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
• • 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
• • 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
  • A61B17/7019—Longitudinal elements having flexible parts, or parts connected together, such that after implantation the elements can move relative to each other
  • A61B17/7026—Longitudinal elements having flexible parts, or parts connected together, such that after implantation the elements can move relative to each other with a part that is flexible due to its form
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2/44—Joints for the spine, e.g. vertebrae, spinal discs
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
  • A61L27/02—Inorganic materials
  • A61L27/04—Metals or alloys
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
  • A61L27/14—Macromolecular materials

Definitions

• spinal fixation devices are used in spine surgery to align and/or secure a desired relationship between adjacent vertebral bodies.
• Such devices typically include a spinal fixation element, such as a relatively rigid fixation rod that is coupled to adjacent vertebrae by attaching the fixation element to various bone fixation elements, such as hooks, bolts, wires, screws, etc.
• the fixation elements can have a predetermined contour, and once installed, the fixation element holds the vertebrae in a desired spatial relationship preferably until desired healing or spinal fusion takes place.
• Dynamic fixation elements are desirable, at least in part, because they absorb shock, for example, in the extension and compression of the spine.
• the removal of bone structure, such as facet joints or laminae result in instabilities of the motion segments of the spine. Consequently, a fixation system should stabilize the motion segment in antero-posterior translation as well as in axial rotation. Both motion patterns result in shear stress within the
• the present invention is related to a dynamic or flexible stabilization system that can be used for stabilization of a portion of a patient's spine.
• the dynamic stabilization system can be implanted to the patient's spine using pedicle screws as is currently performed in conventional pedicle screw systems.
• the dynamic stabilization system preferably includes a first fixation element, and a second fixation element such as for example bone screws mounted to a first and second vertebrae respectively an elongated fixation element such as a rod, including a first portion and a second portion, the first portion mounted to the first fixation element and the second portion mounted to the second fixation element, and a dampening element mounted between the first and second portions, the dampening element including a plurality of segments and a plurality of bridging elements connecting the plurality of segments to permit movement of the first portion relative to the second portion.
• the dampening element preferably comprises multiple dampening elements.
• the segments and bridging element may be formed using Electrical
• the segments can be diagonal grooves that are separated by slots which are created through the process of machining the center of the dampening element.
• the bone fixation elements are bone screws and comprise a channel in their head for receiving the elongated fixation element in an implanted position.
• multiple dampening elements are located in series along the elongated fixation element between a first fixation element and a second fixation element.
• FIG. 1 is a top perspective view of a dynamic stabilization system according to a first preferred embodiment of the present invention mounted to a spine;
• FIG. 2 is a side perspective view of a dynamic stabilization system of Fig. 1;
• Fig. 3 is a side perspective view of a dampening element of the dynamic stabilization system of Fig. 1;
• Fig, 4 is an alternate side perspective of the dampening element of the dynamic stabilization system of Fig. 1;
• Fig. 5 is a cross-sectional view of the damping element of Fig. 3, taken along line 5-5 of Fig. 3;
• Fig. 6 is side elevational view of multiple dampening elements on an elongated fixation element according to a second preferred embodiment of the present invention.
• Fig. 7 is a cross-sectional view of the elongated fixation element of Fig. 6, taken along line 7-7 of Fig. 6;
• Fig. 8 is side perspective view of a dampening element on an elongated fixation element according to a third preferred embodiment of the present invention.
• Fig. 9 is a cross-sectional view of the elongated fixation element of Fig. 8, taken along line 9-9 of Fig. 8.
• the dynamic stabilization system may include one or more dynamic bone fixation elements for flexibly connecting an elongated fixation element to two or more bones.
• the dynamic stabilization system preferably further includes a flexible dampening element which preferably permits the elongated fixation element to move with respect to the bone fixation element and hence with respect to the bone affixed thereto.
• a first preferred embodiment of a dynamic stabilization system 100 of the present invention includes a plurality of bone fixation elements 110, an elongated fixation element (shown here as an elongated rod) 120 and a dampening element 130.
• the bone fixation elements or bone screws 110 are configured for securing the elongated fixation element 120 to a patient's bone, preferably a patient's vertebra V.
