THERMO-CHEMICALLY ACTIVATED INTRAMEDULLARY BONE STENT
The present invention provides a bone fixation device for implantation into the intramedullary canal of a bone. The bone fixation device may include a support structure and a thermo-chemically activated matrix. The support structure may be radially expandable and contractible, and sufficiently flexible to be inserted into the intramedullary canal through an opening which is not parallel to the intramedullary canal. The matrix may attain a first thermo-chemical state via the addition of energy, and a second thermo-chemical state via the dissipation of energy. While in the first thermo-chemical state, the matrix is deformable and can conform to a shape matching the contours of the intramedullary canal of the bone. As the matrix attains the second thermo-chemical state, it may crystallize and becomes relatively hardened. An implant deformation apparatus may be used to expand the device within the intramedullary canal. The device may include a series of nested telescoping components.
1 . A thermo-chemically activated composite device for bone stabilization, the composite device comprising:
a thermo-chemically activated thermoplastic matrix which is sufficiently deformable to conform to a bone at a first thermo-chemical state and sufficiently hardened to stabilize the bone at a second thermo-chemical state; and
a support structure connected to the thermo-chemically activated thermoplastic matrix to support the thermo-chemically thermoplastic matrix.
2 . The composite device of claim 1 , wherein the support structure passes through the thermo-chemically activated thermoplastic matrix.
3 . The composite device of claim 1 , wherein the thermo-chemically activated thermoplastic matrix is capable of being repetitively transformed from the first thermo-chemical state to the second thermo-chemical state, and from the second thermo-chemical state to the first thermo-chemical state.
4 . The composite device of claim 1 , where the thermo-chemically activated thermoplastic matrix is capable of being transformed from the second thermo-chemical state to the first thermo-chemical state by application of energy to the thermo-chemically activated thermoplastic matrix from an outside source and is capable of being transformed from the first thermo-chemical state to the second thermo-chemical state by dissipation of energy from the thermo-chemically activated thermoplastic matrix to surrounding matter.
5 . The composite device of claim 1 , wherein the composite device is capable of being implanted in a patient while the thermo-chemically activated thermoplastic matrix is at the first thermo-chemical state, the thermo-chemically activated thermoplastic matrix is transformable to the second thermo-chemical state while the composite device is in the patient, and the composite device is configured to remain in the patient until the thermo-chemically activated thermoplastic matrix returns to the first thermo-chemical state.
6 . The composite device of claim 1 , wherein the thermo-chemically activated thermoplastic matrix is biocompatible and comprises a polymer selected from the group consisting of polylactic acid (PLA), poly ε-caprolactone (PCL), trimethylene carbonate (TMC), polyglycolic acid (PGA), poly l-lactic acid (PLLA), poly d-l-lactide (PDLLA), polyethylene terephthalate (PET), aliphatic polyesters, polyanhydrides, polyphosphazenes, polyorthoesters, poly(p-dioxane), polyaminoacids, pseudopolyaminoacids, erodable hydrogels, and natural polymers.
7 . The composite device of claim 6 , wherein the thermo-chemically activated thermoplastic matrix further comprises a blend of polymers selected from the group consisting of polylactic acid (PLA), poly ε-caprolactone (PCL), trimethylene carbonate (TMC), polyglycolic acid (PGA), poly l-lactic acid (PLLA), poly d-l-lactide (PDLLA), polyethylene terephthalate (PET), aliphatic polyesters, polyanhydrides, polyphosphazenes, polyorthoesters, poly(p-dioxane), polyaminoacids, pseudopolyaminoacids, erodable hydrogels, and natural polymers, wherein the blend of polymers has a glass transition temperature selected to be near the body temperature of a patient.
8 . The composite device of claim 6 , wherein the thermo-chemically activated thermoplastic matrix further comprises a bioactive material, wherein the bioactive material is selected to enhance healing of the bone, wherein the bioactive material is selected from the group consisting of hydroxyl apatite, tetracalcium phosphate, β-tricalcium phosphate, fluorapatite, magnesium whitlockite, β-whitlockite, apatite/wollastonite glass ceramic, calcium phosphate particle reinforced polyethylene, bioactive glasses, bioactive glass ceramics, polycrystalline glass ceramics, and polyethylene hydroxyl apatite.
