Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/70—Spinal positioners or stabilisers, e.g. stabilisers comprising fluid filler in an implant
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
  • A61B17/86—Pins or screws or threaded wires; nuts therefor
  • A61B17/8685—Pins or screws or threaded wires; nuts therefor comprising multiple separate parts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B35/00—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws
  • F16B35/04—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws with specially-shaped head or shaft in order to fix the bolt on or in an object
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
  • A61B17/86—Pins or screws or threaded wires; nuts therefor
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
  • A61B17/86—Pins or screws or threaded wires; nuts therefor
  • A61B17/8605—Heads, i.e. proximal ends projecting from bone
  • A61B17/861—Heads, i.e. proximal ends projecting from bone specially shaped for gripping driver
  • A61B17/862—Heads, i.e. proximal ends projecting from bone specially shaped for gripping driver at the periphery of the screw head
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
  • A61B17/86—Pins or screws or threaded wires; nuts therefor
  • A61B17/8625—Shanks, i.e. parts contacting bone tissue
  • A61B17/863—Shanks, i.e. parts contacting bone tissue with thread interrupted or changing its form along shank, other than constant taper
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
  • A61B17/86—Pins or screws or threaded wires; nuts therefor
  • A61B17/864—Pins or screws or threaded wires; nuts therefor hollow, e.g. with socket or cannulated
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
  • A61B17/86—Pins or screws or threaded wires; nuts therefor
  • A61B17/866—Material or manufacture
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B35/00—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/70—Spinal positioners or stabilisers, e.g. stabilisers comprising fluid filler in an implant
  • A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
  • A61B17/7035—Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
  • A61B17/86—Pins or screws or threaded wires; nuts therefor
  • A61B17/8625—Shanks, i.e. parts contacting bone tissue
  • A61B17/8635—Tips of screws
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B23/00—Specially shaped nuts or heads of bolts or screws for rotations by a tool

Definitions

• the present invention relates to bone screws that can be fixed to animal bones.
• a bone screw made almost entirely of metal causes artifacts when taking medical images, and becomes an obstacle when performing surgery, etc. while checking the medical images.
• PEEK registered trademark
• the bone screw of the present invention is a bone screw containing reinforcing fibers, and includes a shaft portion, a tip portion located at the end of the shaft portion in the insertion direction, and a head portion located at the end of the shaft portion in the withdrawal direction. and a screw thread located spirally in the axial direction of the shaft part on the outer circumferential part of the shaft part, and the reinforcing fiber is arranged in the shaft part at a position extending in the axial direction of the shaft part. be done.
• a bone screw with sufficient strength can be provided.
• FIG. 4(a) is a diagram showing the head of the bone screw of this embodiment.
• FIG. 4(b) is a sectional view taken along line BB of the bone screw of this embodiment. It is a perspective view of the bone screw of this embodiment. It is a perspective view of the bone screw of this embodiment.
• FIG. 2 is a sectional view taken along line CC of the bone screw of the present embodiment.
• FIG. 1 is a side view and a sectional view of the bone screw of this embodiment.
• FIG. 2 is a cross-sectional view of the shaft portion and screw thread of the bone screw of this embodiment.
• the bone screw 1 of this embodiment is a bone screw containing reinforcing fibers, and includes a shaft portion 2 and a tip portion 3 located at the end of the shaft portion 2 in the insertion direction. , a head 4 located at the end of the shaft portion 2 in the removal direction, and a screw thread 5 located spirally in the axial direction of the shaft portion 2 on the outer circumference of the shaft portion 2.
• FIG. 1(b) is a cross-sectional view taken along line AA in FIG. 1(a). As shown in FIG. 1(b), the reinforcing fibers 100 are arranged in the shaft portion 2 at a position extending in the axial direction of the shaft portion 2.
• FIG. 1(c) is an enlarged cross-sectional view of the thread 5 of FIG. 1(b). As shown in FIG. 1(c), the reinforcing fiber 100 is bent at the thread 5.
• the reinforcing fibers 100 are arranged in the thread 5 at a position extending in the same direction as the helical direction of the thread 5.
• the reinforcing fibers 100 are arranged at positions extending along the helical direction of the threads 5.
