CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 63/357,642, filed on July 1, 2022 and titled MEDICAL SCREW IMPLANTS FOR GENERATING FUSION BETWEEN TWO BONES, the entire disclosure of which is hereby incorporated herein by reference in its entirety for all purposes.

FIELD OF THE INVENTION

The present invention relates to screw-based devices for generating fusion between two or more bones to promote healing. The invention finds particular utility in the ability to reduce a gap between two or more bones, generate a compressive force between the bones, and promote fusion between said two or more bones. While the invention has applications throughout the body, its utility will be illustrated in the context of fusing the sacroiliac joint.

BACKGROUND

In the field of orthopedics, it is common to join together two or more bones and hold them in place so as to minimize motion and promote healing or fusion across the bony elements. This is commonly accomplished using screws. Screws may have heads or may be headless. They may utilize a differential thread pitch to generate compression between bones and hold them in place during fusion. However, traditionally manufactured screws have a minimal surface area and are not optimized for bone to grow onto and into in order to aid with fusion. Additive manufacturing allows for the creation of screws with porous/lattice surfaces; however, in order to maintain clinically relevant screw dimensions these screws are weaker in bending then their traditionally manufactured counterparts. Additionally, attempts have been made to coat screw implant surfaces to increase their bioactivity; however, these coatings are fragile and often are removed by the act of inserting the screw. Thus, there exists a clinical need for screws that can generate compression between two or more bone fragments, have a porous surface to allow for bone on growth and in growth, and have a surface finish that enhances the bioactivity of the screw. SUMMARY

The present invention provides a novel orthopedic screw-based implant which can generate compression between two or more bone fragments to enable fusion of the bones.

The screw-based implant can be metallic (such as titanium alloy) and manufactured via an additive manufacturing process (such as EBM or Laser additive manufacturing). Alternatively, the screw may be made out of a polymer such as polyether ether ketone (PEEK) or Polyetherketoneketone (PEKK) and manufactured via an additive manufacturing process (such as EBM or Laser additive manufacturing). The screw may be headless or headed. The screw may have a thread pitch differential between a proximal threaded region and a distal threaded region, may have a continuous thread that changes pitch from the proximal end to the distal end, or may have a constant pitch. The screw may have a porous region either in the middle of the screw (between a distal and proximal threaded region) or may have a porous region located in the thread valleys. The screw may be fenestrated to allow for bone in growth. The screw may be treated after manufacturing to remove the passive titanium oxide coating, and selectively oxidize the screw so as to contain calcium and phosphorus within the titanium oxide layer.

In one embodiment, the screw is a cannulated headless compression screw with a distal and proximal threaded region. A thread pitch differential exists between the proximal and distal threads. Between the threaded regions is a central shaft. The central shaft is comprised of solid metal covered in porous metal. The porous metal has pore sizes engineered to allow for bone ingrowth and on-growth. The screw has one or more fenestrations that radiate axially from the central axis of the screw. The screw has a nano-rough surface, and an oxide layer rich in calcium and phosphorous.

In another embodiment, the screw is a cannulated fully threaded headless screw. The screw may have the same thread over its length or may vary over the length of the screw (so as to create compression). The screw is comprised of a central shaft that a screw thread is helically wound around. A region of porous metal is helically wound around the screw between adjacent screw threads. The screw has a nano-rough surface and an oxide layer rich in calcium and phosphorous.

In another embodiment the screw is a cannulated headed screw. The screw is comprised of a screw head, and a cannulated shaft. A screw thread is helically wound around the cannulated shaft. The screw thread may run the entire length of the cannulated shaft, or may only run over a partial length of the cannulated shaft (starting at the end of the screw). A region of porous metal is helically wound around the cannulated shaft. The porous metal may also be located between adjacent screw threads. A washer may be placed under the head of the screw. The screw has a nano-rough surface and an oxide layer rich in calcium and phosphorous.

