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WO2009073655A9 - Ensemble pour fixation spinale - Google Patents

Ensemble pour fixation spinale Download PDF

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Publication number
WO2009073655A9
WO2009073655A9 PCT/US2008/085251 US2008085251W WO2009073655A9 WO 2009073655 A9 WO2009073655 A9 WO 2009073655A9 US 2008085251 W US2008085251 W US 2008085251W WO 2009073655 A9 WO2009073655 A9 WO 2009073655A9
Authority
WO
WIPO (PCT)
Prior art keywords
washer
head
rod
fixation device
locking mechanism
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/US2008/085251
Other languages
English (en)
Other versions
WO2009073655A1 (fr
Inventor
David A. Walsh
Leon W. Bester
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.)
CORMED NV/SA
Original Assignee
CORMED NV/SA
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 CORMED NV/SA filed Critical CORMED NV/SA
Publication of WO2009073655A1 publication Critical patent/WO2009073655A1/fr
Anticipated expiration legal-status Critical
Publication of WO2009073655A9 publication Critical patent/WO2009073655A9/fr
Ceased legal-status Critical Current

Links

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
    • A61B17/7001—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

Definitions

  • the present invention relates generally to prostheses for treating spinal pathologies, and more specifically to spinal fixation assemblies including an anchor for holding a fixation device and a stabilization rod.
  • Internal fixation refers to therapeutic methods of stabilization that are wholly internal to the patient and include commonly known devices such as bone plates, screws, rods and pins.
  • External fixation in contrast, involves at least some portion of the stabilization device being located external to the patients' body.
  • internal fixation eventually became the favored method of immobilization since it is less restrictive on the patient.
  • Internal fixation of the spine may be used to treat a variety of disorders including kyphosis, spondylolisthesis and rotation, segmental instability, such as disc degeneration and/or fracture caused by disease, trauma, congenital defects and tumor diseases.
  • segmental instability such as disc degeneration and/or fracture caused by disease, trauma, congenital defects and tumor diseases.
  • One of the main challenges associated with internal spinal fixation is securing the fixation device to the spine without damaging the spinal cord.
  • the pedicles of a vertebra are commonly used for fixation as they generally offer an area that is strong enough to hold the fixation device in place even when the patient suffers from degenerative instability such as osteoporosis.
  • the present invention includes a novel fixation device.
  • a locking mechanism comprising: a body having a bottom portion and a side portion, the side portion being configured to receive a rod; a fixation device extending at least partially through a hole in the bottom portion of the body, the fixation device comprising an at least partially spherical head; and a washer.
  • the washer includes an opening for receiving a top portion of the head at least two internal steps, each having an edge configured to engage the top portion of the head.
  • the edge of one of the internal steps may define the opening of the washer and the cross sections of the washer may be generally circular.
  • the edges of the internal steps may define generally circular openings.
  • the body may also have a bottom portion that has at least one lip configured to engage a bottom portion of the head of the fixation device.
  • each of the at least one lips may define a distinct edge, which may be a right angle.
  • the lips may also define generally circular openings.
  • the method comprises: placing a fixation device having a generally spherical head through a hole in the top portion of a body of the locking mechanism; placing a washer having opening and at least two internal steps through the hole in the top portion of a body of a locking mechanism; placing a rod in a side portion of the body such that the rod and head are on opposite sides of the washer; and urging the rod toward the washer such that the at least two internal steps of the washer engage a top portion of the head.
  • the method may further comprise causing the hole in the top portion of the body to expand prior to placing the washer through the hole.
  • step of urging the rod may further comprise causing an edge of each of the internal steps of the washer to engage the top portion of the head.
  • the method may further comprise urging the washer and head toward the bottom portion of the body and causing a bottom portion of the head to engage at least one lip in the bottom portion of the body.
  • Figure 1 is a cross-sectional view of a locking mechanism of the present invention with a fixation device and a rod in a locked position; and [0017] Figures 2A-B are full and cross-sectional perspective views of an embodiment of the novel washer of the present invention.
  • the invention relates to a novel locking mechanism and method for locking the relative positions of a rod and a fixation device.