• the reinforcing fiber 100 is spirally wound in the axial direction around at least one of the shaft portion 2 and the screw thread 5.
• a mixed composition of the reinforcing fiber 100 for example, 1 mm carbon fiber
• a resin for example, vinyl ester
• the reinforcing fibers 100 are mixed with the resin so that the reinforcing fibers 100 are arranged in a predetermined direction.
• the reinforcing fibers 100 are mixed with the resin so that the reinforcing fibers 100 are arranged in the axial direction of the bone screw 1.
• the reinforcing fibers 100 are mixed with the resin so that the reinforcing fibers 100 are arranged at a position extending at a predetermined angle with respect to the axial direction of the bone screw 1.
• the reinforcing fibers 100 are mixed into the resin so that they are arranged in the helical direction of the threads 5 of the bone screw 1.
• the resin includes at least one of a thermosetting resin and a thermoplastic resin.
• the resin may be selected from epoxy resins, phenolic resins, unsaturated polyester resins, and the like.
• the reinforcing fibers 100 are stretched in the axial direction of the shaft part 2 in the shaft part 2.
• the reinforcing fiber 100 may be bent at the thread 5 or may be arranged at a position extending in the same direction as the helical direction of the thread 5, or the reinforcing fiber 100 may be bent at the thread 5, or may be arranged at a position where it extends in the same direction as the helical direction of the thread 5. , and may be arranged in a position where it is wound spirally around the axial direction.
• the reinforcing fibers 100 are appropriately arranged in a predetermined direction to strengthen at least one of compressive strength, tensile strength, shear strength, torsional strength, and hardness of the bone screw 1. Can be done.
• the reinforcing fiber 100 is preferably at least one of carbon fiber, aramid fiber, and glass fiber, but is not limited to these.
• FIG. 2 is a cross-sectional view of a bone screw 1 in which a mixed composition of reinforcing fibers 100 and a resin is injection molded into a mold for the bone screw 1.
• the angle of the thread 5 is 60 degrees or more and 80 degrees or less.
• the inventor injected a mixed composition of reinforcing fibers 100 and resin into a mold for the bone screw 1, and determined the angle of the thread 5 for appropriately molding the thread 5 of the bone screw 1. I found out. If the angle of the threads in the mold is too small, the mixed composition will not be sufficiently injected to the threads, and the threads 5 will not be properly molded. On the other hand, if the angle of the threaded portion of the mold is too large, the fixing strength of the bone screw 1 to the bone will be insufficient and it will easily come off from the bone.
• the angles of the threads 5 are 120 degrees and 100 degrees, respectively. As shown in FIGS. 2(a) and 2(b), although the mixed composition is sufficiently injected to the threaded portion, the angle of the threaded portion is too large and easily detaches from the bone.
• the angles of the threads 5 are 80 degrees and 60 degrees, respectively.
• the mixed composition is sufficiently injected to the threaded portion, and the angle of the threaded portion is not too large and does not easily detach from the bone. Therefore, it is appropriate that the angle of the thread 5 is 60 degrees or more and 80 degrees or less.
• the angle of the thread 5 is 60 degrees or more and 75 degrees or less. More preferably, the angle of the thread 5 is 65 degrees or more and 70 degrees or less.
• FIG. 3 is a diagram showing that the angle of the thread 5 increases in the range of 60 degrees to 80 degrees as it goes toward the insertion direction of the bone screw 1.
• the angles ⁇ 1 to ⁇ 3 of the screw threads 5 increase in the range of 60 degrees to 80 degrees as the direction of insertion of the bone screw 1 increases ( ⁇ 1 ⁇ 2 ⁇ 3).
• the angle of the thread 5 increases in the range of 60 degrees or more and 75 degrees or less as it goes toward the insertion direction of the bone screw 1. More preferably, the angle of the thread 5 increases in the range of 65 degrees or more and 70 degrees or less as it goes toward the insertion direction of the bone screw 1.
• the angle of the thread 5 may gradually increase within the above range or may increase intermittently as it goes in the insertion direction of the bone screw 1, or a part of the thread 5 may It may become larger within the above range as it goes in the insertion direction of the screw 1. Further, the heights h1 to h3 of the screw threads 5 may become lower toward the insertion direction of the bone screw 1. The heights h1 to h3 of the threads 5 may vary depending on the angle of the threads 5.