9 . The composite device of claim 1 , wherein the support structure comprises an elongated shape having a longitudinal axis, wherein the composite device is capable of radial expansion from a contracted state into an expanded state, wherein the support structure is further capable of greater flexion about the longitudinal axis while in the contracted state than while in the expanded state.
10 . The composite device of claim 1 , wherein the composite device is shaped to be implanted into an intramedullary canal of the bone.
11 . The composite device of claim 10 , wherein the composite device is implantable into the intramedullary canal along a pathway that is not parallel to the intramedullary canal.
12 . The composite device of claim 10 , wherein the composite device is removable from the intramedullary canal of the bone after healing of the bone.
13 . The composite device of claim 10 , wherein the thermo-chemically activated thermoplastic matrix is configured to conform to the shape of the intramedullary canal.
14 . The composite device of claim 1 , wherein the support structure comprises at least one rod.
15 . The composite device of claim 14 , wherein the support structure comprises an array of rods interconnected such that the array is capable of radial expansion from a contracted state to an expanded state.
16 . The composite device of claim 1 , wherein the support structure comprises a cage.
17 . The composite device of claim 16 , wherein the cage is capable of radial expansion and contraction.
18 . The composite device of claim 17 , wherein the cage has an hourglass-like shape selected to conform to the intramedullary canal of the bone.
19 . The composite device of claim 17 , wherein the support structure further comprises at least one rod, wherein the rod is retained by the cage.
20 . The composite device of claim 19 , wherein the cage and the rod are formed substantially of metallic materials.
21 . The composite device of claim 1 , wherein the support structure comprises a plurality of nested components which are telescopically extendable.
22 . The composite device of claim 1 , further comprising a first composite device and a second composite device, wherein the first composite device is configured to be nestable inside the second composite device within the intramedullary canal of the bone.
23 . A thermo-chemically activated device for internal bone stabilization, the device comprising:
a thermo-chemically activated thermoplastic matrix which is sufficiently deformable to conform to a bone at a first thermo-chemical state and sufficiently hardened to stabilize the bone at a second thermo-chemical state;
wherein the thermo-chemically activated thermoplastic matrix comprises an elongated shape selected to enable insertion of the thermo-chemically activated thermoplastic matrix into an intramedullary canal of the bone.
24 . The device of claim 23 , wherein the thermo-chemically activated thermoplastic matrix is configured to conform to the shape of the intramedullary canal.
25 . The device of claim 23 , wherein the device is implantable into the intramedullary canal along a pathway that is not parallel to the intramedullary canal.
26 . The device of claim 23 , wherein the thermo-chemically activated thermoplastic matrix is capable of being repetitively transformed from the first thermo-chemical state to the second thermo-chemical state, and from the second thermo-chemical state to the first thermo-chemical state.
27 . The device of claim 23 , where the thermo-chemically activated thermoplastic matrix is capable of being transformed from the second thermo-chemical state to the first thermo-chemical state by application of energy to the thermo-chemically activated thermoplastic matrix from an outside source and is capable of being transformed from the first thermo-chemical state to the second thermo-chemical state by dissipation of energy from the thermo-chemically activated thermoplastic matrix to surrounding matter.
28 . The device of claim 23 , wherein the device is capable of being implanted in a patient while the thermo-chemically activated thermoplastic matrix is at the first thermo-chemical state, the thermo-chemically activated thermoplastic matrix is transformable to the second thermo-chemical state while the device is in the patient, and the device is configured to remain in the patient until the thermo-chemically activated thermoplastic matrix returns to the first thermo-chemical state.
29 . The device of claim 23 , further comprising a longitudinal axis, wherein the device is capable of radial expansion into an expanded state, radial contraction into a contracted state, wherein the device is further capable of greater flexion about the longitudinal axis while in the contracted state.