The disclosure contemplates all combinations of any one or more of the foregoing aspects and/or embodiments, as well as combinations with any one or more of the embodiments set forth in the detailed description and any examples.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

Fig. 1 is a schematic view showing a novel headless compression screw formed in accordance with the present invention.

Fig. 2 is a schematic cross-sectional view of the novel headless compression screw formed in accordance with the present invention.

Fig. 3 is a schematic view of a novel headed compression screw formed in accordance with the present invention.

Fig. 4 is a schematic cross-sectional view of the novel headed compression screw formed in accordance with the present invention.

Fig. 5 is a schematic view of a novel headed compression screw with a washer formed in accordance with the present invention.

Fig. 6 is a schematic view of a novel fully threaded headless compression screw formed in accordance with the present invention.

Fig. 7 is a schematic cross-sectional view of the novel fully threaded headless compression screw formed in accordance with the present invention.

Fig. 8 is a schematic view of the nano-rough surface found on all screw embodiments disclosed with the present invention. Fig. 9 is an EDS spectrum showing the presence of calcium and phosphorous in the oxide layer of the screw disclosed with the present invention.

Fig. 10 is a table showing the surface roughness of the screw in the lattice region and in the thread valley.

Fig. 11 is a table showing a summary of the porous lattice physical properties including thickness, tissue interface height, volume percent void percentage, and mean void intercept length.

Fig. 12 is a schematic view of the screw head containing a left handed reverse thread formed in accordance with the present invention.

Fig. 13 is a schematic view of the screw head and a removal tool formed in accordance with the present invention.

Fig. 14 is a schematic view of a removal tool engaging the screw head formed in accordance with the present invention.

Fig. 15 is a schematic view of an instrument kit for performing sacroiliac joint fusion formed in accordance with the present invention.

Fig. 16 is a schematic view of an alternative instrument kit for performing sacroiliac joint fusion formed in accordance with the present invention.

Fig. 17 is a schematic view of an instrument sealed within a sterile barrier formed in accordance with the present invention.

DETAIEED DESCRIPTION

In accordance with one or more embodiments, orthopedic screw implants are disclosed. The implants may generally promote fusion between two or more pieces of bone to facilitate healing. In some embodiments, the screws may reduce a gap between two or more bones, generate a compressive force between the bones, and promote fusion between said two or more bones. The screws can generate compression between two or more bone fragments, have a porous surface to allow for bone on growth and in growth, and have a surface finish the enhances the bioactivity of the screw. Structural features of the screw implants, such as but not limited to void space, surface roughness and porosity, as disclosed herein may generally promote bone growth and fusion. In some non-limiting embodiments, the disclosed screw implants may find particular utility in orthopedic applications. Tn one specific embodiment, the implants may be used for sacroiliac (SI) joint fusion.

Looking first at Fig. 1 there is shown a novel headless compression screw 100 for generating compression between two or more bone fragments and to promote fusion between them. Headless compression screw 100 is additively manufactured from metal such as titanium or titanium alloy such as Titanum-6Aluminum-4Vanadium; however, it can be made of any other biocompatible metal or polymer. In one embodiment, headless compression screw 100 is additively manufactured from poly ether ether ketone (PEEK) or Poly etherketoneketone (PEKK). Headless compression screw 100 has a proximal threaded region 110, a distal threaded region 120, and a central shaft 130. Proximal threaded region 110 may have a larger diameter than distal threaded region 120. In one embodiment proximal threaded region 110 may have a major diameter ranging from 9mm to 15mm, and preferably between 11mm and 13.5mm. Distal threaded region 120 may have a major diameter between 7mm and 13mm, and preferably between 9 and 11mm. Proximal threaded region 110 may have a shallower thread than distal threaded 120. In one embodiment proximal threaded region 110 has a thread depth of 0.5 to 1.5mm, and preferably between 0.75 and 1.25mm. Distal threaded region 120 has a thread depth of between 1.0 and 2.0mm and preferably between 1.25 and 1.75mm. In a preferred embodiment, the distal threads 120 have a courser thread pitch than proximal threaded region 110, so as to generate compression between bone fragments during insertion. Proximal threaded region 110 has a thread pitch of between 2.0 and 4.0 mm, preferably 3.0mm and distal threaded region 120 has a thread pitch of between 2.5 and 4.5mm, preferably 3.5mm. When used to fuse the sacroiliac joint, the screw thread pitch differential is capable of reducing a gap between the sacrum and the ilium of between 0.5mm and 3mm. This represents the clinically relevant distance between the sacrum and the ilium that should be reduced for optimal fusion. Reducing this gap allows for the generation of compression between the two bones and promotes fusion. Screw 100 may have a total length of between 20mm and 150mm, and preferably between 30mm and 100mm.

