Patent Description:
Currently in the United States there are no regulatorily approved products on the market indicated as a temporary intramedullary antimicrobial eluting spacer for treatment of localized infection of the intramedullary canal of a long bone like a tibia while providing a filling to the cavity created by the infected nail. Surgeons for many years have resorted to the use of off-label available products to fashion such an implant with limited stability as compared to intramedullary locking nails and limited control of the localized release rate of antimicrobial drug.

Current treatment protocol consists of poly(methyl methacrylate) (PMMA) cement mixed with antimicrobials to create a bone cement with drug eluting properties, which is then shaped using a chest tube or hand-rolled with an inserted metallic core for rigidity and anchorage. Handmade tibial spacer nails made intraoperatively have a number of issues including: time and complexity required to make the implant intraoperatively, possibility of cement fracture; lack of mechanism to capture fractured cement during removal; non-uniformity of implant from patient to patient; complexity of making implant; and, occasional need to remake implant due to insufficient or irregular cement coverage.

Thus, a need exists for a standardized treatment of care that will provide surgeons with the reliable ability to intraoperatively prepare antimicrobial-loaded cement intramedullary spacers, and reliably remove them when the infection treatment protocol has finished.

<CIT> describes a disposable intramedullary device for temporary use for treatment of limb infections comprising a variable cross-sectional solid core, including a distal portion, a middle portion and a proximal portion, said proximal portion and distal portion including anchoring regions consisting of through-holes for passing anchoring means to the bone. Outside said anchoring regions said solid core is coated with a polymer layer including antibiotic, the outer diameter of the core and layer assembly being equivalent to that of an intramedullary channel, and the outer diameter of said solid core in said anchoring regions is equivalent to that of an intramedullary channel.

<CIT> describes a temporary knee replacement assembly and kit including a tibial plate that attaches to the tibia, a tibial rod that extends through the plate into the medullary cavity and abuts the plate. A femoral plate attaches to the femur, and a femoral rod extends through the second plate into the femur medullary cavity and abuts the plate. A locking spacer connects the two rods. The spacer may be length adjustable or may be provided in multiple sizes for length selection. One or both of the rods may include a bone cement/antibiotic coating to provide antibiotic treatment to the tissue. The kit may include multiple tibial and femoral rods, multiple tibial and femoral plates, and multiple locking spacers, to accommodate different applications.

<CIT> describes a disposable device for treatment of infections of human limbs, particularly limbs having long bones susceptible to stabilization by intramedullary nailing. The device comprises a tubular member made of a relatively rigid and biologically compatible base material, having pores for impregnation with drugs or medicaments for infection treatment prior to or during insertion thereof in the stabilization site.

Accordingly, the present disclosure is directed to the treatment of surgical site infections (SSIs) containing an infected implantable medical device. More specifically, the present disclosure is directed to temporary antimicrobial-eluting cement spacer implants, and assemblies, kits, and methods for forming the same. Particularly preferred disclosures are to modular spacers, assemblies, and kits, as well as methods of manufacturing the same, where the modular nature of the spacer permits the selection of specific desired length spacers, as well as specific selection of antimicrobial compounds and dosages, along with the components and processes for forming the same. A particular benefit is the ability of a surgeon, or other qualified healthcare professional, to perioperatively design a spacer that is specific to the needs of the particular patient conditions present at the time of surgery.

Typically, these temporary spacer implants are used in cases of infected orthopedic implants where revision surgery will be necessary; for example, intramedullary nails used in the femur or tibia.

A first aspect of the present invention concerns a temporary cement spacer as defined in claim <NUM>.

According to certain embodiments, the outer rod surface includes a threaded surface at the proximal rod end, and wherein the distal locking end defines a distal locking opening configured to threadingly engage with the proximal rod end. In additional embodiments, the outer rod surface includes a threaded surface at the distal rod end, and wherein the proximal cap end defines a proximal cap opening configured to threadingly engage with the distal rod end. In still further embodiments, the outer surface of the rod includes a continuously threaded surface extending from the distal rod end to the proximal rod end.

According to certain embodiments, the at least one locking bore includes a plurality of locking bores.

According to certain embodiments, the locking component extends in axial direction from the distal locking end to the proximal locking end such that the proximal locking end can be angular offset in a radial direction with respect to the central axis by an angle theta, θ. In certain embodiments, the angular offset angle is in the range of about <NUM> degrees to about <NUM> degrees.

In certain embodiments, the cap defines a cross-sectional area in a plane perpendicular to the central axis, and wherein the cap cross-sectional area defines the maximum cross sectional area of the temporary spacer.

According to certain embodiments, the temporary spacer includes one or more centering members extending radially outward from the outer rod surface. In further embodiments, each centering member of the one or more centering members defines four arms, each arm extending radially outward from the outer rod surface.

According to additional embodiments, the locking component defines an outer locking surface extending from the proximal locking end to the distal locking end. In further embodiments, the outer locking surface can define at least one planar portion extending in a direction from the proximal locking end to the distal locking end. In still further embodiments, the at least one planar portion includes a plurality of planar portions, each of the plurality of planar portions spaced equidistant from another of the planar portions along the outer locking surface.

According to yet additional embodiments, the outer locking surface further defines at least one surface channel extending in a direction from the proximal locking end to the distal locking end. In certain additional embodiments, the at least one surface channel is directly adjacent to at least one of the at least one planar portions. According to certain embodiments, the at least one surface channel includes a plurality of surface channels such that each surface channel of the plurality of surface channels is directly adjacent to the at least one planar portion.

According to certain embodiments, the plurality of fenestrations are evenly distributed around the cap.

According to certain embodiments, the curable polymer material comprises poly(methyl methacrylate) (PMMA) or a copolymer thereof.

According to certain embodiments, the antimicrobial agent comprises antibiotics, antifungals, or combinations thereof. For example, certain suitable antibiotic classes can include aminoglycosides and glycopeptides. Specific agents can include, for example, gentamicin, tobramycin, vancomycin, amikacin, rifampin, clindamycin, erythromycin, colistin, linezolid, daptomycin, fosfomycin, and amphotericin B, or combinations thereof. Preferred agents can include gentamicin, tobramycin, and vancomycin, or combinations thereof.

According to certain embodiments, the rod comprises a metal or metal alloy, or a thermoplastic polymer material. According to further embodiments, the locking component comprises a metal or metal alloy, or a thermoplastic polymer material. In still further embodiments, the cap comprises a metal or metal alloy, or a thermoplastic polymer material.

A second aspect of the present invention concerns a mold assembly for forming the temporary cement spacer as defined in claim <NUM>.

According to certain embodiments, the at least one locking bore includes a plurality of locking bores. In certain embodiments, the at least one bore plug comprises a plurality of bore plugs. In certain additional embodiments, each locking bore of the plurality of locking bores has a bore plug of the plurality of bore plugs disposed within it such that an amount of the plurality of locking bores is equal to an amount of the plurality of bore plugs. In alternative embodiments, a first portion of the plurality of locking bores has the plurality of bore plugs disposed within it, and wherein a second portion of the plurality of locking bores do not have the plurality of bore plugs disposed within it.

According to certain embodiments, the mold body further comprises at least one mold bore, the at least one mold bore extending through the mold body and the mold lumen in a radial direction with respect to the central axis, and wherein the at least one bore plug is configured to be disposed in the at least one mold bore. In certain embodiments, the at least one mold bore is aligned with the at least one locking bore such that the at least one bore plug can be disposed within both the at least one locking bore and the at least one mold bore. In certain embodiments, the at least one mold bore comprises a plurality of mold bores.

According to certain embodiments, the mold body includes separation means extending along the mold body in an axial direction from the proximal mold end to the distal mold end. In certain embodiments, the mold body further defines an outer mold surface extending between the proximal mold end and the distal mold end, and wherein the separation means include a plurality of perforations in the outer mold surface, a groove in the outer mold surface, or a strip of material disposed within the mold body, or a combination thereof. In certain embodiments, the mold body further comprises one or more reinforcing members. In still further embodiments, the mold assembly further includes one or more tabs disposed at either the proximal mold end or the distal mold end of the mold body.

According to certain embodiments, the spacer core further comprises a cap configured to operably couple to the distal rod end.

According to certain embodiments, the adapter defines a proximal end operably coupled to the distal end of the mold body and defining a proximal opening. Additionally, the adapter further defines an opposing distal end configured to operably couple to the bone cement injection device and having a distal opening such that the adapter comprises an adapter recess extending between the distal opening and the proximal opening that provides the continuous fluid pathway. In certain additional embodiments, the adapter comprises an inner wall, the inner wall defining an adapter receptacle having a receptacle opening, and wherein the distal end of the rod is disposed in the adapter receptacle.

A third aspect of the present invention concerns a kit for forming a temporary cement spacer as defined in claim <NUM>.

According to certain further embodiments, the at least one rod comprises a plurality of rods, wherein each rod of the plurality of rods has a length measured between the proximal rod end and the distal rod end, and wherein each rod length is different than any other rod length of the plurality of rods. In certain embodiments, the at least one rod defines an outer rod surface extending from the proximal rod end to the distal rod end, and further wherein the outer rod surface comprises a continuously threaded surface.

According to certain embodiments, the at least one bore plug comprises a plurality of bore plugs.

According to certain embodiments, the kit further includes at least one locking bone screw, wherein the at least one locking screw is configured to be disposed in the at least one locking bore and further configured to secure the temporary spacer to bone.

According to certain embodiments, the kit includes an insertion instrument, the insertion instrument configured to operably couple to the proximal end of the locking component, wherein the insertion instrument is configured for implanting the temporary spacer.

A fourth aspect of the present invention concerns a method of forming an antimicrobial eluting temporary cement spacer as defined in claim <NUM>.

According to certain embodiments, the method further comprises prior to the step of inserting the spacer core into the mold lumen, connecting the rod to the locking component. In certain embodiments, the method further includes operably coupling a proximal end of the rod to a distal end of the locking component.

According to certain embodiments, the rod has a rod length measured from a proximal rod end to an opposing distal rod end, the method further includes, prior to the step of inserting the spacer core, removing a portion of the rod length from either the proximal rod end or the distal rod end.

According to additional embodiments, the mold body defines a mold length measured from a proximal mold end to an opposing distal mold end, and the method includes removing a portion of the mold body length from either the proximal mold end or the distal mold end.

According to certain embodiments, the mold body defines an outer mold surface extending from the proximal mold end to the distal mold end, and the mold body includes at least one mold bore extending from the outer mold surface through the mold lumen, the method includes aligning the at least one locking bore with the at least one mold bore. According to further embodiments, the step of disposing the at least one bore plug into the at least one locking bore further includes disposing the at least one bore plug in the at least one mold bore.