• FIG. 4(a) is a diagram showing the head 4 of the bone screw 1.
• FIG. 4(b) is a sectional view of the bone screw 1 taken along line BB.
• the head 4 includes a head protrusion 41 in the insertion direction, and the head protrusion 41 fits into the shaft recess 21 of the shaft portion 2.
• the joint between the head 4 and the shaft portion 2 (the convex head portion 41) has higher at least one of compressive strength, tensile strength, shear strength, torsional strength, and hardness than the shaft portion 2.
• the head convex portion 41 is made of at least metal (e.g., titanium, stainless steel, iron, nickel, cobalt, cemented carbide, etc.), ceramic (e.g., zirconia), cermet, and reinforcing fibers having a composition different from that of the reinforcing fibers 100.
• the reinforcing fibers having a different composition from the reinforcing fibers 100 may be reinforcing fibers of the same type as the reinforcing fibers 100, as long as at least one of the mixing ratio, length, shape, and arrangement of the reinforcing fibers 100 is different.
• the reinforcing fibers having a different composition from the reinforcing fibers 100 may be reinforcing fibers of the same type as the reinforcing fibers 100 if other reinforcing fibers are mixed therein.
• the joint between the head 4 and the shaft portion 2 has higher compressive strength, tensile strength, shear strength, torsional strength, and hardness than the shaft portion 2. It is sufficient that at least one of them is high.
• the shaft portion 2 may include a shaft protrusion in the removal direction, and the shaft protrusion may fit into a head recess of the head 4. That is, in FIG. 4, the head 4 is provided with a convex portion and the shaft portion 2 is provided with a concave portion, but conversely, the shaft portion 2 may be provided with a convex portion and the head 4 may be provided with a concave portion.
• the core part may be fitted into a head recess of the head 4 and a shaft recess of the shaft part 2. That is, the head 4 and the shaft portion 2 are provided with recesses, and the recesses are connected by the core.
• a portion having at least one of compressive strength, tensile strength, shear strength, torsional strength, and hardness higher than that of the shaft portion 2 may be provided at the joint portion between the head portion 4 and the shaft portion 2.
• the joint may be a boundary between the head 4 and the shaft 2 made of different materials, as shown in FIG. There does not have to be any boundary surface.
• the compressive strength is higher than that of the shaft part 2.
• a portion having high at least one of tensile strength, shear strength, torsional strength, and hardness may be provided between the head 4 and the shaft portion 2.
• At least one of compressive strength, tensile strength, shear strength, torsional strength, and hardness can be strengthened in the part between the head 4 and the shaft part 2 where the load is applied, and the bone screw 1 can be broken. and deformation can be prevented.
• FIG. 5 is a perspective view of the bone screw 1.
• FIG. 6 is a perspective view of the bone screw 1 of FIG. 5.
• FIG. 7 is a sectional view taken along line CC of the bone screw 1 in FIG.
• the head 4 includes a head protrusion 41 in the insertion direction, and the head protrusion 41 fits into the shaft recess 21 of the shaft portion 2.
• the head convex portion 41 includes a polygonal portion 41-1 whose cross section perpendicular to the axial direction is a polygon.
• the polygonal portion 41-1 has a substantially rectangular cross section perpendicular to the axial direction, and is chamfered.
• the polygonal portion 41-1 is preferably approximately triangular to approximately hexagonal. Since the head protrusion 41 has a polygonal cross-section perpendicular to the axial direction, when torque is generated in the rotational direction of the bone screw 1, the head protrusion 41 slides or comes off from the shaft recess 21 in the rotational direction. This can be prevented.
• the head protrusion 41 includes a notch 22.
• the cutout portion 22 may include a rotation surface in the rotational direction of the bone screw 1, or may have a flange shape.
• the head protrusion 41 may include a screw thread located in a reverse helical direction to the screw thread 5.
• the shaft recess 21 may include at least one of a polygonal section whose cross section perpendicular to the axial direction is a polygon, a thread located in a reverse helical direction with respect to the thread 5, and a notch.