  • the locking mechanism provides an improved lock between a rod and the head of a fixation device, such as a screw.
  • the apparatus includes a body and a washer that partially surrounds the head of the fixation device.
  • the washer has multiple steps, each preferably providing a contact surface with the head of the fixation device.
  • Figure 1 illustrated is a cross-sectional view of a locking mechanism of the present invention in a locked position.
  • the locking mechanism 100 is configured to engage and lock the position of a fixation device 104 with respect to the position of a rod 106.
  • the locking mechanism 100 includes a body 102, a washer 1 10 and a locking element 1 12.
  • “above” or “top” means posterior with respect to the patient and “below” or “bottom” means anterior with respect to the patient.
  • the bottom portion 1 14 of the body 102 is anterior with respect to the patient and the rod 106 is received by the body 102 as the rod 106 is moved in a posterior to anterior direction.
  • the body 102 includes a bottom portion 1 14 that includes a hole 1 18.
  • the fixation device 104 passes partially through the hole 118.
  • the hole 1 18 is large enough to allow the shaft 142 of the fixation device 104 to pass through but not large enough to allow the bottom portion 148 of the head 140 of the fixation device 104 to pass through.
  • the hole 1 18 is preferably dimensioned to prevent the fixation device 104 from passing entirely there through and exiting the body 102.
  • the fixation device 104 is preferably inserted through the top of the body 102 prior to insertion of the washer 1 10 and rod 106.
  • the washer is then preferably inserted through the top of the 102 so that the bottom portion of the washer 1 10 is positioned for interaction with the top portion 146 of the head 140 of the fixation device.
  • the washer 1 10 may be wider than the opening in the top of the body 102.
  • a tool may be used to increase the size of the opening in the top of the body 102.
  • the body 102 also includes a side portion 120 that is configured to receive the rod 106, such as by way of a channel 124 that enables placement of the rod 106 by either sliding the rod 106 through the side portion 120 of the body or by inserting the rod 106 into the channel 124 through the top portion of the body 102.
  • the washer 1 10 is preferably inserted into the body 102 prior to insertion of the rod 106 such that the washer 1 10 is eventually positioned between the rod 106 and the head 140 of the fixation device 104.
  • the locking mechanism 100 may also include a locking element 1 12 that is configured to engage the body 102 and the rod 106 so as to force the rod 106 toward the fixation device 104.
  • the locking element 1 12 and body 102 may be, for example, slidably engageable, rotatably engageable and/or snapably engageable.
  • the body 102 may include threads 122 for engaging the locking element 1 12.
  • Figure 1 shows internal threads, it will be understood by those of ordinary skill in the art that the threads may also be external threads and the locking element 1 12 may surround the body 102 during engagement.
  • the locking element 1 12 is a set screw, which may be either internally or externally threaded to engage either an externally or internally threaded body 102.
  • the locking mechanism 100 includes a body 102, a washer 1 10 and a locking element 1 12 for engaging a fixation device 104 and a rod 106.
  • Each of the body 102, the washer 1 10, the locking element 1 12, the fixation device 104 and the rod 106 may be made from a variety of materials known in the art and preferably is made from a biocompatible material when the locking mechanism 100 is used for bone fixation.
  • Such materials include, but are not limited to, titanium, titanium alloys (e.g.
  • Ti/AI/V alloys titanium/aluminum/vanadium alloys
  • cobalt-chromium alloys stainless steel
  • ceramics alumina ceramic, zirconia ceramic, yttria zirconia ceramic, etc.
  • high strength polymers e.g. PEEK, PEKK, etc.
  • pyrolytic carbon tantalum, carbon composite materials and combinations thereof, which may include mechanically compatible mixtures of the above materials.
  • the materials are rigid and in one embodiment, the body 102, fixation device 104, rod 106, washer 1 10 and locking element 1 12 are all made from Ti/AI/V alloys, such as Ti/6AI/4V ELI.
  • fixation devices 104 other than a screw can be used without departing from the scope of the present invention
  • a screw is shown and described herein to illustrate the engagement of the fixation device 104 and the body 102, as well as the method for locking the relative positions of a fixation device 104 and a rod 106.
  • various types of screws may be used.
  • the fixation device 104 has an at least partially spherical head 140.
  • the size of the body 102 may be similar to that of known devices.
  • the height of body 102 may range from about 0.4 inch to about 1 inch.
  • the width of body 102 may range from about 0.25 inch to about 1 inch.
  • the body 102 has a side portion 120 and a bottom portion 1 14.
