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WO2007045899A1 - Dispositif de fixation destine a un element support spinal allonge - Google Patents

Dispositif de fixation destine a un element support spinal allonge Download PDF

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Publication number
WO2007045899A1
WO2007045899A1 PCT/GB2006/003918 GB2006003918W WO2007045899A1 WO 2007045899 A1 WO2007045899 A1 WO 2007045899A1 GB 2006003918 W GB2006003918 W GB 2006003918W WO 2007045899 A1 WO2007045899 A1 WO 2007045899A1
Authority
WO
WIPO (PCT)
Prior art keywords
channel
transverse arm
vertebra
fixation device
support element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB2006/003918
Other languages
English (en)
Inventor
Paul Firkins
Chris Gowland
Allard Bonemma
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DePuy International Ltd
Original Assignee
DePuy International Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by DePuy International Ltd filed Critical DePuy International Ltd
Publication of WO2007045899A1 publication Critical patent/WO2007045899A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • A61B17/7049—Connectors, not bearing on the vertebrae, for linking longitudinal elements together
    • 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
    • A61B17/7032—Screws or hooks with U-shaped head or back through which longitudinal rods pass
    • 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
    • A61B17/7002—Longitudinal elements, e.g. rods
    • A61B17/7004—Longitudinal elements, e.g. rods with a cross-section which varies along its length
    • A61B17/7005—Parts of the longitudinal elements, e.g. their ends, being specially adapted to fit in the screw or hook heads
    • 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
    • A61B17/7002—Longitudinal elements, e.g. rods
    • A61B17/701—Longitudinal elements with a non-circular, e.g. rectangular, cross-section
    • 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
    • A61B17/7037—Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other wherein pivoting is blocked when the rod is clamped
    • 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
    • A61B17/7056—Hooks with specially-designed bone-contacting part
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B2017/00831—Material properties
    • A61B2017/00867—Material properties shape memory effect

