Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • 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, setting implements or the like
  • 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, e.g. tourniquets
  • 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, setting implements or the like
  • 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 ; Bone stabilisers comprising fluid filler in an implant
  • A61B17/7097—Stabilisers comprising fluid filler in an implant, e.g. balloon; devices for inserting or filling such implants
  • A61B17/7098—Stabilisers comprising fluid filler in an implant, e.g. balloon; devices for inserting or filling such implants wherein the implant is permeable or has openings, e.g. fenestrated screw
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • 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, setting implements or the like
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/74—Devices for the head or neck or trochanter of the femur
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • 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, setting implements or the like
  • 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
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • 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, setting implements or the like
  • A61B17/88—Osteosynthesis instruments; Methods or means for implanting or extracting internal or external fixation devices
  • A61B17/8802—Equipment for handling bone cement or other fluid fillers
  • A61B17/8805—Equipment for handling bone cement or other fluid fillers for introducing fluid filler into bone or extracting it
  • A61B17/8822—Equipment for handling bone cement or other fluid fillers for introducing fluid filler into bone or extracting it characterised by means facilitating expulsion of fluid from the introducer, e.g. a screw pump plunger, hydraulic force transmissions, application of vibrations or a vacuum
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B2017/00831—Material properties
  • A61B2017/00955—Material properties thermoplastic
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • 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, setting implements or the like
  • 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
  • A61B2017/8655—Pins or screws or threaded wires; nuts therefor with special features for locking in the bone