• the convex part of the shaft part 2 when the convex part of the shaft part 2 fits into the recessed part of the head part 4, or when the core part fits into the head recessed part of the head part 4 and the shaft recessed part of the shaft part 2,
• the convex part of the shaft part 2, the concave part of the head part 4, and the core part have a polygonal part whose cross section perpendicular to the axial direction is a polygon, or a thread located in a reverse spiral direction with respect to the thread 5, and a notch part. At least one may be provided.
• the core portion may include reinforcing fibers arranged at at least one of a position extending in the axial direction and a position spirally wound around the axial direction.
• the bone screw 1 includes a hole 20 that can pass through the inside of the bone screw 1 in the axial direction. 6 and 7, the hole 20 passes through the interior of the bone screw 1 from the recess 40 of the head 4 to the distal end 3.
• the hole 20 passes through the interior of the bone screw 1 from the recess 40 of the head 4 to the distal end 3.
• the hole 20 is made of at least one of metal (e.g., titanium, stainless steel, iron, nickel, cobalt, cemented carbide, etc.), ceramic (e.g., zirconia), cermet, and reinforcing fiber having a composition different from that of the reinforcing fiber 100.
• metal e.g., titanium, stainless steel, iron, nickel, cobalt, cemented carbide, etc.
• ceramic e.g., zirconia
• cermet e.g., cermet
• reinforcing fiber having a different composition from the reinforcing fibers 100 may be reinforcing fibers of the same type as the reinforcing fibers 100, as long as at least one of the mixing ratio, length, shape, and arrangement of the reinforcing fibers 100 is different.
• the reinforcing fibers having a different composition from the reinforcing fibers 100 may be reinforcing fibers of the same type as the reinforcing fibers 100 if other reinforc
• Hole 20 surrounded by a material including metal (e.g., titanium, stainless steel, iron, nickel, cobalt, and cemented carbide), ceramic (e.g., zirconia), cermet, and reinforcing fibers having a composition different from reinforcing fiber 100
• metal e.g., titanium, stainless steel, iron, nickel, cobalt, and cemented carbide
• ceramic e.g., zirconia
• cermet e.g., cermet
• reinforcing fibers having a composition different from reinforcing fiber 100
• the hole 20 is made of metal (e.g., titanium, stainless steel, iron, nickel, cobalt, cemented carbide, etc.), ceramic (e.g., zirconia), cermet, or reinforced fiber having a composition different from that of the reinforcing fiber 100. It suffices if it is surrounded by a material containing at least one fiber.
• metal e.g., titanium, stainless steel, iron, nickel, cobalt, cemented carbide, etc.
• ceramic e.g., zirconia
• cermet e.g., zirconia
• reinforced fiber having a composition different from that of the reinforcing fiber 100. It suffices if it is surrounded by a material containing at least one fiber.
• FIG. 8 is a diagram showing examples of the types of threads 5 of the bone screw 1.
• the flank angle of the thread 5 in the insertion direction is larger than the flank angle of the thread 5 in the removal direction.
• the shaft portion 2 becomes thinner toward the insertion direction, and the diameter of the valley of the thread 5 becomes thinner and smaller toward the insertion direction.
• the outer diameter of the thread 5 is substantially constant.
• the height of the thread 5 increases toward the insertion direction.
• the length of the top of the screw thread 5 in the axial direction becomes smaller toward the insertion direction.
• the bone screw 1 Due to the shape of the screw thread 5, the bone screw 1 can be reliably fixed to the bone and can be easily removed from the bone.
• FIG. 9 is a diagram showing another example of the type of thread 5 of the bone screw 1.
• FIG. 9 is a cross-sectional view of the thread 5 of the bone screw 1.
• the flank angle ⁇ of the thread 5 in the insertion direction is larger than the flank angle ⁇ of the thread 5 in the removal direction.
• the heights H1, H2, and H3 of the screw threads 5 increase toward the insertion direction.
• the bone screw 1 shown in FIG. 9 the bone screw 1 shown in FIG.
• the axial lengths L1, L2, and L3 of the tops of the screw threads 5 are in the insertion direction. The smaller it becomes.
• the diameter of the valley of the thread 5 and the angle ⁇ of the thread 5 are substantially constant.
