STERNOTOMY SPACING DEVICE

Abstract

A device and a method for keeping the sternal edges apart for the procedure of delayed sternal closure is disclosed in which one or more, specifically shaped struts or stents are insinuated horizontally between the edges of the open sternum, keeping the two edges of the divided sternum apart by a distance determined by the length of the middle bar of the device. The disclosed device has lateral ends which are manually engaged to the medial ends of the sternal edges, by an insinuating movement while the said lateral ends of the apparatus hold onto the medial portion of the sternal edges by a passive, cupping grip which can be further secured by anchoring sutures. The whole of the disclosed device is in the form of a single piece, without any moving parts, joints, screws or nuts & bolts. The present device provides a method and an instrument which occupies minimum inter-sternal space and provides maximum sub-sternal space for accommodating cardiac oedema.

Claims

1. A device for keeping apart the sternal edges of a patient with mid-Sternotomy, the device comprising; an elongate member which act as a strut between the sternal edges to keep these apart, the two outer ends of the apparatus dimensioned & configured to clasp and firmly engage with the severed edges of the sternum and provided with means of further securing the apparatus to the severed halves of the sternum; the whole device is one solid configuration, without any moving parts or joints.

2. The device as set forth in claim 1, wherein the elongate member is in the form of a horizontal bar/rod between the outer ends of the device.

3. The device as set forth in claim 1, wherein the length of the elongate member determines the gap between the sternal edges.

4. The device as set forth in claim 1, wherein the elongate member is eccentrically positioned at the most superficial level of the device, being either straight or outwardly convex, providing free space between the sternal edges.

5. The device as set forth in claim 1, wherein the elongate member join the lateral grasping ends of the device at or near its superficial aspect.

6. The device as set forth in claim 1, wherein the two outer ends of the device have substantially U shaped cross-section, shaped like two horizontally disposed horse-shoes, with their open ends towards the sternal edges, dimensioned and configured to clasp and firmly engage with the severed edges of the sternum, at a broader plane than the middle elongate member.

7. The device as set forth in claim 6 wherein the outer ends of the device are provided with strategically placed notches in its prongs and grooves along the surface of the outer ends for securing the outer ends to the sternal halves by means of suture ligation.

8. The device as set forth in claim 1, wherein the middle elongate member and the two outer ends of the device, make one continuum, without any joints, moving parts or coupling devices.

9. The device as set forth in claim 1, wherein the sternal spacing device is provided as a set of graduated, ready-to-use, sizes with small to large middle elongate member as well as the outer ends, configured to engaging with the sternal halves, of patients of various ages and body sizes.

10. The device as claimed in claims 1, 6 and 7, the prongs of the outer ends of the device can be fabricated of a Thermoplastic material like Nylon, Polycarbonates or poly-ketones so as to exert a clasping grip over the severed edges of the sternum.

11. The device as claimed in claims 1-10, wherein the device may be impregnated with suitable antibiotic coating to reduce the risk of local wound infection.

12. The device as claimed in claim 1-11, the device may be fabricated with a suitable material as to be lucent to X-rays.

13. The device as claimed in claim 1 wherein the device being provided in a set of graduated sizes to be suitable for patients of various ages and sizes.

14. The device as claimed in claim 1 wherein the device being fabricated of bio-compatible material.

15. A method for maintaining a pre-determined space between the divided edges of the Sternum or any two bony parts of the patients; the method comprising; horizontally inserting an elongate member between the two divided ends of the bony part in such a way that the two lateral end portions engage with the medial portions of the severed sternal ends and these lateral ends could further be secured by suture fixation with the sternal or divided bony ends, the fixation being facilitated by strategically placed notches and grooves in and on the lateral end portions.

16. A method for maintaining a pre-determined space between the divided edges of the Sternum or any two bony parts of the patients; the method comprising, as set forth in claim 15, by using one or multiple number of these devices which may be of different sizes in length of the middle part as well as the lateral ends, being placed at different parts of the severed sternal or bony edges.

Description

BRIEF INTRODUCTION TO DRAWINGS

[0058] The invention will now be described solely by way of example and with reference to the accompanying drawings in which:

[0059] FIGS. 1-23 are the drawings of the referred prior art.

[0060] FIG. 24: shows a sketch of one embodiment of the present device wherein the device comprise a solid, metallic body, without any joints or mobile parts, comprising two lateral sternal ends opening in the opposite direction and a central, eccentrically placed, joining bar or strut.

[0061] FIG. 25: shows the profile view of one particular embodiment of the present device.