• the dampening element 130 permits movement of the bone fixation elements or bone screws 110 and the associated vertebrae V with respect to each other.
• the bone fixation elements 110 may be in the form of poly-axial or mono-axial pedicle or bone screws, hooks (both mono-axial and poly-axial) including pedicle hooks, transverse process hooks, sublaminar hooks, or other fasteners, clamps or implants or any other
• the elongated fixation element 120 may be in the form of a longitudinal rod, bone plate, or any other device now or hereafter known in the art that is generally rigid to secure at least two bone fixation elements 110 together. It will be recognized by one having ordinary skill in the art that the elongated fixation element 120 may include, but is limited to, a solid rod, a non-solid rod, a polymeric flexible or dynamic rod, etc.
• the dynamic stabilization system 100 of the present application is preferably not limited to use with any particular type of bone fixation element 110 or elongated fixation element 120.
• the bone fixation element 120 preferably includes a first portion 120a and a second portion 120b that are mounted to the bone fixation elements 110 in an implanted position.
• the bone fixation element 120 of the first preferred embodiment also includes a third portion 120c that is mounted to a third bone fixation element 110 in the implanted position.
• the bone fixation element 120 is not limited to inclusion of the first, second and third portions 120a, 120b, 120c and may include additional portions for mounting to additional bone fixation elements 110, but preferably include at least the first and second portions 120a, 120b for mounting to two bone fixation elements 110.
• the preferred dampening element 130 is constructed by cutting or forming a plurality of concentric or almost concentric narrow grooves 304a, 304b, 304c, bridged together in a horizontal plane by bridging elements 303a, 303b, 303c and separated by concentric segments 302a, 302b, 302c for damping motion between the first and second portions 120a, 120b of the elongated fixation element 120.
• These concentric or almost concentric grooves 304a, 304b, 304c are preferably constructed using Electrical Discharge Machining ("EDM”), although other machining methods can be utilized.
• EDM Electrical Discharge Machining
• a series of rapidly recurring electrical discharges or sparks are passed between two electrodes separated by a dielectric liquid. The electrical discharges are passed between one of the electrodes and the
• first and second portions 120a, 120b and the dampening element 130 may be constructed of separate pieces of material and subsequently joined together in a manufacturing assembly process via welding, a threaded connection, adhesive bonding or alternative joining methods to attach the first and second portions 120a, 120b to the dampening element 130.
• first portion 120a may be threadably mounted to a first side of the dampening element 130 along a longitudinal axis 10 and the second portion 120b may be threadably mounted to a second side of the dampening element 130 along the longitudinal axis 10.
• the dampening element 130 and the elongated fixation element 120 may be constructed of at least one of the group of metals consisting of Ti-Mo, CoCr, a fatigue resistant biocompatible metal, Titanium, Titanium alloy, Cobalt-Chromium alloy, a biocompatible polymer, a biocompatible mixture of polymers, Nitinol, shape memory material, ceramic, and a composite material.
• the concentric grooves 304a, 304b, 304c and the concentric segments 302a, 302b, 302c are disclosed in the first preferred embodiment as being generally concentric about the longitudinal axis 10 of the elongated fixation element 120, but are not so limited.
• the grooves 304a, 304b, 304c and segments 302a, 302b, 302c may be otherwise formed in the
• the segments 302a-c are preferably continuously closed shapes, i.e., the segments 302a-c form a closed space and, preferably, are shaped as closed rings or O-shaped rings.
• the segments 302a-c may be of any shape, including, but not limited to, circular, rectangular, oval, C-shaped, horseshoe, triangular, octagonal, U-shaped or kidney shaped.
• the number of segments 302a-c and bridging elements 303a-c may vary and are not limited to any particular number, value or range.
• the first preferred embodiment includes the substantially closed concentric segments 302a-c, the segments 302a-c may also be open, forming, for example, a C-shaped segment, horseshoe shaped, or any other suitable shape.
• the segments 302a-c of dampening element 130 preferably allow for movement in at least six degrees of freedom between the first and second portions 120a, 120b of the elongated fixation element 120, including flexion, extension, lateral bending, axial rotation, horizontal shifting, and dampening of the spine.
• the deflection and translation of the segments 302a-c and bridging elements 303a-c in response to compressive forces creates a dampening effect in the dynamic stabilization system 100.
• the plurality of segments 302a-c and bridges 303a-c define the concentric or almost concentric narrow grooves 304a-c that are oriented in such a way to control and/or limit anterior and posterior shifts, medial and lateral shifts, axial rotation (both clockwise and counter clockwise), anterior and posterior flexion and extension, lateral movement and combinations thereof.