Definitions

  • This invention relates to a fixation device for connecting an elongate support element to a patient's vertebra, and to an implant kit which includes a fixation device.
  • EP-A-470660 discloses apparatus for correcting the shape of a spinal column.
  • the apparatus includes a rod which is formed from a nickel-titanium alloy which has been treated so that it exhibits shape memory properties, in bending or in torsion or both.
  • Articles formed from shape memory alloys can exhibit shape memory properties associated with transformations between martensite and austenite phases of the alloys. These properties include thermally induced changes in configuration in which an article is first deformed from a heat-stable configuration to a heat-unstable configuration while the alloy is in its martensite phase. Subsequent exposure to increased temperature results in a change in configuration from the heat-unstable configuration towards the original heat- stable configuration as the alloy reverts from its martensite phase to its austenite phase.
  • the transformation from austenite to martensite on cooling begins at a temperature known as the M s temperature, and is completed at a temperature known as the M 1 - temperature.
  • the transformation of martensite to austenite upon heating begins at a temperature known as the A s temperature and is complete at a temperature known as the A f temperature.
  • the rod of the apparatus disclosed in EP-A-470660 is fastened to a patient's vertebrae while in the configuration from which it has to recover.
  • the temperature of the rod is then increased so that it is greater than the A s temperature of the alloy.
  • the rod then recovers towards its heat-stable configuration, applying a corrective force to the spinal column.
  • Rods or other support elements which are used to support a spinal column can be fastened to the patient's vertebrae by means of fastening devices such as screws or hooks.
  • Such devices can include a channel in which the support element can be fitted, and retained by means of a lock screw.
  • the channel can have a through hole in its base, through which the shank of a fixation screw can extend.
  • the channel can have a hook which extends beyond the base of the channel, to engage a projection provided by the bone tissue of the vertebra.
  • the forces which are imposed on a patient's vertebrae by a rod (or other support element) can be significant. It is important to ensure that the rod is fastened securely to the vertebrae, and that the tissue to which the rod is fastened is capable of carrying the imposed loads. Problems that can arise due to inappropriate fixation include pull-out of a fixation screw, fracture of a fixation screw, and fracture of the vertebra into which the screw is fixed.
  • a bridge connector which includes a channel in which the support element can be fitted, and a pair of transverse arms. Each of the transverse arms can be fastened to a vertebra by means of two bone screws or other fastening devices.
  • This arrangement has been found to be satisfactory to secure a support rod to vertebrae in the sacral, lumbar, and lower thoracic regions of the spinal column.
  • this fastening arrangement in the upper thoracic and cervical region can be difficult because of the small size of the vertebrae.
  • the present invention provides an implant kit for correcting spinal deformities, which includes a housing for an elongate spinal support element, especially a rod, formed by a channel and a closure cap, and having a connection portion such as a screw or a hook which protrudes beyond the base of the channel to engage a vertebra so that the channel is connected directly to the vertebra, and a transverse arm extending from a side wall of the channel which can be connected to a vertebra using a secondary connection portion.
  • a housing for an elongate spinal support element especially a rod, formed by a channel and a closure cap, and having a connection portion such as a screw or a hook which protrudes beyond the base of the channel to engage a vertebra so that the channel is connected directly to the vertebra, and a transverse arm extending from a side wall of the channel which can be connected to a vertebra using a secondary connection portion.
  • the invention provides a fixation device for connecting an elongate support element to a patient's vertebra in order to correct a spinal deformity, which comprises: a. a primary housing for the support element formed by a channel and a closure cap, in which the element can be received in the channel, and be retained in the channel by the cap, b. a primary connection portion which protrudes beyond the base of the channel to engage a vertebra so that the channel is connected directly to the vertebra, and c. a transverse arm extending from a side wall of the channel.
  • the invention provides a fixation device for connecting an elongate support element to a patient's vertebra in order to correct a spinal deformity, which comprises: a. a primary housing for the support element formed by a channel and a closure cap, in which the element can be received in the channel, and be retained in the channel by the cap, b. a first bone screw which protrudes beyond the base of the channel to penetrate a vertebra so that the channel is connected directly to the vertebra, c. a transverse arm extending from a side wall of the channel, d. a secondary connector for engaging the transverse arm at a position that is spaced apart along the transverse arm from the primary housing, which includes a second bone screw which can penetrate a vertebra so that the transverse arm is connected to the vertebra.
  • the fixation of the invention has the advantage that it enables the forces which are applied to the spinal column by a support element to be applied at two spaced points which are spaced apart across the axis of the spinal column, usually on a single vertebra, but possible on adjacent vertebrae. Furthermore, this is possible in locations in which there is not sufficient space to use a bridge connector of the known kind which is described above. Accordingly, loads can be spread across more than one connection portion which can reduce the risk of damage to a patient's vertebra as a result of a load being applied at a single point.
  • the ability to use multiple points of fixation for a spinal rod or other support element, where there is limited space represents a considerable advance.
  • the invention provides an implant kit which includes a fixation device as discussed above, and a secondary connection portion for connecting the transverse arm to a vertebra at a position that is spaced apart transversely from the primary connection portion.
