Patent Application
20140039499
Conventional devices and techniques used to treat bone fractures include external fixation structures, such as Illizarov and Taylor Spatial Frame, and internal fixation structures, such as plates, nails, pegs, screws, and other fixators. Each type of technique relies on providing proper stability to the bone so that it can heal naturally by normal growth and regeneration processes.
Fractures that involve load bearing bones, such as femurs and tibias, are particularly difficult to treat due to their substantial load bearing requirements. Devices used must provide sufficient axial, torsional and bending strength across the fracture site to support the loading. External fixation devices and methods typically encompass the fracture site and sit external to the patient's skin. They can be cumbersome, uncomfortable, carry a risk of infection, and limit ambulation and therefore often fail to fully satisfy a patient's desires for care and treatment.
Internal devices are installed on or in the fractured bone across the fracture site. An example is an intramedullary (IM) nail that is installed longitudinally into the intramedullary canal of a fractured bone. Some structures used in internal repair provide less than optimal biocompatibility and support for the patient's normal biological healing processes. Furthermore, after the fracture is healed, a second surgery may be required to remove the IM nail from the patient. This increases the risk of infection to the patient and cost to the healthcare system. Hence, considerable research and development has focused on techniques for replacing traditional fracture fixation devices with biodegradable (also referred to as resorbable, bioerodible, degradable, or bioabsorbable) implants. In the case of segmental defects or other serious fractures to a load bearing bone, such as a tibia or femur, managing the challenges recited above and others to find an appropriate balance of strength, biocompatibility, bioabsorbability and patient comfort can be particularly complicated.
Disclosed herein are systems, methods and devices for repairing a fractured bone, for example a load-bearing bone (e.g., a tibia or femur) with a segmental defect or other serious fracture. Example devices and systems include load bearing support implants, such as sleeves and struts, for use in supporting a bone. A sleeve is placed inside the patient so it encases the fracture site and fixes and supports the fractured bone during healing. A strut is used to till bone gaps, such as may arise from a serious segment defect. Struts are structured to be placed between bone segments to fixate the fracture and further support the restructured bone against axial, bending and torsional stresses that occur when the patient walks or otherwise loads the bone. One or more scaffold materials (e.g., putties or filler materials) may be disposed within the sleeve to secure the sleeve to the bone and stabilize the implant. One or more scaffold materials may be disposed within or about the strut to stabilize the strut within its fixation position between the segmented bones. The scaffold material acts as a scaffold for bone regeneration during healing. Sleeves and struts may be used separately or in combination.
In one aspect, a fracture repair implant is provided for use in repairing a load-bearing bone. The implant includes a biodegradable, load-bearing sleeve that supports ends of a fractured bone. The implant may include a biodegradable scaffold disposed within the sleeve. In certain implementations the biodegradable scaffold includes a plurality of interconnected channels, which may include at least one axial channel interconnected with at least one radial channel. In certain applications the scaffold is substantially brittle. The sleeve is arced, for example in the form of a tubular shell, and may be pre-formed in that configuration and then applied to the bone. The sleeve may be shaped so it tapers (e.g., between proximal and distal openings) or configured to otherwise provide a contoured fit to the bone fracture area. The sleeve may be hard plastic or other stiff shell. In alternative configurations, the sleeve is formed front a pliable material, such as a polymer, that can be cured or otherwise formable into a hard shell. The hardening process may be applied after application of the pliable material to the bone whereby the material is applied in a pliable state and cures so it hardens after application to the bone. In certain implementations the sleeve has at least one through-hole, such as an open window, along a longitudinal surface of the sleeve. Porous material such as foam may be disposed within the window. The porous material extends through the through-hole and provides a pathway between the bone or implant and muscle or soft connective tissue located external to the sleeve through which fluid can pass to the bone, and through which blood vasculature can grow.