The present disclosure is directed to temporary antimicrobial-eluting cement spacer implants, and assemblies, kits, and methods for forming the same for the use in the treatment of surgical site infections (SSIs). Typically, these temporary spacer implants are formed with an antimicrobial agent mixed into a polymer or ceramic cement material, and are used in cases of infected orthopedic implants where revision surgery will be necessary; for example, intramedullary nails used in the femur or tibia. The temporary spacer generally approximates the shape of the removed infected implant. Once the infected implant is removed, the temporary antimicrobial-eluting spacer implant is inserted into the same location and the cement material including the antimicrobial agent provides a local drug depot that elutes the antimicrobial agent to reduce the infection and prevent bacterial growth on the spacer at the implant site. Once the infection has been resolved, the temporary spacer is removed, and a new permanent revision implant is then placed in that location.

The present disclosure is particularly directed to modular temporary spacers, where the modular nature of the spacer permits both the selection of specific desired length spacers, as well as specific selection of antimicrobial compounds and dosages to be mixed into the cement material. Additionally, the temporary cement spacer can be utilized with locking screws to secure the spacer into adjoining bone, which provides the benefit of maintaining the position and stability of the temporary spacer in the desired location. In essence, the temporary spacers of the present disclosure are customizable to the specific criteria of the individual patient and can be properly secured once implanted. An additional benefit is the ability of a surgeon, or other qualified healthcare professional, to perioperatively design and form a temporary spacer according to the present disclosure at, or near, the time of surgery. Thus, the surgeon can evaluate the circumstances at the time of removing the infected implant and contemporaneously prepare a temporary spacer implant to most appropriately address the surgical site conditions.

As will be described in greater detail below, the present disclosure includes assemblies and kits including a mold body and spacer core that are used in forming the temporary spacer. The mold body has a lumen configured to house the spacer core and receive an injected antimicrobial cement material, which will cure and harden forming a cement coating around the spacer core, and thus the mold body is configured to substantially define the shape of the temporary spacer. The present disclosure additionally describes methods of forming the temporary spacer utilizing the mold body, the spacer core, and the antimicrobial cement material.

Words and phrases representing anatomical references, such as "proximal" and "distal" may be used throughout this disclosure in reference to both the implant, assemblies, kits, and methods described herein, as well as a patient's natural anatomy. Such terms have well-understood meanings in both the study of anatomy and the field of orthopedics. Use of such terms in the specification and claims is intended to be consistent with their well-understood meanings unless noted otherwise.

According to the present disclosure, and with reference to <FIG>, an antimicrobial eluting temporary spacer <NUM> is disclosed, the temporary spacer <NUM> including a spacer core <NUM> and an antimicrobial cement coating <NUM> surrounding at least a portion of the spacer core <NUM>. The cement coating <NUM> includes a cement material comprising a curable polymer material or curable ceramic material, mixed with one or more antimicrobial agents, and is configured for use in treatment of an infection. The temporary spacer core <NUM> is configured to provide the structural framework of the temporary spacer <NUM>, and includes a rod <NUM>, a locking component <NUM>, and a cap <NUM>. The locking component <NUM> and the cap <NUM> are configured to couple to opposing ends (i.e., proximal and distal ends) of the rod <NUM> as will be explained in greater detail below.

According to certain embodiments, the rod <NUM> comprises a metal or metal alloy, or a thermoplastic polymer material. According to further embodiments, the locking component <NUM> comprises a metal or metal alloy, or a thermoplastic polymer material. In still further embodiments, the cap <NUM> comprises a metal or metal alloy, or a thermoplastic polymer material. Suitable metals can include, for example, standard orthopedic implant grade metals or alloys such as <NUM> stainless steel, titanium, Ti-6Al-4V alloy, Ti-6Al-7Nb alloy, or cobalt-chrome alloys. Suitable thermoplastics can include, for example, any polymer or co-polymer of the polyaryletherketone family, such as polyetheretherketone (PEEK), as well as polyethylene, polypropylene, or nylon.

With reference to <FIG>, the rod <NUM> is elongate in a longitudinal direction L and defines a central axis C of both the spacer core <NUM> and the temporary spacer <NUM> that extends in the longitudinal direction. As used herein, terms such as "axial" or "axially" or derivatives thereof are intended to define a directional component that is substantially or completely coextensive with the central axis C.

The rod <NUM> further defines a proximal rod end <NUM> and a distal rod end <NUM> opposite the proximal rod end <NUM> along the central axis C and an outer rod surface <NUM> extending from the proximal rod end <NUM> to the distal rod end <NUM>.

The rod <NUM> is configured to attach to the locking component <NUM> at the proximal rod end <NUM>. The rod <NUM> is additionally configured to attach to the cap <NUM> at the distal rod end <NUM>. Accordingly, with reference to <FIG>, a portion of the outer rod surface <NUM> at the proximal rod end <NUM> can be configured as a threaded surface <NUM> such that it can threadingly engage with the locking component <NUM>. Additionally, a portion of the outer rod surface <NUM> at the distal rod end <NUM> can be configured as a threaded surface <NUM> such that it can threadingly engage with the cap <NUM>. Alternatively, and with reference to <FIG>, substantially an entirety of the outer rod surface <NUM> can be configured as a threaded surface <NUM>. As used herein with respect to the threaded surface <NUM>, "substantially" means a range of at least <NUM>% up to <NUM>% (such as <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>%, or any suitable subrange derivable from the percentages listed herein) of the outer rod surface <NUM> is a threaded surface <NUM>. For example, as shown <FIG>, <NUM>% of the outer rod surface <NUM> is configured as a threaded surface <NUM>, such that it can be said that the outer rod surface <NUM> is a continuously threaded surface <NUM> extending from the distal rod end <NUM> to the proximal rod end <NUM>. This particular example of a continuously threaded rod <NUM> provides a benefit with regards to the modular nature of the temporary spacer <NUM> that was previously described. With a continuously threaded rod <NUM>, a surgeon can cut the rod <NUM> to any desired length and still maintain threaded surfaces <NUM> at both the proximal rod end <NUM> and the distal rod end <NUM> to threadingly engage with both the locking component <NUM> and cap <NUM>, respectively.

With reference to <FIG>, the spacer core <NUM> includes a locking component <NUM> configured to attach to the rod <NUM> at the proximal rod end <NUM>. The locking component <NUM> is configured to provide the structure for locking screws to secure the temporary spacer <NUM> to adjoining bone as will be explained in greater detail below. The locking component <NUM> is generally elongate in the axial direction (i.e., elongate along the central axis C in the same direction as the rod <NUM>). The locking component <NUM> includes a distal locking end <NUM> configured to attach to the proximal rod end <NUM>, and a proximal locking end <NUM>, opposite the distal locking end <NUM> along the central axis C. An outer locking surface <NUM> extends from the proximal locking end <NUM> to the distal locking end <NUM>.

The distal locking end <NUM> is configured to operably couple to the proximal rod end <NUM> and can include a distal locking opening <NUM> and an inner distal locking surface <NUM> that defines a distal locking recess <NUM> extending proximally from the distal locking opening <NUM> towards the proximal locking end <NUM>. The distal locking recess <NUM> is configured to receive the proximal rod end <NUM> such that when the rod <NUM> is operably coupled to the locking component <NUM>, the proximal rod end <NUM> is disposed, at least partially, in the distal locking recess <NUM>. In certain examples, such as shown in <FIG>, the inner distal locking surface <NUM> can be threaded and configured to threadingly connect with a corresponding threaded surface <NUM> of proximal rod end <NUM> as has been previously described.

With reference to <FIG>, <FIG> , the locking component <NUM> includes at least one locking bore <NUM> that is configured to receive a locking screw, which can secure the temporary spacer <NUM> to adjoining bone. Locking screws are well-known in the field of orthopedic implants and are used to pass through an opening in the implant and secured into the bone adjacent to the implant. One benefit of utilizing a locking component <NUM> including at least one locking bore is the ability to provide a level of stability once it is implanted into the patient through the use of the locking screws. While the use of the locking screws is not intended to provide weight-bearing stability as they would in a standard orthopedic implant, the ability to partially stabilize the temporary spacer <NUM> minimizes the chances of it being damaged or otherwise migrating from its intended location during the time it is implanted in the patient.

With continued reference to <FIG>, <FIG>, the at least one locking bore <NUM> of the locking component <NUM> extends in a radial direction R with respect to central axis C through locking component <NUM>. As used herein, terms such as "radial" or "radially" or derivations thereof are directions or locations defined with respect to the central axis C and can include radially inward direction towards the central axis C as well as radially outward direction away from the central axis C. In certain examples, the radial direction is oriented perpendicular to the central axis C and in other examples the radial direction can be angularly offset from a direction that is perpendicular to the central axis C but is not coaxial or parallel with the central axis C. Preferably, the radial extension of at least one locking bore <NUM> is perpendicular with respect to the central axis C.

With reference to <FIG> and <FIG>, the at least one locking bore <NUM> can comprise a plurality of locking bores <NUM>, such as two, three, four, five, up to six locking bores <NUM>. The advantage of a plurality of locking bores <NUM> is that it can provide a surgeon with multiple approaches for securing the temporary spacer <NUM> to adjoining bone with the locking screw or multiple locking screws as desired. It should be appreciated that the anatomical region receiving the temporary spacer <NUM> has already been subject to an invasive infection as well as the morbidity associated with the removal of the infected primary implant. As such there is likely to be tissue damage, particularly damaged bone tissue in the area where a surgeon would normally attempt to secure the temporary spacer <NUM> with a locking screw. Thus, providing multiple options to locate healthy bone tissue for securement is a benefit to the surgeon in successfully implanting the temporary spacer <NUM>.

The locking component <NUM> can be further configured to engage with one or more insertion instruments that aid a surgeon or other medical professional in the placement of the temporary spacer <NUM> into the desired anatomical location of the patient. In one example, as shown in <FIG>, the proximal locking end <NUM> includes a proximal locking opening <NUM> and a proximal locking inner surface <NUM> defining a proximal locking recess <NUM> extending distally from the proximal locking opening <NUM> towards the distal locking end <NUM>. In certain examples, such as is shown in <FIG> and explained in further detail below, the proximal locking end <NUM> is configured to receive an insertion instrument <NUM> within the proximal locking recess <NUM>. In certain examples, the proximal locking inner surface <NUM> can be threaded and configured to threadingly connect with a corresponding threaded component or surface of the insertion instrument <NUM>.

