WO2000019922A1 - Spinal fixings - Google Patents

Spinal fixings Download PDF

Info

Publication number
WO2000019922A1
WO2000019922A1 PCT/GB1999/003080 GB9903080W WO0019922A1 WO 2000019922 A1 WO2000019922 A1 WO 2000019922A1 GB 9903080 W GB9903080 W GB 9903080W WO 0019922 A1 WO0019922 A1 WO 0019922A1
Authority
WO
WIPO (PCT)
Prior art keywords
fixing
components
component
spine
fixing according
Prior art date
Application number
PCT/GB1999/003080
Other languages
French (fr)
Inventor
Hugh Davies
David Marks
Original Assignee
Depuy International Limited
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 Limited filed Critical Depuy International Limited
Priority to AU60994/99A priority Critical patent/AU6099499A/en
Publication of WO2000019922A1 publication Critical patent/WO2000019922A1/en

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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, 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
    • A61B17/7047—Clamps comprising opposed elements which grasp one vertebra between them
    • 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
    • A61B17/7001—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

Definitions

  • This invention concerns improvements in and relating to fixings, particularly, but not exclusively for the spines of children.
  • a number of medical conditions require corrective surgery to the spine. In some cases this involves the shaping or support of the spine by a rod or other relatively rigid member. Such systems are used for correction of spinal deformity.
  • the rod generally extends along at least part of the length of the spine and is fixed thereto at a number of locations.
  • the fixing locations can be provided in a number of ways including hooks which engage with parts of the spine or pedicle screws which are actually inserted into the bone.
  • a fixing suitable to stop movement of the fixation system is necessary. This must resist forces in a number of directions.
  • the intermediate fixations generally only need to maintain the spine to rod position. To provide the rigid location two fixings in opposition to one another are usually employed.
  • a typical existing hook consists of a head portion to which the rod is later attached and a hook portion extending from the head and adapted to engage with a part of the spine. Two such hooks are applied to opposing sides of a lamina process to provide a firm end fixing with the rod separately attached to each.
  • the size of the fixings and in particular the limit to which they can be brought together cause significant problems and prevents their successful use in paediatric applications as the fixing can still be relatively loose .
  • the present invention aims to provide an improved fixing, particularly for use in paediatric cases.
  • a spinal fixing comprising a first component and a second component, the first and second components being provided with a body portion and a spine engaging portion, means for coupling the first and second components, the fixing provided a connecting location for a separate element.
  • first and/or second components and/or coupling means are discretely formed.
  • the body portion of the first and/or second component may be integral with the spine engaging portion and/or with the connecting location or a part thereof.
  • the body portions of the first and second components may be provided with opposing faces.
  • the opposing faces are planar.
  • the opposing faces may abut one another in the assembled state.
  • the body portion may be semi-circular, in cross-section.
  • the opposing face may be defined by the diameter of the semi-circular section .
  • the spine engaging portion may depend from the body portion.
  • the spine engaging portion of the first and/or second component may comprise a first part and a second part, the first and second parts engaging different parts of the spine in use.
  • the first and second parts may oppose one another.
  • the first and second parts may be joined by a third part.
  • the third part may be spaced from the spine in use.
  • the first part may form the under surface of the body portion.
  • the second part may form the distal end of the spine engaging portion to the body portion .
  • the spine engaging portion may comprise a recess.
  • the spine engaging portion may be a hook.
  • the first and/or second parts of the spine engaging portion of the first and second component may be provided with opposing faces.
  • the opposing faces may be planar.
  • the opposing face(s) may share a common plane with the opposing face(s) of the body portion(s).
  • the opposing faces may abut one another in the assembled state.
  • the means for coupling may comprise an element engaging both first and second components.
  • the coupling means may maintain the first and second components in contact with one another.
  • the coupling means may cooperate or receive a portion of the first and second component. The received portion may be the connecting location of a component or a part thereof.
  • the coupling means may surround a portion of the first and second component.
  • the coupling means may comprise a ring or collar.
  • the coupling means may comprise a screw threaded member which cooperates with a portion of the first and second component provided with a screw thread.
  • the coupling means is detachable from the received portion.
  • the connecting location may comprise a recess or groove into which the separate element is received.
  • the recess or groove may be defined in both components.
  • the recess or groove may be defined by one component forming one side wall and the other component forming the other side wall of the groove or recess.
