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
  • A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
  • A61B17/7035—Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, 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
• • 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
• • 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
  • A61B17/7041—Screws or hooks combined with longitudinal elements which do not contact vertebrae with single longitudinal rod offset laterally from single row of screws or hooks

Definitions

• the present invention relates to a sequential connection device intended to connect together a rod and a screw head of spherical symmetry, said rod and said screw head being located in proximity to one another.
• a field of application envisaged is notably but not exclusively that of orthopedics and more particularly that of the stabilization of the spine.
• Stabilization devices comprising pedicle screws 0 inserted in the pedicle of the vertebrae, and at least one connecting rod capable of connecting the head of said screws to each other are well known.
• the pedicle screws are inserted into the pedicle of the successive vertebrae to be stabilized so that their heads project from each side of the spinous process.
• the screw heads on the same side of the spine are capable of being interconnected by a rod to maintain the vertebrae in a fixed position relative to one another.
• the pedicle screws of these devices generally have a U-shaped receiving head capable of receiving the rod and the internal wall of the head is tapped in the axis of said screw so as to allow screwing. a blocking piece against said rod.
• the rod which is inserted into the aligned reception heads is made integral with said screws by direct tightening of the locking pieces which form a vice with the bottom of the reception heads.
• the axis of the rod is necessarily located in a plane also comprising the axis of the screw.
• the position of the screw head is determined by the pedicles of the vertebrae into which they are screwed and this position is not the best position for the passage of the rod, in particular for reasons of space.
• devices making it possible to connect a screw head and a rod located close to each other have been devised in order to arrange the rod between the alignment of the spinous processes and the alignment of the screw heads. .
• a problem which arises and which the present invention aims to solve is then to provide a device which allows, not only to firmly maintain in a fixed position the screw heads and the rod located nearby, but also which allows, during assembly , to partially block said rod relative to said heads, in particular its orientation without blocking the rod in rotation about its axis or in translation along this axis.
• the device comprises: a first longitudinal piece, elastically deformable, extending between a first first end and a first second end and having an internal face, said first first end having an upper part and a lower part curved facing said upper part, said lower part having lower support points on which said screw head is capable of bearing, said upper part comprising adjustable support means arranged at sight of said lower part and spaced from said screw head, the adjustable support means and said lower support points defining a polyhedron inside which the center of said screw head is capable of being located; the device comprises a second longitudinal piece, elastically deformable, capable of cooperating with said first longitudinal piece, which extends between a second first end and a second second end and which has a first side and a second side, said first side having said second first end of the intermediate support points, said second first end of said second longitudinal part being capable of being engaged between said screw head and said adjustable support means, said intermediate support points being in abutment against said screw head, said second second end being disposed
• a characteristic of the invention resides in the position of the intermediate support points and of said lower support points, which define a polyhedron inside which the center of said screw head is capable of being located.
• said lower support points and the intermediate support points are capable of forming a vice so as to hold in fixed position said second first end of said second longitudinal piece against the spherical head and to block together said head and said longitudinal parts without the disengagement of the spherical symmetry head is possible.
• a sphere is perfectly blocked by at least four support points if these four points define a polyhedron containing the center of the sphere.
• the middle parts of the internal face and of the second face are kept spaced from each other in a fixed position so that said rod is capable of being guided at least in translation according to its longitudinal axis and at least in rotation about said axis while being held in one direction relative to said screw head.
• said rod being partially movable relative to said devices.
• the adjustable connecting means of each of the devices can be actuated to block said rod and said devices together.
• the adjustable connection means that a perfect locking of the rod is obtained relative to the screw heads.
• said lower part has a recess whose edge defines said lower support points.
• the screw head is capable of bearing on the edge of the recess, while the screw rod passes through it, so that the head is locked symmetrically, on each side of the rod.
• the edge of said recess forms at least three lower support points, said three support points defining a triangle the angles of which are all less than 90 °, so that said screw head of spherical symmetry, resting on said three support points is blocked in translation relative to said lower part in a direction parallel to the plane defined by said three support points.