  • the invention provides an implant kit which includes a fixation device as discussed above, and an elongate support element which can be fastened to a patient's vertebrae using the fixation device in a deformed configuration, from which it attempts to recover after implantation and so to apply a corrective force to the patient's spine.
  • the primary connection portion or the secondary connection portion or both can comprise a bone screw.
  • the screw should be designed with an appropriate thread having regard to the nature of the tissue into which it is to extend. The factors affecting the suitability of a thread to engage bone tissue of a vertebra are well known, including thread pitch, shank diameter, thread diameter and so on.
  • the primary connection portion of the secondary connection portion or both can comprise a hook.
  • the design of hooks which are suitable for fixing an elongate spinal support element to a vertebra is known.
  • connection portion When one or each connection portion comprises a bone screw, it can be used with a channel in which the element and/or the transverse arm can be received, which has a through hole in its base.
  • the bone screw can have a head and a shank which are sized so that the shank can extend through the through hole, and the head is retained in the channel.
  • the element or the transverse arm (as the case might be) can be retained in its respective channel by means of a closure cap having threads which can engage corresponding threads on the walls of the channel.
  • the threads can be provided on the internal walls of the channel or on the external walls of the channel.
  • the channel can be provided with threads on both its internal walls and its external walls to provide different options for engagement of a lock screw.
  • the opening in the through hole to the inside of the channel is rounded when viewed from one side, and that the face of the head of the bone screw which faces towards the base of the channel has a corresponding rounded shape.
  • This can enable the bone screw to be screwed into bone tissue with the angle between the axis of the screw and the axis of the through hole being greater than 0°, for example at least about 5°, or at least about 10°, or possibly at least about 15°.
  • the transverse arm can be permanently connected to the wall of the channel.
  • it can be formed as one piece with the channel by a technique such as casting or machining, or it can be fastened permanently to the channel, for example by a technique such as welding.
  • the channel and the transverse arm can be provided as separate parts.
  • the side wall of the channel can provide a socket in to which an end of the transverse arm can be received.
  • the end of the transverse arm can be fastened into the socket by means of cooperating threads. This can provide a suitably secure connection, particularly when the transverse arm is secured against twisting about its axis as a result of the connection at its other end to the secondary connection portion.
  • the transverse arm can have a through hole towards the end which is remote from the primary housing, through which a bone screw of the secondary connection portion can extend.
  • the bone screw of the secondary connection portion includes a secondary housing for the transverse arm, in which the transverse arm can be clamped.
  • a secondary housing for the transverse arm in which the transverse arm can be clamped.
  • the features of the housing of the secondary connection portion can include the features of the housing of the primary connection portion. It can be preferred for the transverse arm to have at least one longitudinally extending spline which extends along at least part of its length. This can help to secure the arm within a housing against twisting about its axis.
  • the housing can be provided with splines on at least a portion of at least one wall which are positioned to engage with the splines on the transverse arm to restrict rotation of the arm about its axis.
  • the splines on the transverse arm can still provide the desired restriction of rotation of the arm due to engagement with other housing features, such as the edges of the housing channel in which the arm is received.
  • the transverse arm can have a cross-section which is non-circular to enable it to fit securely in a channel in such a way that it can transmit torque to the channel.
  • the arm can have at least one flat face.
  • Polygonal (regular or irregular) shapes can be useful, for example with at least four faces, including square or rectangular or trapezoidal (when the element has four faces when viewed in cross-section), or with six or eight or more faces.
  • An arm which has a generally rounded cross-section might have a flat face.
  • the transverse arm is cranked so that the angle between the axes defined by the arms at its opposite ends (when viewed from one side of the primary housing generally along the superior-inferior axis) is less than 180°, for example not more than about 170°, and possibly not more than about 160°. This can help to align the transverse arm with the connection portion of the implant kit which is used to fasten the arm to the vertebra.
  • the housing can be provided with more than one transverse arm. hi particular, it can be preferred that the housing is provided with a transverse arm extending from each of two opposite side walls.
  • the angle between two such transverse arms at the points where they are connected to the housing, when viewed from above (along the axis of the channel) will generally be 180°. However, the angle might be less than 180°, for example not more than about 170°, and possibly not more than about 160° . This can help to align the transverse arm with the connection portion of the implant kit which is used to fasten the arm to the vertebra.
  • connection portions, the housing and the transverse arm might be made from a metallic material as is generally known for components of spinal implant kits. Suitable metals include certain stainless steels, and titanium and its alloys. It can be preferred that the transverse arm at least is formed from a material which enables the arm to be cut to length to suit a particular application.
  • the cross-sectional area of the transverse arm will often be approximately constant over at least most of its length, with the possibility that the cross-section might vary in at least one end region to facilitate connection directly or indirectly to a vertebra or to the primary housing.
  • the cross-sectional area of the support element might be at least about 10 mm 2 , preferably at least about 20 mm 2 , more preferably at least about 30 mm 2 , for example about 40 mm 2 .