• a dampening effect will therefore be possible due to the freedom in the vertical plane.
• the bridging elements 303a-c of the first preferred embodiment connect the segments 302a-c and may permit and provide resistance to relative movement of the segments 302a-c and the dynamic stabilization system 100.
• the resistance to relative movement of the segments 302a-c, and consequently the dynamic stabilization system 100 may be varied and controlled by altering the number, height, material, thickness (or width), shape, or other properties of the segments 302a-c and, consequently, the size, shape and/or thickness of the bridging elements 303a-c and the grooves 304a-c.
• the resistance to relative movement of the segments 302a-c and, consequently, the dynamic stabilization system 100 may also be varied and controlled by altering the number, width, thickness, material, shape, or other properties of the bridging elements 3O3a-c. Resistance to the relative movement of the segments 302a-c, and consequently, the dynamic stabilization system 100, may further be varied and controlled by increasing the number of bridging elements 303a-c that connect two adjacent segments 302a-c, such as the first segments 302a and the second segment 302b. For example, multiple bridging elements 3O3a-c may be used to connect adjacent segments 302a-c to vary the resistance to relative movements between the segments 302a-c.
• the first preferred embodiment of the dynamic stabilization system 100 includes three bridging elements 302a-c aligned along a medial/lateral axis
• the bridging elements 303a-c may be positioned in any manner between the segments 302a-c of the dampening element 130.
• the bridging elements 3O3a-c generally prevent contact between the separate segments 302a-c under biomechanically relevant load. Accordingly, the lack of contact between the separate segments 302a-c generally limits metal-debris that could result if the segments 302a-c rubbed against each other during use.
• the dynamic stabilization system 100 may engage one or more vertebrae V via the bone fixation elements 110, which engage one or more elongated fixation elements 120 at its first and/or second portions 120a, 120b so that the dynamic stabilization system 100 dynamically stabilizes the vertebrae V with respect to one another.
• the dynamic stabilization system 100 may be used in a spinal construct in combination with an intervertebral implant (not shown) for fusing adjacent vertebrae V or dynamically replacing an intervertebral disc D between adjacent vertebrae V.
• the dynamic stabilization system 100 of the first preferred embodiment may permit the vertebrae V to settle (e.g.
• the dynamic stabilization system 100 may be used in connection with an articulating intervertebral implant (not shown) or any other implant known in the art, or none at all.
• the amount and type of movement that is permitted by the dynamic stabilization system 100 can be tailored for individual patients. For example, for patients with less severe pathologies (e.g., better bone structure), a less stiff system may be desirable to permit additional movement. Likewise, for patients with severely degenerated discs, a stiffer system may be desirable to permit less or no movement.
• the elongated fixation element 120 can be provided in different degrees of softness to enhance stress-shielding, especially for patients with osteoporotic bones.
• the elongated fixation element 120 can be further be adapted to a rigid type device by blocking or binding the dampening element 130.
• the dynamic stabilization system 100 may be configured such that the first portion 120a is engaged by a pair of bone fixation elements 110 secured to adjacent vertebrae V (not shown) to generally hold the adjacent vertebrae V in place and promote fusion, while the second portion 120b is engaged to a third bone fixation element 110 secured to a third vertebra V to permit movement between this third
• the dynamic stabilization system 100 may be configured to promote fusion of selected pairs of vertebrae V, generally in combination with a fusion implant to replace a disc D, and to preserve motion in an adjacent disc D, at the spinal motion segment spanned by the damping element 130, with or without the combination of a total disc replacement implant.
• the individual vertebrae V are preferably stabilized posteriorly using the dynamic stabilization system 100 of the first preferred embodiment.
• the bone fixation elements 110 are secured into three vertebrae V from the posterior direction and are preferably mounted in pedicles P of the vertebrae V. Heads of the bone fixation elements 110 each preferably have a U-shaped channel or a rod-receiving channel 115, for accommodating and/or receiving the first, second and third portions 120a, 120b, 120c of the elongated fixation element 120, respectively.
• the dynamic stabilization system 100 is preferably capable of being fixed to the elongated fixation element 120 by securing the first, second and third portions 120a-c in the channels 115 by, for example, a closure cap, set screw or locking cap 110a, as generally understood by one of ordinary skill in the art. In this manner, the spine of the patient can be stabilized.
• the dynamic stabilization system 100 permits the attached vertebrae V to move with respect to one another such that the patient does not lose all motion at the impacted motion segment or segments of the spine.