In certain implementations, a biodegradable sleeve is provided with first and second openings (such as proximal and distal openings), wherein the first opening has a different cross-sectional shape than the second opening. In certain examples, at least one of a C-shape cross section and an O shape cross section are used for two respective openings of the sleeve, Each opening may be sized to receive an end of a fracture bone. The sleeve may also have at least one through-hole along, a longitudinal surface of the sleeve, in certain embodiments the at least one through-hole is placed adjacent to a fracture in the bone. The sleeve is configured with cross-sectional dimensions needed to treat the bone. In certain embodiments the sleeve has regions with varying thickness, for example, a region with thicker walls that are placed at locations of high tension along the bone (e.g., posterior tibia) and thinner walls or regions of the sleeve placed at locations of the bone with higher compression (e.g., an anterior tibial region). The sleeve may have at least one of a pliable material and a pliable sheet.
In certain embodiments, a bone implant includes at least one longitudinal strut, constructed to be disposed between opposing faces of a segmented bone for providing at least axial support to the bone, wherein the longitudinal strut includes a central axis, and a wing with a surface that extends radially from the central axis. In certain implementations, the implant includes biodegradable material disposed on or about the longitudinal strut. The implant may have at least two wings with the biodegradable on-aerial disposed between the wings. The biodegradable material may be porous. In certain implementations, the longitudinal strut has a proximal portion configured to mate with a slot or hole formed within a face of a proximal segment of a patient's segmented bone, and a distal portion configured to mate with a slot or hole formed within a face of a distal segment of the patient's segmented bone.
In another aspect, a fracture repair system is provided having one or more of the implants disclosed herein. In certain implementations, the system includes a biodegradable sleeve configured with proximal and distal openings, with each opening sized to receive an end of a segmented bone, and at least one longitudinal strut. The strut is constructed to be disposed between opposing faces of the segmented bone for providing axial support and, in certain implementations, torsional strength to the bone. The strut has a proximal portion configured to mate with a face of a proximal segment of the segmented bone, and a distal portion configured to mate with a face of a distal segment of the segmented bone. The sleeve is positioned so it contains and envelops the strut and fracture site. For added stability, holes or slots can be formed within the opposing faces of the segmented bone, and end portions of the strut are configured to mate with such slots or holes. The strut can be configured according to any of those embodiments disclosed herein, or variations. For example, the longitudinal strut may include a central axis, and a wing with a surface that extends radially from the central axis. In certain applications, the sleeve has at least one through-hole, such as an open window, along a longitudinal surface of the sleeve. A porous matrix may be disposed within the through-hole. The porous matrix may also extend through the through-hole. In certain applications, the sleeve is unitary and molded without a longitudinal seam.
In another aspect, a fracture repair system is provided for use in repairing a load-bearing bone, comprising an implant configured to be disposed within a segmental bone defect, the implant having at least one longitudinal strut, constructed to be disposed between opposing faces of a segmented bone the providing axial support and, in certain implementations, torsional strength to the bone. The longitudinal strut may have a proximal portion configured to mate with a slot or hole formed within a face of a proximal segment of a patients segmented bone, and a distal portion configured to mate with a slot or hole formed within a face of a distal segment of the patient's segmented bone. The longitudinal strut may include one or more proximal and distal wings with surfaces that extend radially about a central axis. One or more wings may be structured to fit within a mating hole bored into proximal and distal faces of the bone segments. One or more wings may include proximal and distal surfaces that abut the faces of proximal and distal segments, without penetrating into the faces. The proximal end of the longitudinal strut may have a different cross sectional shape than the distal end of the strut. The plurality of wings may be structured to form a well between them.
Certain fracture repair systems and devices include an implantable sleeve structure that surrounds the fracture site and is secured to the bone by a bioabsorbable putty or resin. The sleeve is sized to receive segment ends of a segmented bone and provide load-bearing support to the bone. In certain implementations, for example where a piece of the fractured bone is missing (e.g., from a serious segmentation wound), the sleeve encases and supports a resorbable intramedullary strut disposed between bone segments (e.g., to fill the gap from the missing bone) and resorbable porous putty filler materials (where included) as well as the bone itself. The sleeve may also be structured to further facilitate healing, and support vascularization and further strengthen the bone during the healing process.
