Medical implant with tie configured to deliver a therapeutic substance

Embodiments of the invention comprise a medical implant that delivers a therapeutic substance. In some embodiments, a component that carries a therapeutic substance is a tie secured to all or a portion of a surgical construct, surgical screw, pedicle screw, spinal rod cross-link, other element or device, or an anatomical structure.

FIELD OF THE INVENTION

The present invention relates generally to the field of medical implants, and more particularly relates to a medical implant that is configured to deliver a therapeutic substance and methods of applying a therapeutic substance.

BACKGROUND

The use of therapeutic substances in combination with medical implants is a growing trend and has beneficial characteristics in many treatments. Therapeutic substances may be useful in promoting healing, fighting infection and disease by killing various pathogens such as bacteria, viruses, and microorganisms, promoting favorable cellular activity, killing cancer cells, or any of a wide variety of beneficial results. It may be advantageous to associate a therapeutic substance with a medical implant where the medical implant is implanted in a particularly advantageous location for effective application of the therapeutic substance.

It is a continuing challenge in the art to provide medical implants that may be conveniently and securely placed to deliver effective amounts of therapeutic substances in effective locations. Improved devices may provide secure connection to anatomical structures or to other medical device structures. It may be favorable for some improved implants that are capable of delivering a therapeutic substance to capture and securely fasten to existing medical device structures so that limited or no alteration to existing medical devices is necessary to implement the improved medical implants. It may be advantageous to provide medical implants capable of delivering a therapeutic substance that may be placed in a sequence that is complementary to existing surgical procedures.

SUMMARY

An embodiment of the invention is a medical implant configured to deliver a therapeutic substance. The medical implant may include a tie configured to couple with one or more of a medical device and an anatomical structure. The tie may particularly include a strap, and a pawl configured to receive the strap to form a loop comprising at least a portion of the strap and at least a portion of the pawl. The medical implant may also include a therapeutic substance incorporated with the tie. In some embodiments, the strap is retained in the pawl and prevented from moving out of the pawl as the strap is advanced into the pawl to lock the size of the loop at a progressively smaller size as the strap is advanced into the pawl. The tie may also be configured to release at least a portion of the therapeutic substance when the tie is exposed to an at least in part aqueous substance.

Another embodiment of the invention is a method of applying a therapeutic substance. The method may include receiving a tie that incorporates a therapeutic substance. The tie may include at least a strap, and a pawl configured to receive the strap to form a loop comprising at least a portion of the strap and at least a portion of the pawl. The method may also include wrapping the strap around at least a portion of a medical device and tightening the loop by moving the strap relative to the pawl to connect the tie to the medical device.

Yet another embodiment of the invention is a method of applying a therapeutic substance to a patient. The method may include receiving a tie that incorporates a therapeutic substance, where the tie includes at least a strap, and a pawl configured to receive the strap to form a loop comprising at least a portion of the strap and at least a portion of the pawl. The method may also include wrapping the strap around at least a portion of an anatomical structure of the patient, and tightening the loop by moving the strap relative to the pawl to connect the tie to the patient.

DETAILED DESCRIPTION

A medical implant1configured to deliver a therapeutic substance is illustrated inFIGS. 1 and 2. The medical implant1is shown in cross-sectional views. The medical implant1includes a tie10and a therapeutic substance that is incorporated with the tie10. The tie10is configured to couple with one or more of a medical device and an anatomical structure. The illustrated tie10includes a strap11and a pawl12. The therapeutic substance may be incorporated in all or a part of the strap11and the pawl12. The strap11includes teeth13on one side of the strap11. The teeth13that are shown inFIGS. 1 and 2are ratchet teeth that are designed to allow movement in a first direction, but to stop movement in a second direction substantially opposite from the first direction. In other embodiments, teeth on one or more sides of the strap13may be, without limitation, gear teeth that are part of a rack and pinion drive system or ridges or other roughenings that provide one or more places to grasp, catch, or engage. In some embodiments, a strap may friction fit with or be securely grasped by a pawl and not include any teeth or similar mechanisms.

The strap11is shown entering the pawl12inFIG. 2approximately perpendicular to the direction from which the strap11extends from the pawl12at the strap's permanent connection end. However, in various embodiments the strap11may enter into or couple with the pawl12at any functional angle or from any functional orientation. For example and without limitation, the strap11may loop completely around so that the distal end19substantially aligns with the direction from which the strap11extends from a pawl.