Projecting axially from the central axis of the compression screw are a series of one or more fenestrations 140. These fenestrations allow bone to grow into the screw. The fenestrations may be located along the length of the screw such that when the screw is fully inserted the fenestrations align with the joint space. The cannulated screw and fenestrations allow bioactive bone growth agents (e.g., demineralized bone, bioactive glass, etc.) to be inserted into the screw and when packed the agent exits through the fenestrations into the joint space where fusion is desired. In one application, the fenestrations are located over the central axis of the screw so as to promote self-harvesting of bone as the screw is inserted into the bone. In this case, the fenestrations will fill the central cannulation with bone material. Fenestrations may be between 2 and 8mm in length. Headless compression screw 100 has a drive feature 150 to allow for the screw to be inserted and removed.

In orthopedics, it is common to utilize porous metal as a means to promote bone ingrowth and on-growth to an implant. Unfortunately, porous metal does not have the same mechanical properties as solid metal. Screws often experience bending moments when they are anchored into one bone segment, and the second bone segment is loaded. A screw with a porous metal region will not perform as well as a solid metal screw. It is possible to create a screw with two separate regions, a solid metal region, and an outer layer of porous metal. Still, it is difficult to match the mechanical properties of a traditional solid metal screw without creating diameters that are clinically too large for use on all patients. Additionally, the addition of fenestrations creates stress risers when the screw is loaded in bending. These stress risers cause the screw to fail prematurely in bending fatigue. Fenestrations 140 are surrounded by solid material to provide the required strength to cut into bone to aid in the harvesting of bone graft during insertion.

Looking now at Fig. 2 a cross-section of the central shaft region 130 of the screw is shown. Central shaft region 130 is comprised of a solid metal core 160 and a porous metal outer layer 165. Utilizing additive manufacturing allows for the outer porous metal 165 layer to be built into and overlap the solid core 160 so that the two layers are fused as one. Opposite each fenestration 140 is a reinforcing beam 141 that protrudes out from the solid metal core 160, but is still below the porous metal outer layer 165. This beam reinforces the screw in bending and counteracts the stress risers created by the fenestrations while still allowing for a surface that bone can grow into and onto. This allows for more and larger fenestrations to be used in the manufacturing of the screw while still providing the required mechanical strength. Screw 100 has a bending stiffness of greater than 40,000 N/m. Tn a preferred embodiment, the headless compression screw 100 is electrochemically treated to create a nano-rough surface with nano features between 10 and 75 nm and surface oxide rich in calcium and phosphorous.

Looking now at Fig. 3 there is shown a novel headed compression screw 200 for generating compression between two or more bone fragments and to promote fusion between them. Headed compression screw 200 is additively manufactured from metal such as titanium or titanium alloy such as Titanum-6Aluminum-4Vanadium; however, it can be made of any other biocompatible metal or polymer. In one embodiment, headless compression screw 100 is additively manufactured from poly ether ether ketone (PEEK) or Poly etherketoneketone (PEKK). Headed compression screw 200 has a proximal headed region 210, a distal threaded region 220, and a central shaft 230. Proximal headed region 210 is larger in diameter than threaded region 220. Screw 200 may have a total length of between 20mm and 150mm, and preferably between 30mm and 100mm.