The sleeve is prepared in certain implementations as a unitary molded, cylindrical hollow tube of high-strength biodegradable material, such as a degradable polyester (e.g. PLA or PGA) or a high-strength polyurethane which has sufficient torsional, bending, and compressive strength to support the loaded limb against bending, axial and torsional forces that impact the limb as it is loaded. In certain implementations, the sleeve is cylindrical in shape, or may be tapered. The sleeve may be unitary, co-molded without a longitudinal seam. The sleeve may be a degradable polymer and may be sized to encompass a strut. In certain embodiments, the sleeve is used to contain and envelope a strut. Struts and sleeves disclosed herein may be used in combination.
In certain implementations, the sleeve includes a biodegradable foam dispersed in windows placed within the sleeve, where the foam protrudes through the wails of the sleeve and contacts the bone or an intramedullary implant, such as a strut. The foam is placed in the sleeve to act as a scaffold to aid vascularization of the defect area by allowing blood vessels to grow from the surrounding soft tissues and muscles into the fillers or putties on the strut, in certain implementations, all of the components of the systems and devices are biodegradable.
A biodegradable putty may be disposed on or about any of the struts disclosed herein. A biodegradable putty may be packed around at least one strut, preferably within a well or a plurality of wells. Any of the putties disclosed herein may be contained within any of the sleeves disclosed herein.
A wrap or sealant may be packed on or about any of the struts disclosed herein for insertion within an intramedullary area of a fracture. Any of the wraps disclosed herein may be contained within any of the sleeves disclosed herein. A wrap may include biodegradable foam. A biodegradable putty or resin may be disposed about any of the wrapped implants disclosed herein. Where a sleeve is used to secure an intramedullary implant with respect to a bone, putty or resin may be disposed between the implant (and bone) and the sleeve to further secure the implant and fill in space between the sleeve and the implant and bone. The filler resin or putty may have a different composition than the composition of resin and putty that packs about any of the struts.
Variations are also contemplated for biocompatible struts and sleeves, along with methods of application and manufacture. In certain embodiments, a shell can be prepared from a pliable material configurable into a sleeve about the wound site. The pliable material is moldable and therefore formable about the wound side, e.g., by hand molding. In certain examples, the material is provided as a wrap. The material is durable and may be curable into a strong, hard shell. Upon curing, the shell is sufficiently strong to bear the full load of the patient and, accordingly, fully supports the patient's bone load during the healing process. The material can be constructed and applied in various implementations. For example, the material can be formed from a wrap material that includes a first formable and degradable layer having an outer surface and an diner surface, and a second layer disposed on the inner surface of the first layer, the second layer being comprised of a formable polymer that is moldable into a sleeve that cures and forms a hard, biocompatible shell about the patient's bone. One or more through-holes, such as a window, can be disposed in the sleeve, fur example in the first layer. One or more through-holes or windows may include a transparent portion of the first layer. One or more windows may provide an opening that extends through first layer, second layer, or both. Each window may be configured with biocompatible porous material such as foam, disposed over a surface oldie window or even disposed within the window so it extends across the border of the shell after it has hardened.
The formable polymer can be applied to the first layer in either a single, unitary layer, or in a plurality of portions (or drops of material) that provide a plurality of portions spaced apart from each other on the first layer. The portions (or drops) may be formable and hardenable. Such structures may be combined with one or more windows, such that the portions of polymer are applied so as to surround or otherwise extend along one or more borders of the window. In some applications, a first portion (or drop of material) extends along a first border of a window and a second portions extends along a second border of the window. In a further implementation, a foam portion is disposed between two formable polymer portions, to provide a window structure to facilitate blood and fluid flow between the bone and external fluid. In certain implementations, the polymer layer has a first thickness, the foam has a second thickness, and the second thickness is greater than the first thickness.
One or more chemical catalysts or other curing agents (e.g., photo curing agents) may be disposed within the second layer to help facilitate hardening after the wrap is applied to the patient. In certain applications the catalyst is included in a concentration within the second layer sufficient to catalyze curing of the second layer in an exothermic reaction. In certain applications, the catalyst is selected from tin-based catalysts and zinc.