  • the length of the transverse arm can be selected according to the requirements of a particular application. It is expected that it will seldom be required to be longer than about 50 mm. The length of the transverse arm will usually be at least about 15 mm.
  • the material of the transverse arm is selected so that the arm can be cut to length to suit the requirements of a particular implantation.
  • the support element is capable of recoverable deformation towards its original undeformed configuration (from which it had been deformed) such that the angle between its ends changes through at least about 20°, more preferably at least about 25°, especially at least about 30°.
  • Recoverable deformation is deformation that can be recovered substantially completely back to the undeformed configuration when applied stress is removed, or otherwise when allowed to recover (for example as a result of heating to allow a transformation to austenite phase).
  • the support element will preferably be a rod, especially with a solid cross-section.
  • a rod support element can be hollow along at least part of its length.
  • One or more of the support elements can be a plate.
  • the cross-sectional area of the support element will often be approximately constant over at least most of its length, with the possibility that the cross-section might vary in at least one end region to facilitate connection directly or indirectly to a vertebra at the end or to an adjacent support element.
  • the cross-sectional area of the support element might be at least about 10 mm 2 , preferably at least about 20 mm 2 , more preferably at least about 30 mm 2 , for example about 40 mm 2 .
  • the support element might have a rounded cross-sectional shape, especially circular. It can be preferred for the element sometimes to be non-circular to enable it to fit securely in a channel of a connection housing in such a way that it can transmit torque to the housing.
  • the element can have at least one flat face. Polygonal (regular or irregular) shapes can be useful, for example with at least four faces, including square or rectangular or trapezoidal (when the element has four faces when viewed in cross-section), or with six or eight or more faces.
  • An element which has a generally rounded cross-section might have a flat face.
  • the support element can be formed from a shape memory alloy.
  • the alloy can be treated so that it is implanted while in the martensite phase.
  • the treatment of the alloy can be such that its A s and A f temperatures are between ambient temperature and body temperature
  • the alloy is fully austenite phase at body temperature (for example by virtue of the A f temperature being about 32°C).
  • a f temperature being about 32°C.
  • Shape memory alloys can exhibit enhanced elastic properties compared with materials which do not exhibit martensite-austenite transformations and it is these properties that the present invention is concerned with in particular.
  • the nature of superelastic transformations of shape memory alloys is discussed in "Engineering Aspects of Shape Memory Alloys", T W Duerig et al, on page 370, Butterworth-Heinemann (1990). Subject matter disclosed in that document is incorporated in this specification by this reference to the document.
  • a principal transformation of shape memory alloys involves an initial increase in strain, approximately linearly with stress. This behaviour is reversible, and corresponds to conventional elastic deformation. Subsequent increases in strain are accompanied by little or no increase in stress, over a limited range of strain to the end of the "loading plateau".
  • the loading plateau stress is defined by the inflection point on the stress/strain graph. Subsequent increases in strain are accompanied by increases in stress. On unloading, there is a decline in stress with reducing strain to the start of the "unloading plateau" evidenced by the existence of an inflection point along which stress changes little with reducing strain. At the end of the unloading plateau, stress reduces with reducing strain.
  • the unloading plateau stress is also defined by the inflection point on the stress/strain graph. Any residual strain after unloading to zero stress is the permanent set of the sample.
  • a preferred way in which non-linear superelastic properties can be introduced in a shape memory alloy involves cold working the alloy by one of several deformation methods, for example, swaging, drawing, pressing, stretching or bending.
  • the cold working step is followed by an annealing step at a temperature less than the recrystallization temperature of the alloy, for a time sufficient to cause dislocations to rearrange, combine and align themselves (so-called "recovery” processes).
  • the resulting recovered dislocation structure should ideally be dense enough to make plastic deformation difficult, but not so dense as to prevent the martensite phase from transforming upon the application of a load, and growing in a relatively unimpeded manner.
  • the alloy should by processed so that its A f temperature is below temperatures to which the alloy is likely to be subjected during implantation, that is preferably below about ambient temperature.
  • the A f temperature might be not more than about 20 0 C.
  • a device is to be used in a shape other than that which can be practically produced by cold working processes.
  • a straight wire can be conveniently produced by cold drawing, but a wire loop or other formed shape cannot be.
  • it is customary to form the drawn, cold worked wire into the desired "heat stable" shape, to constrain the wire in that shape, and then to perform the above described recovery heat treatment to "shape set" the component.
  • the final annealing operation has two purposes: to adjust the superelastic properties of the alloy, and to properly set the shape of the article.
  • the time and temperature of this heat treatment step are critical. If held too long at temperature, the material over-ages, causing the A f temperature to rise above the application temperature.
  • annealing temperature is too short, or the temperature too low, the shape will be insufficiently formed, and too much of -l ithe original dislocation structure will remain to allow free martensite movement.
  • This "forming" treatment may introduce still further cold work into the part, but that cold work is usually small compared to that introduced into the wire by drawing. Moreover, forming operations are often not uniform, and thus forming itself is not generally a convenient way to introduce cold work.