In the illustrated embodiment, the pawl12is configured to receive the strap11to form a loop15. The loop15of some embodiments includes at least a portion of the strap11and at least a portion of the pawl12. The illustrated pawl12includes stay teeth14configured to engage with the teeth13on the strap11. The stay teeth14are part of a shoe16connected to the remainder of the pawl12through a living hinge17. In operation of the illustrated embodiment, the strap11is retained in the pawl12and prevented from moving out of the pawl12as the strap11is advanced into the pawl12. As used herein, moving or advancement “into” the pawl12is movement that includes the distal end19of the strap11first contacting the pawl12, or once in contact with the pawl12, continuing to move further away from the pawl12. Moving “out of” the pawl12includes moving the strap11such that the distal end19is moving toward and then through and out of the pawl12. The illustrated tie10is configured to lock the size of the loop15at progressively smaller sizes as the strap11is advanced into the pawl12. The teeth13of the strap11interface with the stay teeth14of the shoe16to progressively lock the tie10as the strap11is advanced into the pawl12. The shoe16is biased toward the strap11, as illustrated inFIG. 2. The shoe16articulates with respect to the rest of the pawl12about the living hinge17, but because of its bias, the stay teeth14are forced into engagement with the teeth13of the strap11. In other embodiments, the engagement between a pawl and a strap may be of any effective type. For example and without limitation, the engagement may be frictional, may be driven or held in place by a rack and pinion mechanism, may include gears or teeth on multiple sides of a strap, or may be driven or controlled by instruments or inputs external to a tie. A tie of various embodiments may include a release mechanism for loosening, moving, or ex-planting the tie. The tie10of the embodiment shown inFIGS. 1 and 2may be released by inserting a tool between the teeth13and the stay teeth14. Use of a tool in this manner may hinge the shoe16away from the strap11and allow the strap11to move out of the pawl12. Other embodiments may include release mechanisms with different mechanism but that achieve the same effect of allowing a loop, such as the loop15, to be opened and a strap to be moved out of a pawl.

The medical implant1will be described herein with specific reference to embodiments that may comprise minor variations to the medical implant1. Each of the medical implants1A,1B,1C,1D,1E,1F,1G,1H,1J,1K,1L,1M, and1N is essentially similar to the medical implant1and will be referred to as having like numbered components that may be more specifically described with reference toFIGS. 1 and 2.

In the illustrated embodiment, a therapeutic substance is incorporated with the tie10to form the medical implant1. The tie10may be configured to release at least a portion of the therapeutic substance when the tie10is exposed to an at least in part aqueous substance. The aqueous substances of some embodiments are bodily fluids. The bodily fluids may contact all or a part of the medical implant1when the medical implant1is enclosed at least in part within a patient.

Embodiments of the tie10in whole or in part may be constructed of biocompatible materials of various types. Examples of tie materials include, but are not limited to, non-reinforced polymers, reinforced polymer composites, metals, ceramics and combinations thereof. In some embodiments, the tie10may be constructed of sections of bone or other tissues. Tissue materials include, but are not limited to, autograft, allograft, or xenograft, and may be resorbable or non-resorbable in nature. Examples of other tissue materials include hard tissues, connective tissues, demineralized bone matrix, and combinations thereof.

All or a part of the tie10may include a polymeric body configured to elute the therapeutic substance. The polymeric body may further elute the therapeutic substance at a predetermined rate. Alternatively or in addition, the tie10may at least in part be porous, and the therapeutic substance may be at least in part disposed in the pores of the tie10.