One or more layers may be used, and may be configured in a pliable flat sheet that is hand-moldable. The flat sheet is the rolled into a tube to surround the circumference of the patient's bone. The width of the one or more layers, together, may wrap completely about the circumference of the bone (such as the patient's femur), or may extend partially but not completely around a circumference of the bone when rolled into a tube. In certain embodiments, first and second layers are used and, together, have a thickness of between about 1 mm to about 10 mm. The thickness may alternatively be between about 4 mm to about 5 mm. In certain applications, the first layer of material is a biocompatible polymer, such as polycaprylactone, and the second layer is a biocompatible resin, which may comprise hydroxylapatite. A biocompatible filler may also be used with the polymer to improve the modulus of the polymer. For example, a filler such as hydroxylapatite or calcium phosphate could be suitable.
Certain methods of use include methods of repairing a segmented bone, comprising the step of securing an intramedullary implant, such as any one or more of those disclosed herein, between two bone segments. Method of setting a segmented bone fracture are also contemplated, including steps of inserting a longitudinal strut between opposing faces of a segmented bone, and applying at least one of a biodegradable sleeve and a pliable sheet about the longitudinal strut. Certain implementations of the methods include a step of injecting a biodegradable porous material in between the strut and at least one of the sleeve and the sheet. The porous material may be positioned between the bone and an inner surface of at least one of the sleeve and the sheet to allow fluid to flow from outside the sleeve into the bone. In certain implementations, the sheet covers a substantial portion of the circumference of the bone. Methods are also contemplated for repairing a bone fracture. In certain embodiments the methods involve steps of positioning at least one of a biodegradable sleeve and a pliable biodegradable sheet (having a through hole along a longitudinal surface of the at least one of the sleeve and the sheet around the bone), and injecting a biodegradable porous material in between the bone and at least one of the sleeve and the sheet. In the methods, the through-hole may be positioned adjacent to a fracture in the bone.
In certain embodiments, an implantable, load-bearing, orthopedic support sleeve is provided, having an interior tube, an exterior rounded configuration, and a midsection comprising a material of any of those described herein. The sleeve may be configured with a midsection that has a first thickness at a first location along the sleeve's length and a second thickness at a second location along the length. The varying thickness of the sleeve is selected to correspond with particular bone configurations (e.g., anterior and posterior tibial structures).
In certain implementations, a formable wrap, such as that described herein, is combined in a repair system with a longitudinal strut (such as those described herein) that is designed to fit between opposing faces of a segmented bone to fill a bone gap and provide at least one of axial support and torsional strength to the bone. The longitudinal strut is configured with a proximal portion that mates with a face of a proximal segment of a patient's segmented bone, and a distal portion configured to mate with a face of a distal segment of the patient's segmented bone. The strut mates directly with the faces of the segment. In certain implementations, the strut has one or more ends that are configured to fit within a slot or hole formed within a segment face (such as proximal, distal or both). One or more wings may be included on the strut. The one or more wings may include a surface that extends radially from a center axis of the strut. The longitudinal strut may also include a plurality of wings, with at least two wings form a well between them. In the system, the proximal end of the longitudinal strut may have a different cross sectional shape than a distal end of the strut. To form the system, the pliable flat sheet is preferably rolled into a sleeve, and the longitudinal strut is disposed within the rolled sleeve.
In another aspect, methods are included for setting a segmented bone fracture. Methods include applying a biocompatible material (such as those described herein) about the fractured bone to stabilize the fracture and support it during healing. In certain embodiments, the methods include installing a biodegradable sleeve, such as a hard shell, so that first and second ends of the fractured bone are disposed within the sleeve, whereby the sleeves envelops the fracture site. In certain implementations, the methods include steps of inserting a longitudinal strut between opposing faces of a segmented bone, and applying a biodegradable sleeve about the fracture and about the longitudinal strut. The step of applying a biodegradable sleeve may include applying a formable material, such as those described herein, about the fracture site (and the longitudinal strut, if used) so that the segmented bone fracture is enveloped by the sleeve. One or more windows may also be positioned within the material, and foam optionally applied as described herein. Methods include setting a bone fracture by steps of positioning opposing faces of first and second portions of a the bone to create an interface that facilitates bone growth between such faces, and applying biodegradable material about the interface. Methods may include the steps of inserting first and second portions of a fractured bone within a bioabsorbable sleeve, and placing a bioabsorbable scaffold about the interface within the sleeve. The methods may also include the step of installing a longitudinal strut between first and second bone portions. Methods are included for repairing a segmented bone, comprising the step of securing an intramedullary implant to secure two bone segments. Methods are also included for configuring a surgical device. Examples include steps of inserting an implant, such as those disclosed herein, within a sleeve. The end of the implant are aligned within the sleeve so as to be accessible through corresponding ends of the sleeve.