In certain examples, such as shown in <FIG>, the locking component <NUM> can extend axially from the distal locking end <NUM> to the proximal locking end <NUM> such that the proximal locking end <NUM> can be radially offset from the distal locking end <NUM> with respect to the direction of the central axis C by an angle theta θ. The purpose of the angular offset is to, where appropriate, better align the shape of the temporary spacer <NUM> with the natural anatomy of the bone of the patient in which the temporary spacer <NUM> will be implanted both in regards to the step of inserting the temporary spacer <NUM>, as well as maintaining proper anatomical alignment after implantation is completed. In certain embodiments, the angular offset, θ, can be anywhere in the range of about <NUM> degrees to about <NUM> degrees, for example in the range of about <NUM> degrees to about <NUM> degrees, or about <NUM> degrees to <NUM> degrees, or any subcombination of the range endpoints listed here.

With reference to <FIG> and <FIG>, the cap <NUM> defines a proximal end <NUM> that is configured to attach to the rod <NUM> at the distal rod end <NUM>. The cap <NUM> further defines a cross-sectional area measured in a plane perpendicular to central axis C and the cap <NUM> cross-sectional area can define the maximum cross-sectional area of the temporary spacer <NUM>. In other words, the cap <NUM> is designed to preferably be the widest portion of the temporary spacer <NUM>, although in other embodiments the locking component can define the maximum cross-sectional area of the temporary spacer <NUM>. The cap <NUM> defining the maximum cross-sectional area provides two benefits. First, during implantation, the cap <NUM> is configured to be the leading end of the temporary spacer <NUM> and as such can be frequently subject to significant mechanical forces, such as compressive and shear forces. Thus, the cap <NUM> provides a forward buttress to absorb those forces and clear a path as the temporary spacer <NUM> penetrates into the desired anatomical location. This protects portions of the cement coating <NUM> from fracturing or otherwise dislodging from the temporary spacer <NUM> and damaging the functionality of the temporary spacer <NUM> in vivo. Second, as previously described, the temporary spacer <NUM> of the present disclosure require explantation once the clinically proscribed antimicrobial treatment period has expired. The function of the cap <NUM> during explantation is to collect any cement coating <NUM> debris that was created. In other words, the cap <NUM> is preferably designed such that when the temporary spacer <NUM> is removed from the patient, cap <NUM> functions to force upwards (or collect) any broken cement fragments from the cement coating <NUM> that had become dislodged or fractured during, or prior to, explantation of the temporary spacer <NUM>.

With continued reference to <FIG>-4B, the cap <NUM> includes a distal cap end <NUM>, opposite the proximate cap end <NUM> along the central axis C. An outer cap surface <NUM> extends from the proximal cap end <NUM> to the distal cap end <NUM>. The proximal cap end <NUM> includes a cap opening <NUM> and an inner cap surface <NUM> that defines a cap recess <NUM> that extends into the cap <NUM> in a distal direction D from the cap opening <NUM> towards the distal cap end <NUM>, such that it can be said the cap recess <NUM> extends distally from the cap opening <NUM>. The cap recess <NUM> is configured receive the distal rod end <NUM> such that, when coupled, the distal rod end <NUM> is, at least partially, disposed in the cap recess <NUM>. In certain examples, such as is shown in <FIG>, the inner cap surface <NUM> can be threaded and configured to threadingly connect with a corresponding threaded surface <NUM> of distal rod end <NUM>.

With reference to <FIG>, in certain examples, the spacer core <NUM> of the temporary spacer <NUM> can include one or more centering members <NUM> extending radially outward from the outer rod surface <NUM>. As will be explained in greater detail below, a mold assembly <NUM> is disclosed where the spacer core <NUM> is configured to be inserted into a mold body <NUM> in order to form the temporary spacer <NUM>, for example, such as shown in <FIG>. Thus, in certain examples, there are elements of the spacer core <NUM> that function to interact with the mold body <NUM> in forming the temporary spacer <NUM>. In certain embodiments, the centering members <NUM> can be attached to the rod <NUM>, and in alternative embodiments, the rod <NUM> and the centering members <NUM> can be formed as a single monolithic structure. Centering members <NUM> function to provide an offset between the rod <NUM> and the mold body <NUM> and keep the rod <NUM> aligned along central axis C when it is disposed in the mold body <NUM> (for example, as shown in <FIG>) This alignment of the rod <NUM> longitudinally along central axis C assists in forming a uniform distribution of the cement material used to form cement coating <NUM> around spacer core <NUM> because the rod <NUM> will be centered within the mold body <NUM>.

The centering members <NUM> can include at least a single arm that extends radially outward from the rod <NUM>. For instance, each of the centering members <NUM> can include a plurality of arms. The arms of the centering members <NUM> can be circumferentially spaced apart from one another about the outer surface. For example, as shown in <FIG>, (and <FIG>5B) two centering members <NUM> are attached to rod <NUM> and have a substantially cross-shaped (or X-shape) cross-section, with four (<NUM>) arms extending radially outward from rod <NUM>. This cross-shaped design provides spaces between the arms of the centering members to allow cement material to flow past the centering members <NUM> and coat the outer rod surface <NUM> during the process of forming the cement coating <NUM>. It should also be appreciated that the centering members <NUM> may assume any suitable cross-sectional geometry provided that they do not block, or otherwise inhibit, the flow of the fluid cement material.

As previously described, the temporary spacers <NUM> of the present disclosure are designed to have a modular functionality that allows for a desired length of rod <NUM> to be used by a surgeon depending upon the specific conditions of the patient's anatomy. As such, it should be appreciated that more or less than two centering members <NUM> may extend from the rod <NUM> depending on the desired selected length of the rod <NUM>. For example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or up to <NUM> centering members <NUM> could extend outward from the rod <NUM>.

With reference to <FIG>and <FIG>, the outer locking surface <NUM> can define at least one planar portion <NUM> extending in a direction from the proximal locking end <NUM> to the distal locking end <NUM>. This is an additional element of the spacer core <NUM> that is configured to function with the mold body <NUM> to form the temporary spacer <NUM>. A potential benefit to the planar portion <NUM> is that it creates a gap or void between the mold body <NUM> and the locking component <NUM> when the spacer core <NUM> is disposed within the mold body <NUM>. This gap or void provides a space for access along a portion of the outer locking surface <NUM> when cement material is injected into the mold body <NUM> for forming the cement coating <NUM>. In certain examples, as shown in <FIG>, the outer locking surface <NUM> can include a plurality of planar surfaces <NUM>, for example, two planar portions <NUM>. In a preferred embodiment, the planar portions <NUM> are disposed equidistant from one another on the locking outer surface <NUM>.

In certain further embodiments, and with continued reference to <FIG>, the outer locking surface <NUM> can define at least one surface channel <NUM> extending in a direction from the proximal locking end <NUM> to the distal locking end <NUM>. An advantage to including surface channel <NUM> along the outer surface <NUM> is that as the fluid cement material that forms cement coating <NUM> flows into the mold body <NUM>, it can fill the at least one surface channel <NUM> and harden, and once hardened it will provide resistance to forces acting on the cement coating <NUM> during implantation or explantation (e.g. torsion) that could cause fracture or delamination of the cement coating <NUM> from the locking component <NUM>. In other words, portions of the cement coating <NUM> are shielded within the surface channel <NUM> from the mechanical forces that occur during implantation and explantation that can inadvertently pry, dislodge, or fracture the cement coating <NUM> from the spacer core <NUM>. In one example, as shown in <FIG>, the at least one surface channel <NUM> is adjacent to the planar portion <NUM>. The at least one surface channel <NUM> can include a plurality of surface channels <NUM>, for example, two, three, four, five, six, up to <NUM> surface channels <NUM>. In some preferred embodiments, the at least one surface channel <NUM> can be disposed on the outer locking surface <NUM> directly adjacent the planar portion <NUM>. In particularly preferred embodiments, the planar portion <NUM> has two surface channels <NUM> directly adjacent where one surface channel <NUM> is directly adjacent to one side of the planar portion <NUM> and the second surface channel <NUM> is directly adjacent an opposing side of the planar portion <NUM>.

In certain examples, and with reference to <FIG>, the cap <NUM> can be formed as a solid body. In embodiments where the cap <NUM> is a solid body, the cap <NUM> will be attached to the rod <NUM> after the fluid cement material has been injected into the mold body <NUM>. However, according to the invention, and with reference to <FIG>, the cap <NUM> includes a plurality of fenestrations <NUM>. The fenestrations <NUM> are configured to permit the flow of the fluid cement material into the mold body <NUM> to form the cement coating <NUM>. The advantage of a cap <NUM> with fenestrations <NUM> is that the cap <NUM> can be attached to the rod <NUM> prior to the spacer core <NUM> being inserted into the mold body <NUM> while still providing one or more fluid pathways into the mold body <NUM> at the distal cap end <NUM> for introduction of the cement material into the mold body <NUM> to form the cement coating <NUM>.

With continued reference to <FIG>, the plurality of fenestrations <NUM> extend through the cap <NUM> from the distal cap end <NUM> to the proximal cap end <NUM>. In certain embodiments, the fenestrations <NUM> extend in a direction generally coaxial with central axis C. In certain embodiments, the fenestrations extend in a generally linear direction. In certain examples, such as shown in <FIG>, the fenestrations <NUM> are evenly distributed around the cap <NUM>; however, it should be appreciated that there can be any number of fenestrations <NUM> assuming any type of geometry or shape provided that they provide a fluid pathway into the mold body <NUM> from the distal cap end <NUM>.

According to the present disclosure, and with reference to <FIG>, a mold assembly <NUM> for forming the temporary cement spacer <NUM> is described including a mold body <NUM>, the previously described spacer core <NUM>, which is configured to be disposed within the mold body <NUM>, at least one bore plug <NUM>, which is configured to be disposed within the at least one locking bore <NUM> of the locking component <NUM>, and an adapter <NUM>, which is configured to operably couple the mold body <NUM> to a bone cement injection device that will fill the mold body <NUM> with the cement material that forms the cement coating <NUM> of the spacer core <NUM>.

For purposes of discussion regarding the mold assembly <NUM>, and in the interest of brevity, all of the features and embodiments, combinations and sub-combinations, previously described above with respect to the spacer core <NUM> (e.g., rod <NUM>, locking component <NUM>, cap <NUM>, etc.) are considered to be within the scope of disclosure regarding the mold assembly <NUM>, as well as any subsequent disclosure directed to kits, and methods of manufacture.

