative to the inter-rib spaces, then shortened in the transverse direction to press or draw the sternal halves together. In the embodiment as shown, body members 11 and 13 are L-shaped sleeve members that receive L-shaped tongue body members 12 and 14. Alternatively, each body member 11, 12, 13 and 14 may comprise one end that is a sleeve and the other end that is a tongue, or the body members 11, 12, 13 and 14 may comprises various rail-like or tongue-and-groove configurations which allow for adjustment of the overall size of the clamp 10 in the two orthogonal directions.

[0017] The sternal clamp 10 further comprises means for securing the body members 11, 12, 13 and 14 in the fixed, contracted position, with the securing means preferably being releasable so that the clamp 10 can be removed as necessary. The securing means may comprise simple setscrews 19, as shown in FIG. 1, or ratchet mechanisms 20, as shown in FIGS. 2 and 3, or like systems that allow relative movement of the body members 11, 12, 13 and 14, all of which mechanisms are well known in the sternal clamp art.

[0018] It is contemplated that equivalents and substitutions for certain elements set forth above may be obvious to those of ordinary skill in the art, and therefore the true scope and definition of the invention is to be as set forth in the following claims.