In certain applications, the material is circumferentially wrapped around the bone so that the material covers at least a portion of a circumference along a portion of the bone's length, and then at least one (preferably an inner, second) layer of the material changes its physical structure to harden and support the bone. A first layer (such as an outer layer) of the material can degrade after application to the bone.
The thickness of the wrappable material can be varied to correspond to particular bone structures being treated, as discussed herein. For example, tibial fractures could be treated by forming a formable wrap about the tibial fracture site but creating a first thickness in the anterior wrap, to correspond to the patient's shin, and a second thickness corresponding to a distal portion of the tibia, the second thickness being greater than the first thickness. In another aspect, kits are provided having materials that are configurable into implants and systems for use in repairing fractured bones. In certain embodiments the kits include a first material, such as a polymer that can be rolled out into a sheet having an outer surface and inner surface. The polymer is preferably formable into a first layer that is moldable and degradable. A second material is provided that can be configured into a curable layer that is formable and can be hand-molded about the bone. Upon curing, the second layer hardens into a hard shell and is biocompatible with the patient's bone. An intramedullary strut may also be provided, having a first and second end with a longitudinal axis. One or more wings may be provided to extend radially from the axis. The embodiments of struts and additional components discussed herein can be provided in the kits.
Variations and modifications will occur to those of skill in the art after reviewing this disclosure. The disclosed features may be implemented, in any combination and subcombinations (including multiple dependent combinations and sub-combinations), with one or more other features described herein. The various features described or illustrated above, including any components thereof, may be combined or integrated in other systems. Moreover, certain features may be omitted or not implemented. Further areas of applicability of the disclosed methods, systems and devices will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating particular embodiments, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure or any claims that may be pursued.
The foregoing and other objects and advantages will be appreciated more fully from the following further description thereof. With reference to the accompanying drawings, these depicted embodiments are to be understood as illustrative and not as limiting in any way.
The figures illustrate examples of internal fixation devices used to stabilize a fractured limb. In preferred implementations, the devices have biodegradable implants that provide support and at least one of torsional, axial and bending strength for treating a fractured, load-bearing bone. In certain implementations, the devices include a sleeve disposed about the fracture site. In certain implementations, the devices include a strut and sleeve, in combination. Procedures for surgically installing the devices are also contemplated.
The central hub and wings, which extend away from the hub in different directions, provide a strut that supports a load on the bone substantially across the segment face, thereby improving the implant's stability and strength. As shown, the opposing wings 106 and 107 of the strut 100 are longer (the “long wings”) than the opposing wings 104 and 105 (the “short wings”). The proximal ends of the long wings 106 and 107 form a continuous proximal tip 83 and the distal ends form a continuous distal tip 85 with tips extending beyond the respective proximal and distal ends of the short wings 104 and 105. This is shown it
In operation, the strut 100 mates with the bone segments in a way that enhances the implants axial and torsional strength. As shown in
The structure of the strut can vary, for example in the number and arrangement of the wings as well as the structure of the connection between the strut and the bone segments. The strut 100 has four wings that form a cross-section in the form of a “+” but with two wings that are longer than the other two. The slots 93 and 94 are each cut in the shape of a single channel that extends substantially across the faces 97 and 98 of the segment and receive the tips 83 and 85 of the two longer wing pairs. In alternative implementations, additional wings could be extended about the hub 90 to form a more complex strut end. For example, a third wing could be extended, being molded to the same length as the tip 83 for tip 85, and the slot on the bone face 97 could include a branch channel, forming a “Y” shaped slot, that accommodates the extended third wing. In other alternatives, all four wings 104, 105, 106 and 107 (or at least three of them) could be extended and molded to the same length about hub 90, forming a molded head with four wings. A corresponding slot with a “+” shape (see
The strut 100 is preferably made of a degradable material, such as high-strength polyurethane, which allows it to degrade over time while bone regrowth and regeneration occurs across the fracture site. This bone regrowth and regeneration may be facilitated by biodegradable materials, such as a porous scaffold, that are applied in conjunction with the strut 100. Examples of a porous scaffold may include putty particles or resin.