As previously described, the present disclosure provides a modular aspect to the manufacture of the temporary spacer <NUM> such that at least one benefit is providing a surgeon with the ability to customize the length of the temporary spacer <NUM> to match a patient anatomy. Therefore, according to certain embodiments, once the surgeon determines the appropriate length of the rod <NUM>, and therefore the spacer core <NUM>, the mold body <NUM> is configured to have its length customizable to match that desired length. As such, the mold body <NUM> is configured to have a portion of its length removed, if necessary, to correspond to the determined length for the temporary spacer <NUM>. The mold body <NUM>, in one example, can be cut to a desired length using surgical scissors or a scalpel. In certain embodiments, the mold body <NUM> may include interval markings or scoring corresponding to specific lengths (e.g., <NUM> intervals) to provide a visual aid for determining the desired length. Therefore, it is preferred that the mold body <NUM> be formed from a material that includes one or more elastomers. Suitable elastomeric materials can include, for example, silicone or polyurethane (PUR), or copolymers thereof. In certain additional embodiments, the mold body <NUM> comprises one or more thermoplastic materials. Suitable thermoplastic materials can include, for example, polytetrafluoroethylene (PTFE), perfluoroalkoxy alkanes (PFA), polyethylene, polypropylene, nylon, thermoplastic polyurethanes (TPU), or copolymers thereof.

With respect to the following disclosure of the mold body <NUM>, for the purpose of convenience and ease of describing directional relationships and locations of, or along, the mold body <NUM>, all references will be in relation to the previously identified directional identifiers used for the temporary spacer <NUM> and the spacer core <NUM>. This is primarily because the mold assembly <NUM> includes the spacer core <NUM> disposed within the mold body <NUM>. Therefore, for example, the use of terms such as "axial," "radial," "proximal," "distal," "longitudinal," and any derivations thereof are intended to be consistent between the previously defined temporary spacer <NUM> and spacer core <NUM>, and the mold assembly <NUM> and the mold body <NUM> that will be further described. For example, as will be described below, a central axis C of the mold body <NUM> is intended to be at the same as previously described with respect to the temporary spacer <NUM> and the spacer core <NUM>. Accordingly, the mold assembly <NUM> includes a mold body <NUM> that is elongate in the same longitudinal direction L as the rod <NUM> such that the central axis C defined by the rod <NUM> likewise defines the central axis C of the mold body <NUM>. The mold body <NUM> further defines a proximal mold end <NUM> and a distal mold end <NUM> opposite the proximal mold end <NUM> along the central axis C and an outer mold surface <NUM> extending therebetween.

The mold body <NUM> additionally defines a proximal mold opening <NUM> at the proximal mold end <NUM> and a distal mold opening <NUM> at the distal mold end <NUM> and an inner mold surface <NUM> extending therebetween. The inner mold surface <NUM> defines a mold lumen <NUM>. The mold lumen <NUM> is configured to have the spacer <NUM> disposed within it. In other words, the mold assembly <NUM> includes the spacer core <NUM> disposed within the mold lumen <NUM>, for example as shown in <FIG>.

With continuing reference to <FIG>, the mold assembly <NUM> further includes at least one bore plug <NUM> configured to be disposed within the at least one locking bore <NUM> of the locking component <NUM>. The function of the at least one bore plug <NUM> is to fill the at least one locking bore <NUM>. Because the locking bores <NUM> are configured to receive one or more locking screws that will secure the temporary spacer <NUM> to bone, the function of at least one bore plug <NUM> is to prevent any cement material from becoming lodged in the locking bores <NUM> during the injection of the cement material into the mold body <NUM> during formation of the cement coating <NUM>. The at least one bore plug <NUM> can be inserted into the at least one locking bore <NUM> prior to any injection of cement material into the mold body <NUM>, and once the temporary spacer <NUM> has been formed, the at least one bore plug <NUM> is configured to be removed from the at least one locking bore <NUM>.

In certain examples, the spacer core <NUM> can include more locking bores <NUM> than will be utilized by locking screws during implantation. As was previously described, the locking component <NUM> of the spacer core <NUM> can include multiple locking bores <NUM> to provide a surgeon with multiple options for utilizing a locking screw, or multiple locking screws, to secure the temporary spacer <NUM> to the adjacent bone. Thus, a surgeon, or other medical professional, can determine prior to the formation of the temporary spacer <NUM>, which, or how many, of the locking bores <NUM> will be designated to receive a locking screw, and therefore utilize the corresponding number of bore plugs <NUM> to fill those designated locking bores <NUM>. Accordingly, those locking bores <NUM> not designated to receive a bore plug <NUM> can be left open and cement material could therefore fill the unused radial bores <NUM>. This could be advantageous in further strengthening the attachment of the cement coating <NUM> to the spacer core <NUM>. Thus, it can be said that a first portion of a the plurality of locking bores <NUM> contain a bore plug <NUM> disposed within them, and a second portion of the locking bores <NUM> are open, or do not contain a bore plug <NUM> disposed within them.

Alternatively, a surgeon or other medical professional may not be able to determine which, or how many, of the locking bores <NUM> they will need to utilize for receiving locking screws until they contemporaneously evaluate the anatomical conditions at the implant site. In such examples, in order to preserve the availability of each of the locking bores <NUM> for locking screws, each of the locking bores <NUM> can be filled with bore plugs <NUM>.

With continuing reference to <FIG>, the mold body <NUM> can include at least one mold bore <NUM> that is configured to receive a bore plug <NUM>. The at least one mold bore <NUM> is also configured to align with at least one of the locking bores <NUM> when the spacer core <NUM> is disposed within the mold body <NUM>. The at least one mold bore <NUM> extends radially with respect to the central axis C through the mold lumen <NUM>. As previously noted, directional modifiers used with respect to the mold body <NUM> are to be understood to be used consistently with respect to the spacer core <NUM> such that the use of the terms "radial" or "radially" or derivations thereof are directions or locations defined with respect to the central axis C and can include radially inward direction towards the central axis C as well as radially outward direction away from the central axis C. In certain examples, the radial direction R is oriented perpendicular to the central axis C and in other examples the radial direction R can be angularly offset from a direction that is perpendicular to the central axis C but is not coaxial or parallel with the central axis C.

The function of the at least one mold bore <NUM> is to allow the at least one bore plug <NUM> to be inserted into the at least one locking bore <NUM> when the spacer core <NUM> is disposed within the mold body <NUM>, and further to permit the removal of the at least one bore plug <NUM> from the at least one locking bore <NUM>, after the formation of the temporary spacer <NUM> (i.e., after the cement material has been injected into the mold body <NUM> and the cement coating <NUM> has been formed) while the temporary spacer <NUM> is still disposed within the mold body <NUM>. One benefit to having the bore plug <NUM> be configured to fit in both the at least one locking bore <NUM> of the spacer core <NUM> and the at least one mold bore <NUM> of the mold body <NUM> is that such a mold assembly <NUM> can act as a self-aligning feature. In other words, when the spacer core <NUM> is disposed within the mold body <NUM>, the mold body <NUM> and the spacer core <NUM> can be considered properly oriented and aligned with respect to each other when the mold bores <NUM> and the locking bores <NUM> of the spacer core <NUM> are in alignment with one another, and are a capable of receiving a bore plug <NUM>, as can be seen, for example in <FIG>. Accordingly, it can be said that in certain examples of the mold assembly <NUM>, the at least one bore plug <NUM> is disposed within and extends through both the at least one locking bore <NUM> and the at least one mold bore <NUM>.

In certain embodiments, the number of mold bores <NUM> is the same as the number of locking bores <NUM>. In alternative embodiments, the number of mold bores <NUM> is less than the number of locking bores <NUM>. As previously described, the spacer core <NUM> can include a number of locking bores <NUM> that will exceed the actual number of locking screws that will be utilized by the surgeon. Thus, in certain embodiments, the mold body <NUM> may be constructed to include a smaller number of mold bores <NUM> than the corresponding number of locking bores <NUM> formed in the spacer core <NUM>. For example, in embodiments where there are a plurality of locking bores <NUM>, there may be certain locking bore <NUM> positions in the spacer core <NUM> that have a higher percentage, or likelihood, of being utilized in a surgical procedure, and certain locking bore <NUM> locations of the spacer core <NUM> with a lower percentage of being used. Therefore, the mold body <NUM> can include, on the one hand, the same exact number of mold bores <NUM> as the locking bores <NUM> of the spacer core <NUM>, or alternatively can have less. The potential benefit to having less is that it can minimize the number of locations where the cement material could potentially leak out from along the mold body <NUM>, which could potentially compromise the integrity of the resulting cement coating <NUM>.

According to certain embodiments, the at least one bore plug <NUM> can comprise a plurality of bore plugs <NUM>, such as , for example, two, three, four, five, six, or even up to eight bore plugs <NUM>. For instance, as shown in <FIG>, there are two radial bore plugs <NUM> configured to fit within each of the two mold bore <NUM> and the corresponding two locking bores <NUM> of the spacer core <NUM>.

With continued reference to <FIG>, as well as <FIG> and 10A-10B, the mold assembly <NUM> can further include an adapter <NUM> configured to operably couple the mold body <NUM> to a cement injection device <NUM> so as to provide a continuous fluid pathway from the cement injection device <NUM> into the mold lumen <NUM> where the spacer core <NUM> is disposed for the cement material to form the cement coating <NUM> on the spacer core <NUM>, and thus form the temporary spacer <NUM>. While the following description of the adapter <NUM> and the accompanying figures describe the adapter <NUM> operably coupled to the distal mold end <NUM> of the mold body <NUM>, it should be appreciated that the adapter <NUM> can be coupled to the proximal mold end <NUM> of the mold body <NUM> as well.

As shown, the adapter <NUM>, when coupled to the distal mold end <NUM>, extends from the mold body <NUM> along the longitudinal direction L such that the adapter <NUM> is aligned with the mold body <NUM> along the central axis C. The adapter <NUM> defines a proximal adapter end <NUM> that is configured to couple to the distal mold end <NUM>, and a distal adapter end <NUM>, opposite the proximal adapter end <NUM> along the central axis C. As shown, the distal adapter end <NUM> is configured to operably couple to the cement injection device <NUM>. Additionally, the adapter <NUM> further defines a distal adapter opening <NUM> at the distal adapter end <NUM>, and an adapter inner wall <NUM> that extends from the distal adapter opening <NUM> towards the proximal adapter end <NUM>. The adapter inner wall <NUM> defines an adapter recess <NUM>. Adapter recess <NUM> provides a continuous fluid pathway from the cement injection device <NUM> into the mold body lumen <NUM>. According to certain embodiments such as shown in <FIG>, the adapter inner wall <NUM> can be threaded such that operably coupling the adapter <NUM> to the cement injection device <NUM> comprises threadingly coupling the adapter <NUM> with the cement injection device <NUM>. Alternatively, such as shown in <FIG>, the adapter <NUM> can include a clamp in order to securely couple cement injection device <NUM> to the distal mold end <NUM>.