Definitions

• the invention relates in general to sonic fusion technology, it relates more particularly to a device and a method for the fixation of fractures, with a screw for augmenting within a fractured object, wherein said object might be, for example, a bone or a wooden or plastic object like furniture.
• the system in accordance with prior art comprises a screw having a flow cavity, i.e. an axial through bore through which bone cement can be introduced into the portion at the tip of the screw.
• the bone cement is advanced by a device which is releasably attached to the subsequent end of the screw.
• This device is similar to a commercially available syringe in comprising substantially a cylindrical barrel and a plunger.
• the barrel forms a cavity in which the plunger is movable to and fro.
• fixation cement is filled into the barrel, after which the plunger is urged against the cement.
• the fixation cement is jetted into the axial through bore of the screw. Due to the pressure the fixation cement is adequately fluidized so that it can pass through the proximal end of the screw into the bone, as a result of which the screw is augmented in the bone.
• This system has the drawback that the manual pressure applied to the fixation cement varies, not only basically from application to application but also during the application itself so that the distribution of the fixation cement within the portion of the bone at the tip of the screw is neither reliable nor even.
• An object of the invention is to define a device and a method by means of which a reliable and even augmentation of a screw at an installation site in an object can now be assured.
• a device for fixation of a fracture having a screw comprising a shank having a first threaded end and having along its longitudinal center line an axial through bore having a first bore portion with a first diameter and a second bore portion with a second diameter, wherein the first diameter is larger than the second diameter and the second bore portion is adjacent the first shank end, and a step in the bore between the first and the second bore portions.
• a method for fixation of a fracture comprises the steps of screwing a screw having an axial bore therein with transverse passageways connecting the bore with an outer surface of the screw into an object across a fracture site; combining a polymer pin with a insert; inserting the polymer pin together with the insert into the axial through bore in the screw; pressuring and vibrating the polymer pin, wherein the polymer pin is supported by the insert which is in turn supported by a step in the diameter in the through bore, resulting in the polymer pin being fluidized at its tip, the fluidized polymer material being pressed out of the screw.
• FIG. 1 is a section view of a screw in accordance with the invention.
• FIG. 2 is a detail view of the tip of the screw as shown in FIG. 1.
• FIG. 3 is a view of a polymer pin in accordance with a first embodiment of the invention.
• FIGs. 4a and 4b are a side view and respectively a plan view of an insert in accordance with the first embodiment of the invention.
• FIG. 5 is a view of a polymer pin in accordance with a second embodiment of the invention.
• FIG. 6 is a detail view of the tip portion of the polymer pin in accordance with the second embodiment of the invention.
• FIG. 7 is a side view of an insert in accordance with the second embodiment of the invention.
• FIG. 8 is a view of the polymer pin together with the insert in accordance with the second embodiment of the invention.
• FIG. 9 is a detail view of the tip portion of the polymer pin, together with the insert in accordance with the second embodiment of the invention.
• FIG. 10 is a section view of a device for fixation of a fracture in accordance with the invention, with the screw as shown in FIG. 1 in which the polymer pin as shown in FIG 5 and the insert as shown in FIG. 7 are inserted.
• FIG. 11 is a detail view of the tip of the device as shown in FIG. 10.
• the screw comprises a shank and a thread 12 machined in an end portion of the shank, wherein the thread may also cover the shank of the screw full length.
• the screw 10 is canulated.
• a through bore composed of two bore portions 16, 17.
• the bore portion 16 comprises a first diameter and the bore portion 17 a second diameter, the first diameter being larger than the second diameter.
• the bore portion 16 forms the main portion of the through bore.
• the transition from the bore portion 16 to the bore portion 17 is formed by a step 18 in the diameter.
• the step 18 in the diameter forms an annular ridge having substantially right-angled edges at the wall of the through bore within the screw.
• Each edge of the step 18 in the diameter may be machined flat or rounded or conical.
• the position of the step in diameter together with the holes in the wall can be positioned optionally along the longitudinal centre line and thus the siting of the augmentation can be determined in accordance with the particular application and the desired effect.
• the screw 10 features holes 14 radially configured through the wall of the screw.
• the holes 14 may be configured in differing directions perpendicular to the longitudinal centre line of the screw and arranged in the end portion with the thread 12.
• the holes 14 are arranged in a region of the end portion which also features the bore portion 16.
• two holes 14 each are configured axially juxtaposed in the bore portion 16 and through the thread 12.
• four such pairs of holes are evenly distributed about the circumference of the screw, in other words, circumferentially spaced by 90°. It is, however, just as possible that three, four, five or more holes may be provided circumferentially and it is not necessary that the holes circumferentially distributed are all at same level. It is, the holes might also be distributed circumferentially along the thread turn. Apart from this, transverse or longitudinal oblong holes, slots, or the like may be provided.
• FIG. 2 there is illustrated the tip of the screw as shown in FIG. 1 but on a magnified scale, the step 18 in the diameter between the bore portion 16 and bore portion 17 now being particularly evident. Apart from this, a few of the holes 14 are shown which are configured passing through the thread 12 in the bore portion 16.
• a polymer pin 20 according to a first embodiment of the invention, elongated in shape and slightly tapered at a conically tapered end 22.
• a cavity 24 in the end face.
• the cavity 24 is substantially cylindrical having a constant diameter and a blunt end.
• the polymer pin 20 may also be made of other materials such as for instance a thermoplastic material suitable for augmenting a screw, both resorptive and non-resorptive materials being useful.