The tie10in whole or in part may comprise a polymeric material into or onto which a therapeutic substance is incorporated. Any polymeric material may be used. The polymeric material may be biocompatible and capable of presenting or eluting the therapeutic substance in an effective amount. Biocompatible polymers may be obtained from natural or synthetic sources, and may be bioresorbable. Examples of natural materials of which the polymer may be composed include collagen, elastin, silk, and demineralized bone matrix. Other examples of suitable polymeric materials include organic polymers such as silicones, polyamines, polystyrene, polyurethane, acrylates, polysilanes, polysulfone, methoxysilanes, and the like. Other polymers that may be utilized include polyolefins, polyisobutylene and ethylene-alphaolefin copolymers; acrylic polymers and copolymers, ethylene-covinylacetate, polybutylmethacrylate; vinyl halide polymers and copolymers, such as polyvinyl chloride; polyvinyl ethers, such as polyvinyl methyl ether; polyvinylidene halides, such as polyvinylidene fluoride and polyvinylidene chloride; polyacrylonitrile, polyvinyl ketones; polyvinyl aromatics, such as polystyrene, polyvinyl esters, such as polyvinyl acetate; copolymers of vinyl monomers with each other and olefins, such as ethylene-methyl methacrylate copolymers, acrylonitrile-styrene copolymers, resins, and ethylene-vinyl acetate copolymers; polyamides, such as Nylon 66 and polycaprolactam; polycarbonates; polyoxymethylenes; polyimides; polyethers; epoxy resins; polyurethanes; rayon; rayon-triacetate; cellulose; cellulose acetate, cellulose butyrate; cellulose acetate butyrate; cellophane; cellulose nitrate; cellulose propionate; cellulose ethers; carboxymethyl cellulose; polyphenyleneoxide; polytetrafluoroethylene (PTFE); polyethylene, low density polyethylene; polymethylmethacrylate (PMMA); polyetheretherketone (PEEK); and polyetherketoneketone (PEKK). The polymer may also be a polymeric hydroxyethylmethacrylate (PHEMA). Suitable bioresorbable synthetic polymers include poly(L-lactide), poly(D,L-lactide), poly(L-co-D,L-lactide), polyglycolide, poly(lactide-co-glycolide), poly(hydroxylbutyrate), poly(hydroxyvalerate), tyrosine-derived polycarbonate, polyanhydride, polyorthoester, polyphosphazene, poly(dioxanone), and polyglyconate. Other similar polymers known to the art may be used and various mixtures of polymers may be combined to adjust the properties of the composition as desired.

A therapeutic substance may be incorporated into or coated on a polymeric material of the tie10using any known or developed technique. For example, the therapeutic substance may be adhered to a surface of any part of the tie10, adsorbed into the tie10, or compounded into the polymeric material that forms the tie10. Accordingly, the therapeutic substance may be embedded, coated, mixed or dispersed on or in the material of the tie10. A coating method may be determined by the material of the tie10and the therapeutic substance utilized. Such methods include but are not limited to, dipping, spraying, rolling, plating and embedding the coating into the surface by any means. For example, a polymeric tie may be coated by dip or spray coating polymeric resin and crosslinker with the therapeutic substance as substituent or dissolved within the polymer. Curing may be achieved chemically, photochemically or thermally. Other common methods include dip or spray coating water insoluble resin containing a therapeutic substance followed by drying or grafting directly onto the substrate chemically or photochemically.

Additional examples of ways to form at least a portion of the tie10include blending a therapeutic substance with a polymer and then forming the polymer into the tie10, or portion of the tie10. Alternatively, the therapeutic substance may be in a solution with the polymer to form a coating. The therapeutic substance may be attached to a polymeric material by a chemical modification of the surface such as surface grafting by hydrolyzable linkage of the therapeutic substance to the surface or by photolinking the therapeutic substance to the surface. Surface polymerization, derivatization or absorption may also be used. Other examples of obtaining a surface bound therapeutic substance include any existing means, such as ion implantation, chemical modification of the surface, photochemical or chemical grafting or formation of a crosslinked surface immobilized network. Silver ions, where used, may be deposited on the surface of the tie10by vacuum deposition, ion sputtering or surface deposition, among others. The surface of the tie10may be pretreated according to known methods such as plasma treatment prior to exposure to the coating material. Where solvents are present in the therapeutic substance, such solvents may be biocompatible if residue remains after the therapeutic substance is applied.