30 . The device of claim 23 , wherein the thermo-chemically activated thermoplastic matrix is biocompatible and comprises a polymer selected from the group of polymers consisting of polylactic acid (PLA), poly ε-caprolactone (PCL), trimethylene carbonate (TMC), polyglycolic acid (PGA), poly l-lactic acid (PLLA), poly d-l-lactide (PDLLA), polyethylene terephthalate (PET), aliphatic polyesters, polyanhydrides, polyphosphazenes, polyorthoesters, poly(p-dioxane), polyaminoacids, pseudopolyaminoacids, erodable hydrogels, and natural polymers.
31 . The device of claim 30 , wherein the thermo-chemically activated thermoplastic matrix further comprises a blend of polymers selected from the group consisting of polylactic acid (PLA), poly ε-caprolactone (PCL), trimethylene carbonate (TMC), polyglycolic acid (PGA), poly l-lactic acid (PLLA), poly d-l-lactide (PDLLA), polyethylene terephthalate (PET), aliphatic polyesters, polyanhydrides, polyphosphazenes, polyorthoesters, poly(p-dioxane), polyaminoacids, pseudopolyaminoacids, erodable hydrogels, and natural polymers, wherein the blend of polymers has a glass transition temperature selected to be near the body temperature of a patient.
32 . The device of claim 30 , wherein the thermo-chemically activated thermoplastic matrix further comprises a bioactive material selected to enhance healing of the bone, wherein the bioactive material is selected from the group consisting of hydroxyl apatite, tetracalcium phosphate, β-tricalcium phosphate, fluorapatite, magnesiumwhitlockite, β-whitlockite, apatite/wollastonite glass ceramic, calcium phosphate particle reinforced polyethylene, bioactive glasses, bioactive glass ceramics, polycrystalline glass ceramics, and polyethylene hydroxyl apatite.
33 . A method for stabilizing a fractured bone, comprising:
conforming a composite device to the bone, the composite device comprising a support structure connected to a thermo-chemically activated thermoplastic matrix which is deformable at a first thermo-chemical state and hard at a second thermo-chemical state, and
transforming the thermo-chemically activated thermoplastic matrix from the first thermo-chemical state to the second thermo-chemical state to harden the thermo-chemically activated thermoplastic matrix.
34 . The method of claim 33 , wherein conforming the composite device to the bone further comprises radially expanding the composite device.
35 . The method of claim 33 , wherein transforming the thermo-chemically activated matrix from the first thermo-chemical state to the second thermo-chemical state further comprises allowing energy to dissipate from the thermo-chemically activated matrix.
36 . The method of claim 33 , further comprising inserting the composite device into the intramedullary canal of the bone, wherein conforming the composite device to the bone comprises conforming the composite device to the intramedullary canal.
37 . The method of claim 36 , wherein inserting the composite device into the intramedullary canal of the bone comprises inserting the composite device along a path that is not parallel to the intramedullary canal of the bone.
38 . The method of claim 36 , wherein the support structure further comprises a series of telescoping nestable components, wherein inserting the composite device into the intramedullary canal further comprises nesting the telescoping nestable components within the intramedullary canal of the bone.
39 . The method of claim 33 , further comprising removing the composite device from the intramedullary canal of the bone after healing of the bone.
40 . A method for stabilizing a fractured bone, comprising:
inserting a thermo-chemically activated device into an intramedullary canal of the fractured bone; and
conveying energy to or from the thermo-chemically activated device to trigger transformation of the thermo-chemically activated device from a first thermo-chemical state to a second thermo-chemical state to increase rigidity of the thermo-chemically activated device within the intramedullary canal.
41 . The method of claim 40 , further comprising inserting the thermo-chemically activated device into the intramedullary canal along a pathway that is not parallel to the intramedullary canal.
42 . The method of claim 41 , wherein the thermo-chemically activated device comprises a longitudinal axis, wherein inserting the thermo-chemically activated device into the intramedullary canal further comprises flexing the thermo-chemically activated device about the longitudinal axis.
43 . The method of claim 40 , further comprising radially expanding the thermo-chemically activated device to conform to the shape of the intramedullary canal prior to transformation of the thermo-chemically activated device from the first thermo-chemical state to the second thermo-chemical state.
44 . The method of claim 40 , further comprising removing the thermo-chemically activated device from the intramedullary canal after healing of the bone.