  • the coupling means and/or separate retaining means preferably retains the separate element to the fixing, most preferably to the connecting location.
  • the coupling means closes the groove or recess to form a through passage.
  • the separate element is received and most preferably retained in the through passage.
  • the coupling means contacts the separate element in use.
  • the separate element may also contact one or both walls of the groove or recess and/or the base of the groove or recess in use.
  • the connecting location may comprise a cylindrical element with a connecting location provided within it.
  • the connecting location may be provided with an internal and/or external screw thread for engaging with the coupling means or separate retaining means .
  • the connecting location may be provided by on body portion of one or both components of the fixing. Preferably the connecting location is provided by both components.
  • the connecting location may be provided on a separate element to the first and/or second components.
  • the separate element may engage with one or both components of the fixing.
  • the separate element may be a component connecting the fixing to one or more other fixings, in use.
  • the other fixings may be of the same type and/or different.
  • the separate element is an elongate element, such as a bar or rod.
  • the separate element extends for a significant portion of the spine, in use.
  • the body portions and/or spine engaging portions and/or connecting means of the first and second component may abut one another in use.
  • the opposing faces of the body portions abut.
  • the first and second components abut on a plan of symmetry, at least for the body portion and, more preferably, the spine engaging portion too.
  • the body portions of the first and second components may form a cylinder, most preferably with an axis lying on a plane of symmetry for the body portions. Each component may provide half of the total body portion.
  • the connecting locations of the first and second components may form a cylinder, most preferably with an axis lying on a plane of symmetry for the connecting location. Each component may provide half of the total connecting location.
  • the first and second components may each form a half of the fixing, excluding the coupling means.
  • the first and second component body portions and/or spine engaging portions and/or connecting locations may be of the same configuration.
  • the first component and second component are preferably the same in configuration.
  • the fixing may further comprise retaining means for the first and second components to maintain their position during assembly.
  • the retaining means engage the connecting location of the first and/or second components or a part thereof.
  • the retaining means may comprise a member placed over a portion of the first and second components. Preferably these portions are abutting one another.
  • the retaining means may be a ring, washer or collar.
  • the retaining means are provided on the first and second components prior to the introduction of the separate element.
  • the separate element is introduced to the connecting location prior to the coupling means.
  • a face of the body portion of the first and second components abut one another, the spine engaging portions oppose one another and the coupling means cooperates with a received portion formed by a part of the first and a part of the second component.
  • a fixing component comprising a first or second component of a fixing provided according to the first aspect of the invention, the first or second component comprising one or more features or possibilities therefor.
  • a fixing component comprising a body portion and spine engaging portion, the component being provided with only a portion of the means for coupling it to coupling means.
  • the means for coupling may be a screw thread, a portion of the screw thread only being provided on the component. Preferably only a portion of one or more pitches of the thread is provided on the component. Preferably the remainder of the thread is provided on a second component. Preferably the screw thread is externally provided on the component. Preferably the coupling means is provided with an internal screw thread.
  • a fixation construction system comprising :- a fixing according to the first aspect of the invention; optionally one or more other types of fixings; one or more separate elements for connecting between a series of the fixings; and optionally one or more releasable fasteners for attaching the element to the optional other fixings.
  • the first type fixing may include or incorporate any of the features, options and possibilities set out elsewhere in this document .
  • the intermediate fixings may be provide with a single body portion, attachment portion and spine engaging portion.
  • the portions may be provided integral with one another.
  • the entire coupling between the intermediate fixings and the releasable fastener may be provided by the attachment portion of a single fixing .
  • the separate element may be a rod or bar.
  • the element is of circular cross-section.
  • the element has a deformable configuration during construction of the system and has a substantially resilient configuration in use.
  • the releasable fasteners may engage the fixings by means of a screw thread.
  • the screw thread is an internal one on the fastener and an external one on the fixing.
  • a fifth aspect of the invention we provide a method of fastening comprising engaging a first component according to the first or second aspect of the invention with a portion of the spine, engaging a second component according to the first or second aspect of the invention with a portion of the spine in opposition to the first, introducing an elongate element to the first and second components of the fixing and applying a coupling means to retain the first and second components and elongate element together.