Metals which can be used to form all or a part of the tie10include but are not limited to stainless steel and other steel alloys, cobalt chrome alloys, tantalum, titanium, titanium alloys, titanium-nickel alloys such as Nitinol and other superelastic or shape-memory metal alloys. Metals can be formed into supportive frameworks by a variety of manufacturing procedures including combustion synthesis, plating onto a “foam” substrate, chemical vapor deposition (see U.S. Pat. No. 5,282,861), lost mold techniques (see U.S. Pat. No. 3,616,841), foaming molten metal (see U.S. Pat. Nos. 5,281,251, 3,816,952 and 3,790,365), and replication of reticulated polymeric foams with a slurry of metal powder. Sintering of metals and polymers of various types and other methods of forming porous structures to make all or part of the tie10may be accomplished as disclosed at least in U.S. Pat. Nos. 6,572,619, and 6,673,075. Metal particles may have to be fused at elevated temperatures and therefore cannot be readily formed directly on surfaces which would be adversely affected by the fusion temperature needed for metal particles. Metal particles may be bonded onto a surface with an adhesive acting to bond the particles with a particle-surface coating matrix which does not fill the pores. By proper selection of the amount (the relative amount of polymer binder to metal), the pore size can be tightly controlled and the metal/binder materials applied to a wide array of surfaces. Various types of polymer binders such as thermoplastic binders (applied by melting the polymer of applied from solution, dispersion, emulsion or suspension or even direct polymerization on the surface of the polymers by heat, catalysis, or radiation), thermoset binders (also provided by reaction on the surface of the particles) or by fusion of the particles (with or without additional cross linking), or the like, may be used. Among the useful classes of polymers would be at least polyamides, polyacrylates, polyurethanes, silicon polymers (e.g., polysiloxanes, silicone rubbers, siloxane graft or block polymers or copolymers, etc.), polyester resins, highly fluorinated resins (e.g., polytetrafluoroethylene), polyimides, and the like. These same classes of polymers may also comprise the mass of the therapeutic substance delivery element itself. Particularly when latices are used to mold the tie10or particles are fused (thermally or by solvents) to form the tie10, the degree of pressure applied, the level of heat applied, the duration of the solvent, and other obvious parameters may be used to control the degree of fusion of the polymer and its degree of porosity. Porosity can also be created in polymeric materials useful for the tie10by including a soluble or leachable or flowable pore-leaving component with the polymer, forming the tie, and then removing the pore-leaving component. Techniques in this category include mixing a highly soluble particle (soluble in a solvent in which the polymer is not soluble), such as NaCl, into the polymer. Casting or molding the tie10, and then leaching out or dissolving out the salt with water. By controlling the volume of salt, and the size of the salt particles, the pore size can be readily controlled. Alternatively, it is known to mix a non-solvent liquid from the polymer to form an emulsion or dispersion. When the polymer is solidified as the tie10or component of the tie10, the non-solvent remains as a dispersed phase which can be readily removed from the tie by washing. Thermoplastic particles may be fused under controlled pressure to form the tie10with controlled pore size, as with the ceramics and the metal particles.

Ceramic materials that can be used to form all or a part of the tie10include but are not limited to inorganic metal oxides such as aluminum oxide, silica, zirconium oxide, titanium oxide, and composites of mixtures of inorganic oxides. Ceramic materials can be fabricated at both room temperatures and elevated temperatures and so can be provided as both separate materials as part of a tie, and as materials on substrates which could suffer from exposure to elevated temperatures. For example, many ceramics can be formed by solidification (dehydration) of sol-gel dispersions or suspensions of inorganic oxide particles. Other ceramics must be dehydrated and bonded together at elevated temperatures. By controlling the pressure applied to the ceramic material during hardening or fusing, the pore size can be controlled. The use of ceramic-forming particles of different average sizes will also affect the average pore size according to conventional packing and distribution laws. The structure of the tie10may be altered to control the elution rate or release rate of the drug. For example, the size of the pores on the outer surface which are exposed to the body liquids is a significant rate limiting factor in the design, while at the same time, the pore size controls the amount of therapeutic substance that can be retained within the tie10. As the pore size increases internally, larger amounts of therapeutic substance may be stored, while larger pore sizes on the surface increase the therapeutic substance release rate. One design would therefore have pore openings on the surface of the tie10with smaller average diameters of the pores than larger pores within the body of the tie10which are fluid transferring connected to the pores on the surface of the tie10. In some embodiments, the interior pores have average pore dimensions which are at least 10-50% greater in average diameter than the pores open at the surface of the tie10. Combinations of the materials noted above for use in making the tie10or portions of the tie10may be used in any effective amount or assembly.

The therapeutic substance may comprise one or more of the following: antibiotics, antiseptics, analgesics, bone growth promoting substances, anti-inflammatants, anti-arrhythmics, anti-coagulants, antifungal agents, steroids, enzymes, immunosuppressants, antithrombogenic compositions, vaccines, hormones, growth inhibitors, growth stimulators, and the like. The therapeutic substance may be any drug or bioactive agent which can serve a useful therapeutic or even diagnostic function when released into a patient. More than one therapeutic substance may be present in or on the tie for a particular treatment within the scope of the invention.

It may be desirable that the one or more antibiotics selected kill or inhibit the growth of one or more bacteria that are associated with infection following surgical implantation of a medical device. Such bacteria may includeStapholcoccus aureusandStaphlococcus epidermis. The one or more antibiotics selected may be effective against strains of bacteria that are resistant to one or more antibiotics. To enhance the likelihood that bacteria will be killed or inhibited, it may be desirable to combine one or more antibiotics. It may also be desirable to combine one or more antibiotics with one or more antiseptics. Agents having different mechanisms of action and/or different spectrums of action may be most effective in achieving such an effect. In a particular embodiment, a combination of rifampin and minocycline is used.

