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
  • A61B17/84—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
• • 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
  • A61B17/88—Osteosynthesis instruments; Methods or means for implanting or extracting internal or external fixation devices
  • A61B17/8875—Screwdrivers, spanners or wrenches
  • A61B17/8877—Screwdrivers, spanners or wrenches characterised by the cross-section of the driver bit
• • 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
  • F16B23/0007—Specially shaped nuts or heads of bolts or screws for rotations by a tool characterised by the shape of the recess or the protrusion engaging the tool
• • 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
  • F16B31/00—Screwed connections specially modified in view of tensile load; Break-bolts
  • F16B31/02—Screwed connections specially modified in view of tensile load; Break-bolts for indicating the attainment of a particular tensile load or limiting tensile load
  • F16B31/021—Screwed connections specially modified in view of tensile load; Break-bolts for indicating the attainment of a particular tensile load or limiting tensile load by means of a frangible part
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
  • A61B90/03—Automatic limiting or abutting means, e.g. for safety
  • A61B2090/037—Automatic limiting or abutting means, e.g. for safety with a frangible part, e.g. by reduced diameter

Definitions

• Screw for insertion into a bone and unscrewing tool therefor
• the invention relates to a screw for insertion into a bone, in particular for fastening plates that support the fixing of bone parts, with a screw body that has a threaded section and an indirectly or directly adjoining head, on which a device for screwing the screw body into the bones is provided.
• the invention further relates to a boring tool for such a screw or its screw body.
• Bone screws are very small, with a head size that is usually less than 5 mm
• a flat slot or a cross slot for screwing the screw into the bone.
• Such screws are mainly used to fasten plates that support the fixation of bone parts.
• the very flat design means that the slot or the cross slot for screwing in or out the screw can only be very flat. Not only does this mean that the tool for manipulating the screw is very difficult to apply, there is also a risk that the blade of the tool will slip and cause damage.
• the screw according to the invention is characterized in that the device for screwing in the screw body is a shaft formed in one piece with the head, at least one predetermined breaking point being formed in the connection area between the head and the shaft. Screw body and insertion tool are thus initially available as one unit. This unit can be screwed into the bone using a suitable rotary drive with low speeds. After the screw-in depth has been reached, the torque acting on the predetermined breaking point increases so much that the screw body breaks off the shaft and is thus placed in the bone.
• the at least one predetermined breaking point therefore advantageously defines a surface which is dimensioned in accordance with a desired maximum tightening torque of the screw.
• the size of such an area can be determined by experiments, possibly also depending on the choice of material.
• the screw body has a web on the head to which the shaft is connected.
• the predetermined breaking point is located on the side of the web facing the shaft.
• Such a web which is expediently designed as a central web, can be produced by immersing a milling cutter on two sides, offset from the central axis of the screw body, which leaves the desired web straight.
• the unscrewing tool for such a screw or its screw body is then characterized in that a slot is provided at a free end of the unscrewing tool body, which slot is dimensioned such that it engages the head of the screw body via a coupling section, for example the web.
• the boring tool has a shape in the area of the slot in such a way that lugs defining the slot lie snugly in notches which are formed on both sides of the web in the head of the screw body.
• Figure 1 is a side view of a screw for insertion into a bone according to an embodiment of the present invention
• FIG. 2 shows a sectional view through the screw in the area of her head
• Figure 3 is a plan view of the head, with the shaft broken away;
• Figure 4 is a side view, partially in longitudinal section, of the boring tool for a screw or its screw body according to the invention.
• FIG. 5 shows a side view of the boring tool rotated by 90 ° in relation to FIG. 4, again partially cut away.
• FIG. 1 shows a side view of a screw according to the invention for insertion into a bone.
• the screw consists of a screw body 10 and a screw-in tool 20, which are integrally formed with one another, a predetermined breaking point 28 being defined in the connection area between screw body 10 and screw-in tool 20.
• the screw body 10 consists in the usual way of a threaded section 12 and a head 14 directly or indirectly adjoining it.
• the screwing tool 20 is formed from an elongated shaft 22 which extends in the direction of the head 14 of the screw body 10 over a certain section 24 rejuvenated. At the end of shaft 22 opposite section 24, a coupling part 26 is provided for an angle piece or the like.
• Figure 2 shows a longitudinal sectional view of the head 14 of the screw body 10.
• the central axis and notches 18 set apart from this, for example by means of a corresponding milling tool, so that a web 16 remains within the head 14, on its exposed surface, as can be seen directly in FIG. 3, the predetermined breaking point 28 is provided.
• the predetermined breaking point is shown in FIG. 3 as a circular surface, but other surface shapes and thus surface sizes are also possible, so that the desired maximum tightening torque for the screw in the bone can be determined via the dimension of this surface.
• the screwing tool 20 breaks off at the tapered section 24 or at the predetermined breaking point 28 from the web 16 of the screw body 10 .
• an unscrewing tool is expediently used, as is shown in partial side views in FIGS. 4 and 5. It is essential for the boring tool 30 that a slot 34 is formed at the free end of the boring tool body 32, which can be seen particularly well in the partially cut-away area of FIG. 5, the slot 34 being dimensioned such that it overlaps engages the web 16 in the head 14 of the screw body 10. To a fuller. To ensure the fit of the boring tool 30 in the head 14, lugs 36 are formed on both sides of the slot so that they lie essentially in a positive manner in the notches 18 in the head 14 of the screw body 10.
• the unscrewing tool 30, like the screwing-in tool 20, can be provided with a coupling part for an angle piece.

Landscapes

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

Applications Claiming Priority (3)

Publications (1)

Family

ID=7784125

Family Applications (1)

Country Status (8)

Families Citing this family (45)

Family Cites Families (10)

• 1996
  • 1996-01-31 DE DE19603410A patent/DE19603410C2/de not_active Expired - Fee Related
• 1997
  • 1997-01-28 CN CN97192003A patent/CN1210456A/zh active Pending
  • 1997-01-28 BR BR9707322A patent/BR9707322A/pt not_active Application Discontinuation
  • 1997-01-28 WO PCT/DE1997/000195 patent/WO1997027812A1/de not_active Ceased
  • 1997-01-28 JP JP09527246A patent/JP2000514669A/ja active Pending
  • 1997-01-28 CA CA002244217A patent/CA2244217A1/en not_active Abandoned
  • 1997-01-28 AU AU21507/97A patent/AU2150797A/en not_active Abandoned
  • 1997-01-28 EP EP97914109A patent/EP0959794A1/de not_active Withdrawn

Non-Patent Citations (1)

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