With continued to reference to <FIG>, the inner wall <NUM> can further include an adapter receptacle <NUM> disposed within the adapter recess <NUM> and extending proximally towards the mold body <NUM>. The adapter receptacle <NUM> can have a receptacle opening <NUM> facing the proximal adapter end <NUM>. In certain embodiments, the distal rod end <NUM> can be configured to engage with and be disposed within the receptacle opening <NUM>. The function of the receptacle opening <NUM> is, when the distal rod end <NUM> is seated within the receptacle opening <NUM>, to properly center the rod <NUM> within the mold body to better permit the formation of a uniform cement coating <NUM> along the rod outer surface <NUM>. According to certain embodiments, the adapter receptacle <NUM> can have an inner threaded surface and the distal rod end <NUM> can be threadingly engaged in the adapter receptacle <NUM>.

With reference to <FIG>, in certain instances the mold body <NUM> includes separation means extending generally along the central axis C from the proximal mold end <NUM> to the distal mold end <NUM> that are configured to separate the mold body <NUM>. The function of the separation means is to split or otherwise separate the mold body <NUM> so as to provide a way for the temporary spacer <NUM> to be freed from the mold body <NUM> without damage after the cement coating <NUM> has cured.

In certain embodiments, and with reference to <FIG> and <FIG>, the separation means comprises a plurality of perforations <NUM> arranged in a row extending in an axial direction along the mold body <NUM> from the proximal mold end <NUM> towards the distal mold end <NUM>. In certain embodiments, there can be multiple rows of the plurality of perforations <NUM> along the mold body <NUM>, for example, as shown in the embodiment depicted in <FIG>, two separate rows of perforations <NUM> can extend axially along the mold body <NUM> between the proximal mold end <NUM> and the distal mold end <NUM>.

Alternatively, and with reference to <FIG>, separation means can include at least one strip of material <NUM> extending axially and disposed within the mold body <NUM> between the outer mold surface <NUM> and the inner mold surface <NUM>. For examples, as shown in <FIG>, there are two strips of material <NUM> that extend axially between the proximal mold end <NUM> and distal mold end <NUM>.

In a further alternative embodiment, as shown in <FIG>, the mold body <NUM> can include a groove <NUM>, or a plurality of grooves <NUM>, such as two grooves <NUM>, formed in the outer mold surface <NUM>, extending axially along the length of the mold body <NUM> from the proximal mold end <NUM> towards the distal mold end <NUM>. With reference to <FIG>, the mold body <NUM> can additionally include one or more reinforcing members <NUM> disposed within mold body <NUM>, which in combination with the grooves <NUM>, are configured to permit the controlled directed separation of the mold body <NUM> along grooves <NUM>. In other words, the inclusion of the reinforcing members <NUM> in the mold body <NUM> direct the separation of the mold body along the path of the grooves <NUM>, so as to reduce the possibility of the mold body <NUM> tearing in an unintended direction.

With continued reference to <FIG>, the mold body <NUM> can further include one or more tabs <NUM> disposed at either the proximal mold end <NUM> or the distal mold end <NUM>. The one or more tabs <NUM> are configured to be grasped, for example manually or mechanically, and pulled in order to initiate the separation of the mold body <NUM> along the direction of the separation means. For example, a user can grasp the one or more tabs <NUM> and pull, thus applying a force that will cause the separation means to separate the mold body <NUM> along the defined separation means. For example, when the mold body <NUM> includes perforations <NUM>, as shown in <FIG> and<FIG>or groove <NUM>, as shown in <FIG>, pulling the one or more tabs <NUM> will apply a force to the mold body <NUM> along the row of perforations <NUM> or the grooves <NUM> causing the mold body <NUM> to split along the separation means. When the mold body <NUM> includes strips of material <NUM>, as shown in <FIG>, a user can pull the tabs <NUM> causing the strips <NUM> to slice the mold body <NUM> along the line of the strips <NUM>.

As previously described, in certain embodiments, the locking component <NUM> can be offset with respect to the direction of the central axis C by an angle theta, θ. In embodiments where the locking component <NUM> is offset, the proximal mold end <NUM> (where the locking component <NUM> is disposed in the mold assembly <NUM>) can be likewise offset from the central axis C by the same angle theta θ (see. e.g. <FIG>).

According to the present disclosure, a kit for forming the temporary cement spacer <NUM> is disclosed. The kit can include a mold body <NUM>, at least one adapter <NUM>, a locking component <NUM>, at least one bore plug <NUM>, at least one rod <NUM>, and a cap <NUM>. It should be appreciated that each of the disclosed components can be provided in the kit as a separate component. Alternatively, each of the disclosed kit components can be provided in the kit already connected with a corresponding component or multiple components in a manner consistent with what has been previously described. For example, the rod <NUM>, the locking component <NUM>, and the cap <NUM> have already been described as elements of the spacer core <NUM> configured to be connected. As such, any combination of the these three components can be provided in the kit already connected, such that the kit can be provided including the rod <NUM> connected to the locking component <NUM>, the rod <NUM> connected to the cap <NUM>, or the rod <NUM> connected to both the locking component <NUM> and the cap <NUM>. As another example, the kit can be provided with a separate mold body <NUM> and adapter <NUM>, or alternatively, the adapter <NUM> can be provided connected to the mold body <NUM>.

In certain examples, the kit can be provided where the at least one rod <NUM> can include a plurality of rods <NUM>, such as, for example, two, three, four, five, six, seven, eight, nine, or ten rods <NUM>. In a preferred embodiment, each rod <NUM> of the plurality of rods <NUM> has a length, measured between the proximal rod end and the distal rod end, and each rod length of the plurality of rods <NUM> is different than any other rod length of the plurality of rods <NUM>. In other words, the kit is provided with multiple rods <NUM> of differing lengths. As previously disclosed, in one respect, the temporary spacers <NUM> of the present disclosure are configured to be modular with respect to their length and the ability of the surgeon to determine and customize the spacer core <NUM> length. Thus, by providing a plurality of rods <NUM>, where each of the rods <NUM> has a different length, a surgeon is able to customize the spacer core <NUM> to have the desired length that most closely approximates the patient's anatomical dimensions.

Alternatively, as previously described, the rod <NUM> can include an outer surface <NUM> that comprises a substantially, or even entirely, threaded surface <NUM>. In such instances, the kit can include a single rod <NUM> that includes a continuously threaded surface <NUM> and a surgeon can determine the appropriate length for the rod <NUM> and cut the rod <NUM> to the desired length.

The kit can further include at least one locking bone screw, for example the kit can include a plurality of locking screws, such as two, three, four, five, six, seven, or eight locking screws that are configured to be disposed in the locking bore <NUM> and secure the temporary spacer <NUM> to bone.

With reference to <FIG>, the kit can include an insertion instrument <NUM> configured to operably couple to the locking component <NUM>. As shown in <FIG>, insertion instrument <NUM> is operably coupled to the proximal locking end <NUM> through the placement of insertion screw <NUM> into proximal locking recess <NUM>.

The present disclosure additionally describes a method of forming an antimicrobial eluting temporary cement spacer. The method can include the steps of:.

The method can further include, prior to the step of inserting the spacer core <NUM> into the mold lumen <NUM>, connecting the rod <NUM> to the locking component <NUM>, such as for example, operably coupling the proximal rod end <NUM> to the distal locking end <NUM> as previously described.

As previously described the rod <NUM> has a rod length, and the method can further include, removing a portion of the length of the rod <NUM> from either the proximal rod end <NUM> or the distal rod end <NUM>. In a preferred embodiment, after the step of removal, the length of the spacer core <NUM> is less than or equal to a length of the mold body <NUM>. Additionally, and as previously described, the mold body <NUM> has a length, and the method can further include removing a portion of the length of the mold body <NUM> from either the proximal mold end <NUM> or the distal mold end <NUM>.

According to additional embodiments, the mold body <NUM> comprises at least one mold bore <NUM>, and the step of inserting the spacer core <NUM> into the mold lumen <NUM> can further include aligning the at least one mold bore <NUM> with the at least one locking bore <NUM>. Additionally, the step of disposing at least one bore plug <NUM> into the at least one locking bore <NUM> can further include disposing the at least one bore plug <NUM> into the at least one mold bore <NUM> and the at least one locking bore <NUM>. In certain further embodiments, where the at least one locking bore <NUM> includes a plurality of locking bores <NUM>, the method includes disposing a plurality of bore plugs <NUM> into each locking bore <NUM> of the plurality of locking bores <NUM>. Alternatively, where the at least one locking bore <NUM> includes a plurality of locking bores, the method can include inserting at least one bore plug <NUM> into the plurality of locking bores <NUM> such that at least one locking bore <NUM> of the plurality of locking bores <NUM> does not receive a bore plug <NUM>. In embodiments where at least one locking bore <NUM> does not receive a bore plug <NUM>, the step of injecting the bone cement material can include filling the at least one locking bore <NUM> that did not receive a bore plug <NUM> with the bone cement material. In still further embodiments, where the at least one mold body bore <NUM> includes a plurality of mold bores <NUM>, the method includes disposing the plurality of bore plugs <NUM> into each mold bore <NUM> of the plurality of mold bores <NUM>.

As previously described, according to the invention, the cap <NUM> is configured to be attached to the distal rod end <NUM> such that in such instances the spacer core <NUM> can be said to include the rod <NUM>, the locking component <NUM>, and the cap <NUM>. As such, the methods further include the step of attaching a cap <NUM> to a distal rod end <NUM> of the rod <NUM>. Further, as described, where the distal rod end <NUM> includes a threaded surface <NUM>, the step can include threading the cap <NUM> onto the threaded surface <NUM> of the distal rod end <NUM>. As previously described, the cap <NUM> includes a plurality of fenestrations <NUM> extending through the cap <NUM>. As such, the step of attaching the cap <NUM> to the rod <NUM> can occur at any time prior to the step of injecting the bone cement material, as well as, after the step of decoupling the bone cement injection <NUM> device from the mold body <NUM>. Thus, the step of injecting bone cement material includes injecting bone cement material through the fenestrations <NUM>.