  • the bottom portion 1 14 may be tapered and may have a socket 1 16 and a hole 1 18. Because the general shape of the type of body 102 illustrated in Figures 1 , 2A-B and 4A-B somewhat resembles a tulip flower, the type of body 102 is often referred to as a "tulip" by those skilled in the art.
  • the socket 1 16 is preferably sized to accept the head 140 of the fixation device 104, such as a screw.
  • the hole 1 18 is preferably located at the bottom of the body 102.
  • the washer 1 10 is configured to at least partially surround the head 140 of the fixation device 104.
  • the diameter of the head 140 is preferably larger than the hole 1 18 so that the head 140 cannot be removed through the hole 1 18 in the bottom 1 14 of the body 102.
  • the washer 1 10 also preferably includes a top hole 132 and a bottom hole 126 to provide access to the head 140 of the fixation device 104 from the top of the body 102.
  • a driver or similar device may be used to engage the head 140 of the fixation device 104 via the washer 1 10. In this manner, the fixation device 104 can be tightened using a driver or the like without permanently fixing the position of the fixation device 104 with respect to the body 102 and rod 106.
  • the washer 1 10 includes a bottom hole 126 that is sized to accept part of the top portion 146 of the head 140 of the fixation device 104.
  • the washer 1 10 may be generally circular disc shaped such that cross sections of the washer 1 10 are generally circular.
  • the washer 1 10 also preferably includes at least two internal steps 128a and 128b.
  • the internal steps 128a and 128b each have an edge 130a and 130b, respectively for contacting the surface of the top portion 146 of the head 140 of the fixation mechanism 104 during engagement.
  • the edge 130a may define the opening 126 of the washer 1 10 and both edge 130a and edge 130b may define circular openings.
  • the body 102 also includes a channel 124 in the side portion 120 for receiving the rod 106 or other stabilization element, such as a dynamic stabilization element. While a channel 124 is preferred for receiving the rod 106, it will be understood by those skilled in the art that an aperture in the side portion 120 could also receive the rod 106, though a body 102 with an aperture may be more cumbersome to deploy during surgery as a surgeon would have to place the rod 106 through the aperture instead of placing the rod 106 in the channel 124. Using a channel 124 to receive the rod 106 provides greater flexibility for a surgeon.
  • the side portion 120 of the body 102 also includes threads 122 configured to engage locking element 1 12, which is preferably a set screw. Although internal threads 122 are illustrated in Figure 1 , the threads 122 may be either internal or external to the body 102 depending on the configuration of the body 102 and the locking element 1 12. [0034] The locking element 1 12 is thus engaged with the threads 122 of the side portion 120 of the body 102 to keep the rod 106 within the channel 124. It should be understood, however, that the locking element 1 12 need not engage the body 102 via threaded engagement.
  • the locking element 1 12 and the body 102 may be slidably engageable, rotatably engageable, and/or snapably engageable. In the embodiment disclosed in Figure 1 , the locking element 1 12 and the body 102 are rotatably engageable.
  • the locking element 1 12 preferably is tightened down to apply increasing force to the rod 106 in order to engage and lock the rod 106 and fixation device 104. More specifically, the tightening of the locking element 1 12 causes linear compression of the rod 106 onto the washer 1 10, which in turn forces the fixation device 104 toward the bottom portion 1 14 of the body 102.
  • the socket 1 16 is configured for locking engagement of the fixation device 104.
  • the surface of the socket 1 16 may include a rough or knurled surface and/or a surface fixation mechanism, such as ridges, grooves, bumps, pips, or the like to increase the coefficient of friction of the surface.
  • the head 140 may have rough or knurled surfaces and/or surface fixation mechanisms, such as ridges, grooves, bumps, pips, or the like to increase the coefficient of friction of the surfaces.
  • the surfaces may roughened by blasting, for example, with titanium oxide, glass beads or other suitable blasting material.
  • blasting for example, with titanium oxide, glass beads or other suitable blasting material.
  • the washer 1 10 and head 140 combination is forced downward into the socket 1 16, which preferably includes a lip 1 17.
  • the lip 1 17 is tapered and preferably has an edge. Accordingly, the lower portion 148 of the head 140 is caused to contact the lip 1 17, and preferably, the edge of the lip, thereby preventing the head 140 of the fixation device 104 from moving further through the hole 1 18.
  • the rod 106 is forced more tightly against the top of the washer 1 10 and the edges 130a and 130b are brought into tighter contact with the top portion 146 of the head 140 of the fixation device while the lip 1 17 is brought into tighter contact with the bottom portion 148 of the head 140 of the fixation device 104.
  • the position of the rod 106 is fixed with respect to the position of the fixation device 104.