Any antiseptic suitable for use in a human may be used as or as part of the therapeutic substance. As used herein, “antiseptic” means an agent capable of killing or inhibiting the growth of one or more of bacteria, fungi, or viruses. Antiseptic includes disinfectants. Nonlimiting examples of antiseptics include hexachlorophene, cationic bisiguanides (i.e. chlorhexidine, cyclohexidine) iodine and iodophores (i.e. povidone-iodine), para-chloro-meta-xylenol, triclosan, furan medical preparations (i.e. nitrofurantoin, nitrofurazone), methenamine, aldehydes (glutaraldehyde, formaldehyde), silver sulfadiazine and alcohols. It may be desirable that the one or more antiseptics selected kill or inhibit the growth of one or more microbes that are associated with infection following surgical implantation of a medical device. Such bacteria may includeStapholcoccus aureus, Staphlococcus epidermis, Pseudomonus auruginosa, andCandidia. To enhance the likelihood that microbes will be killed or inhibited, it may be desirable to combine one or more antiseptics. It may also be desirable to combine one or more antiseptics with one or more antibiotics. Antimicrobial agents having different mechanisms of action and/or different spectrums of action may be most effective in achieving such an effect. In a particular embodiment, a combination of chlorohexidine and silver sulfadiazine is used.

A therapeutic substance, such as an antibiotic or antiseptic, may be present in the tie10at any concentration effective, either alone or in combination with another therapeutic substance, to prevent or treat an infection. Generally, a therapeutic substance may be present in the tie10at a range of between about 0.5% and about 20% by weight. For example, the therapeutic substance may be present in the tie10at a range of between about 0.5% and about 15% by weight or between about 0.5% and about 10% by weight.

The therapeutic substance may comprise an antimicrobial material including metals known to have antimicrobial properties such as silver, gold, platinum, palladium, iridium, tin, copper, antimony, bismuth, selenium and zinc. Compounds of these metals, alloys containing one or more of these metals, or salts of these metals may be coated onto the surface of the tie10or added to the material from which the tie10is made during the manufacture of the tie10or compounded into the base material. One therapeutic substance will contain silver ions and may be obtained through the use of silver salts, such as silver acetate, silver benzoate, silver carbonate, silver iodate, silver iodide, silver lactate, silver laurate, silver nitrate, silver oxide, silver palmitate, silver protein, or silver sulfadiazine, among others. In an embodiment where selenium is used, the selenium may be bonded to the surface of the tie10, providing an antimicrobial coating.

Therapeutic substances may be chosen based upon a particular application anticipated for a tie. For example, it may be desirable to use a timed release or leachable content material for a particular use. The material comprising the tie may also affect the choice of therapeutic substance. For example, metal ties which are to be provided with therapeutic substance coatings may require therapeutic substances which can be coated onto the metal with satisfactory adhesion to resist the harboring of infectious organisms, or the ability to kill such organisms present throughout the use of the tie. Alternatively, where the therapeutic substance is to be compounded into a metal tie prior to its formation into a tie, the therapeutic substance should be selected so that the therapeutic substance can be readily incorporated into the metal of the tie. In some embodiments, the tie10may be at least in part titanium and the therapeutic substance will be silver ion.

Likewise, where the tie10comprises a polymeric material, the therapeutic substance may be selected such that the therapeutic substance can be used as a coating material. For example, materials such as silver ions, selenium, and silver zeolite may be used. Separately or in addition, any commercially available additives, such as Heathshield®, among others, may be used.

Use of the tie10may provide a positive therapeutic effect by a variety of mechanisms, including preventing adherence of an organism to a surface of the tie10or adjacent implant or anatomical structures, providing slow release of a therapeutic substance into the surrounding area, or fixing a source for the therapeutic substance on implant structures for long term effects. The rate of release from a tie, such as the tie10, may be intended to be highly tailored to the specific use of an associated medical device.

The therapeutic substance may also comprise an osteoconductive, osteogenic, or osteoinductive material. For example and without limitation, the therapeutic substance may include various bioceramic materials, calcium phosphate and other members of the calcium phosphate family, fluorapatite, bioactive glass, and collagen-based materials. Members of the calcium phosphate family include materials such as hydroxyapatite, α-tricalcium phosphate, β-tricalcium phosphate, tetracalcium phosphate, dicalcium phosphate dihydrate, ocatacalcium phosphate, and the like. The therapeutic substance may include an osteoinductive or osteogenic materials such as osteoblast cells, platelet-derived growth factors (PDGFs), bone morphogenetic proteins (BMPs), insulin-like growth factors (IGFs), basic fibroblast growth factor (bFGF), cartilage derived morphogenetic protein (CDMP), growth and differentiation factors (GDFs), LIM mineralization proteins, transforming growth factor beta family (TGF-β), and other bone proteins, such as CD-RAP. These proteins can be recombinantly produced or obtained and purified from an animal that makes the proteins without the use of recombinant DNA technology. Recombinant human BMP is referred to as “rhBMP”; recombinant human GDF is referred to as “rhGDF”. Any bone morphogenetic protein is contemplated, including bone morphogenetic proteins designated as BMP-1 through BMP-18. Mimetics of growth factors can also be used in the devices of the present invention for inducing the growth of bone.