Alternative biocompatible scaffolding material may be used. For example,
In certain applications, the scaffolding 103 is made by a 3-D plotter from a CAD model. In practice, the CAD model is used to design the size and the structure of the scaffold to fit with the patient's fracture site. The scaffold 103 may also contain variable thickness areas, such as roll 103a, for added stability and strength. In certain applications, the scaffold 103 is contoured or textured to fit within a gap of a segment of the fracture to replace missing bone. The scaffold 103 may be cylindrical or may be designed to match the contouring, and the shape of a bone where it is applied. In certain applications, the scaffold 103 is prepared by the technician or surgeon identifying by tactile feeling or by visually determining the needed structure and contouring, and then programming corresponding design dimensions and coordinates within a software system to generate a CAD model based number that needed structure and contouring. One or more pores and channels are also preferably programmed within the CAD model and included in the design. The 3-D plotter or rapid prototyping machine is used to generate the scaffold 103 from the CAD model. In certain applications, the scaffold 103 is used in lieu of the biocompatible putty shown in
Example scaffolding 103 is made of HA or tricalcium phosphate (TCP), or a combination thereof. In certain implementations, the scaffold 103 is designed to have a predetermined level of porosity and connectivity between its pores or channels. For example, it may have a 20 to 50 percent porosity. In some implementations the porosity is more finely determined, for example about 30 to about 40 percent, or about 35 to 36 percent porosity. Connectivity between the channels will be at a desired level, for example 90 to 95 percent, or even 95 to 99 percent, for example 98 percent connectivity. The pore sizes may also be adjusted as desired, for example certain applications would use pore sizes of 400 to 600 micrometers.
In certain implementations, a biocompatible sleeve is used to secure a fracture site. The sleeve may be used by itself or in combination with an intramedullary strut. For example, a sleeve may be used to further secure the strut 100 within the intramedullary canal of the bone, between the bone segments 102a and 102b.
Suitable sleeve materials may include, for example, a biodegradable, high-strength polyurethane. Other examples of suitable sleeve materials include biodegradable polyesters (e.g., polylactide, polyglycolide), blended materials containing two or more different biodegradable polymers (e.g., PLA, PGA together), and biodegradable composites, such as polyurethane combined with HA. When using blended or composite materials, components may be selected so the sleeve has a desired stiffness without becoming too brittle. For example, composites that include a polyurethane and HA typically increase in stiffness as the composition of HA increases, but they also become more brittle and therefore potentially have a shorter useful life. In certain implementations, the composition of HA is selected, for example, to be within the range of about 20% to about 50%. In one implementation, the sleeve is structured from a composite having about 70% polyurethane and about 30% HA.
As shown in
The sleeve 120 is molded as a unitary cylindrical structure. It may be manufactured, for example, by injection molding or other methods known to one skilled in the art. The unitary structure strengthens the sleeve by minimizing the weak areas along its length. Alternative implementations may provide the sleeve in a clam shell-type structure that has a top and a bottom portion clamped together or buckled together by biodegradable latches, ties or screws. The sleeve 120 and the foam 130 may also be manufactured or molded as an integral device. The sleeve 120 may also have selective portions which are porous and raised above the sleeve surfaces 131 and 133.