• the insert features a substantially disk-shaped end 32 and a substantially pin- shaped end 34.
• the disk-shaped end 32 has an outer diameter somewhat smaller than the diameter of the bore portion 16 of the screw 10 and somewhat larger than the diameter of the bore portion 17 of the screw 10.
• the pin-shaped end 34 is configured so that it can be inserted into the cavity 24 in the polymer pin 20.
• the insert includes instead of the pin-shaped end a protruding end suitable for snap mounting, the polymer pin in this case having a snap mounting end corresponding to the protruding end.
• the insert is snap mounted with the polymer pin, both elements can be inserted together into the screw, it being of advantage when the snap mount comprises a slight clearance when connected.
• This clearance has the advantage that when the polymer pin is pressurized it can be better fluidized at the joint with the insert to thus easier jetted from the screw into the object easier, wherein said object might be a bone or a furniture or another object made of wood, plastic or another porous material.
• FIG. 5 there is illustrated a polymer pin 40 according to a second embodiment of the invention, elongated in shape and slightly tapered at a conically tapered end 42.
• a cavity is provided in the end face of the conically tapered end 42 of the polymer pin 40.
• the cavity comprises a cylindrical portion 44 having a substantially constant diameter, and a ball shaped portion 46.
• the hollow cylindrical portion 44 is orientated substantially in the direction of the centre axis of the polymer pin 40 and connects the end surface of the polymer pin with the hollow ball shaped portion 46 inside the polymer pin 40.
• the pin 40 may also be made of other materials then polymer, for instance of a thermoplastic material suitable for augmenting a screw, wherein both resorptive and non-resorptive materials being useful.
• the insert includes a substantially disk-shaped end 52 and a substantially pin-shaped portion 54.
• the disk-shaped end 52 has an outer diameter somewhat smaller than the diameter of the bore portion 16 of the screw 10 and somewhat larger than the diameter of the bore portion 17 of the screw 10.
• the insert according to the second embodiment further comprises a ball head 56 located at an end of the pin-shaped portion 54, opposite to the disc-shaped end 52.
• FIGs. 8 and 9 show a combination of an insert and a polymer pin according to the second embodiment of the invention.
• the ball head 56 together with at least a part of the pin-shaped portion 54 are configured so that they can be inserted into the cavity in the polymer pin 40, the cavity having a correspondingly dimensioned ball-shaped portion 46 and a pin-shaped portion 44.
• the insert has to be made from a material which is harder with an higher melting temperature than the material of the polymer pin such that the polymer pin will melt at the contact area between the insert and the pin, and a suitable augmentation might be achieved.
• the insert is made of a metal.
• the insert may alternatively be made of an alloy or a ceramic material.
• a plastic material is possible, as long as said plastic material of the insert is harder with an higher melting temperature than the chosen material of the pin which should be fluidized.
• the insert instead of including a pin-shaped end or a snap mounting end, has a through bore into which a corresponding end of the polymer pin can engage.
• the polymer material is jetted axially from the screw not only through the holes 14 but also through the hole in the insert.
• the proportion of the polymer material emerging from the holes and bores can be varied by the size thereof.
• a snap mount may also be provided in combination with axial and/or radial holes, it being just as possible, however, to configure the insert integrally with the screw.
• the step in the diameter between two portions of the bore is configured by a larger difference in diameter; indeed, even an axial blind hole may be configured instead of the axial through bore in the screw.
• a K-wire is powered up to the site in a bone at which the screw is to be located. Via the K-wire the screw is then advanced and ultimately screwed into place until it is sited as desired. After insertion of the screw in the bone the K-wire is removed. This procedure makes it necessary that the screw features a full length through bore. This is a popular operation technique because the operator can best check the position of the screw.
• the K-wire is also used to measure the necessary screw length.
• the passageway or through bore along the longitudinal centre line of the screw is free to receive the polymer pin together with the insert, the tip of the pin shaped end of the insert being inserted into the concavity of the polymer pin.
• step 18 in the diameter forms, within the screw, a counterhold for the insert which in turn supports the polymer pin when the polymer pin is pressurized by an ultrasonic handpiece which, for this purpose, is mounted on the free end of the screw.
• the vibration and pressure generated by the ultrasonic handpiece and applied to the polymer pin fluidizes the polymer pin so that the material of the polymer pin emerges from the radially arranged holes 14 into the bone. It is in this way that the polymer pin furnishes the material for augmenting the screw in the bone.
• inside-out technology is not just limited to the indications as recited above.
• all screw applications which can be supplied by cannulated screws can be potentially supplied by the inside-out technology and thus with the device in accordance with the invention.

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• Health & Medical Sciences (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Life Sciences & Earth Sciences (AREA)
• Surgery (AREA)
• Neurology (AREA)
• Heart & Thoracic Surgery (AREA)
• Engineering & Computer Science (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)
• Surgical Instruments (AREA)
• Dowels (AREA)

Priority Applications (4)

Applications Claiming Priority (4)

Publications (1)

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Cited By (8)

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Citations (5)

• 2008
  • 2008-07-11 JP JP2010515426A patent/JP5302306B2/ja active Active
  • 2008-07-11 CN CN2008800245054A patent/CN101765411B/zh not_active Expired - Fee Related
  • 2008-07-11 WO PCT/EP2008/005701 patent/WO2009010247A1/en active Application Filing
  • 2008-07-11 AU AU2008277955A patent/AU2008277955B2/en not_active Ceased
  • 2008-07-11 CA CA2693395A patent/CA2693395C/en not_active Expired - Fee Related

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