  • the fixing is provide at, or towards one end of the portion of the spine to be treated.
  • a fixing of this type is provided at, or towards both ends of the system in use .
  • One or more intermediate fixings may be provided.
  • the intermediate fixings may be provided with a unitary body portion, attachment portion and hook portion.
  • the portions may be provided integral with one another.
  • Other fixing types, such as pedicle screws, may be employed.
  • the element may be a rod or bar.
  • the rod has a deformable configuration during assembly of the system, but has a substantially resilient configuration during use.
  • the element is received in a slot or groove in the component (s) of the fixing. components.
  • the element may be retained relative to the fixing by means of a releasable fastener.
  • the releasable fastener may engage the fixing by means of a screw thread.
  • the screw thread is an internal one on the fastener and an external one on the fixing.
  • Means may be applied to retain the first and second components relative to one another prior to introduction of the elongate element.
  • the means may be a ring, collar or washer.
  • the means may threadedly engage the first and second components.
  • Figure 1a illustrates a side view of a prior art fixing
  • Figure 1b illustrates a front view of the prior art fixing of Figure 1a
  • Figure 2 illustrates a component of a fixing according to the invention
  • FIG. 3 illustrates an assembled fixing according to the invention.
  • Figure 4 illustrates a series of fixings in use including a fixing according to the invention in use.
  • the prior art fixing comprises a body portion 2 from which the hook 4 extends in one direction and the rod attachment portion 6 in the other.
  • the gap 8 between the back portion 9, top portion 10 and foot portion 12 of the hook 4 is dimensioned to accommodate a portion of the spine, normally of the lamina process, in use.
  • the rod attachment portion 6 is provided with a recess 14 into which the rod is introduced in use.
  • a variety of systems exist for retaining the rod in position including an internally threaded cap, not shown, which cooperates with the external thread 16 provided on the rod attachment portion 6.
  • the size of the hooks needed to perform the task, and more particularly the size of the body portions means that the gap 8 for both hooks combined is fixed at a particular minimum size, distance X. This size is too large for the lamina process of children's spines giving an impaired fixing as a result.
  • the fixing of the present invention is exemplified by two components equivalent to that shown in Figure 2.
  • This fixing component consists of a body portion 20 and hook 22 depending from it.
  • the body portion is also provided with a rod attachment portion 24 with a through groove 25 to accommodate the rod in use.
  • the fixing is distinguished in that the body portion 20 and rod attachment portion 24 form only a half of a complete unit.
  • one side 26 of the body portion 20 and rod attachment portion 24 has a circular external profile, but the other side 30 has a flat face.
  • the semi-circular side 26 of the rod attachment portion 24 is provided with an external screw thread 31.
  • a complete fixing is provided.
  • the two components designated a, b, form a completed rod attachment portion from the two halves of the body portions 20a, 20b and rod attachment portions 24a, 24b, and with an aligned through groove.
  • the assembled fixing also presents opposing hooks 22a, 22b, with a significantly reduced total gap X2 between them.
  • a ring 23 is pushed down over the two halves of the rod attachment portions 24a, 24b.
  • a rod 27 is then introduced into the groove 25 and an internally screw threaded ring tightened down on screw thread 31 to provide firm retention.
  • the combined fixing of Figure 3 is used to form an end fixing 100 capable of withstanding forces in either direction as it snugly engages a spinal process 102.
  • the first component 101a and second component 101b form an equivalent head portion 103 to that of a conventional fixing 104.
  • Another fixing 104 of the conventional type is positioned on another lamina process 106 within the spinal column with in this case a hook 106 and presented in one direction only and a head portion 105.
  • a further end fixing with opposing hooks of the type according to the invention defines the other end of the fixing system, not shown.
  • the corrective rod is positioned in the slot 110 in the head of each fixing 100, 104, and retained by a screw cap.
  • the screw cap also serves to provide a more permeant retaining force to keep the two halves of the hooks together.
  • a standard screw cap can be used for each.
  • the system of the present invention presents a number of advantages, particularly for paediatric applications.
  • the smaller gap between hooks provides a firmer fixing on the spine and is less prone to movement and slippage as a result.
  • the reduced volume of body and rod attachment portion a 50% reduction, makes the fixing less intrusive.
  • the use of a retaining ring maintains the hooks in position on the spine pending the introduction of the rod.
  • the fixing of the rod to the end fixing also only requires the rod to be introduced and clamped to one attachment rather than two so reducing the time spent. Significantly all these benefits are achieved whilst using standard size rods and fixings for the attachment portions. This allows existing instruments also to be employed.