Projecting axially from the central axis of the compression screw are a series of one or more fenestrations 240. These fenestrations allow bone to grow into the screw. The fenestrations may be located along the length of the screw such that when the screw is fully inserted the fenestrations align with the joint space. The cannulated screw and fenestrations allow bioactive bone growth agents (e.g., demineralized bone, bioactive glass, etc.) to be inserted into the screw and when packed the agent exits through the fenestrations into the joint space where fusion is desired. In one application, the fenestrations are located over the central axis of the screw so as to promote self harvesting of bone as the screw is inserted into the bone. In this case, the fenestrations will fill the central cannulation with bone material. Headed compression screw 200 has a drive feature 250 to allow for the screw to be inserted and removed.

In orthopedics, it is common to utilize porous metal as a means to promote bone ingrowth and on-growth to an implant. Unfortunately, porous metal does not have the same mechanical properties as solid metal. Screws often experience bending moments when they are anchored into one bone segment, and the second bone segment is loaded. A screw with a porous metal region will not perform as well as a solid metal screw. It is possible to create a screw with two separate regions, a solid metal region, and an outer layer of porous metal. Still, it is difficult to match the mechanical properties of a traditional solid metal screw without creating diameters that are clinically too large for use on all patients. Additionally, the addition of fenestrations creates stress risers when the screw is loaded in bending. These stress risers cause the screw to fail prematurely in bending fatigue. Fenestrations 240 arc surrounded by solid material to provide the required strength to cut into bone to aid in the harvesting of bone graft during insertion.

Looking now at Fig. 4 a cross-section of the central shaft region 230 of the screw is shown. Central shaft region 230 is comprised of a solid metal core 260 and a porous metal outer layer 265. Utilizing additive manufacturing allows for the outer porous metal 265 layer to be built into and overlap the solid core 260 so that the two layers are fused as one. Opposite each fenestration 240 is a reinforcing beam 242 that protrudes out from the solid metal core 260 but is still below the porous metal outer layer 265. This beam reinforces the screw in bending and counteracts the stress risers created by the fenestrations while still allowing for a surface that bone can grow into and onto. This allows for more and larger fenestrations to be used in the manufacturing of the screw while still providing the required mechanical strength. Screw 200 has a bending stiffness of greater than 40,000 N/m.

In a preferred embodiment, the headless compression screw 200 is electrochemically treated to create a nano-rough surface with nano features between 10 and 75nm and surface oxide rich in calcium and phosphorous.

Looking now at Fig. 5, headed compression screw 200 is shown with a washer 280. Washer 280 has an inner diameter and an outer diameter. The inner diameter of the washer may be sized so that the distal threaded region 220 can pass through the washer, or, the washer may be manufactured with the screw during the additive manufacturing process. This creates a captive washer that cannot be removed from the screw - the inner diameter of the washer does not allow the distal threads to pass through it). Washer 280 allows the screw head 210 to articulate within the inner diameter of the washer. Washer 280 allows compression generated from threading screw 200 into the bone to be distributed on the surface of the bone and allow for compression without the head of the screw stripping into the bone.

Looking now at Fig. 6, a fully threaded compression screw manufactured in accordance with the present invention is shown. Fully threaded compression screw 300 is additively manufactured from metal such as titanium or titanium alloy such as Titanum-6Aluminum- 4 Vanadium; however, it can be made of any other biocompatible metal or polymer. In one embodiment, fully threaded compression screw 300 is additively manufactured from polyether ether ketone (PEEK) or Polyetherketoneketone (PEKK). Compression screw 300 has a thread 310 that is helically wrapped around the central shaft of the compression screw. The screw may have the same thread over its length or may vary over the length of the screw (so as to create compression). Screw 300 may have a constant thread pitch of between 3 and 4mm.

Alternatively, screw 300 may have a thread pitch that varies from 3mm to 4mm over the length of the screw. A drive feature 320 is located on the proximal head of the screw. Axial fenestration 330 may radiate along the central axis of the screw. Between each thread, a region 340 of porous metal is placed.