Referring now to <FIG>, an additional embodiment of a mold assembly <NUM> for forming a temporary cement spacer <NUM> is described. The mold assembly <NUM> includes a mold body <NUM> and a temporary spacer core <NUM> configured to be disposed within the mold body <NUM>. The spacer core <NUM> is configured to provide the structural framework of the temporary spacer <NUM>, and includes a rod <NUM>, a locking component <NUM>, and a cap <NUM>. The mold assembly includes at least one bore plug <NUM> configured to be disposed within the at least one locking bore <NUM> of a locking component <NUM>. The mold assembly <NUM> also includes an adapter <NUM> configured to operably couple the mold body <NUM> to a bone cement injection device that will fill the mold body <NUM> with the cement material that forms a cement coating <NUM> of the spacer core <NUM>. The mold assembly <NUM> can also include a proximal plug member <NUM> configured to couple with the proximal end of the locking component.

For purposes of discussion regarding the mold assembly <NUM>, and in the interest of brevity, all of the features and embodiments, combinations and sub-combinations, described above with respect to the spacer core <NUM> (e.g., rod <NUM>, locking component <NUM>, cap <NUM>, etc.) are considered to be within the scope of disclosure regarding the mold assembly <NUM>, as well as any subsequent disclosure directed to kits, and methods of manufacture. The following disclosure will focus on differences between the mold assembly <NUM>, and components thereof, relative to the mold assemblies and components described above with reference to <FIG>.

The rod <NUM> is configured similar to the rod <NUM> described above. The rod <NUM> defines a proximal rod end <NUM>, a distal rod end <NUM> opposite the proximal rod end <NUM> along the central axis C, and an outer rod surface <NUM> extending from the proximal rod end <NUM> to the distal rod end <NUM>. The proximal rod end <NUM> is configured to attach to the locking component <NUM>. For example, a portion of the outer rod surface <NUM> at the proximal rod end <NUM> can define a locking feature, such as a threaded surface <NUM>, that can lock with a complimentary locking feature, such as an inner distal locking surface <NUM>, of the locking component <NUM>. The distal rod end <NUM> is configured to attach to the cap <NUM>. For example, a portion of the outer rod surface <NUM> at the distal rod end <NUM> can define a locking feature, such as a threaded surface <NUM>, that can lock with a complimentary locking feature, such as a threaded inn cap surface <NUM>, of the cap <NUM>. In the present embodiment, the rod outer surface <NUM> is preferably smooth and devoid of protrusions between the threaded surfaces <NUM> at the proximal and distal rod ends <NUM>, <NUM>. For example, the rod outer surface <NUM> of the present embodiment can be devoid of centering members, such as the centering members <NUM> described above.

Referring now to <FIG>, the locking component <NUM> is configured similar to the locking components <NUM> described above. Accordingly, the locking component <NUM> can include the various associated features described above, including, for example, the proximal locking end <NUM>, proximal locking opening <NUM>, proximal locking inner surface <NUM>, proximal locking recess <NUM>, distal locking end <NUM>, distal locking opening <NUM>, inner distal locking surface <NUM>, distal locking recess <NUM>, outer locking surface <NUM>, one or more locking bores <NUM>, and offset angle θ.

One difference in the present embodiment, however, is that the outer locking surface <NUM> can define one or more projections <NUM>, which can define radially outward portions of the one or more locking bores <NUM>. The one or more projections <NUM> can also be referred to as "bosses" or "islands," and can each define an outer projection surface <NUM> that is spaced outward from a main recessed surface portion <NUM> of the outer locking surface <NUM> by a distance R1 measured along the radial direction R. The one or more projections <NUM> can beneficially increase the gap or void volume between the mold body <NUM> and the locking component <NUM> when the spacer core <NUM> is disposed within the mold body <NUM>. This increased gap or void volume provides additional space along the outer locking surface <NUM> to receive and be occupied by cement material injected into the mold body <NUM> for forming the cement coating <NUM>.

In the illustrated embodiment, the one or more projections <NUM> can include a first pair of radially opposed projections 49a along at least a first locking bore 55a and a second pair of radially opposed projections 49b along at least a second locking bore 55b. It should be appreciated that each projection <NUM> can extend along a single locking bore <NUM> or along a plurality of locking bores <NUM>. Additionally or alternatively, the one or more projections <NUM> can extend along other features, such as along the proximal locking end <NUM>. For example, the one or more projections <NUM> can include a proximal mounting projection 49c configured to couple with a complimentary geometry of an instrument, such as the insertion instrument <NUM>. The proximal mounting projection 49c can define one or more surface channels <NUM>, which can be configured to vent gas (e.g., air) as the cement <NUM> progresses through the mold. The one or more surface channels <NUM> can also beneficially provide a visual indication of when the mold has been filled (or at least substantially filled) with cement <NUM>, and can additionally provide a simplified "clean up" feature through which excess cement <NUM> can be extruded and discarded from the mold. As shown, the proximal mounting projection 49c can define a single surface channel <NUM> that has a dovetail cross-sectional profile, which can be configured to retain the cement <NUM> therein after curing. Alternatively, the surface channel <NUM> can have other profile shapes, such as a U-shaped cross-sectional profile or a V-shaped cross-sectional profile, by way of non-limiting examples. It should be appreciated that the proximal locking end <NUM> is preferably configured to selectively mount to a plurality of instruments, such as various insertion instruments <NUM> (e.g., various aiming arms and the like). In this manner, the spacer core <NUM> can be mountable to various types of surgical instruments based on patient needs.

The one or more projections <NUM> can also define retention structures for interfacing with the injected cement after hardening for enhancing stability of the interface between the cement coating <NUM> and the locking component <NUM>. Such retention structures can include inwardly tapered surfaces or "notches" along one or more various sides and/or ends of the projection <NUM>. For example, one or both of the first pair of radially opposed projections 49a can include tapered side surfaces <NUM> that taper inwardly towards each other as they extend radially inward toward the central axis C. Additionally or alternatively, one or both of the second pair of radially opposed projections 49b can include tapered side surfaces <NUM> that taper inwardly towards each other as they extend radially inward toward the central axis C. These tapered side surfaces <NUM> can also define channels which, similar to the channels <NUM> described above, can receive portions of the cement coating <NUM> and provide shielding from the mechanical forces that occur during implantation and explantation. Additionally, the tapered side surfaces <NUM>, <NUM> can cause the respective outer projection surfaces <NUM> to radially overhang respective portions of the main recessed surface portion <NUM>, which can facilitate retention of the cement coating <NUM> along the locking component <NUM>, particularly during exposure to forces acting on the cement coating <NUM> during implantation or explantation (e.g. torsion) that could cause fracture or delamination of the cement coating <NUM> from the locking component <NUM>. It should be appreciated that other retention structure geometries can be employed along the one or more projections <NUM>.

As shown in <FIG>, the proximal plug member <NUM> can be configured to temporarily couple with the proximal locking inner surface <NUM> of the locking component <NUM>. The proximal plug member <NUM> can include a distal insertion portion <NUM> for insertion within the proximal locking recess <NUM>. Preferably, the distal insertion portion <NUM> is externally threaded for threadingly engaging the internal threads of the proximal locking inner surface <NUM>. In this manner, the proximal plug member <NUM> can occlude and prevent flow of cement <NUM> into the proximal locking opening <NUM> during the cement injection process. Accordingly, the proximal plug member <NUM> can also be referred to as a "thread protector" for the proximal locking end <NUM> of the locking component <NUM>.

Referring now to <FIG>, the cap <NUM> is configured similar to the caps <NUM> described above. Accordingly, the cap <NUM> can include the various associated features described above, including, for example, the proximal cap end <NUM>, proximal cap opening <NUM>, inner cap surface <NUM>, cap recess <NUM>, distal cap end <NUM>, and outer cap surface <NUM>. In the present embodiment, however, instead of fenestrations <NUM>, the cap <NUM> can include a distal cap opening <NUM>, which is preferably centrally arranged with respect to the central axis C. The distal cap end <NUM> is defined by a distal cap portion <NUM> that is connected to a proximal hub portion <NUM> by a plurality of arms <NUM>, which are circumferentially spaced from each other about the central axis C. In this manner, the cap <NUM> defines openings or channels <NUM> that are located circumferentially between the arms <NUM> and are in fluid communication with the distal cap opening <NUM> so as to facilitate the flow of cement <NUM> therethrough. One advantage of a cap <NUM> configured in this manner is that the channels <NUM> can be wider and can present less contact surface area along the cap <NUM> body than fenestrations, such as the fenestrations <NUM> described above, and can thus provide less resistance to the cement <NUM> during injection thereof. The proximal hub portion <NUM> can define the proximal cap end <NUM>, the cap opening <NUM>, the inner cap surface <NUM>, and the cap recess <NUM>, which can be configured as described above.

As shown, the cap <NUM> can have three (<NUM>) arms, which are preferably evenly spaced from each other circumferentially (i.e., at <NUM> degree intervals) about the central axis C. It should be appreciated that in other embodiments the cap <NUM> can have one (<NUM>), two (<NUM>), four (<NUM>), five (<NUM>), or more than five arms <NUM>, which can be evenly or unevenly spaced from each other. As shown, the arms <NUM> preferably define distal surfaces <NUM> that taper to leading edges <NUM> for reducing resistance (e.g., drag) to cement <NUM> being injected through the distal cap opening <NUM>. The leading edges <NUM> of the arms <NUM> can also taper radially inwardly and distally from the distal cap portion <NUM> to the proximal hub portion <NUM>. A distal surface <NUM> of the proximal hub portion <NUM> can be rounded or otherwise configured to facilitate flow of cement <NUM> through the cap <NUM>.

The cap <NUM> can define a maximum cap cross-sectional area that is similar to the maximum cross-sectional area of the temporary spacer <NUM>. For example, the maximum cap cross-sectional area can be in a range of <NUM> percent to <NUM> percent of the maximum cross-sectional area of the temporary spacer <NUM>, or more particularly in a range of <NUM> percent to <NUM> percent of the maximum cross-sectional area of the temporary spacer <NUM>, or preferably in a range of about <NUM> percent to about <NUM> percent of the maximum cross-sectional area of the temporary spacer <NUM>. It should be appreciated that for the foregoing example ranges, the maximum cross-sectional area of the temporary spacer <NUM> can be defined by the locking component <NUM>.

