JP2009527261A - Surgical fasteners having bioabsorbable components and associated implant devices - Google Patents

Abstract

  A surgical implant comprising a partially bioabsorbable fastener and associated device. The implant consists of a non-bioabsorbable base comprising metal and / or high strength plastic material. The base is partially or fully coated with a bioabsorbable material that can itself have mechanical features such as screw threads. An attachment element is provided on the base to enhance the mechanical attachment of the bioabsorbable material to the base. The implant can withstand the torques and stresses experienced during surgery and subsequent implantation in the human body.

Description

  The present invention relates to surgical fasteners and associated devices that are implanted in the human body. In particular, the present invention relates to an improved surgical implant made with a base comprising metal and / or high strength plastic material. The bioabsorbable material is molded or otherwise applied to the base and attached to the base. A base is produced having elements that enhance the mechanical attachment of the bioabsorbable material to the base. Thus, the product of the present invention can withstand the torques and stresses experienced during surgery on the human body and subsequent surgery while providing the benefit of bioabsorbability to the patient.

  Bioabsorbable surgical fixation devices such as screws, pins, scissors, bolts, nails, suture anchors, staples, etc., and related devices such as rods, plates, wires, etc. for use in surgery Currently available. Such a device is generally used in fixing bone and bone, soft tissue and bone, or soft tissue and soft tissue. To date, only these devices of metal or non-bioabsorbable high strength plastic materials have been available.

  Development of stronger bioabsorbable polymers as described in US Pat. However, for fixation applications and other applications that require strong materials, bioabsorbable materials typically do not have sufficient strength to withstand the stresses experienced during and following human body surgery. If such material breaks during surgery, a wider and longer surgical procedure may be required. And when such a material breaks in the human body, it is usually necessary to perform another surgical operation.

Coated implants such as in US Pat. No. 6,057,056 which describe bi-directional suture anchors that can be composed of non-absorbable biocompatible materials coated with a bioabsorbable coating having a low coefficient of friction are It is described as limiting. A low coefficient of friction is believed to aid in implant placement.
US Pat. No. 6,406,498 US Pat. No. 5,571,139 US Pat. No. 6,632,503 US Pat. No. 6,583,232 US Patent Application Publication No. 2004 / 0153125A1

  The present invention provides a surgical fastener and associated device to which the bioabsorbable component is sufficiently attached to an underlying non-bioabsorbable base to the extent that the bioabsorbable component does not separate from the base during surgery. By overcoming the problems associated with the prior art.

  In some embodiments, the present invention further provides an implant having a base coated with a bioabsorbable material that itself has mechanical functional properties such as bioabsorbable threads not embodied in the base.

  The present invention relates to an improved surgical fastener and related devices having a tissue-friendly metallic or high-strength plastic material as a base that is not bioabsorbable. Fasteners include any type of surgical fastener that can be fully or partially implanted in the human body. Examples of such fasteners include screws, cannula screws, suture anchors, bone anchors, pins, scissors, bolts, nails, staples and the like. Related devices include rods, plates, wires and the like. The base is fully or partially coated with a bioabsorbable material and the bioabsorbable material is attached to the base.

  A base is produced having attachment elements that allow mechanical attachment of the bioabsorbable material to the base. This base can include, for example, recesses, protrusions, corrugations, partial holes or through holes, slits, bumps, pockets, ridges, splines, knurls, sanding, sandblasting, bead blasting, shot peening, tumbling or Mechanical irregularities such as by etching, coating or plating using adhesion strengthening alloys or other compositions, etc. can be included. Combinations of two or more of such attachment elements can also be used. Alternatively, the base may be manufactured from a mesh material or cable that allows attachment of the bioabsorbable material by the mesh or cable structure. In addition to biocompatibility, the purpose of selecting the material for the base is to have sufficient strength for a particular application, and at the same time, in many instances, sufficient flexibility when implanted into the human body Is to find For example, a screw that is sufficiently flexible to allow tremors has little chance of coming out, absorbs shocks, and causes or stimulates bone growth.

  The bioabsorbable material can selectively have mechanical functional properties that are not features of the base. For example, if the fastener is a screw, the bioabsorbable material can be screwed even if the base is not screwed.

  The drawings are intended to be illustrative, are not drawn to scale, and are not intended to limit the scope of the claims to the illustrated embodiments.