In orthopedics, it is common to utilize porous metal as a means to promote bone ingrowth and on-growth to an implant. Unfortunately, porous metal does not have the same mechanical properties as solid metal. Screws often experience bending moments when they are anchored into one bone segment, and the second bone segment is loaded. A screw with a porous metal region will not perform as well as a solid metal screw. It is possible to create a screw with two separate regions, a solid metal region, and an outer layer of porous metal. Still, it is difficult to match the mechanical properties of a traditional solid metal screw without creating diameters that are clinically too large for use on all patients. Additionally, the addition of fenestrations creates stress risers when the screw is loaded in bending. These stress risers cause the screw to fail prematurely in bending fatigue. Fenestrations 330 are surrounded by solid material to provide the required strength to cut into bone to aid in the harvesting of bone graft during insertion.

Looking now' at Fig. 7 a cross-section of the screw is shown. The cross-section is comprised of a solid metal core 360 and a porous metal outer layer 365. Utilizing additive manufacturing allows for the outer porous metal 365 layer to be built into and overlap the solid core 260 so that the two layers are fused as one. Opposite each fenestration 340 is a reinforcing beam 341 that protrudes out from the solid metal core 360 but is still below the porous metal outer layer 365. This beam reinforces the screw in bending and counteracts the stress risers created by the fenestrations while still allowing for a surface that bone can grow into and onto. This allows for more and larger fenestrations to be used in the manufacturing of the screw while still providing the required mechanical strength. Screw 300 has a bending stiffness of greater than 40,000 N/m. Tn a preferred embodiment, the headless compression screw 300 is electrochemically treated to create a nano-rough surface with nano features between 10 and 75 nm and surface oxide rich in calcium and phosphorous.

In all embodiments of the screw disclosed in the present invention, the porous metal region of the screw has a pore size ranging between 100mm and 700mm, and a pore size most preferably around 3OO-5OOmm. In the region of porous metal, the volume percent void is between 25 and 75%, and a volume percent void of between 35 and 50% is preferable.

Additionally, in the field of orthopedics, it is common to utilize a nano-rough surface to enhance bone growth. Current methods of creating nano-rough surfaces are typically line-of- sight processes; thus, for a porous material the outer surface will have nano-roughness features, but within the pores and within the inner cannulation and fenestrations the surface remains unchanged.

Looking now at Fig. 8, the electrochemical processing creates a uniform surface covered by a thin nano-textured roughness that exhibited a “net-like” structure comprising thin nanometric sharp crests. The crest-to-crest nano-texture roughness measures between 10 and 75nm in connection with a non-limiting representative implant. The nano-rough surface is on all surfaces of the screw, both on the outer surfaces, and within the porous materials and the internal regions of the cannulation and fenestrations.

Looking now at Fig. 9, an EDS spectrum of the surface of the non-limiting representative screw shows the oxide layer containing calcium and phosphorous. Unlike traditional methods for coating a screw with calcium and phosphorous (i.e., plasma spray) the calcium and phosphorous in the oxide layer of the screw is chemically bound to the screw and is not easily removed while inserting the screw. Traditional coatings on a screw can easily be removed by the stresses of inserting the screw. Additionally, traditional methods for adding biologically active agents (calcium and phosphorous) to the surface of implants is a line-of-sight process. Thus, the biologically active agent will coat the outer surface of the implant, but not coat the inner surfaces of the porous region, or the internal regions of the cannulation and fenestrations. The oxide layer of the screw in the present invention has an oxide layer on all surfaces (external and internal) of the screw that has calcium and phosphorous within the oxide.