• the combination of the bone fixation elements 110, elongated fixation element 120 and dampening elements 130 may absorb some or all of the movement
• NY 72200 50 4v3 e.g., translation, articulation, rotational (e.g., twisting), etc.
• associated loads and/or stresses and portions of the loads and/or stresses are also carried by the patient's spinal anatomy.
• the length of the dynamic stabilization system 100 will depend on the size and number of vertebrae V being secured or supported.
• the length of the elongated fixation element 120 may be up to one meter (1 m) long, if the patient's entire spine is being secured and/or instrumented.
• the diameter of the elongated fixation element 120 and dampening elements 130 will be sized to absorb the expected loads.
• the dynamic stabilization system 100 of the first preferred embodiment is shown as being mounted in and is preferably sized for use in the lumbar region of the spine and will typically have a larger diameter than one sized for use in the thoracic or cervical regions.
• multiple dampening elements 130a, 130b are arranged or mounted in series between the first and second portions 120a, 120b of the elongated fixation element 120. This may be particularly beneficial for multiple-level constructs.
• Using multiple dampening elements 130a, 130b in succession between fixation elements 110 and the first and second portions 120a, 120b preferably allows more flexibility for the elongated fixation element 120 and movement for the dynamic stabilization system 200 of the second preferred embodiment.
• the dampening elements 130a, 130b can be spaced closer or farther apart to increase or decrease the dampening effect, as desired by the designer or user.
• a dampening element 130c of the third preferred embodiment may be constructed by machining diagonally through the center of the dampening element 130c. Machining the dampening element 130c in this manner forms grooves 802 that are separated by slots 803 in multiple locations throughout the dampening element 130c. In the third preferred embodiment, the creation of the grooves 802 and the slots 803 preferably results in a smaller diameter D 3 for the dampening element 130c and increased flexibility of the dynamic stabilization system 300.
• the dampening element 130 of the third preferred embodiment preferably attains increased movement in at least six degrees of motion, including flexion, extension, lateral bending, axial rotation, horizontal shifting, and dampening via construction of the dampening element 130c with the grooves 802 and slots 803.
• the dampening element 130c of the third preferred embodiment can be situated in series along the elongated fixation element 120 between the first and second portions 120a, 120b to create an increased dampening effect.
• the grooves 802 and slots 803 of the third preferred embodiment may be constructed utilizing the above-described EDM process and the dampening element 130c may be integrally constructed from a single piece of material with the first and second portions 120a, 120b.
• the grooves 802 and slots 803 may be constructed utilizing high speed machining techniques and the dampening element 130c may be separately constructed from the first and second portions 120a, 120b and the first and second portions 120a, 120b may be subsequently joined to the dampening element 130c.
• any or all of the components described herein such as, for example, the bone fixation elements 110, the elongated fixation elements 120 and the dampening elements 130, 130a-c may be provided in sets or kits so that the
• each segment 302a-c is approximately between two tenths and two millimeters (0.2 mm - 2.0 mm) in width and between eight and thirty millimeters (8 mm - 30 mm) in depth.
• Each concentric segment 302a-c preferably allows at least thirty degrees (30°) of movement of the dynamic stabilization system 100 of the first preferred embodiment relative to the spine.
• an incision is formed in a patient's back to gain access to the spine and, particularly, the vertebrae V at the motion segments that will be instrumented utilizing the preferred dynamic stabilization system 100, 200, 300.
• An appropriate number of the bone fixation elements 110 are mounted to the appropriate vertebrae V, preferably in the pedicles P of the vertebrae V.
• the elongated fixation element 120 is arranged relative to the mounted bone fixation elements 110 such that the first, second and/or third portions 120a, 120b, 120c are positioned within the channels 115 of the bone fixation elements 110 and the dampening elements 130, 130a, 130b, 130c are positioned between the bone fixation elements 110 at spinal levels where dynamic fixation between vertebrae V is desired.
• the elongated fixation element 120 is then fixed to the bone fixation elements 110, by securing locking caps 110a to the bone fixation elements 110 to fix the first, second and or third segments 120a-c in the channels 115. Instrumentation is removed from the incision and the incision is closed. As was described above, the first segment 120a may be mounted between two bone fixation elements 110a and
• NY 7220Q5Q4v3 110b to generally fix the position of the bone fixation elements 110a and 110b relative to each other, while a third bone fixation element 110c may be fixed to the second segment 120b to permit dampened movement between the two fixed bone fixation elements 110a and 110b and the third bone fixation element 110c.