  The multiple screw bases shown can also be used for the pins and, as will be apparent to those skilled in the art, various example mounting elements can be used for all of the fasteners and associated devices of the present invention. Note that it can be used for any, though not.

  FIG. 1A shows a base 1 having a shank 2 and a head 3. The shank 2 includes a groove 4 that functions as an attachment element. In FIG. 1B, a bioabsorbable thread 5 is attached to the base so as to form a screw 6. 1C is a cross-sectional view of the screw 6 along the cross-sectional line aa of FIG. 1B. Slot 7 is shown in the head. After the screw 6 is implanted and, as a result, the thread 5 is absorbed by the human body, the base 1 can be selectively removed smoothly from the human body. In the prior art, when non-bioabsorbable screws are used, the threads may stick to the surrounding tissue, and in such cases, the patient may be injured when attempting to remove the screws. The above problems are avoided when the screw of the present invention is used.

  FIG. 2A shows the same base as shown in FIG. 1A. In FIG. 2B, a bioabsorbable coating 8 with bioabsorbable threads 9 is coated over and attached to the base shank to form a screw 6A. This embodiment is further illustrated in FIG. 2C, which is a cross-sectional view along section line aa of FIG. 2B. The bioabsorbable coating 8 and the bioabsorbable thread 9 are easily identified in a cross-sectional view.

  FIG. 3A also shows the same base as shown in FIG. 1A. FIG. 3B shows a screw 6B having a bioabsorbable coating 10 and a bioabsorbable thread 11 coated over and attached to the base 1. The cross-sectional view of FIG. 3C shows the base 1 that is completely coated with a bioabsorbable material along the cross-sectional line aa of FIG.

  FIG. 4A shows a base 13 having a shank 14 with a partial hole 15. The partial hole 15 is an attachment element. FIG. 4B shows a screw 6 </ b> C formed by gluing the bioabsorbable thread 16 to the base 13. FIG. 4C shows a cross-sectional view of the screw 6C having a cross-section along the cross-sectional line aa of FIG. 4B.

  FIG. 5 shows a cross-sectional view of the base 17 of the surgical screw. The through hole 18 is an attachment element.

  FIG. 6 shows a surgical screw base 19 having a recess or pocket 20 as an attachment element.

  FIG. 7 shows a surgical screw base 21 with a protrusion, ridge or hump 22 as an attachment element.

  FIG. 8 shows a surgical screw base 23 having a corrugated portion 24 as an attachment element.

  FIG. 9 shows a surgical screw base 25 with a through slit 26 as an attachment element.

  FIG. 10 shows a surgical screw base 27 with splines 28 as attachment elements.

  FIG. 11 shows a surgical screw base 29 with threads 30 as attachment elements.

  FIG. 12 shows a surgical screw base 31 with a knurled 32 as an attachment element.

  FIG. 13 shows a surgical screw base 33 having an uneven surface 34 as an attachment element. For example, an uneven surface can be imparted to the base by sanding or sandblasting. Note that the attachment element 34 is shown over the entire surface of the base 33 and that this structure is suitable for screws, pins, and other implant devices that are completely coated with a bioabsorbable material. Other attachment elements can be fully or partially applied to any base of the invention, and combinations of two or more attachment elements can be used, as will be apparent to those skilled in the art.

  FIG. 14 shows a base 35 having an etched surface 36 as an attachment element.

  FIG. 15A shows the base having an adhesion promoting surface coated or plated on the base 37 of the surgical screw. The adhesion promoting surface can also be seen in FIG. 15B, which is a cross-sectional view taken along section line aa of FIG. 15A.

  FIG. 16 shows a surgical screw base 39 having a shank 40 of cable.

  FIG. 17 shows a surgical screw base 41 having a shank 42 made of or covered with a mesh material.

  FIG. 18 shows a cross-sectional view of the base having a hole 44 that extends the entire length of the surgical screw base 43 in the longitudinal direction. This base can be used to form a cannula screw or cannula pin according to the present invention.