Each BMP may be homodimeric, or may be heterodimeric with other BMPs (e.g., a heterodimer composed of one monomer each of BMP-2 and BMP-6) or with other members of the TGF-β superfamily, such as activins, inhibins and TGF-β 1 (e.g., a heterodimer composed of one monomer each of a BMP and a related member of the TGF-β superfamily). Any of these substances may be used individually or in mixtures of two or more. One or more statins may also be included in the therapeutic substance. Non-limiting examples of statins that may be included in the devices of the present invention include atorvastatin, cerivastatin, fluvastatin, lovastatin, mavastatin, pitavastatin, pravastatin, rosuvastatin and simvastatin. The therapeutic substance may include various other organic species known to induce bone formation, and combinations thereof.

The therapeutic substance may also or in addition include pharmaceuticals that target particular cells, such as but not limited to, cancer cells.

Three medical implants1A,1B,1C are shown inFIG. 3in combination with a spinal rod and screw system in various configurations. The spinal rod and screw system includes three pedicle screws31,32,33and a spinal rod39. The medical implant1A is shown in combination with the spinal rod39. In the illustrated embodiment, a strap11extends around the spinal rod39to capture the spinal rod39within the loop15(FIG. 2) formed by the strap11of the tie10of the medical implant1A.

The medical implant1B also is shown in combination with the spinal rod39. The medical implant1B includes a strap11that extends around the spinal rod39to capture the spinal rod39within the loop15(FIG. 2) formed by the tie10of the medical implant1B. The medical implant1B is additionally shown simultaneously in combination with a pedicle screw32and the spinal rod39. The pedicle screw32includes a shaft34and a receiver35. As illustrated inFIG. 3, the spinal rod39is coupled with the receiver35of the pedicle screw32. The strap11of the medical implant1B is shown extending around the spinal rod39at a first side of the spinal rod39. As illustrated, the first side of the spinal rod39is the bottom of the spinal rod39. The strap11is also shown adjacent to the receiver35on the near side, as illustrated, of the receiver35where the strap11extends around the bottom of the spinal rod. The medical implant1B shown further extends around the spinal rod39at a second side of the spinal rod39(top side of the spinal rod39as illustrated) that is adjacent to a second substantially opposite side of the receiver35such that the medical implant1B captures the spinal rod39and the receiver35within the loop15(FIG. 2) formed by the strap11of the tie10of the medical implant1B.

The medical implant1C also is shown in combination with a bone screw embodied in the pedicle screw33. The pedicle screw33is an example of a bone screw that includes at least a shank36and an enlarged head. The enlarged head is embodied in a receiver37. In other embodiments, the enlarged head may be a screw head that is formed as part of the bone screw, a washer, or any other device of generally larger diameter or size than an associated screw shank. The strap11of the medical implant1C extends around the shank36to capture the shank36within the loop15(FIG. 2) formed by the strap11of the tie10of the medical implant1C.

FIG. 4illustrates three medical implants1D,1E,1F coupled to a spinal rod, screw, and cross-link construct. The spinal rod, screw, and cross-link construct is in place on portions of a sacral and lumbar spinal segment. The medical implants1D and1F are shown in combination with respective spinal rods49. Configurations and embodiments of the medical implants1D and1F are substantially similar to the embodiments described in association with the medical implant1A herein. The medical implant1E is shown in combination with a cross-link41. The cross-link41is configured to extend between the spinal rods49. The medical implant1E includes a strap11that extends around the cross-link41to capture the cross-link41within the loop15(FIG. 2) formed by the strap11of the tie10of the medical implant1E. An alternate embodiment of a cross-link51is illustrated inFIG. 5. The medical implant1E similarly is shown inFIG. 5extending around the cross-link51to capture the cross-link51within the loop15(FIG. 2) formed by the strap11of the tie10of the medical implant1E. The cross-link51is shown with a broken section to illustrate that it may be of any functional length.