Abstract

The invention provides a spinal fixing and spinal fixing system based around spinal fixings comprising a first component and a second component, the first and second components each being provided with a body portion (20) and a spine engaging portion (22) and means such as an internally screw-threadedring for coupling the first and second components, the fixing providing a connecting location (25) for a separate element. Fixings of this type allow firm anchors on spines to be constructed on relatively small portions of the spine, such as encountered in children. The connecting location so provided allows for a separate element, such as a spinal supporting rod (27) to be introduced and firmly located.

Description

SPINAL FIXINGS
This invention concerns improvements in and relating to fixings, particularly, but not exclusively for the spines of children.
A number of medical conditions require corrective surgery to the spine. In some cases this involves the shaping or support of the spine by a rod or other relatively rigid member. Such systems are used for correction of spinal deformity. The rod generally extends along at least part of the length of the spine and is fixed thereto at a number of locations.
The fixing locations can be provided in a number of ways including hooks which engage with parts of the spine or pedicle screws which are actually inserted into the bone. At each end of the fixation system a fixing suitable to stop movement of the fixation system is necessary. This must resist forces in a number of directions. The intermediate fixations generally only need to maintain the spine to rod position. To provide the rigid location two fixings in opposition to one another are usually employed.
Particular problems are encountered when undertaking such procedures on children due to the reduced size of the spine and parts thereof. A typical existing hook consists of a head portion to which the rod is later attached and a hook portion extending from the head and adapted to engage with a part of the spine. Two such hooks are applied to opposing sides of a lamina process to provide a firm end fixing with the rod separately attached to each. The size of the fixings and in particular the limit to which they can be brought together cause significant problems and prevents their successful use in paediatric applications as the fixing can still be relatively loose . The present invention aims to provide an improved fixing, particularly for use in paediatric cases.
According to a first aspect of the invention we provide a spinal fixing comprising a first component and a second component, the first and second components being provided with a body portion and a spine engaging portion, means for coupling the first and second components, the fixing provided a connecting location for a separate element.
Preferably the first and/or second components and/or coupling means are discretely formed.
The body portion of the first and/or second component may be integral with the spine engaging portion and/or with the connecting location or a part thereof. The body portions of the first and second components may be provided with opposing faces. Preferably the opposing faces are planar. The opposing faces may abut one another in the assembled state. The body portion may be semi-circular, in cross-section. The opposing face may be defined by the diameter of the semi-circular section .
The spine engaging portion may depend from the body portion.
The spine engaging portion of the first and/or second component may comprise a first part and a second part, the first and second parts engaging different parts of the spine in use. The first and second parts may oppose one another. The first and second parts may be joined by a third part. The third part may be spaced from the spine in use. The first part may form the under surface of the body portion. The second part may form the distal end of the spine engaging portion to the body portion .
The spine engaging portion may comprise a recess. The spine engaging portion may be a hook. The first and/or second parts of the spine engaging portion of the first and second component may be provided with opposing faces. The opposing faces may be planar. The opposing face(s) may share a common plane with the opposing face(s) of the body portion(s). The opposing faces may abut one another in the assembled state.
The means for coupling may comprise an element engaging both first and second components. The coupling means may maintain the first and second components in contact with one another. The coupling means may cooperate or receive a portion of the first and second component. The received portion may be the connecting location of a component or a part thereof.
The coupling means may surround a portion of the first and second component. The coupling means may comprise a ring or collar. The coupling means may comprise a screw threaded member which cooperates with a portion of the first and second component provided with a screw thread.
Preferably the coupling means is detachable from the received portion.
The connecting location may comprise a recess or groove into which the separate element is received. The recess or groove may be defined in both components. The recess or groove may be defined by one component forming one side wall and the other component forming the other side wall of the groove or recess.
The coupling means and/or separate retaining means preferably retains the separate element to the fixing, most preferably to the connecting location.
Preferably the coupling means closes the groove or recess to form a through passage. Preferably the separate element is received and most preferably retained in the through passage. Preferably the coupling means contacts the separate element in use. The separate element may also contact one or both walls of the groove or recess and/or the base of the groove or recess in use.