• said recess has an edge defining at least a portion of a circle the length of the periphery of which is greater than the length of the periphery of the corresponding semicircle. In this way, the spherical symmetry screw head is also locked in translation in a direction parallel to the plane defined by said edge when it is compressed perpendicular to said plane.
• the surface of the upper edge of said recess forms a portion of a truncated spherical ring capable of cooperating with said screw head.
• the lower support points form support surfaces whose shape is complementary to the shape of the screw head and provide a larger contact surface.
• the surface of the upper edge of said recess forms a portion of truncated frustoconical ring capable of cooperating with said screw head so as to form a line of support for the spherical head against the frustoconical portion to allow firmer blocking.
• said intermediate support points form a surface defining at least one portion of a spherical cap capable of cooperating with said screw head so as to present a large support surface against said screw head.
• said first adjustable support means consist of a tapped hole passing right through said upper part of said first first end and of screw means capable of being screwed into said tapped hole.
• the screwable means which comprise an asymmetrical upper recess in which screwing means are likely to be engaged, are capable of being moved in translation towards said curved lower part.
• said second first end of said second longitudinal part has a through hole through it intended to allow the passage of screw means capable of being engaged in said screw head of spherical symmetry to drive said screw in rotation.
• said first adjustable support means and said second face to said second first end of said second longitudinal part on which they bear have abutment means capable of blocking said longitudinal part with respect to said first support means adjustable in a direction substantially perpendicular to the direction of the support force.
• said intermediate support means are perfectly integral with said first adjustable support means and the locking of said screw head between said lower support means and said intermediate support points is made more firmly.
• said screwable means have a support end having a shoulder which forms a projecting end, said shoulder being capable of bearing against the periphery of said bore of said second first end, said end in projection projecting to be embedded in said bore of said second first end to form said stop means.
• said adjustable connection means are formed by two coaxial threads formed in the second ends of said longitudinal parts, and a clamping screw comprising a threaded portion capable of cooperating with said two threads and an intermediate portion located between said threaded portion and the head capable of being free with respect to said threads so that said threaded portion is capable of cooperating only with the tapping of one of the two longitudinal parts and said head of cooperating with the other of said longitudinal parts to bring said second ends closer to one another and compress said rod between said median parts.
• the rod which is trapped between their middle part is compressed so that the two longitudinal parts are capable of being locked in a fixed position relative to to the stem.
• the actuation of the screw of the adjustable connecting means allows first of all the displacement of the longitudinal parts towards one another and their support on the rod then, the compression of the rod between the two parts, which are liable to flex.
• the actuation of the adjustable connecting means allows the pivoting of the two longitudinal parts around the rod which induces the additional compression of the screw head of spherical symmetry between the curved lower part and the second first end of the second longitudinal piece which are driven towards each other.
• maintaining the device in accordance with the invention in a fixed position on the head of a spherically symmetrical screw is produced more firmly than that provided by direct clamping between two parts forming a vice, because the effect lever provided by the rod located between the two longitudinal parts increases the compression forces against the head.
• the two second ends of the longitudinal parts are tapped so as to be able to secure said clamping screw to one of the two parts before connecting their end together.
• the two second ends can be brought towards each other during tightening as soon as the threaded portion has left the thread of the part on which the head rests and that it is engaged in the thread of the other part.
• the clamping screw is pre-screwed in the first second end of the first longitudinal part to then be screwed in the second second end of the longitudinal part.
• said median part of said internal face and said median part of said second face have semi-cylindrical recesses capable of being arranged opposite one another to form a housing of cylindrical symmetry in which said rod is capable of being moved in rotation around its axis and in translation along its axis.
• the orientation of the rod is capable of being maintained in a fixed position relative to the screw head of spherical symmetry and it is movable in translation and in rotation relative to its longitudinal axis. In this way, the deformations which are exerted on the rod during mounting induce minimal stresses on the devices which it passes through.