Looking now at Fig. 10, surface roughness properties are provided of the surface of the lattice region, and of the threaded region in connection with a non-limiting representative screw implant. Tt should be appreciated that the surface roughness (Ra) of the lattice region, 400, is approximately 0.0608mm, while the surface roughness of the screw thread region, 410, is 0.0430mm. Thus, the roughness of the lattice region is greater than that of the surface roughness of the threaded region. This is purposeful, as it is beneficial for the lattice region to have a greater roughness to promote early bone attachment and to ensure contact with the drilled hole. Additionally, the inner surface of the screw drive feature 150 may have a similar roughness to the roughness of screw thread region. This is intentional and helps the screw firmly affix to the screwdriver.

Looking now at Fig. 11, physical properties of the lattice of a non-limiting representative screw implant are provided. The mean thickness of the lattice is approximately 753pm, the tissue interface height is approximately 998p.m, and the mean void intercept length (pore size) is approximately 335p.m.

Looking now at Fig. 12, the head of a representative screw of the present invention is shown. Screw head 450 has internal drive feature 150. Drive feature may be a hex, a hexalobe, a flat head, a Phillips, or other drive feature geometry known in the art. In a preferred embodiment, drive feature 150 is a hexalobe. Inscribed in the inner diameter of the hexalobe is a left handed reverse thread 460. Looking now at Fig 13, reverse thread 460 is sized to accept a removal tool 470. Removal tool 470 has a left handed reverse thread screw engagement feature 480. Fig 14 shows the screw and removal tool engaged. A left handed reverse thread is used so that if the screw needs to be removed intra or post operatively, the action of unscrewing the screw will lock the screw to the removal tool. This allows the screw to be removed even if it becomes stripped in the bone.

In accordance with one or more embodiments, a method of transfixing two adjacent bones is disclosed. The method may generally involve providing an implant as described herein.

In accordance with one or more embodiments, the implants disclosed herein may be used to transfix bones throughout the body of a subject. In some embodiments, the bones to be transfixed may be associated with an orthopedic application. In some non-limiting embodiments, the bones to be transfixed pertain to the sacroiliac (SI) joint of the subject.

In accordance with one or more embodiments, a repaired bone is disclosed. The repaired bone may generally involve an implant as described herein positioned between two adjacent bones. Tn accordance with one or more embodiments, a stabilized joint is disclosed. The stabilized joint may generally involve an implant as described herein positioned between two adjacent bones. In some embodiments, the two adjacent bones are in close proximity. In other embodiments, the implant reduces the gap between the two adjacent bones. The space or gap may be less than a millimeter to approximately 3mm.

In accordance with one or more embodiments, a method of facilitating the transfixing of two adjacent bones is disclosed. The method may generally involve providing an implant as described herein. Instructions for use of an implant as described herein may also be provided.

In accordance with one or more embodiments, a kit is disclosed. The kit may generally include a screw implant as described herein. Said screw may be provided sterile, packaged in a Tyvek or other conventional sterile barrier material. Other components for clinical use as described herein may also be included in the kit. The screw and/or kit may include a washer.

Additionally, kits may be constructed specifically for the intended surgical use of the screw. In one example, looking at Fig 15., the kit 500 may be constructed for use when performing sacroiliac joint fusion using a lateral approach. The kit 500, is designed to include a sterile instrument kit which may provide, for example, one or more of a guide wire / k-wire, 510, an exchange pin, 520, a combination one tissue dilator and screw sizer, 530, a tissue shield or drill guide, 540, one or more drill bits, 550, a screwdriver, 560, and a drive handle or ratchet, 570. Additionally, the kit may include one or more parallel guides, 580.

In another example, looking at Fig. 16, the kit 600, may be constructed for use when performing sacroiliac joint fusion using a posterolateral or oblique approach. The kit, 600, is designed to include a sterile instrument kit which may provide for example one or more of a guide wire I k-wire, 510, an exchange pin, 520, a combination one step tissue dilator and screw sizer, 530, a tissue shield or drill guide, 540, one or more drill bits, 550, a screwdriver, 560, and a drive handle or ratchet, 570. Additionally, the kit may include a Jamshidi or biopsy needle, 580 (Figure 13). Guide wire / k-wire, 510 may have anti migration features.