  • shape memory alloys which might be used in the first and possibly other support elements in the kit of the invention include nickel-titanium based alloys, especially the binary alloy which contains 50.8 at-% nickel. Suitable alloys include those which satisfy ASTM F2063-00. It will often be particularly preferred for both the first and second support elements to be formed from shape memory alloys, especially for each support element to be formed from shape memory alloys.
  • Other metals which might be used to form support elements which do not exhibit shape memory properties include titanium and alloys thereof, for example Ti6A14V alloys such as satisfy ASTM F136-02a or ASTM F1472-02a or both. Materials which exhibit shape memory properties, other than alloys, can be used. For example, polymeric materials can be used.
  • Shape memory properties can be imparted to polymeric materials by forming them in a desired ultimate shape (for example by moulding), crosslinking the material, heating the material to a temperature at which it softens, deforming the material while soft and restraining the material in the deformed configuration while it cools. The material will tend to revert towards the initial "as formed” configuration when reheated.
  • suitable polymeric materials which can be used in this way include oligomers, homopolymers, copolymers and polymer blends which include, as monomers, 1-, d- or d/1-lactide (lactic acid), glycolide (glycolic acid), ethers, ethylene, propylene and other olefins, styrene, norbornene, butadiene, poly- functional monomers such as acrylates, methacrylates, methyl acrylates, and esters such as caprolactone.
  • oligomers oligomers, homopolymers, copolymers and polymer blends which include, as monomers, 1-, d- or d/1-lactide (lactic acid), glycolide (glycolic acid), ethers, ethylene, propylene and other olefins, styrene, norbornene, butadiene, poly- functional monomers such as acrylates, methacrylates, methyl acrylates, and esters such
  • Figure 1 is a side view of a primary housing for a support element for use in the kit of the invention.
  • Figure 2 is an isometric view of an implant construct which comprises an elongate spinal support rod and two fixation devices which each include primary housings, connection portions and transverse arms.
  • Figure 3 is an isometric view of another embodiment of fixation device in which the primary housing and transverse arm are provided as separate parts.
  • Figure 4 is an isometric view of a portion of an implant kit with another embodiment of fixation device in which a fixation hole is provided in the transverse arm.
  • Figure 5 is an isometric view of a fixation device in which the primary connection portion comprises a hook to engage the tissue of a patient's vertebra.
  • Figure 1 shows a fixation device 2 which can be used to provide two-point fixation of an elongate spinal support rod to a patient's vertebra.
  • the device comprises a primary housing provided by a channel part 4 having a base 6 and first and second opposite side walls 8, 10. The gap between the side walls is dimensioned so that the support rod is a tight fit in the channel.
  • the side walls of the channel part have threads 12 on their internal and external surfaces to engage a locking nut, which can be an internal nut or an external nut, for retaining the rod in the channel. It is also envisaged that both internal and external nuts might be used to provide secure engagement.
  • a through-hole 16 is provided in the base 6 of the channel, through which the shaft of a fixation screw 18 can extend.
  • the fixation screw 18 has a head whose transverse dimension is too big for to fit through the through-hole.
  • the engaging surfaces of the through-hole and of the screw head are rounded when viewed from one side so that the screw head engages the through-hole surface securely over a range of angles between the axes of the screw and the through-hole.
  • the fixation device includes a transverse arm 20 which extends from and is formed integrally with one of the side walls 10 of the channel.
  • the transverse arm has a circular cross-section, and has longitudinally extending splines on its lower surface 22.
  • Figure 2 shows an implant kit which includes two fixation devices 2 of the type described above with reference to Figure 1.
  • An elongate spinal support rod 30 formed from a NiTi shape memory alloy is received in the channels of the fixation device primary housings and is retained there by means of internal nuts 32 which engage ' the threads 12 on the internal surfaces of the channel parts 4.
  • the implant kit includes two secondary connectors 34, each having a channel 36 and a fixation screw 38 extending through a through-hole in the base of the channel.
  • Each of the transverse arms 20 fits into the channel on a respective one of the connectors, and is retained in the channel by means of an internal nut 38.
  • Features of the connectors 34 and of the engagement of the transverse arms in the channels are similar to the corresponding features of the primary housing described above. Note however that the cross-section of the spinal support rod, and therefore of the base of the channel in the primary housing, are square, whereas the cross-section of the transverse arm, and therefore of the base of the channel in the secondary connectors, is rounded.
  • FIG. 3 shows a fixation device 60 in which the side wall 62 of a channel on a housing has a socket 64 formed on it.
  • a transverse arm 66 has a reduced diameter spigot portion 68 at one end which is a tight fit in the socket.
  • the socket and the spigot portion might engage one another by means of mating threads.
  • Figure 4 shows a part of an implant construct which includes a spinal support rod 70 with a square cross-section, which is received in the channel of a primary housing 72 as discussed above.
  • the transverse arm 74 which extends from a side wall 76 of the housing has a through-hole at the end which is remote from the housing for receiving a bone screw 78.
  • FIG. 5 shows a fixation device 80 which includes a primary housing for a support element formed by a channel 82. As discussed above with reference to Figure 1, a support rod can be retained in the channel by means of one or more nuts.
  • a hook 84 extends from the base of the channel and is arranged so that it can engage the patient's vertebra to restrain the support element against movement relative to the vertebra.
  • a transverse arm 86 with a round cross-section extends from one of the side walls of the channel.
  • Secondary connection portions which can be used to anchor the transverse arm to the patient's vertebra include a bone screw or hook (for engaging the vertebra), having a channel in which the arm can be received and locked.
  • Such screws and hooks are known, as used for example to fasten spinal support rods directly to a patient's vertebrae.