  FIG. 19A shows a surgical screw 45 having a shank coated with a bioabsorbable coating 46 and a bioabsorbable thread 47. The head 48 is shown in the plan view of FIG. 19A. The opening 49 communicates with the tapered slit 50 shown in FIG. 19B. FIG. 19B shows the base of the screw 45 before being coated with a bioabsorbable material. The pin 52 shown in FIG. 19A can be inserted into the opening 49 and pushed into the slit 50. The diameter of the pin 52 is smaller than the diameter of the opening 49 and larger than the width of the slit at the distal end 53. After the screw 45 is implanted in the patient, the pin 52 can be pushed into the screw to obtain a tighter fit, which can cause the bioabsorbable coating 46 and threads 47 to expand or crack. It is understood that nevertheless, the fixation of the screw to the patient is improved. Note that the hump 54 is optionally provided as an attachment element, and the slit 50 also functions as an attachment element.

  FIG. 20 shows a cross-sectional view of the base 55 of the surgical screw of the present invention. A transverse hole 56 is formed across and through the entire diameter of the shank 57.

  FIG. 21 shows a cross-sectional view of the base 58 of the surgical screw of the present invention. The transverse hole 59 passes across and through the entire diameter of the head 60.

  Hole 44 of FIG. 18, hole 56 of FIG. 20 and hole 59 of FIG. 21 are formed in accordance with the present invention capable of receiving a suture and having a base as shown in the drawings of FIGS. Note that the threaded screw can be used as a suture anchor or bone anchor.

  FIG. 22 shows a pin 61 of the present invention having a bioabsorbable coating 62.

  FIG. 23 shows the pin 63 of the present invention having a tapered slit 64 communicating with the opening 65 of the head 66. The pin is coated with a bioabsorbable coating 67. A pin 52 of the type shown in FIG. 19A can be pushed into the pin 63 to secure the pin 63 in place on the patient.

  FIG. 24 shows the scissors attached to the scissors 68, with a portion having a bioabsorbable coating 69. FIG.

  FIG. 25 shows the bolt having a bioabsorbable thread 71 and a nut 72 attached to the bolt 70.

  FIG. 26 shows the nail having a bioabsorbable coating 74 attached to the nail 73.

  FIG. 27 shows the staple having a bioabsorbable coating 76 attached to the staple 75.

  FIG. 28 shows the rod having an attachment hole 78 and a bioabsorbable coating 79 attached to the rod 77.

  FIG. 29 shows the wire having a bioabsorbable coating over and attached to the surface of the wire 80.

  FIG. 30 shows a plate 81 having a mounting hole 82. A bioabsorbable coating is provided over the surface of the plate and attached to the plate.

  FIG. 31A shows a screw 83 having a bioabsorbable thread 84. The screw 83 has a head 85 attached to the shank 86. An annular ring 87 is attached to the shank 86. The washer 88 shown in FIGS. 31B and 31C is provided with a protrusion 89, a central opening 90, a radial opening 91 and a finger 92. The fingers are somewhat flexible and, as shown in FIG. 32, the washer is placed through the ring 87 so that the washer is rotatably disposed between the head 85 and the ring 87 and is stationary. Allows mating. The distance d between the head 85 and the ring 87 is larger than the thickness t of the washer 88, and the radius of the central opening 90 is larger than the outer radius of the thread 84 but smaller than the outer radius of the ring 87. . When the screw is attached to the patient's surgical site, the protrusion 89 enters into contact with the surgical surface and prevents the washer from rotating when the screw is tightened downward. The combination of screw 83 and washer 88 is particularly suitable as a tissue anchor.

  FIG. 33 shows plan views of various head shapes of screws and pins of the present invention. 33A is a Philips head, FIG. 33B is a slotted head, FIG. 33C is a spannon head, FIG. 33D is a torque head, FIG. 33E is a hex head, and FIG. 33F is a new structure head. It is. Head G can be used for pins.

  Having described the base structure of the present invention for various types of screws and pins, it will be apparent to those skilled in the art that the base can have various shapes and sizes depending on the design requirements of the final product. One skilled in the art can design any implant according to the present invention, taking into account the constraints and advantages of the materials used. Thus, any final that is fully or partially coated with the bioabsorbable material, taking into account that the bioabsorbable material itself can have mechanical features such as protrusions, recesses, threads, etc. Appropriate base can be designed for the product.

  Suitable materials for the base of the present invention include tissue-friendly metals, alloys, synthetic metals, ceramics, plastics and reinforced plastics commonly used for all types of surgical implants. Such materials include materials that are strong enough to achieve the objectives of the present invention and approved by the US Food and Drug Administration (FDA) for surgical implant applications.