The connecting location may comprise a cylindrical element with a connecting location provided within it. The connecting location may be provided with an internal and/or external screw thread for engaging with the coupling means or separate retaining means .
The connecting location may be provided by on body portion of one or both components of the fixing. Preferably the connecting location is provided by both components.
The connecting location may be provided on a separate element to the first and/or second components. The separate element may engage with one or both components of the fixing.
The separate element may be a component connecting the fixing to one or more other fixings, in use. The other fixings may be of the same type and/or different. Preferably the separate element is an elongate element, such as a bar or rod. Preferably the separate element extends for a significant portion of the spine, in use.
The body portions and/or spine engaging portions and/or connecting means of the first and second component may abut one another in use. Preferably the opposing faces of the body portions abut. Preferably the first and second components abut on a plan of symmetry, at least for the body portion and, more preferably, the spine engaging portion too.
The body portions of the first and second components may form a cylinder, most preferably with an axis lying on a plane of symmetry for the body portions. Each component may provide half of the total body portion. The connecting locations of the first and second components may form a cylinder, most preferably with an axis lying on a plane of symmetry for the connecting location. Each component may provide half of the total connecting location.
The first and second components may each form a half of the fixing, excluding the coupling means.
The first and second component body portions and/or spine engaging portions and/or connecting locations may be of the same configuration. The first component and second component are preferably the same in configuration.
The fixing may further comprise retaining means for the first and second components to maintain their position during assembly. Preferably the retaining means engage the connecting location of the first and/or second components or a part thereof. The retaining means may comprise a member placed over a portion of the first and second components. Preferably these portions are abutting one another. The retaining means may be a ring, washer or collar.
Preferably the retaining means are provided on the first and second components prior to the introduction of the separate element. Preferably the separate element is introduced to the connecting location prior to the coupling means.
In a particularly preferred form a face of the body portion of the first and second components abut one another, the spine engaging portions oppose one another and the coupling means cooperates with a received portion formed by a part of the first and a part of the second component.
Features and possibilities may be possessed by the first and/or second components independently of each other. According to a second aspect of the invention we provide a fixing component comprising a first or second component of a fixing provided according to the first aspect of the invention, the first or second component comprising one or more features or possibilities therefor.
According to a third aspect of the invention we provide a fixing component comprising a body portion and spine engaging portion, the component being provided with only a portion of the means for coupling it to coupling means.
The means for coupling may be a screw thread, a portion of the screw thread only being provided on the component. Preferably only a portion of one or more pitches of the thread is provided on the component. Preferably the remainder of the thread is provided on a second component. Preferably the screw thread is externally provided on the component. Preferably the coupling means is provided with an internal screw thread.
According to a fourth aspect of the invention we provide a fixation construction system comprising :- a fixing according to the first aspect of the invention; optionally one or more other types of fixings; one or more separate elements for connecting between a series of the fixings; and optionally one or more releasable fasteners for attaching the element to the optional other fixings.
The first type fixing may include or incorporate any of the features, options and possibilities set out elsewhere in this document .
The intermediate fixings may be provide with a single body portion, attachment portion and spine engaging portion. The portions may be provided integral with one another. The entire coupling between the intermediate fixings and the releasable fastener may be provided by the attachment portion of a single fixing .
The separate element may be a rod or bar. Preferably the element is of circular cross-section. Preferably the element has a deformable configuration during construction of the system and has a substantially resilient configuration in use.
The releasable fasteners may engage the fixings by means of a screw thread. Preferably the screw thread is an internal one on the fastener and an external one on the fixing.
According to a fifth aspect of the invention we provide a method of fastening comprising engaging a first component according to the first or second aspect of the invention with a portion of the spine, engaging a second component according to the first or second aspect of the invention with a portion of the spine in opposition to the first, introducing an elongate element to the first and second components of the fixing and applying a coupling means to retain the first and second components and elongate element together.
Preferably the fixing is provide at, or towards one end of the portion of the spine to be treated. Preferably a fixing of this type is provided at, or towards both ends of the system in use .