[0062] FIG. 26 shows the top view, from the superior or the external aspect of the stenting device of the present invention

[0063] FIG. 27: shows one particular embodiment of the present invention with a specific configuration of the intermediate bar/strut.

[0064] FIG. 28: shows another particular embodiment of the present invention with a specific configuration of the intermediate bar/strut.

[0065] FIG. 29: shows one particular embodiment of the present invention which is fabricated with strong though light-weight non-metallic material.

[0066] FIG. 30: shows one particular embodiment of the present invention with suture anchoring configuration along the lateral ends of the said stenting device.

[0067] FIG. 31: shows one particular embodiment of the present invention depicted as a set of graduated sizes.

DETAILED DESCRIPTION OF THE INVENTION

[0068] The present invention relates to the device which firmly stents & keeps the Sternal edges apart. The said device provides a fundamentally different, safer & more effective design for keeping the sternal edges apart, at a fixed separation. It also provides maximum sub-sternal while clasping the sternal edges, eliminating the risk of cut-through by the looping wires.

[0069] Referring to the drawings the particular embodiments of the device of the present innovation, comprises of FIG. 24, where its one particular embodiment is shown with two sternal ends (1), shaped approximately like letter “C” though opening in opposite directions. The two sternal ends (1) are interconnected by an intermediate bar/strut or elongate member (2). Each sternal end (1) has an upper lip (3) and a lower lip (4), providing a hollow cusp laterally (5) at either end. When the divided sternum is to be kept apart for delayed closure, the device of proper size is manually insinuated between the sternal edges so that its lateral end's (1), upper lip (3) lies superficial to the external table of the sternum and its lower lip (4) lies underneath the inner table of the sternal edge, thus the lateral end's hollow cusp (5) engages firmly with the divided edge of the sternum. The sternal edges are kept apart by the width and strength of the intermediate bar/strut (2). As is clear from the FIG. 24, that the interconnecting, intermediate bar (2) is placed eccentrically between the two sternal ends, thus it provides maximum sub-sternal space for the oedematous mediastinal tissues, relieving the heart from temponade effect. After engaging the sternal ends (1) to the Sternotomy edges the device could be further secured to the sternal edges by passing suture ligature through the upper & lower lips' suture ligature slot (6) and securely tying the suture by virtue of suture-holding groove (7) along the inner side of the sternal ends (1). FIG. 25 shows one sketch-in profile, of a particular embodiment of the device of the present innovation, where the eccentric, superficial position of the interconnecting bar/strut (2) is highlighted, providing maximum space in front of the mediastinal tissues to accommodate for their oedema, without compressing the heart. FIG. 25 also shows the cusp like configuration of the sternal ends (1), in this particular embodiment, whereby the upper lip (3) and the lower lip (4) of the sternal end and its hollow cusp (5) firmly engages with the medial portions of the divided sternum. FIG. 26 shows the superior aspect view of the device whereby the suture-ligature slot (6) and the two diverging suture-holding grooves (7) allow stable fixation of the device to the sternal halves by double suture ligation on both sides. FIG. 26 also highlights the width of the upper (3) and lower lips (4), in sagittal plane, providing firm anchorage over the edges of the divided sternum. FIGS. 27 & 28 depict particular embodiments of the device where the interconnecting, intermediate bar/strut (2) is either angulated or gently convex in an outward dimension, so as to provide extra space for the swollen mediastinal tissues. FIG. 29 depicts the lateral profile drawing of a device made with non-metallic, carbon-fibre reinforced Thermoplastic polymer material, exhibiting the one piece, solid fabrication with an upwardly convex interconnecting, and intermediate bar/strut (2) providing minimal occupation of mediastinal space by the device itself and at the same time providing maximum sub-sternal space for tissue oedema to expand. FIG. 30 shows the configuration of the suture-holding groove (7), extending along the medial side of the sternal end (1), providing a secure suture ligature anchoring facility. FIG. 31 shows a particular embodiment of the proposed innovation whereby a set of several devices are provided with increasing dimensions of their lateral sternal ends (1), the interconnecting bars (2) and the upper & lower lips (3 and 4) of the devices to allow the surgeon to choose one or more than one devices to be deployed in patients of varying body sizes.

[0070] Devices of varying sizes, based upon measurements of the various levels of divided sternii in different age groups (as acquired during the developmental phase of the present invention), can be deployed in the same patient, at different levels of the divided sternum, providing extra secure stenting of the sternum.