Two medical implants1H,1G are shown inFIG. 6in combination with a bone plate60and associated hardware. More particularly, the illustrated bone plate60is a four level spinal plate. In other embodiments, the bone plate may be a general orthopedic plate or a spinal plate of any size or configuration. For example and without limitation, a spinal plate may be configured to stabilize or fuse one or more levels, or may be configured for placement from any surgical approach or for any surgical placement, such as anterior, posterior, lateral, and variations oblique by some degree from each. Configurations and embodiments of the medical implants1G and1H are substantially similar to the embodiments described in association with the medical implant1A herein. The medical implant1G is shown in combination with the bone plate60around which a strap11of the medical implant1G extends to capture portions of the bone plate60within the loop15(FIG. 2) formed by the strap11of the tie10of the medical implant1G. The bone plate60includes multiple openings65. The illustrated openings65are round and are intended to provide sight holes for alignment of the bone plate60with the anatomy of a patient, but in other embodiments the openings65may be of any configuration and for any purpose. In the illustrated embodiment, the strap11of the medical implant1G extends through the opening65to capture a portion of the bone plate60within the loop15(FIG. 2).

The medical implant1H is shown in combination with the bone plate60around which a strap11of the medical implant1H extends to capture portions of the bone plate60within the loop15(FIG. 2) formed by the strap11of the tie10of the medical implant1H. The bone plate60includes multiple portions with a relatively smaller cross-sectional area61. At least a portion of each of the straps11of the medical implants1G and1H extends around respective relatively smaller cross-sectional areas61of the bone plate60. Each of the medical implants1G and1H of the illustrated embodiment is also configured to be adjacent to a spinal disc of a patient when the bone plate60is implanted as an anterior fusion plate.

A medical implant1J is shown in combination with an interbody implant70inFIG. 7. Configurations and embodiments of the medical implant1J are substantially similar to the embodiments described in association with the medical implant1A herein. The illustrated interbody implant70is configured to space apart lumbar vertebrae and is configured for insertion from anterior and oblique approaches. However, in other embodiments, an interbody implant may be of any size or shape and configured for use in any spinal region and for insertion from any approach. The interbody implant70in particular includes two threaded inserter holes73,75and an alignment hole74. The medical implant1J includes a strap11that extends to capture a part of the interbody implant70with the loop15(FIG. 2) formed by the strap11of the tie10of the medical implant1J. In particular with the embodiment shown, the strap11extends through the inserter holes73,75to capture a portion of the interbody implant that is between the inserter holes73,75within the loop15. In other embodiments, other portions and devices of an interbody implant may be used to capture the interbody implant, such as but not limited to, the alignment hole74.

A medical implant1K is shown in combination with an interbody implant80inFIG. 8. Configurations and embodiments of the medical implant1K are substantially similar to the embodiments described in association with the medical implant1A herein. The illustrated interbody implant80is configured to space apart lumbar vertebrae and is configured for insertion from an anterior approach. However, in other embodiments, an interbody implant may be of any size or shape and configured for use in any spinal region and for insertion from any approach. The interbody implant80includes three holes81,82,83for receiving respective anchoring screws86,87,88. The medical implant1K includes a strap11that extends to capture the interbody implant80with the loop15(FIG. 2) formed by the strap11of the tie10of the medical implant1K. In particular with the embodiment shown, the strap11extends around the entire interbody implant80to capture the interbody implant80. In some embodiments, the strap11of the medical implant1K may be aligned and retained within a slot89to maintain the medical implant1K in a particular orientation relative to the interbody implant80. The strap11of the medical implant1K of the illustrated embodiment extends around the interbody implant80and in part blocks the three holes81,82,83. The medical implant1K may by this mechanism also assist in preventing the anchoring screws86,87,88from backing out of bone in which they are implanted. In other embodiments, a strap of a medical implant may be used to block a hole through which graft material is inserted into an interbody implant or to retain graft material within an interbody implant, or for any other useful purpose.

Medical implants1L,1M, and1N are shown inFIG. 9coupled to various spinal structures of lumbar vertebrae V1and V2. The implants1L,1M, and1N are shown coupled to bony spinal structures, but may also be coupled to other anatomical structures in various embodiments. The medical implant1L is shown coupled around portions of a pedicle region92and a superior articular process93. Medical implants1M and1N are shown coupled around portions of respective spinous processes99. Other medical implants may be coupled around anatomical structures, such as but not limited to, any portion of a transverse process91, another portion of the spinous process99, the pedicle region92, the superior articular process93, a lamina, or any of these or other regions that are altered to create on or more coupling points.