• the present invention provides a spinal stabilization assembly, comprising: a plurality of pedicle screws having a spherical head of symmetry; a plurality of sequential linkers according to the present invention; and, at least one rod capable of connecting together said sequential connecting devices.
• FIG. 1 is a schematic perspective view of the device according to the invention, mounted on a screw and crossed by a rod;
• - Figure 2 is a schematic view in longitudinal section of the device illustrated in Figure 1;
• - Figure 3 is a schematic exploded perspective view of the device according to the invention;
• - Figure 4 is a schematic cross-sectional view of the device illustrated in Figure 1 to the right of said screw; and
• FIG. 5 is a schematic bottom view showing a part of said device.
• Figure 1 shows the device according to the invention which connects together a spherical head screw 10 and a rod 12 disposed near the screw 10.
• a first longitudinal part 14 and a second longitudinal part 16 that the will be described in more detail in the description which follows.
• This type of screw is capable of being inserted into the pedicle of the vertebrae and the screw heads of a plurality of screws are capable of being connected together on the same side by a rod disposed between the screw heads and the processes thorny vertebrae which protrude at the center of the posterior wall of the vertebrae.
• FIG 3 we will describe the constituent elements of the sequential link device according to the invention.
• the first longitudinal part 14 has a first first end 20 and a first second end 22.
• the first first first end 20 has an upper part 24 and a lower part 26 curved facing the upper part 24 and the internal face 28 of the first longitudinal part 14 As illustrated in FIG. 3, the curved lower part 26 has a recess 30 of which only a part is seen since the part is cut longitudinally to facilitate observation.
• FIG. 5 in which we find the first longitudinal part 14 seen from below and in particular the recess 30 whose upper edge 32, illustrated in Figure 3, forms lower support points on which the head screw 18 is likely to be supported.
• the edge 34 of the recess 30, as it appears in Figure 5, forms three lower support points 36, 38, 40, which define a triangle whose angles are all less than 90 ° because the edge 34 of the recess 30 forms a portion of a circle 42 whose length of the periphery is greater than the length of the periphery of the semicircle defined by said portion of circle 42.
• the portion of circle 42 corresponds to a center angle greater than 180 degrees.
• the upper edge 32 of the lower part 26 shown in Figure 3, extends circularly, between the support points 40 and the support point 36 which appears only in Figure 5.
• the surface of the upper edge 32 forms a portion of a truncated spherical ring having a radius of curvature substantially equivalent to that of the spherical head 18 so as to conform to its shape.
• the length of the periphery of the truncated spherical ring portion corresponds, of course, to the length of the periphery of the circle portion 42 illustrated in FIG. 5.
• the surface of the upper edge 32 forms a portion of truncated frustoconical ring, so that the spherical head 18 is in contact with said portion of ring along a circular line also corresponding to the portion of circle 42 . So, for an equivalent pressure of the spherical head 18 against the upper edge 32, one will obtain a force per unit of upper surface and therefore better locking.
• the first longitudinal part 14, as illustrated in FIG. 3, comprises first adjustable support means formed by a tapped hole 44 passing right through the upper part 24, substantially perpendicular to the longitudinal axis of the part 14 and oriented towards the lower part 26; screw means 46 being capable of being screwed into the threaded bore 44.
• the screw means 46 are intended to be driven in rotation by means of a key capable of cooperating with the hexagonal orifice 48 formed in the part upper screw means 46 in order to drive them in translation towards the lower part 26, through the space between the upper part 24 and the lower part 26.
• first second end 22 comprises a first thread 50 in which a screw 52 is capable of being screwed and which is capable of forming with a second internal thread 54 formed in the second longitudinal part 16 which will be described in the description which follows, adjustable connection means.
• the second longitudinal part 16 has a second first end 56 and a second second end 58, as well as a first face 60 and a second face 62.
• the first face 60 has at the second first end an intermediate bearing surface 64 having intermediate bearing points appearing in Figure 3 thanks to the cutaway.
• the intermediate bearing surface 64 as shown defines a surface forming a spherical cap portion whose curvature is substantially identical to that of the spherical screw head 18 so as to form a large contact surface between the spherical screw head 18 and the first face 60.
• the second first end 56 has a recess 66 passing right through it and opening out facing the head of the spherical screw 18 when it is engaged against the intermediate bearing surface 64. This recess 66 makes it possible, if necessary, to be able to introduce means of screwing the screw 10 into the spherical head 18 which has a hexagon socket.
• the middle part 68 of the second face 62 of the second longitudinal part 16 has a first semi-cylindrical recess 70 in which the rod 12 is capable of coming to bear; the middle part 71 of the internal surface of the first longitudinal part 14 has a second recess 72 of cylindrical symmetry capable of facing the first semi-cylindrical recess 70.
• the head of ball screw 18 has a center C, and it is supported, on the one hand, on the upper edge 32 which extends circularly on each side of the head of ball screw 18 to the support points 36 and 40 which appear in dotted lines.