  In general, there are three main types of alloys used today in orthopedic metals: titanium alloys, cobalt alloys and iron alloys. An exhaustive list is available on the FDA website that also provides ASTM or ISO standard reference numbers and effective dates for materials. Some examples are non-alloyed titanium and alloyed titanium, molybdenum, chromium, cobalt, tungsten, aluminum, niobium, manganese or vanadium in various combinations as alloys or alloy components, various stainless steels and other iron alloys, oxidation Contains aluminum, zirconium oxide, tantalum phosphate and calcium phosphate.

  In addition, many types of high-strength plastic materials that are not considered bioabsorbable are used to make implants, and many of these are not only found on the FDA website, but also on the ASTM web. Also confirmed on the site. Examples of suitable high strength plastic materials are polyetheretherketone (PEEK), epoxy, polyurethane, polyester, polyethylene, vinyl chloride, polysulfone, polytetrafluoroethylene (PTFE), polycarbonate, polyaryletherketone (PAEK), Including polyoxymethylene, nylon, carbon fiber polyester, polyether ketone ether ketone ketone (PEKEKK), silicon and the like. If a plastic material is used, a small wire or other material can be incorporated into the base body to detect x-rays.

  The above material list is applicable to some embodiments of the present invention, but other embodiments as will be apparent to those skilled in the art based on requirements for strength, flexibility, machinability, etc. for a particular application. Not applicable. The list is intended to be illustrative and not exhaustive. Other materials and novel materials may be used based on the principles of the invention described herein.

  For the purposes of this specification, the term “high-strength plastic material” is sufficient to withstand the torques and stresses of the present invention or its associated implant devices that are typically performed during surgery or in the human body without breakage. Refers to any tissue-friendly non-bioabsorbable polymer, copolymer, polymer blend or polymer alloy having strength.

  The term “bioabsorbable material” as used herein includes materials that are partially or completely bioabsorbable in the human body.

  Suitable bioabsorbable materials are polyglycolide, poly (lactic acid), copolymers of lactic acid and glycolic acid, poly-L-lactide, poly-L-lactic acid, incorporated herein by reference (Patent Literature). 3) Crystalline plastics as disclosed in 3), bioresorbable as described in US Pat. No. 5,637,097 incorporated herein by reference and comprising ceramic particles or reinforcing fibers. Including polymers, copolymers or polymer alloys, bioabsorbable polymers and mixtures thereof as described in US Pat. No. 6,057,834 incorporated herein by reference, copolymers of polyethylene glycol and polybutylene terephthalate, etc. . The above list is not intended to be exhaustive. Other bioabsorbable materials can be used based on the principles of the invention described herein.

  The bioactive material may be mixed with the bioabsorbable material, impregnated in the bioabsorbable material and / or coated on the outer surface of the bioabsorbable material and / or coated on the base, or It can be provided at the interface with the bioabsorbable material. These materials can include, for example, bioactive ceramic particles, capsules or reinforcing fibers, and the materials include, for example, antimicrobial fatty acids and related coating materials as described in US Pat. Antibiotics and antibacterial compositions, immunostimulants, tissue growth promoters or bone growth promoters, and other active ingredients and pharmaceutical materials known in the relevant arts.

  The product of the present invention can be produced by molding, heat shrinking or coating a bioabsorbable material on a base provided with attachment means. If the bioabsorbable material has mechanical functional properties that are not formed from the base material, the bioabsorbable material can be molded into the base in a desired shape. Alternatively, the bioabsorbable material can be coated on the base, shrink-wrapped or molded and then processed to the desired shape and / or dimensions.

~ 1 is a drawing of various surgical screws according to the present invention. 2 is a cross-sectional view of the base of the surgical screw of the present invention. FIG. ~ 1 is a drawing of various base structures of a surgical fastener of the present invention. 2 is a cross-sectional view of the base of the surgical screw of the present invention. FIG. 1 is a drawing of a surgical screw of the present invention. 2 is a cross-sectional view of the base of the surgical screw of the present invention. FIG. 2 is a cross-sectional view of the base of the surgical screw of the present invention. FIG. 2 is a drawing of two pin structures according to the present invention. 2 is a drawing of two pin structures according to the present invention. 1 is a drawing of a bag according to the present invention. 1 is a drawing of a bolt according to the present invention. 1 is a drawing of a nail according to the present invention. 1 is a drawing of a staple according to the present invention. 1 is a drawing of a rod according to the present invention. 1 is a drawing of a wire according to the present invention. 1 is a drawing of a plate according to the present invention. 1 is a drawing of a screw and washer combination according to the present invention. 1 is a drawing of a screw and washer combination according to the present invention. 6 is a drawing of six different head shapes of the screw of the present invention and one head shape of the pin of the present invention.