Referring now to Figs. 15A-15C, the mold body <NUM> is configured similar to the mold bodies <NUM> described above for forming a temporary spacer <NUM>. Accordingly, the mold body <NUM> can include the various associated features described above, including, for example, the proximal mold end <NUM>, proximal mold opening <NUM>, outer mold surface <NUM>, distal mold end <NUM>, distal mold opening <NUM>, mold lumen <NUM>, mold inner surface <NUM>, and one or more mold bores <NUM>, for example. Similar to the mold body <NUM> described above, the mold body <NUM> of the present embodiment is configured to have its length customizable to match the desired length of the spacer core <NUM>. Accordingly, the mold body <NUM> preferably includes visual indicia, such as a series of markings <NUM> spaced at intervals corresponding to specific lengths (e.g., <NUM>-mm intervals) to provide a visual aid for determining the desired length. The markings <NUM> can be drawn, painted, etched, anodized, and/or scored on the mold outer surface <NUM>. Preferably, the mold body <NUM> is also formed of a material that is translucent or at least semi-translucent, thereby allowing a surgeon or other qualified medical professional to view the spacer core <NUM> and/or cement disposed inside the mold body <NUM> during the formation process. It should be appreciated that, based on the length of the selected rod <NUM>, the distal cap end <NUM> preferably substantially aligns with one of the markings <NUM> when the spacer core <NUM> is placed alongside the mold body <NUM>. Thus, the surgeon can visually reference the distal cap end <NUM> alongside the mold body <NUM> to identify the desired customized length of the mold body <NUM>. Moreover, the surgeon can optionally designate one of the visual markings as the desired location to cut the mold body <NUM>. The mold body <NUM> preferably defines weakened portions, such as scoring, along the markings <NUM> to facilitate or otherwise direct the cut to occur at the select marking <NUM>.

Referring now to <FIG>, the mold body <NUM> is configured to be cut to the desired length using a cutting device, such as a multi-function cutting device or "cutter" <NUM> of the mold assembly <NUM>. It should be appreciated that the mold body <NUM> is also configured to facilitate being cut to the desired length using other cutting devices, such as surgical scissors or a scalpel, by way of non-limiting examples. The multi-function cutter <NUM> of the present embodiment includes a first support member <NUM> that has a guide formation <NUM> for removably coupling with the mold body <NUM> for multi-function cutting (e.g., selective multi-directional cutting), as described in more detail below. The cutter <NUM> includes a second support member <NUM> that carries a cutting member, such as a blade <NUM>, and is pivotably connected to the first support member <NUM> via a hinge structure <NUM>. In the present embodiment, the hinge structure <NUM> is a compliant (i.e., flexible) member, which can be defined by a plurality of voids or apertures configured to induce bending along the hinge structure <NUM>. The hinge structure <NUM> can be monolithic with both the first and second support members <NUM>, <NUM>, as shown.

The guide formation <NUM> can be configured to multi-directional cutting by defining first and second mounting formations for performing first and second respective cuts along first and second respective cutting directions. For example, the first mounting formation can be a first pair of slots <NUM> aligned along a first guide axis X1, which is configured to be substantially coaxial with the central axis C when the mold body <NUM> extends through the first pair of slots <NUM>, thereby aligning the blade <NUM> (and thus the first cutting direction) along a transverse direction T that is substantially perpendicular to the longitudinal direction L. In this manner, the mold body <NUM> can be inserted through the first pair of slots <NUM> for cutting the mold body <NUM> to the desired length. The guide formation <NUM> can also include a reference formation, such as one or more visualization projections <NUM> defining a gap therebetween, which can be configured for providing the surgeon with a visual reference of the cutting path of the blade <NUM>. In this manner, when performing the length-determining cut of the mold body <NUM>, the surgeon can use the reference formation <NUM> to align the cutting path with the desired marking <NUM>. The second mounting formation can be a second pair of slots <NUM> aligned along a second guide axis X2, which is configured to be substantially coaxial with the central axis C when the mold body <NUM> extends through the second pair of slots <NUM>, thereby aligning the blade <NUM> (and thus the second cutting direction) along the longitudinal direction L. In this manner, the mold body <NUM> can be inserted through the second pair of slots <NUM> for cutting (e.g., slicing) the mold body <NUM> longitudinally along its length to decouple the mold body <NUM> from the temporary spacer <NUM> after the cement coating <NUM> has cured.

Referring now to <FIG>, in another example of the cutter <NUM>, the hinge structure <NUM> can employ a pivot pin <NUM> that pivotably joins the first and second support members <NUM>, <NUM>. In this example, proximal ends <NUM> of the first and second support members <NUM>, <NUM> can be pressed toward each other about the pivot pin <NUM>, which acts as a fulcrum, to open the cutter <NUM> for insertion of the mold body <NUM> through one of the first or second pairs of slots <NUM>, <NUM>. The cutter <NUM> of this example can otherwise be configured similarly to the cutter <NUM> described above with reference to <FIG>.

Referring now to <FIG>, the adapter <NUM> is configured generally similar to the adapters <NUM> described above for operably coupling the mold body <NUM> to a component of a cement injection device <NUM>, such as an injection tube <NUM> of an injection syringe <NUM>. Accordingly, the adapter <NUM> includes various features of the adapters described above, including a proximal adapter end <NUM> that is configured to couple to the distal mold end <NUM>, and a distal adapter end <NUM>, opposite the proximal adapter end <NUM> along the central axis C. As described above, the distal adapter end <NUM> is configured to operably couple to the injection tube <NUM>. Additionally, the adapter <NUM> further defines a proximal adapter opening <NUM> at the proximal adapter end <NUM>, a distal adapter opening <NUM> at the distal adapter end <NUM>, and an adapter inner wall <NUM> that extends from the proximal adapter opening <NUM> to the distal adapter opening <NUM>. The adapter inner wall <NUM> defines an adapter lumen <NUM> that provides a continuous fluid pathway from the injection tube <NUM> into the mold body lumen <NUM>. The adapter <NUM> also defines an adapter outer surface <NUM>, which can define a mounting formation, such as an exterior recess <NUM>, which can extend annularly around a circumference or a partial circumference of the adapter <NUM>.

In the present example, as shown in <FIG>, the adapter <NUM> can include one or more internal retention features, such as first and second retention features <NUM>, <NUM>, that are configured to securely grip the mold body <NUM> and the cement injection device <NUM>, respectively, when they are fully inserted or "seated" within the adapter lumen <NUM>. For example, the first and second retention features <NUM>, <NUM> can each be an annular retention ring having a plurality of fingers or teeth <NUM> extending radially inwardly toward the central axis C. The retention rings <NUM>, <NUM> can reside within respective annular recesses <NUM> within the adapter inner wall <NUM>. The teeth <NUM> can have geometries configured to non-destructively grip the respective outer surfaces of the mold body <NUM> and the injection tube <NUM>. For example, the teeth <NUM> can be formed of a flexible material, which can grip the mold body <NUM> and the injection tube <NUM>, respectively, with sufficient retention force to "hold" the mold body <NUM> and injection tube <NUM> is position with the adapter lumen <NUM> during the cement injection process, but also such that the mold body <NUM> and injection tube <NUM> can be subsequently non-destructively decoupled from the teeth <NUM>.

Preferably, the adapter <NUM> also includes one or more release members, such as a first release member <NUM> for releasing the mold body <NUM> from the adapter <NUM> and a second release member <NUM> for releasing the injection tube <NUM> from the adapter <NUM>. One or both of the first and second release members <NUM>, <NUM> can include a tubular insertion body <NUM> and an actuator, such as an actuation flange <NUM> extending radially outwardly from the tubular insertion body <NUM>. The first and second release members <NUM>, <NUM> are shown in <FIG> in respective neutral positions. The release member <NUM>, <NUM> can be selectively actuated to a release position by pressing the respective actuation flange <NUM> in a manner forcing the tubular insertion body <NUM> further into the adapter lumen <NUM>, causing an inner end <NUM> of the tubular insertion body <NUM> to press against the teeth <NUM> of the respective retention ring <NUM>, <NUM>. In this manner, when in the release position, the tubular insertion body <NUM> can deflect the teeth <NUM> out of engagement with the mold body <NUM> or injection tube <NUM>, respectively, thereby allowing the surgeon to retract the respective mold body <NUM> or injection tube <NUM> from the adapter <NUM> as needed.

Preferably, the tubular insertion bodies <NUM> define interior surfaces <NUM> that define respective lumens <NUM> that are sized to snugly receive one but not both of the mold body <NUM> and the injection tube <NUM>. For example, the interior surface <NUM> of the first release member <NUM> can define an inner diameter D1 that is substantially equivalent to an outer diameter of the distal mold end <NUM>, so that the distal mold end <NUM> can be snugly received within the lumen <NUM> of the first release member <NUM>. The foregoing diameters can be greater than an inner diameter D2 of the interior surface <NUM> of the second release member <NUM>, which can in turn be substantially equivalent to an outer diameter of the injection tube <NUM>, so that the injection tube <NUM> can be snugly received within the lumen <NUM> of the second release member <NUM>. In this manner, the distal mold end <NUM> would not fit within the lumen <NUM> of the second release member <NUM>, thus ensuring that the distal mold end <NUM> gets inserted within the proper end of the adapter <NUM> (i.e., the proximal adapter end <NUM>). Thus, once the distal mold end <NUM> is inserted within the adapter <NUM>, the injection tube <NUM> can only be inserted within its associated end of the adapter <NUM> (i.e., the distal adapter end <NUM>). It should be appreciated that, in other examples, the injection tube <NUM> can have an outer diameter that is greater than that of the distal mold end <NUM>. In yet other examples, the injection tube <NUM> and the distal mold end <NUM> can have substantially equivalent outer diameters D1, D2, and each can fit snugly in the lumens <NUM> of both release members <NUM>, <NUM>.

It should be appreciated that the distal adapter end <NUM> is preferably configured to couple with standard-type injection syringes, which provides significant benefits, such as the ability to use adapter <NUM> for injection with a large number of various injection devices that employ such standard-type injection syringes.

Referring now to <FIG>, the mold assembly <NUM> can include a grip or "handle" member <NUM>, such as for use with the adapter <NUM> to provide the surgeon with a grip support during the cement injection process. The handle member <NUM> can include a central mount <NUM> and a pair of extensions <NUM> extending oppositely therefrom along the transverse direction T. The central mount <NUM> can define a slot <NUM> for engaging a complimentary structure of the adapter <NUM>, such as the exterior recess <NUM>. The extensions <NUM> can include grip formations <NUM>, such as scallops configured to provide finger holds, which can provide gripping support for the surgeon's fingers to effectively grasp the adapter <NUM> during the cement injection process.