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  • Molecular Biology (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Surgical Instruments (AREA)

Abstract

L'invention concerne un dispositif de fixation (2) destiné à connecter un élément support allongé (30) aux vertèbres d'un patient afin de corriger une déformation spinale, comportant un boîtier (4) destiné à l'élément support formé par un canal et un capuchon de fermeture (32), dans lequel l'élément peut être logé à l'intérieur du canal, et retenu dans le canal par le capuchon. Une première vis à os (18) fait saillie par rapport à la base (6) du canal de manière à pénétrer dans une vertèbre, de telle façon que le canal est connecté directement à la vertèbre. Le dispositif selon l'invention comporte un bras transversal (20) s'étendant à partir d'une paroi latérale (8, 10) du canal, et un connecteur secondaire (34) destiné à entrer en prise avec le bras transversal dans une position espacée par rapport au boîtier primaire le long du bras transversal. Le connecteur secondaire comporte une vis à os pouvant pénétrer dans une vertèbre de telle manière que le bras transversal est connecté à la vertèbre.
PCT/GB2006/003918 2005-10-22 2006-10-20 Dispositif de fixation destine a un element support spinal allonge Ceased WO2007045899A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0521583A GB0521583D0 (en) 2005-10-22 2005-10-22 A fixation device for an elongate spinal support element
GB0521583.5 2005-10-22