After the segments are prepared, which may also include drying or removing of periosteum or other preparations, the surgical system is installed. To install the system, where a strut is needed to fill a gap, the strut 100 is provided with packed porous puny as described above (
The sleeve (and strut) are then installed in the fracture site. To perform the installation, in one implementation, the proximal end 120a of the sleeve is slid over the face 97 of the proximal segment 102a (
After the implant 140 is installed within the sleeve, the distal boric segment 102b is then inserted within the sleeve and positioned until its respective slot 94 aligns with the distal tip 85 of the long struts on the distal cud of the implant 140. The surgeon pushes the segment 102b into the sleeve so that the slot 94 presses onto the tip 85 and fits snugly.
After securing the bone segments (and the implant, when used) within the sleeve, space will likely remain between the implant 140 (or bone) and the interior surface of the sleeve. That space may be filled with resin or putty to further support and secure the bone within the sleeve. To ensure the resin does not leak out from the ends of the sleeve, the wraps 150a and 150b or other bone sealants may be used to close of the ends of the sleeve.
The wraps 150a and 150b are pulled down over the corresponding ends of the sleeve 120 and secured radially about the ends of the sleeve by twist tie, Tie Vac, polymer, Cerclage wire, suture, elastic material, or other securing mechanism 174 that compresses radially. A connecting member, such as a Luerlock may also be used to engage the dispenser and the sleeve as illustrated in
In certain implementations, all of the components, including all materials used inside the implant are biodegradable, so that over time the entire surgical system erodes away and leaves a healed bone as bone regrowth and vascularization occurs. In other implementations, the system may be used in combination with one or more non-degradable materials, such as an intramedullary nail, plate or screw, or an external fixator (for example a pin or rod as described in
The struts can also be canulated, for example with a central hub similar to hub 90 (sec
Alternative shell implementations are also envisioned. As indicated above, biocompatible wraps and sleeves can be used to provide an exterior support for a treated bone. in certain embodiments a wrap is applied to the bone as a sleeve and then changes its physical state to become a hard, biocompatible shell.
The materials for the wrap also allow the wrap to be formed and molded initially so that it can conform to the contours of the set bone, forming a sleeve that contours to the bone about its circumference to hold in its reduction configuration. After the sleeve is formed about the bone, the materials change their physical state to become a hard, biocompatible shell sufficient to support the load on the orthopedic bone itself. In certain implementations as discussed further below, the sheet 404 is degradable and the settable resin 402 is hardenable and curable. Thus, after application to the patient's bone, the outer sheet layer 404 degrades and the inner resin layer 402 solidifies, forming a stable shell with contouring suitable to the bone being treated. The degradation rate of the sheet 404 can be controlled by type of material and thickness.
Dimensions for the sheet may include sheets with thickness of about 0.005 to about 0.020 inches, while in certain implementations, the thickness is about 0.01 inches, or about 0.08 to about 0.15 inches. The external dimensions of the wrap 400 are adjusted according to the dimensions needed to treat the bone. Examples include a 6″×5″ sheet.
In certain applications, the wrap constructed according to
The wrap 400 can also be applied to a more serious fracture, such as a segment defect with a missing bone piece, using a strut to fill the gap of the missing bone. For example, if the bone segments 410a and 410b were completely segmented with a bone gap similar to segments 102a and 102b of
The wrap can be modified to provide one or more windows or flow pathways, similar to embodiments described shove. For example,
As with the windows in sleeves described above, the windows 422-428 are sized, shaped and positioned based upon at least two factors. One factor is the desire to provide as large of an opening as possible to allow vascular flow in and out of the wrap and into contact with the bone to facilitate healing. The second factor is to ensure that the opening doesn't compromise the strength of the implant to support the bone and reduce stresses around the bone where possible. The size and location of the windows would be determined to meet the particular patient's need.
in certain implementations the Foam window dimensions can be adjusted to enhance or restrict blood flow and interstitial fluid flow.
In certain implementations, adhesive properties are configured in the inner surface 490 of a biocompatible sleeve (e.g., sleeve 120) to improve the surface contact between the resin or other filler material and the sleeve, thereby helping to enhance the stability of the implant for supporting the fracture. Examples of such properties may include channels, recesses, grooves, dimples, knurls or other structural mechanical features added to the sleeve, which enhance surface contact and connection between the sleeve 120 and the patient's bone.