One or more intermediate fixings may be provided. The intermediate fixings may be provided with a unitary body portion, attachment portion and hook portion. The portions may be provided integral with one another. Other fixing types, such as pedicle screws, may be employed.
The element may be a rod or bar. Preferably the rod has a deformable configuration during assembly of the system, but has a substantially resilient configuration during use. Preferably the element is received in a slot or groove in the component (s) of the fixing. components. The element may be retained relative to the fixing by means of a releasable fastener. The releasable fastener may engage the fixing by means of a screw thread. Preferably the screw thread is an internal one on the fastener and an external one on the fixing.
Means may be applied to retain the first and second components relative to one another prior to introduction of the elongate element. The means may be a ring, collar or washer. The means may threadedly engage the first and second components.
Embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which :
Figure 1a illustrates a side view of a prior art fixing;
Figure 1b illustrates a front view of the prior art fixing of Figure 1a;
Figure 2 illustrates a component of a fixing according to the invention;
Figure 3 illustrates an assembled fixing according to the invention; and
Figure 4 illustrates a series of fixings in use including a fixing according to the invention in use.
The prior art fixing comprises a body portion 2 from which the hook 4 extends in one direction and the rod attachment portion 6 in the other. The gap 8 between the back portion 9, top portion 10 and foot portion 12 of the hook 4 is dimensioned to accommodate a portion of the spine, normally of the lamina process, in use. The rod attachment portion 6 is provided with a recess 14 into which the rod is introduced in use. A variety of systems exist for retaining the rod in position, including an internally threaded cap, not shown, which cooperates with the external thread 16 provided on the rod attachment portion 6.
Problems particularly arises when two such fixings are used with the hooks opposing one another to provide a firm end location to a spine support/correction system. The size of the hooks needed to perform the task, and more particularly the size of the body portions means that the gap 8 for both hooks combined is fixed at a particular minimum size, distance X. This size is too large for the lamina process of children's spines giving an impaired fixing as a result.
The fixing of the present invention is exemplified by two components equivalent to that shown in Figure 2. This fixing component consists of a body portion 20 and hook 22 depending from it. The body portion is also provided with a rod attachment portion 24 with a through groove 25 to accommodate the rod in use.
The fixing is distinguished in that the body portion 20 and rod attachment portion 24 form only a half of a complete unit. In this particular embodiment one side 26 of the body portion 20 and rod attachment portion 24 has a circular external profile, but the other side 30 has a flat face. The semi-circular side 26 of the rod attachment portion 24 is provided with an external screw thread 31.
When such a component is combined with an equivalent component, rotated through 180 degrees about axis Z-Z, then a complete fixing is provided. The two components, designated a, b, form a completed rod attachment portion from the two halves of the body portions 20a, 20b and rod attachment portions 24a, 24b, and with an aligned through groove. The assembled fixing also presents opposing hooks 22a, 22b, with a significantly reduced total gap X2 between them.
To assist in maintaining the two halves in position before the rod and screw cap are introduced a ring 23 is pushed down over the two halves of the rod attachment portions 24a, 24b.
A rod 27 is then introduced into the groove 25 and an internally screw threaded ring tightened down on screw thread 31 to provide firm retention.
In use, as illustrated in Figure 4, the combined fixing of Figure 3 is used to form an end fixing 100 capable of withstanding forces in either direction as it snugly engages a spinal process 102. The first component 101a and second component 101b form an equivalent head portion 103 to that of a conventional fixing 104.
Another fixing 104 of the conventional type is positioned on another lamina process 106 within the spinal column with in this case a hook 106 and presented in one direction only and a head portion 105.
A further end fixing with opposing hooks of the type according to the invention defines the other end of the fixing system, not shown. The corrective rod is positioned in the slot 110 in the head of each fixing 100, 104, and retained by a screw cap. The screw cap also serves to provide a more permeant retaining force to keep the two halves of the hooks together. As the head portions 103, 105 are the same size and thread, a standard screw cap can be used for each.
The system of the present invention presents a number of advantages, particularly for paediatric applications. The smaller gap between hooks provides a firmer fixing on the spine and is less prone to movement and slippage as a result. The reduced volume of body and rod attachment portion, a 50% reduction, makes the fixing less intrusive. The use of a retaining ring maintains the hooks in position on the spine pending the introduction of the rod. The fixing of the rod to the end fixing also only requires the rod to be introduced and clamped to one attachment rather than two so reducing the time spent. Significantly all these benefits are achieved whilst using standard size rods and fixings for the attachment portions. This allows existing instruments also to be employed.