[0071] One of the major concerns with DSC is the risk of infection, particularly into the cut surfaces of the sternal bone. To help decrease this risk of infection, in one particular embodiment, the surface of the device of the present invention would be provided with a mechanism of local delivery of antibiotics. Local antibiotic delivery is known to prevent the bacterial colonization onto the device or the implant's surface, thus reducing the risk of implant-related infections. Another benefit of local delivery systems is that high concentrations of the antibiotic are achieved in the desired area without the need for high systemic doses of the antibiotics and its associated side effects.

[0072] To provide such local antibiotic delivery, the device could be either coated with antibiotics or the antimicrobial molecules could be covalently attached onto the device surfaces. Coating of the device with an antibiotic/antimicrobial agent of choice could be either without a carrier (such as spraying the device with a methanol solution containing antibiotics) or with a carrier such as sol-gel, Silicone Polymer, polylactic acid (PLA) coating, Carbonated hydroxyapatite (CHA) or poly (D, L-Lactide) (PDLLA) coating carrying specific antibiotics or various antimicrobial agents (e.g., Chlorhexidine, Polyhexamethylene Biguanides, Hydroxy apatite, Chitosan etc). Another method of antibiotic surface coating could be either by Nanopeptide coating or by using antibiotic-impregnated polymethylmethacrylate cement filling grooves made over the tissue contact areas of the device of the present invention.

[0073] In one particular embodiment of the present invention the device's surface could be permanently rendered antimicrobial by covalent attachment of antibiotics or other bactericidal peptides. The bonding does not allow the antibiotic molecules to elude off the surface of the device, thus decreasing possible local and systemic toxicity while providing long-lasting protection from infection. In such an embodiment the device would be fabricated of Titanium alloys with covalent attachment of vancomycin, Gentamycin and/or other bioactive molecules on its surfaces.

[0074] In one embodiment anti-biotic coating of the surface of the device help further decrease the risk of infection. This could be in the form of using an antibiotic impregnated metal for making the device of the present invention, example being Titanium with covalently-linked Vancomycin on its surface.

[0075] In yet another embodiment of the present invention another method of antibiotic surface coating could be by using antibiotic-impregnated polymethylmethacrylate cement filling grooves made over the tissue contact areas of the device of the proposed invention.

[0076] In another embodiment the device may be fabricated with radiolucent material of required strength; one example of such material being Carbon-fibre-reinforced Thermoplastics (e.g., Nylon, Polycarbonates & polyketones). The clinical advantage with such an embodiment of the present device would be that chest X-rays done, with the device in place, would not be obscured by the shadow of the device.

[0077] In yet another embodiment the advantages of the local antibacterial delivery and the radio-lucency attributes of the device could be combined in a single fabrication with the radio-transparent device providing local antibacterial release as well.

[0078] In yet another embodiment of the present invention, the device being provided in a set of graduated sizes to be suitable for patients of various ages and body sizes.

[0079] Thus the preferred embodiments of the present invention have been described in reference to their application environment; however these depictions are merely illustrative of the principles underlying the present invention.

EXAMPLES

Example 1

[0080] A working prototype of the present invention was used in 4 adult. In all adult patients the stent firmly kept the sternal edges apart and helped improve the haemodynamics of the patients. The device of the present invention as sternal stents remained in situ for an average period of 4 days. There were no instances of slippage, dislodgement or local trauma. The thoracic cage remained stable with the stents in place, allowing optimal ventilatory and nursing care of the patients. Delayed sternal closure was achieved as planned without any subsequent untoward results attributable to the use of the sternal stent devices.

Example 2

[0081] A working prototype of the present invention was used in 12 pediatric cardiac surgical patients where chest could not be closed primarily. The pediatric patients ages ranged from 1-195 days (average age 35.6 days). In all these patients the stent firmly kept the sternal edges apart and helped improve the haemodynamics of the patients. The device of the present invention as sternal stents remained in situ for an average period of 4 days. There were no instances of slippage, dislodgement or local trauma. The thoracic cage remained stable with the stents in place, allowing optimal ventilatory and nursing care of the patients. Delayed sternal closure was achieved as planned without any subsequent untoward results attributable to the use of the sternal stent devices.

Example 3

[0082] The device may be fabricated with radiolucent material of required strength. One example of such material is Carbon-fibre-reinforced Thermoplastics (e.g., Nylon, Polycarbonates & polyketones). Thus fabrication would do away with the obscuring of patient's X-ray picture with the projected shadow of the device in situ. An unobstructed, clear X-ray image would help improve clinical decision-making.