• Figure 4 illustrates the upper edge 32 which extends on each side of the spherical screw head 18.
• the intermediate support points of the intermediate support surface 64 of the second longitudinal piece bears against the head of spherical symmetry screw 18 and facing the upper edge 32 so that the intermediate support points of the intermediate support surface 64 and the lower support points of the upper edge 32 define a polyhedron containing the center C of the spherical screw head 18.
• the second first end 56 of the second longitudinal part 16 is arranged facing the adjustable support means and in particular the screwable means 46, the end 76 of which is in abutment against the second face 62 of the second longitudinal part 16 , at the second first end 56.
• the end 76 of the screwable means 46 has a circular shoulder 77 forming a projecting part 78 which is embedded in the recess 66 of the second first end 56 and which makes it possible to block in translation the second longitudinal piece 16 relative to the screwable means 46.
• the circular shoulder 77 it bears against the periphery of the recess 66.
• the actuation in rotation of the screwable means 46 drives the circular shoulder 77 in translation towards the lower part 26 against the periphery of the recess 66 of the second first end 56.
• the intermediate bearing surface 64 of the second first end of the longitudinal part 16 is applied against at least an upper portion of the spherical surface of the spherical screw head 18.
• a lower portion of the spherical surface of the spherical screw head 18 is in support against the upper edge 32 of the recess 30 of the lower part 26, and is locked in translation along the plane defined by the upper edge 32.
• the support points of the screwable means 46 and of the upper edge 32 are driven towards each other, and that they define at least one polyhedron containing the center C of the spherical screw head 18, and that the points intermediate support of the intermediate support surface 64 are held in a fixed position relative to the screwable means 46 and relative to the head of the spherical screw 18 and that they also define a polyhedron containing the center C, with the points d the lower support of the upper edge 32, the tightening of the screwable means 46 causes the first and second longitudinal piece, 14, 16 to be fixed in fixed position relative to one another and relative to the head of the spherical screw 18.
• the blocking of the spherical screw head 18 and of the two longitudinal parts 14, 16 is carried out so that the head is completely integral with the assembly and the two parts 14, 16 are locked relative to each other without being able to disengage from the spherical screw head 18. Furthermore, whatever the locking angle of the screw 10 and of the longitudinal parts 14, 16, the middle part of the two parts are spaced apart. on the other, so that the rod 12 can be movable at least in rotation about its axis and in translation along this axis.
• the final phase of the assembly consists in actuating in rotation the screw 52 which is found in Figure 2 and which is initially pre-mounted on the first longitudinal part 14 thanks to the first thread 50, before being fully screwed into the second internal thread 54.
• the body of the screw 52 has a non-threaded portion free in translation relative to the threads and located between the head and the threaded end so that the thread is released by the first thread 50 during tightening which causes the second ends 22 and 58 to move towards one another.
• the middle parts 68 and 71 are compressed towards one another and against the rod 12 so as to block it in a fixed position relative to the longitudinal parts 14, 16 and therefore relative to the head of the spherical screw 18.
• the longitudinal parts 14 and 16 are preferably made of titanium alloy, so that their deformation under stress is low.
• the tightening of the screw 52 which causes, in particular the bending of the part 14, makes it possible to ensure a perfectly rigid connection between the head of the spherical screw 18 and the rod 12.
• certain stainless steels may be used .
• Another object of the present invention relates to a spinal stabilization assembly intended to be installed on the spine of a patient.
• This assembly comprises a plurality of pedicle screws with a spherical head, capable of being screwed two by two into the two pedicles of several successive vertebrae so as to form two rows of screw heads on each side of the spinous processes.
• the set includes a plurality of sequential connection devices according to the invention intended to be mounted on each of the spherical screw heads and two rods making it possible to connect the devices of each of the rows of screw heads.

Landscapes

• 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)

Applications Claiming Priority (3)

Publications (1)

Family

ID=27676035

Family Applications (1)

Country Status (8)

Families Citing this family (160)

Family Cites Families (8)

• 2002
  • 2002-02-25 FR FR0202336A patent/FR2836368B1/fr not_active Expired - Fee Related
• 2003
  • 2003-02-24 WO PCT/FR2003/000589 patent/WO2003071963A1/fr not_active Application Discontinuation
  • 2003-02-24 KR KR10-2004-7013201A patent/KR20040088533A/ko not_active Application Discontinuation
  • 2003-02-24 JP JP2003570711A patent/JP2005518241A/ja active Pending
  • 2003-02-24 EP EP03720638A patent/EP1478292A1/fr not_active Withdrawn
  • 2003-02-24 AU AU2003224217A patent/AU2003224217A1/en not_active Abandoned
  • 2003-02-24 US US10/504,409 patent/US20050131404A1/en not_active Abandoned
• 2004
  • 2004-08-11 ZA ZA200406354A patent/ZA200406354B/en unknown

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events