The contents of kits 500 and 600 may be re-usable, re-processible, or fully disposable. Looking at Fig 17, the contents of instrument kit 500 or 600 (for illustrative purposes, instrument kit 500 is shown) may be mounted on a card or thermoformed tray. The instruments and card/tray may be sealed in a sterile barrier, 700. In a preferred embodiment, the instrument kits are sealed under vacuum so that they do not move during distribution. The kits disclosed in Fig 15 and 16, may further include a separately packed source of a bone growth agent or other biologically active agent. The biologically active agent may include bone growth promoting material. In some embodiments, the biologically active agent may include therapeutic agents and/or pharmacological agents for release, including sustained release, into a surrounding tissue to treat, for example, pain, inflammation and degeneration. The agents may include pharmacological agents, such as, for example, antibiotics, pain medications, analgesics, anesthetics, anti-inflammatory drugs including but not limited to steroids, anti-viral and anti-retroviral compounds, therapeutic proteins or peptides, therapeutic nucleic acids (as naked plasmid or a component of an integrating or non-integrating gene therapy vector system), and combinations thereof. In some embodiments, the agent may include bone cement that enhances fixation of the screw 100 with tissue. In some embodiments, the bone cement may include a poly(methyl methacrylate) (PMMA); methyl methacrylate (MMA); calcium phosphate; a resorbable polymer, such as, for example, PLA, PGA or combinations thereof; a resorbable polymer with allograft, such as, for example, particles or fibers of mineralized bone and/or combinations thereof. In other application the biologically active agent may include demineralized bone or bioactive glass.

Kit 500 may be used to perform a lateral sacral iliac joint fusion. Kit 500 is provided sterile. Screws 100 are also provided sterile and packaged individually and separately. As the surgeon performs the steps of sacroiliac joint fusion, the surgeon can read the length of the screw to be used off the combination one step tissue dilator and screw sizer. With the screw length know, the correct sterile packed screw can be opened and used. At the end of the case the contents of the instrument kit may be discarded. In an alternative embodiment the contents of the instrument kit can be placed in a biohazard container, and the instruments can be cleaned, reprocessed to like new condition, and reused.

Kit 600 may be used to perform a posterolateral or oblique sacral iliac joint fusion. Kit 600 is provided sterile. Screws 100 are also provided sterile and packaged individually and separately. As the surgeon performs the steps of sacroiliac joint fusion, the surgeon can read the length of the screw to be used off the combination one step tissue dilator and screw sizer. With the screw length know, the correct sterile packed screw can be opened and used. At the end of the case the contents of the instrument kit may be discarded. In an alternative embodiment the contents of the instrument kit can be placed in a biohazard container, and the instruments can be cleaned, rc-proccsscd to like new condition, and reused.

Modifications of the Preferred Embodiments

It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention.

The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. As used herein, the term “plurality” refers to two or more items or components. The terms “comprising,” “including,” “carrying,” “having,” “containing,” and “involving,” whether in the written description or the claims and the like, are open-ended terms, i.e., to mean “including but not limited to.” Thus, the use of such terms is meant to encompass the items listed thereafter, and equivalents thereof, as well as additional items. Only the transitional phrases “consisting of’ and “consisting essentially of,” are closed or semi-closed transitional phrases, respectively, with respect to the claims. Use of ordinal terms such as “first,” “second,” “third,” and the like in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

Having thus described several aspects of at least one embodiment, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Any feature described in any embodiment may be included in or substituted for any feature of any other embodiment. Such alterations, modifications, and improvements are intended to be part of this disclosure and are intended to be within the scope of the invention. Accordingly, the foregoing description and drawings are by way of example only.

Those skilled in the art should appreciate that the parameters and configurations described herein are exemplary and that actual parameters and/or configurations will depend on the specific application in which the disclosed methods and materials are used. Those skilled in the art should also recognize or be able to ascertain, using no more than routine experimentation, equivalents to the specific embodiments disclosed.