Referring now to <FIG>, the mold assembly <NUM> can include a shaping tool <NUM> for cleaning excess cement <NUM> from the distal end of the temporary spacer core <NUM>. The shaping tool <NUM> has a proximal end <NUM>, an opposed distal end <NUM> spaced from proximal end <NUM> along the longitudinal direction L, and a grip portion <NUM> that extends from the distal end <NUM> toward the proximal end <NUM>. The grip portion <NUM> preferably defines grip features <NUM>, such as recesses, knurls, and the like, to facilitate manipulation by the surgeon. The shaping tool <NUM> includes a cleaning formation <NUM> at the proximal end <NUM>. As shown in <FIG>, the cleaning formation <NUM> is configured for insertion within the mold lumen <NUM> at the distal mold end <NUM> to engage the distal cap end <NUM>. The cleaning formation <NUM> defines an engagement surface <NUM>, which preferably has a concave geometry that is complimentary with the geometry of the distal end <NUM> of the cap <NUM>. The cleaning formation <NUM> also defines a plurality of channels <NUM> for conveying the excess cement away from the cap <NUM>. The channels <NUM> can extend along spiral-like paths and can be in fluid communication with a tool lumen <NUM> that extends from the cleaning formation <NUM> to the distal end <NUM>. The channels <NUM> are preferably configured to receive and contain excess cement <NUM> dislodged from the cap <NUM>, and preferably also to direct excess cement <NUM> inwardly into the tool lumen <NUM> for containment. It should be appreciated that although the channels <NUM> can direct some of the excess cement through the lumen <NUM> and out the distal end <NUM>, such conveyance out the distal end <NUM> need not be necessary for the shaping tool <NUM> to sufficiently clean excess cement from the cap <NUM>.

Referring now to <FIG>, the mold assembly <NUM> can be provided in a kit <NUM> for forming the temporary cement spacer <NUM>. The kit <NUM> of the present embodiment can include a mold body <NUM>, at least one adapter <NUM>, a locking component <NUM>, at least one bore plug <NUM>, at least one rod <NUM>, and a cap <NUM>. It should be appreciated that various combinations of the foregoing components can optionally be provided in the kit <NUM> already connected, as described above. In some embodiments of the kit <NUM>, the at least one rod <NUM> can include a plurality of rods <NUM>, such as, for example, two (<NUM>), three (<NUM>), four (<NUM>), five (<NUM>), six (<NUM>), seven (<NUM>), eight (<NUM>), nine (<NUM>), ten (<NUM>), or more than ten rods <NUM>. In a preferred embodiment, each rod <NUM> of the plurality of rods <NUM> has a length that differs from those of each other rod <NUM>. Thus, the kit <NUM> allows the surgeon or other medical professional to select the rod <NUM> having the desired rod length for use forming the temporary spacer <NUM> having a desired spacer length, thereby allowing the surgeon to customize the spacer core <NUM> based on patient-specific anatomy.

It should be appreciated that the kit <NUM> can be a single-use kit that contains an entire system for forming the temporary spacer <NUM>. In such embodiments, the kit <NUM> can include a cement injection device <NUM>, a cement mixing device, and one or more pre-packaged quantities of cement material. The single-use kit <NUM> of such embodiments can also include components for implanting the formed temporary spacer <NUM> in patient anatomy. For example, the kit <NUM> can include an insertion instrument <NUM> and accompanying insertion screw <NUM> for coupling to the proximal end of the locking component <NUM>. The kit <NUM> can further include at least one locking bone screw, such as a plurality of locking screws, such as two (<NUM>), three (<NUM>), four (<NUM>), five (<NUM>), six (<NUM>), seven (<NUM>), eight (<NUM>), or more than eight locking screws that are configured to be disposed respectively in the locking bores <NUM> and secure the temporary spacer <NUM> to bone.

The kit <NUM> can be employed in a method of performing a surgical revision procedure, such as for removing and temporarily replacing an implant. The procedure can include a method of forming or otherwise constructing an antimicrobial-eluting temporary cement spacer <NUM>. One example of such a method for constructing the temporary spacer includes a step of selecting a rod <NUM> having a desired length from the plurality of rods <NUM> in the kit <NUM>, such as from a plurality of seven (<NUM>) rods <NUM> having respective lengths of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, by way of non-limiting examples. The surgeon can assemble the spacer core <NUM> by coupling the proximal rod end <NUM> of the selected rod <NUM> to the locking component <NUM> and the distal rod end <NUM> to the cap <NUM>, in the manners described above. The desired length mold body <NUM> can be determined, such as by placing the assembled spacer core <NUM> alongside the mold body <NUM>, and identifying the marking <NUM> on the mold body <NUM> that aligns with the distal cap end <NUM>. The surgeon can prepare the mold body <NUM> for cutting at the respective marking <NUM> by inserting the mold body <NUM> into the first pair of slots <NUM> of the cutter <NUM> so that the reference formation <NUM> aligns with the respective marking <NUM>, after which the blade <NUM> can be employed to cut the mold body <NUM> at the marking <NUM>. The cutter <NUM> can then be removed from the mold body <NUM>.

The surgeon can subsequently begin assembling the mold, such as by inserting the assembled spacer core <NUM> through the proximal mold opening <NUM> and into the lumen <NUM>. The surgeon can align the locking bores <NUM> of the locking component <NUM> with the associated mold bores <NUM> in the mold body <NUM> and insert one or more of the bore plugs <NUM> through the respective one or more mold bores <NUM> and respective one or more locking bores <NUM>. It should be appreciated that each bore plug <NUM> can ensure the proper orientation of the spacer core <NUM> in the mold body <NUM> and can also prevent the spacer core <NUM> from moving relative to the mold body <NUM> responsive to the pressure generated while injecting the bone cement into the mold body <NUM>. The adapter <NUM> can be coupled to the mold body <NUM>. In particular, the distal mold end <NUM> can be inserted within the proximal adapter opening <NUM> until fully seated within the adapter lumen <NUM>. At this stage, the mold can be characterized as being fully constructed, or at least substantially fully constructed. The constructed mold can be set aside while the bone cement is mixed and ready for injecting into the mold.

To facilitate cement injection, the injection tube <NUM> of the injection device <NUM> can be inserted within the distal adapter opening <NUM> until fully seated within the adapter lumen <NUM> and in fluid communication with the mold lumen <NUM>. Preferably, as soon as the cement is mixed, the injection device <NUM> is employed to inject the mixed cement through the injection tube <NUM> and into the mold, specifically, through the distal cap opening <NUM> and along the channels <NUM> and into the annular space between the rod outer surface <NUM> and the inner mold surface <NUM>, preferably at a constant rate. During injection, the surgeon preferably observes the cement advancing through the mold through the translucent mold body <NUM>. Injection is continued so that the cement is forced along the main recessed surface portion <NUM> of the locking component <NUM> and around the one or more projections <NUM> thereof. Preferably, injection continues at least until the cement reaches the channel <NUM> at the proximal end of the locking component <NUM>. If necessary, the proximal plug member <NUM> can be inserted within the proximal locking inner surface <NUM> to prevent the threads therein from contact with the cement.

After the mold is filled, the mold body <NUM> can be removed from the adapter <NUM>, which can be facilitated by depressing the first release member <NUM> in the manner described above. Once removed, the adapter <NUM> and the injection device <NUM> can be discarded. After the adapter <NUM> is removed from the mold body <NUM>, the shaping tool <NUM> employed to remove excess cement from the distal cap end <NUM>. In particular, the cleaning formation <NUM> can be inserted within the mold lumen <NUM> so that the engagement surface <NUM> engages the distal cap end <NUM>, as described above. The surgeon can rotate the shaping tool <NUM> about the central axis C to remove the excess cement. It should be appreciated that the cleaning step can be repeated several times as the cement cures, and may necessarily be repeated until the cement reaches a doughy state in the curing process. Preferably, the distal cap end <NUM> will be visible at the conclusion of the cleaning step. The fully assembled, injected mold can be set aside until the bone cement has fully cured.

After the cement has cured, the surgeon can remove the one or more bore plugs <NUM> and the proximal plug member <NUM> in preparation for removing the mold body <NUM> from the spacer core <NUM>. For removal, the mold body <NUM> can be inserted within the second pair of slots <NUM> of the cutter <NUM>, and the blade <NUM> can be employed to cut a first longitudinal slit along the length of the mold body <NUM>. After the first longitudinal slit is cut, the mold body <NUM> can be rotated about the central axis C relative to the cutter <NUM>, such as by <NUM> degrees about the axis C, and a second longitudinal slit can be cut along the length of the mold body <NUM> in similar fashion. After the first and second full-length slits are cut, the surgeon can grip the opposite portions of the cut mold body and separate the mold body from the spacer core <NUM>. The temporary spacer <NUM> formed according to the foregoing steps is shown in <FIG>. The surgeon can then prepare the temporary spacer <NUM> for implantation, such as be coupling the temporary spacer <NUM> to an insertion instrument <NUM>, as described above.

It should be appreciated that the various features of the temporary spacers <NUM>, mold assemblies, and components thereof that are described above are provided as exemplary features of a surgical system. These features can be adjusted as needed without departing from the scope of the present disclosure.

It should further be appreciated when a numerical preposition (e.g., "first", "second", "third") is used herein with reference to an element, component, dimension, or a feature thereof (e.g., "first" member, "second" member, etc.), such numerical preposition is used to distinguish said element, component, dimension, and/or feature from another such element, component, dimension and/or feature, and is not to be limited to the specific numerical preposition used in that instance. For example, a "first" member can also be referred to as a "second" member in a different context without departing from the scope of the present disclosure, so long as said members remain properly distinguished in the context in which the numerical prepositions are used.

Claim 1:
A temporary cement spacer (<NUM>), comprising:
a spacer core (<NUM>) including:
a rod (<NUM>) defining a central axis (C) of the spacer core and having a proximal rod end (<NUM>) and a distal rod end (<NUM>) opposite the proximal rod end along the central axis, the rod further defining an outer rod surface (<NUM>) extending between the proximal rod end and the distal rod end;
a locking component (<NUM>) defining a distal locking end (<NUM>) and a proximal locking end (<NUM>) opposite the distal locking end along the central axis, the distal locking end attached to the rod at the proximal rod end (<NUM>), the locking component (<NUM>) further defining at least one locking bore (<NUM>) extending through the locking component in a radial direction (R) with respect to the central axis, the at least one locking bore configured to receive a locking screw; and,
a cap (<NUM>) defining a proximal cap end (<NUM>) and a distal cap end (<NUM>) opposite the proximal cap end along the central axis, the proximal cap end attached to the distal rod end (<NUM>); and,
a cement coating (<NUM>) surrounding at least a portion of the outer rod surface, the cement coating comprising a mixture of a cement material and one or more antimicrobial agents;
wherein the cap (<NUM>) is configured to define the leading end of the temporary spacer during implantation, characterised in that
the cap (<NUM>) includes a plurality of fenestrations (<NUM>) which extend through the cap (<NUM>) from the distal cap end (<NUM>) to the proximal cap end (<NUM>).