Claims (31)

  A surgical fastener comprising a base, wherein all or part of the base comprises an attachment element and a bioabsorbable material covering all or part of the base and attached to the base; A surgical fastener wherein the base comprises a metal or high strength plastic material, wherein the surgical fastener is selected from the group consisting of screws, cannula screws, suture anchors, bone anchors, pins, scissors, bolts, nails and staples Surgical fastener.   The attachment element is a recess, a protrusion, a corrugated part, a partial hole, a through hole, a slit, a hump, a pocket, a raised part, a spline or a knurl, or a combination of two or more thereof. The fastener according to 1.   The fastener according to claim 1, wherein the attachment element comprises an uneven surface or an etched surface, a coating adhesion strengthening alloy or a plating adhesion strengthening alloy, or a combination of two or more thereof.   The fastener according to claim 2, wherein the attachment element further comprises an uneven or etched surface, a coating adhesion strengthening alloy or a plating adhesion strengthening alloy, or a combination of two or more thereof.   The fastener of claim 1, wherein the base includes a mesh material or a cable.   The fastener of claim 1, wherein the bioabsorbable material is threaded and selected from the group consisting of a threaded screw, a cannula screw, a suture anchor and a bone anchor.   The fastener of claim 1, further comprising a bioactive material coated on the fastener.   In a surgical implant device selected from the group consisting of a rod, a plate and a wire with a base, all or part of said base covers and is attached to said base and all or part of said base A surgical implant device comprising a bioabsorbable material, wherein the base comprises a metal or a high strength plastic material.   The attachment element is a recess, a protrusion, a corrugated part, a partial hole, a through hole, a slit, a hump, a pocket, a raised part, a spline or a knurl, or a combination of two or more thereof. The surgical implant device according to claim 8.   The surgical implant device according to claim 8, wherein the attachment element comprises an uneven or etched surface, a coating adhesion strengthening alloy or a plating adhesion strengthening alloy, or a combination of two or more thereof.   The surgical implant device of claim 9, wherein the attachment element further comprises an uneven or etched surface, a coating adhesion strengthening alloy or a plating adhesion strengthening alloy, or a combination of two or more thereof.   The surgical implant device of claim 8, wherein the base includes a mesh material or a cable.   The surgical implant device according to claim 8, wherein the bioabsorbable material is screwed, selected from the group consisting of threaded screws, cannula screws, suture anchors and bone anchors.   The surgical implant device of claim 8, further comprising a bioactive material coated on the surgical implant device. A surgical screw with a base having an elongated shank,
All or a portion of the base has an attachment element, the head comprises a proximal surface substantially perpendicular to the longitudinal axis of the shank, and the shank projects distally from the head to a distal end; The head comprises one or more recesses in the proximal surface, and the base comprises a metal or high strength plastic material;
A bioabsorbable material covering all or part of the base and attached to the base, wherein at least a part of the outer surface of the bioabsorbable material is screwed;
Including surgical screws.   The surgical screw of claim 15, having a hole extending from the proximal surface to the distal end over the entire length of the surgical screw.   The head has a first diameter and the shank has a second diameter smaller than the first diameter and extends over the entire length of the first diameter of the head or the first of the shank; The surgical screw according to claim 15, having a hole extending the entire length of two diameters, the hole being substantially perpendicular to the longitudinal axis of the shank.   The shank has an outer surface, the base has an inner surface, and the hole is tapered such that the diameter of the hole on the proximal surface is greater than the diameter of the hole on the distal end; The surgical screw according to claim 16, wherein the shank has at least one longitudinal slit across the outer surface of the shank and the inner surface of the hole from the distal end toward the head.   The surgical screw according to claim 18, wherein the bioabsorbable material has an outer surface, and wherein the at least one longitudinal slit traverses the outer surface of the bioabsorbable material.   19. A cylindrical pin having a diameter smaller than the diameter of the hole in the proximal face and larger than the diameter of the hole in the distal end, wherein the pin is inserted into the hole. A surgical screw as described in.   20. A cylindrical pin having a diameter smaller than the diameter of the hole on the proximal face and larger than the diameter of the hole on the distal end, wherein the pin is inserted into the hole. A surgical screw as described in. A surgical fastener, part of which comprises a bioabsorbable screw, wherein part of the bioabsorbable screw comprises a base having an elongated shank,