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  • Health & Medical Sciences (AREA)
  • Orthopedic Medicine & Surgery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Neurology (AREA)
  • Surgery (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)

Abstract

La présente invention concerne un mécanisme de verrouillage (100) et un procédé de fixation, par exemple la fixation d'un dispositif de fixation (104), tel qu'une vis à os et une tige (106), à la colonne vertébrale. Ledit mécanisme de verrouillage (100) inclut un corps (102), un joint (110) et une vis de serrage (112). Ledit joint (110) présente au moins deux crans internes (128a, 128b) qui viennent en prise sur la tête (140) d'un dispositif de fixation (104), telle qu'une vis dotée d'une tête sphérique (140).
PCT/US2008/085251 2007-12-04 2008-12-02 Ensemble pour fixation spinale Ceased WO2009073655A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US527807P 2007-12-04 2007-12-04
US61/005,278 2007-12-04

Publications (2)

Publication Number Publication Date
WO2009073655A1 WO2009073655A1 (fr) 2009-06-11
WO2009073655A9 true WO2009073655A9 (fr) 2010-11-11

Family

ID=40344716

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2008/085251 Ceased WO2009073655A1 (fr) 2007-12-04 2008-12-02 Ensemble pour fixation spinale

Country Status (1)

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WO (1) WO2009073655A1 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8007522B2 (en) 2008-02-04 2011-08-30 Depuy Spine, Inc. Methods for correction of spinal deformities
US9782204B2 (en) 2012-09-28 2017-10-10 Medos International Sarl Bone anchor assemblies
US9775660B2 (en) 2013-03-14 2017-10-03 DePuy Synthes Products, Inc. Bottom-loading bone anchor assemblies and methods
US10342582B2 (en) 2013-03-14 2019-07-09 DePuy Synthes Products, Inc. Bone anchor assemblies and methods with improved locking
US9724145B2 (en) 2013-03-14 2017-08-08 Medos International Sarl Bone anchor assemblies with multiple component bottom loading bone anchors
US9259247B2 (en) 2013-03-14 2016-02-16 Medos International Sarl Locking compression members for use with bone anchor assemblies and methods
US20140277153A1 (en) * 2013-03-14 2014-09-18 DePuy Synthes Products, LLC Bone Anchor Assemblies and Methods With Improved Locking
WO2022184797A1 (fr) 2021-03-05 2022-09-09 Medos International Sarl Vis polyaxiale à verrouillage sélectif

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6485494B1 (en) * 1996-12-20 2002-11-26 Thomas T. Haider Pedicle screw system for osteosynthesis
EP1570794A1 (fr) * 2004-03-04 2005-09-07 U & I Corporation Système de fixation osseuse, et son outil et procédé d'assemblage correspondant
US7695497B2 (en) * 2005-09-12 2010-04-13 Seaspine, Inc. Implant system for osteosynthesis
WO2007114834A1 (fr) * 2006-04-05 2007-10-11 Dong Myung Jeon Ensemble de vis a os multiaxial a verrouillage double

Also Published As

Publication number Publication date
WO2009073655A1 (fr) 2009-06-11

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