The tie10, and all tie embodiments, may be either placed during the implantation of existing implant systems or may be placed after components of existing implant systems have already been implanted. Therefore, the sequences for placing each of the listed ties are complementary to existing surgical procedures.

The distal ends19of the straps11of the medical implants1A,1B,1C are shown implanted with the respective medical implants. In contrast, distal ends of the medical implants1D,1E,1F,1G,1H,1J,1K,1L,1M, and1N have been removed. The distal ends19of some embodiments may be left in place and implanted with a medical implant1. However, the distal end19of any strap11may be removed to avoid interaction with anatomical structures, as is deemed appropriate by a surgeon. A distal end of a strap may be removed by cutting with a tool. In addition or alternatively, a strap may include areas of reduced cross-sectional area and/or reduced strength where a distal end of the strap may be removed with the assistance of a tool and/or by bending, twisting, or by any effective action.

A method of applying the therapeutic substance may include making an incision in a patient, inserting a medical device, receiving a tie that incorporates a therapeutic substance, wrapping a strap of the tie around at least a portion of a medical device, and tightening a loop of the tie to connect the tie to the medical device. A non-limiting example tie is the tie10describe in more detail inFIGS. 1 and 2. The tie10includes the strap11and the pawl12. The pawl12is configured to receive the strap11to form the loop15that includes portions of strap11and the pawl12. In the illustrated embodiment, the strap11includes the distal end19that is free to wrap around at least a portion of a medical device. In other embodiments, a strap may wrap around a medical device or anatomical structure without having a free end. A captured medical device may be any medical device, and in some embodiments will be one or more of the medical devices illustrated inFIGS. 3-8. The act of tightening the loop15of the illustrated embodiment includes moving the strap11relative to the pawl12. The strap11may be moved by pulling on the strap11directly or by use of a general purpose grasping instrument or specialized instrument. One specialized instrument embodiment would contact the pawl12, move the strap11relative to the pawl12, and also be configured to optionally cut off the strap11at or near the pawl12. Other embodiments may include the act of detaching at least a portion of a distal end of a strap by any effective action or device.

Another method embodiment includes applying a similar tie to an anatomical structure. The anatomical structure may be a spinal structure such as the spinal bony structures described in more detail in association withFIG. 9or any other anatomical structure where application of a therapeutic substance may be beneficial. As a non-limiting example, a method in association with the medical implant1M ofFIG. 9is described. The example method may include making an incision in a patient. The example method may include applying a therapeutic substance to a patient by receiving the tie10of the medical implant1M, where the tie10includes an incorporated therapeutic substance. The tie10may include therapeutic substance in one or both of the strap11and the pawl12, as describe in detail above. An act of the example method includes wrapping the strap11around at least a portion of an anatomical structure, such as the illustrated spinous process99. Another act of the example embodiment includes tightening the loop15(FIG. 2), comprising the strap11and the pawl12, by moving the strap11relative to the pawl12to connect the tie10to the patient. In some embodiments, a method may also include making a passage though an anatomical structure and passing at least a portion of the strap11through the passage during the act of wrapping the strap11around at least a portion of the anatomical structure. For example, as illustrated inFIG. 9, a passage95has been made in a spinous process99. The strap11of the medical implant1N has been passed through the spinous process99in the act of wrapping the strap11of the medical implant1N around at least a portion of the spinous process99. The size, final tightening, and other characteristics of acts of the method may be dictated by the anatomical structure to which a tie is coupled. For example, where a tie is wrapped around a bony structure that includes a periosteum layer with blood vessels and nerves, the tightness or width of the tie may be altered or the tie may include ridges or other devices that allow unpressured areas of tissue to preserve the health of the bony structure. Some embodiments may include the act of detaching at least a portion of a distal end of a strap by any effective action or device, including but not limited to cutting the strap off.

All patents and applications specifically list by number herein are hereby incorporated by reference herein in their entirety.

Various method embodiments of the invention are described herein with reference to particular medical implants. However, in some circumstances, each disclosed method embodiment may be applicable to each of the medical implants, or to some other medical implant operable as disclosed with regard to the various method embodiments.

Terms such as around, near, opposite, below, distal, top, bottom, side and the like have been used herein to note relative positions. However, such terms are not limited to specific coordinate orientations, but are used to describe relative positions referencing particular embodiments. Such terms are not generally limiting to the scope of the claims made herein.

While embodiments of the invention have been illustrated and described in detail in the disclosure, the disclosure is to be considered as illustrative and not restrictive in character. All changes and modifications that come within the spirit of the invention are to be considered within the scope of the disclosure.