Claims

C AIMS :
1. A spinal fixing comprising a first component and a second component, the first and second components being provided with a body portion and a spine engaging portion and means for coupling the first and second components, the fixing provided a connecting location for a separate element.
2. A fixing according to claim 1 in which the first and second components and coupling means are discretely formed.
3. A fixing according to claim 1 or claim 2 in which the body portions of the first and second components are provided with planar opposing faces.
4. A fixing according to any of claims 1 to 3 in which the spine engaging portion of the first and/or second component comprises a first part and a second part, the first and second parts engaging different parts of the spine in use, the first and second parts opposing one another.
5. A fixing according to any preceding claim in which the first and/or second parts of the spine engaging portion of the first and second component are provided with planar opposing faces, the opposing faces abutting one another in the assembled state .
6. A fixing according to any preceding claim in which the means for coupling comprises an element engaging both first and second components, the coupling means maintaining the first and second components in contact with one another.
7. A fixing according to any preceding claim in which the coupling means surrounds a portion of the first and second component .
8. A fixing according to any preceding claim in which the coupling means comprises a screw threaded member which cooperates with a portion of the first and second component provided with a screw thread.
9. A fixing according to any preceding claim in which the connecting location comprises a recess or groove into which the separate element is received.
10. A fixing according to claim 9 in which the coupling means closes the groove or recess to form a through passage, with the separate element received and retained in the through passage.
11. A fixing according to any preceding claim in which the body portions and/or spine engaging portions and/or connecting means of the first and second component may abut one another in use .
12. A fixing according to any preceding claim in which the body portions of the first and second components may form a cylinder with an axis lying on a plane of symmetry for the body portions .
13. A fixing according to any preceding claim in which the fixing further comprises retaining means for the first and second components to maintain their position during assembly.
14. A fixing according to claim 13 in which the retaining means comprises a member placed over a portion of the first and second components .
15. A fixing according to any preceding claim in which a face of the body portion of the first and second components abuts one another, the spine engaging portions oppose one another and the coupling means cooperates with a received portion formed by a part of the first and a part of the second component.
16. A fixation construction system comprising :- a fixing comprising a first component and a second component, the first and second components being provided with a body portion and a spine engaging portion and means for coupling the first and second components, the fixing providing a connecting location for a separate element; optionally one or more other types of fixings; one or more separate elements for connecting between a series of the fixings; and optionally one or more releasable fasteners for attaching the element to the optional other fixings.
17. A system according to claim 16 in which the intermediate fixings are provided with a single body portion, attachment portion and spine engaging portion.
18. A system according to claim 16 or claim 17 in which the separate element is a rod or bar.
PCT/GB1999/003080 1998-10-05 1999-10-05 Spinal fixings WO2000019922A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU60994/99A AU6099499A (en) 1998-10-05 1999-10-05 Spinal fixings