Publications (1)

Publication Number Publication Date
WO2007045899A1 true WO2007045899A1 (fr) 2007-04-26

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2006/003918 Ceased WO2007045899A1 (fr) 2005-10-22 2006-10-20 Dispositif de fixation destine a un element support spinal allonge

Country Status (2)

Country Link
GB (1) GB0521583D0 (fr)
WO (1) WO2007045899A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8313515B2 (en) 2007-06-15 2012-11-20 Rachiotek, Llc Multi-level spinal stabilization system
US8348952B2 (en) 2006-01-26 2013-01-08 Depuy International Ltd. System and method for cooling a spinal correction device comprising a shape memory material for corrective spinal surgery
US8414614B2 (en) 2005-10-22 2013-04-09 Depuy International Ltd Implant kit for supporting a spinal column
EP2413823A4 (fr) * 2009-04-01 2013-12-04 Globus Medical Inc Pince orthopédique et tige d'extension
CN104107085A (zh) * 2013-04-17 2014-10-22 上海市同济医院 一种具有药物剂量精确缓释功能的构件连接杆
EP2677950A4 (fr) * 2011-02-24 2017-11-01 Steib, John, Paul Systèmes et procédés permettant de relier des implants et de réduire des difformités

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0470660A1 (fr) * 1990-08-07 1992-02-12 Acromed B.V. Dispositif pour la correction de la scoliose
FR2813782A1 (fr) * 2000-09-13 2002-03-15 Eurosurgical Ancillaire pour la correction d'un segment rachidien et la mise en place d'un dispositif d'osteosynthese rachidienne reliant chaque vertebre du segment rachidien a corriger
WO2002022030A2 (fr) * 2000-09-15 2002-03-21 Sdgi Holdings, Inc. Systeme de fixation posterieur
US20040260285A1 (en) * 2003-06-17 2004-12-23 Eurosurgical Sa Pedicular hooks for rachidian anchoring device
US20050038430A1 (en) * 2003-08-11 2005-02-17 Mckinley Laurence M. Low profile vertebral alignment and fixation assembly

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0470660A1 (fr) * 1990-08-07 1992-02-12 Acromed B.V. Dispositif pour la correction de la scoliose
FR2813782A1 (fr) * 2000-09-13 2002-03-15 Eurosurgical Ancillaire pour la correction d'un segment rachidien et la mise en place d'un dispositif d'osteosynthese rachidienne reliant chaque vertebre du segment rachidien a corriger
WO2002022030A2 (fr) * 2000-09-15 2002-03-21 Sdgi Holdings, Inc. Systeme de fixation posterieur
US20040260285A1 (en) * 2003-06-17 2004-12-23 Eurosurgical Sa Pedicular hooks for rachidian anchoring device
US20050038430A1 (en) * 2003-08-11 2005-02-17 Mckinley Laurence M. Low profile vertebral alignment and fixation assembly

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8414614B2 (en) 2005-10-22 2013-04-09 Depuy International Ltd Implant kit for supporting a spinal column
US8348952B2 (en) 2006-01-26 2013-01-08 Depuy International Ltd. System and method for cooling a spinal correction device comprising a shape memory material for corrective spinal surgery
US8313515B2 (en) 2007-06-15 2012-11-20 Rachiotek, Llc Multi-level spinal stabilization system
EP2413823A4 (fr) * 2009-04-01 2013-12-04 Globus Medical Inc Pince orthopédique et tige d'extension
EP2677950A4 (fr) * 2011-02-24 2017-11-01 Steib, John, Paul Systèmes et procédés permettant de relier des implants et de réduire des difformités
CN104107085A (zh) * 2013-04-17 2014-10-22 上海市同济医院 一种具有药物剂量精确缓释功能的构件连接杆

Also Published As

Publication number Publication date
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