• the shaft portion 2 becomes thinner toward the insertion direction, and the diameter of the valley of the screw threads 5 (thread threads 5-4, 5-5, 5-6) is in the insertion direction. It becomes thinner and smaller as it goes towards the end.
• the outer diameter of the thread 5 and the angle ⁇ of the thread 5 are substantially constant.
• the heights H4, H5, and H6 of the threads 5 increase toward the insertion direction.
• the axial lengths L4, L5, and L6 of the tops of the screw threads 5 are in the insertion direction. The smaller it becomes.
• the bone screw 1 Due to the shape of the screw thread 5, the bone screw 1 can be reliably fixed to the bone and can be easily removed from the bone.
• FIG. 10 is a diagram showing that the bone screw 1 housed in the housing 6 is fixed within the housing 6 by a nut (not shown) and connected by a rod 7.
• the threads 5-7 of the bone screw 1 have the same shape as the threads 5 in FIG. 8(b). As shown in FIG. 10(b), the pitch of the threads 5 of the bone screw 1 becomes longer toward the insertion direction.
• the bone screw 1 Due to the shape of the screw thread 5, the bone screw 1 can be reliably fixed to the bone and can be easily removed from the bone.
• FIG. 11 is a CT image (medical image) taken with the bone screw 1 screwed into the bone of an animal (pig).
• the bone screw 1 contains tantalum of 0 weight % or more and 30 weight % or less (0 weight %, 10 weight %, 15 weight %, 20 weight %, 25 weight %, 30 weight %) and reinforcing fibers. including mixtures mixed into compositions.
• FIG. 12 is a table evaluating artifacts of the bone screw 1 in CT images (medical images) taken according to the tantalum content shown in FIG. 11.
• the artifact rating is A - , which is acceptable. Similar results are expected for other metals (titanium, stainless steel, iron, nickel, cobalt, cemented carbide, etc.).
• the bone screw 1 (at least one of the shaft portion 2, the tip portion 3, the head 4, and the screw thread 5) contains more than 0% by weight and less than 30% by weight (preferably 10% by weight and less than 20% by weight), More preferably, the reinforcing fiber 100 contains a mixture of a metal (tantalum, titanium, stainless steel, iron, nickel, cobalt, cemented carbide, etc.) containing 10% by weight or more and 15% by weight or less, such as tantalum, titanium, stainless steel, iron, nickel, cobalt, and cemented carbide.
• a metal tantalum, titanium, stainless steel, iron, nickel, cobalt, and cemented carbide.
• the bone screw 1 (at least one of the shaft portion 2, the tip portion 3, the head 4, and the screw thread 5) is imaged with higher brightness than the surrounding area in a medical image while reducing artifacts
• the bone screw 1 ( At least one of the shaft portion 2, the tip portion 3, the head portion 4, and the screw thread 5) functions as a guide for grasping the position and direction of the bone screw 1 in a medical image.
• the tip portion 3 may include a material that is imaged with higher brightness in medical images than the reinforcing fiber 100.
• the tip portion 3 may be made of metal (e.g., tantalum, titanium, stainless steel, iron, nickel, cobalt, cemented carbide, etc.), ceramic (e.g., zirconia), cermet, or reinforcing fiber having a composition different from that of the reinforcing fiber 100. Contains at least one. When such a distal end 3 is imaged with higher brightness than the surrounding area of the distal end 3 in a medical image such as a CT image, the distal end 3 is used for grasping the position and direction of the bone screw 1 in the medical image. Act as a guide.
• the present invention is useful as a bone screw with sufficient strength.

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• Health & Medical Sciences (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Surgery (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Neurology (AREA)
• Heart & Thoracic Surgery (AREA)
• Biomedical Technology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Medical Informatics (AREA)
• Molecular Biology (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Surgical Instruments (AREA)

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• 2023
  • 2023-07-14 KR KR1020257001658A patent/KR20250024085A/ko active Pending
  • 2023-07-14 CN CN202380054286.9A patent/CN119584929A/zh active Pending
  • 2023-07-14 EP EP23846264.2A patent/EP4563830A1/en active Pending
  • 2023-07-14 JP JP2024536967A patent/JPWO2024024533A1/ja active Pending
  • 2023-07-14 WO PCT/JP2023/025979 patent/WO2024024533A1/ja not_active Ceased
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