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9821571.8A GB9821571D0 (en) 1998-10-05 1998-10-05 Improvements in and relating to fixings
GB9821571.8 1998-10-05

Publications (1)

Publication Number Publication Date
WO2000019922A1 true WO2000019922A1 (en) 2000-04-13

Family

ID=10839935

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1999/003080 WO2000019922A1 (en) 1998-10-05 1999-10-05 Spinal fixings

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Country Link
AU (1) AU6099499A (en)
GB (1) GB9821571D0 (en)
WO (1) WO2000019922A1 (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5007909A (en) * 1986-11-05 1991-04-16 Chaim Rogozinski Apparatus for internally fixing the spine
FR2695550A1 (en) * 1992-09-11 1994-03-18 Jbs Sa Pedicular clamp for locating cervical vertebrae supporting plates - comprises grooved cylindrical head with integral hook, cooperating with similar hook movable by screw, with locating positions for clamp lugs
US5454812A (en) * 1993-11-12 1995-10-03 Lin; Chih-I Spinal clamping device having multiple distance adjusting strands
WO1996014801A1 (en) * 1994-11-16 1996-05-23 Advanced Spine Fixation Systems, Incorporated Segmental lamina grapple hooks
US5527314A (en) * 1993-01-04 1996-06-18 Danek Medical, Inc. Spinal fixation system
US5620444A (en) * 1993-09-03 1997-04-15 Sofamor S.N.C. Clamp for stabilizing a cervical spine segment
DE19732187A1 (en) * 1997-07-26 1999-02-18 Ulrich Gmbh & Co Kg Hooks for implants to correct and stabilize the spine

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5007909A (en) * 1986-11-05 1991-04-16 Chaim Rogozinski Apparatus for internally fixing the spine
FR2695550A1 (en) * 1992-09-11 1994-03-18 Jbs Sa Pedicular clamp for locating cervical vertebrae supporting plates - comprises grooved cylindrical head with integral hook, cooperating with similar hook movable by screw, with locating positions for clamp lugs
US5527314A (en) * 1993-01-04 1996-06-18 Danek Medical, Inc. Spinal fixation system
US5620444A (en) * 1993-09-03 1997-04-15 Sofamor S.N.C. Clamp for stabilizing a cervical spine segment
US5454812A (en) * 1993-11-12 1995-10-03 Lin; Chih-I Spinal clamping device having multiple distance adjusting strands
WO1996014801A1 (en) * 1994-11-16 1996-05-23 Advanced Spine Fixation Systems, Incorporated Segmental lamina grapple hooks
DE19732187A1 (en) * 1997-07-26 1999-02-18 Ulrich Gmbh & Co Kg Hooks for implants to correct and stabilize the spine

Also Published As

Publication number Publication date
AU6099499A (en) 2000-04-26
GB9821571D0 (en) 1998-11-25

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