All or part of the base has a mounting element, the head has a first outer diameter with a proximal surface substantially perpendicular to the longitudinal axis of the shank, and the shank is remote from the head Projecting distally to the distal end, the head comprising one or more recesses in the proximal surface, the base covering a metal or high-strength plastic material and all or part of the base, and A bioabsorbable material attached to the base, wherein at least a portion of the outer surface of the bioabsorbable material is threaded and has an outer thread diameter, a portion of the bioabsorbable screw,
An annular ring having a second outer diameter circumferentially attached to the periphery of the shank by a distance along the shank but spaced from the head, the second outer diameter being near the head; An annular ring having a diameter smaller than the first outer diameter and larger than the outer thread diameter;
A washer partially removably coupled to a bioabsorbable screw and having a thickness and a first inner diameter opening, wherein the thickness is less than a distance along the shank; Has an inner diameter larger than the outer thread diameter and smaller than the second outer diameter, fingers are circumferentially spaced around the opening, and the washer is fitted through the annular ring. A washer having sufficient flexibility to allow the washer, the washer having an upper surface facing the head and a lower surface having a plurality of protrusions;
Surgical fastener comprising:   23. The surgical fastener of claim 22, wherein the washer is bioabsorbable or partially bioabsorbable.   The surgical fastener of claim 22, wherein the washer is rotatably disposed between the head and the annular ring.   The surgical fastener of claim 22, further comprising a bioactive material coated on the surgical fastener. A surgical pin comprising a base having an elongated shank,
All or part of the base has an attachment element, the head comprises a proximal surface substantially perpendicular to the longitudinal axis of the shank, and the shank projects distally from the head to a distal end; The base includes a metal or a high strength plastic material; and
A bioabsorbable material covering all or part of the base and attached to the base;
Including surgical pins.   27. The surgical pin of claim 26, having a hole extending from the proximal surface to the distal end over the entire length of the surgical pin.   The shank has an outer surface, the base has an inner surface, and the hole is tapered such that the diameter of the hole on the proximal surface is greater than the diameter of the hole on the distal end; 28. The surgical pin of claim 27, wherein the shank has at least one longitudinal slit across the outer surface of the shank and the inner surface of the hole from the distal end toward the head.   30. The surgical pin of claim 28, wherein the bioabsorbable material has an outer surface, and wherein the at least one longitudinal slit traverses the outer surface of the bioabsorbable material.   29. A cylindrical pin having a diameter smaller than the diameter of the hole in the proximal face and larger than the diameter of the hole in the distal end, wherein the pin is inserted into the hole. The surgical pin as described in. A surgical fastener, the surgical fastener having a portion of a bioabsorbable screw, and a portion of the bioabsorbable screw having a base having an elongated shank to bone soft tissue; The method of attaching to
All or part of the base has a mounting element, the head has a first outer diameter with a proximal surface substantially perpendicular to the longitudinal axis of the shank, and the shank is remote from the head Projecting distally to the distal end, the head comprising one or more recesses in the proximal surface, the base covering a metal or high-strength plastic material and all or part of the base and the base A bioabsorbable material attached to the body, wherein at least a portion of the outer surface of the bioabsorbable material is threaded and has an outer thread diameter, a portion of the bioabsorbable screw,
An annular ring having a second outer diameter circumferentially attached to the periphery of the shank by a distance along the shank but spaced from the head, the second outer diameter being near the head; An annular ring having a diameter smaller than the first outer diameter and larger than the outer thread diameter;
A washer rotatably disposed between the head and the annular ring and having a thickness and an opening having a first inner diameter, the thickness being less than a distance along the shank, wherein the first Has an inner diameter larger than the outer thread diameter and smaller than the second outer diameter, fingers are circumferentially spaced around the opening, and the washer is fitted through the annular ring. Flexible enough to enable the washer, the washer has an upper surface facing the head and a lower surface having a plurality of protrusions;
Inserting the distal end of the fastener through soft tissue and then inserting the distal end of the fastener toward the bone;
Including methods.

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