Landscapes

• Health & Medical Sciences (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Life Sciences & Earth Sciences (AREA)
• Neurology (AREA)
• Surgery (AREA)
• Animal Behavior & Ethology (AREA)
• Veterinary Medicine (AREA)
• Public Health (AREA)
• General Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Molecular Biology (AREA)
• Medical Informatics (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Chemical & Material Sciences (AREA)
• Transplantation (AREA)
• Dermatology (AREA)
• Medicinal Chemistry (AREA)
• Epidemiology (AREA)
• Cardiology (AREA)
• Vascular Medicine (AREA)
• Inorganic Chemistry (AREA)
• Prostheses (AREA)
• Surgical Instruments (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (2)

Family

ID=41264006

Family Applications (1)

Country Status (8)

Cited By (44)

Families Citing this family (2)

Family Cites Families (19)

• 2009
  • 2009-08-14 WO PCT/US2009/053841 patent/WO2010019857A2/en not_active Ceased
  • 2009-08-14 JP JP2011523190A patent/JP2012500061A/ja not_active Abandoned
  • 2009-08-14 CA CA2734106A patent/CA2734106A1/en not_active Abandoned
  • 2009-08-14 BR BRPI0916214A patent/BRPI0916214A2/pt not_active IP Right Cessation
  • 2009-08-14 CN CN2009801307103A patent/CN102119008A/zh active Pending
  • 2009-08-14 US US13/058,409 patent/US20110137346A1/en not_active Abandoned
  • 2009-08-14 EP EP09791525A patent/EP2346423B1/en not_active Not-in-force
  • 2009-08-14 KR KR1020117003009A patent/KR20110055543A/ko not_active Withdrawn

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events