Although not shown, sleeves prepared by use of a wrap embodiment can also be structured, to accommodate screw holes to receive fasteners (either in locking or non-locked-type) to provide supplemental fixation to anchor the sleeve to the bone. Applying fastener holds creates a circular external fixator. The fasteners used can be locking screws or non-locking screws, For example, locking structures, such as those disclosed in U.S. patent application Ser. No. 11/966,795 (“Systems and Methods for Using Polyaxial Plates”), or those in U.S. patent application Ser. No. 12/069,331 (“Systems and Methods for Using Polyaxial Plates”) may be used to lock the sleeve to the bone to enhance the fixation or, if desired, to avoid having to inject putty into the sleeve space. As noted above, such items are not required, but may be used in certain embodiments where desired. The apertures could be provided in the sleeve, or could be created and applied in a position the used desires prior to apply the wrap to the bone.
In certain implementations, the sleeve is designed to closely fit with the bone according to the unique shapes of the bone being treated. The sleeve can also be designed with portions of different thickness to align with regions, on the bone that are subject to different stresses. For example, this sleeve can be designed with portions that are thicker in regions where high stresses will be experienced, and thinner in regions where lower stresses will be present. As depicted in
The file wrap 500 is also configured to vary dons along the bone 502. Also shown in
Alternative implementations of the strut 100 are also envisaged. Examples of alternative strut structures are included in
As one of skill in the art will appreciate, any of the putties, wraps, sleeves, foams, and central hubs or alternatives thereof, as described above, could be implemented with any of the alternative versions of the struts 100, 500, 600 and 700. Any of the implants, methods, systems and devices disclosed herein may include one or more internal or external fixation devices to further anchor a sleeve to a patient's bone. One of the skill and art will also recognize other possible variations.
Any of the devices, systems, implants, and methods may also incorporate bioactive molecules that promote beneficial processes, such as healing, regeneration, bone regrowth and mineralization, and. discourage undesirable processes, such as infection or inflammation. The bioactive molecules may be incorporated, for example, into the loam, wrap, putty, resin or other components of the implants. The molecules may include, but are not limited to antibiotics; growth factors, including, but not limited to, insulin-like growth factors (IGF—I & 11), transforming growth factors (TGFbs 1-3), fibroblast growth factors acidic and basic (aFGF & platelet derived growth factor (PDGF), and bone morphogenetic proteins (BMPS); interleukins (IL), such as IL-1b, IL-3 (Multi CSF), IL-4, UK-6, and IL-8; tumor necrosis factors TNF alpha and TNF beta; interferons (IFNs); colony stimulating factors; hormones, including but not limited to steroids, such as estrogen, and peptide hormones; anti-inflammatory molecules, including non-steroidal anti-inflammatory molecules, or any combination or variation thereof. The bioactive molecules may be incorporated into the implants, devices or components according to any suitable method, including but not limited to, caging, impregnation, complexing, or chemical bonding, including the use of covalent and non-covalent bonds. Examples of beneficial modification with biologically active molecules include modification GRGD (Gly-Arg-Gly-Asp) peptide sequence to encourage host cell attachment and migration, and encapsulation of growth factors, such as TGF-1, which acts to direct cell migration and differentiation.
The data of
The data shown in
It is to be understood that the forgoing description and examples are merely illustrative and are not to be limited to the details given herein. While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems, devices, and methods, and their components, may be embodied in many other specific forms without departing from the scope of the disclosure.
Variations and modifications will occur to those of skill in the art after reviewing this disclosure. The disclosed features may be implemented, in any combination and subcombinations (including multiple dependent combinations and sub-combinations), with one or more other features described herein. The various features described or illustrated above, including any components thereof, may be combined or integrated in other systems. Moreover, certain features may be omitted or not implemented.
Examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the scope of the information disclosed herein. All references cited herein are incorporated by reference in their entirety and made part of this application.
This application claims the benefit of U.S. provisional patent application No. 61/468,991, filed Mar. 29, 2011, the disclosure of which is hereby incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2012/030947 | 3/28/2012 | WO | 00 | 10/22/2013 |
| Number | Date | Country | |
|---|---|---|---|
| 61468991 | Mar 2011 | US |
