US20190336182A1 - Modular rod reduction tower and related methods - Google Patents
Modular rod reduction tower and related methods Download PDFInfo
- Publication number
- US20190336182A1 US20190336182A1 US16/512,268 US201916512268A US2019336182A1 US 20190336182 A1 US20190336182 A1 US 20190336182A1 US 201916512268 A US201916512268 A US 201916512268A US 2019336182 A1 US2019336182 A1 US 2019336182A1
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- United States
- Prior art keywords
- tower
- bone
- coupling
- bone fixation
- fastener
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- Abandoned
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- 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
-
- 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
- A61B17/7002—Longitudinal elements, e.g. rods
-
- 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
- A61B17/7074—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling
- A61B17/7076—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling for driving, positioning or assembling spinal clamps or bone anchors specially adapted for spinal fixation
- A61B17/7077—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling for driving, positioning or assembling spinal clamps or bone anchors specially adapted for spinal fixation for moving bone anchors attached to vertebrae, thereby displacing the vertebrae
- A61B17/708—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling for driving, positioning or assembling spinal clamps or bone anchors specially adapted for spinal fixation for moving bone anchors attached to vertebrae, thereby displacing the vertebrae with tubular extensions coaxially mounted on the bone anchors
-
- 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
- A61B17/7074—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling
- A61B17/7083—Tools for guidance or insertion of tethers, rod-to-anchor connectors, rod-to-rod connectors, or longitudinal elements
- A61B17/7085—Tools for guidance or insertion of tethers, rod-to-anchor connectors, rod-to-rod connectors, or longitudinal elements for insertion of a longitudinal element down one or more hollow screw or hook extensions, i.e. at least a part of the element within an extension has a component of movement parallel to the extension's axis
-
- 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
- A61B17/7074—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling
- A61B17/7083—Tools for guidance or insertion of tethers, rod-to-anchor connectors, rod-to-rod connectors, or longitudinal elements
- A61B17/7086—Rod reducers, i.e. devices providing a mechanical advantage to allow a user to force a rod into or onto an anchor head other than by means of a rod-to-bone anchor locking element; rod removers
-
- 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
- A61B17/7074—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling
- A61B17/7091—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling for applying, tightening or removing longitudinal element-to-bone anchor locking elements, e.g. caps, set screws, nuts or wedges
-
- 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
- A61B17/84—Fasteners therefor or fasteners being internal fixation devices
- A61B17/86—Pins or screws or threaded wires; nuts therefor
- A61B17/8625—Shanks, i.e. parts contacting bone tissue
- A61B17/863—Shanks, i.e. parts contacting bone tissue with thread interrupted or changing its form along shank, other than constant taper
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
- A61B90/03—Automatic limiting or abutting means, e.g. for safety
- A61B2090/037—Automatic limiting or abutting means, e.g. for safety with a frangible part, e.g. by reduced diameter
Definitions
- the present disclosure relates to a bone stabilization system and method, and more particularly to a bone stabilization system and method for implanting within a body of a patient.
- the spinal (or vertebral) column is one of the most important parts.
- the spinal column provides the main support necessary for mammals to stand, bend, and twist.
- the spinal column is generally formed by individual interlocking vertebrae, which are classified into five segments, including (from head to tail) a cervical segment (vertebrae CI-C7), a thoracic segment (vertebrae TI-TI2), a lumbar segment (vertebrae LI-L5), a sacrum segment (vertebrae SI-S5), and coccyx segment (vertebrate Col-CoS).
- the cervical segment forms the neck, supports the head and neck, and allows for nodding, shaking and other movements of the head.
- the thoracic segment attaches to ribs to form the ribcage.
- the lumbar segment carries most of the weight of the upper body and provides a stable center of gravity during movement. The sacrum and coccyx make up the back walls of the pelvis.
- Intervertebral discs are located between each of the movable vertebra.
- Each intervertebral disc typically includes a thick outer layer called the disc annulus, which includes a crisscrossing fibrous structure, and a disc nucleus, which is a soft gel-like structure located at the center of the disc.
- the intervertebral discs function to absorb force and allow for pivotal movement of adjacent vertebra with respect to each other.
- the vertebrae In the vertebral column, the vertebrae increase in size as they progress from the cervical segment to the sacrum segment, becoming smaller in the coccyx. At maturity, the five sacral vertebrae typically fuse into one large bone, the sacrum, with no intervertebral discs. The last three to five coccygeal vertebrae (typically four) form the coccyx (or tailbone). Like the sacrum, the coccyx does not have any intervertebral discs.
- Each vertebra is an irregular bone that varies in size according to its placement in the spinal column, spinal loading, posture and pathology. While the basic configuration of vertebrae varies, every vertebra has a body that consists of a large anterior middle portion called the centrum and a posterior vertebral arch called the neural arch. The upper and lower surfaces of the vertebra body give attachment to intervertebral discs.
- the posterior part of a vertebra forms a vertebral arch that typically consists of two pedicles, two laminae, and seven processes.
- the laminae give attachment to the ligament flava, and the pedicles have a shape that forms vertebral notches to form the intervertebral foramina when the vertebrae articulate.
- the foramina are the entry and exit passageways for spinal nerves.
- the body of the vertebra and the vertical arch form the vertebral foramen, which is a large, central opening that accommodates the spinal canal that encloses and protects the spinal cord.
- each vertebra is composed of cancellous bone that is covered by a thin coating of cortical bone.
- the cancellous bone is a spongy type of osseous tissue
- the cortical bone is a hard and dense type of osseous tissue.
- the vertebral arch and processes have thicker coverings of cortical bone.
- the upper and lower surfaces of the vertebra body are flattened and rough. These surfaces are the vertebral endplates that are in direct contact with the intervertebral discs.
- the endplates are formed from a thickened layer of cancellous bone, with the top layer being denser.
- the endplates contain adjacent discs and evenly spread applied loads.
- the end plates also provide anchorage for the collagen fibers of the disc.
- FIG. 1 shows a portion of a patient's spinal column 2 , including vertebra 4 and intervertebral discs 6 .
- Each disc 6 forms a fibrocartilaginous joint between adjacent vertebrae 4 , allowing relative movement between adjacent vertebrae 4 . Beyond enabling relative motion between adjacent vertebrae 4 , each disc 6 acts as a shock absorber for the spinal column 2 .
- each disc 6 comprises a fibrous exterior surrounding an inner gel-like center which cooperate to distribute pressure evenly across each disc 6 , thereby preventing the development of stress concentrations that might otherwise damage and/or impair vertebrae 4 of spinal column 2 .
- Discs 6 are, however, subject to various injuries and/or disorders which may interfere with a disc's ability to adequately distribute pressure and protect vertebrae 4 .
- disc herniation, degeneration, and infection of discs 6 may result in insufficient disc thickness and/or support to absorb and/or distribute forces imparted to spinal column 2 .
- Disc degeneration for example, may result when the inner gel-like center begins to dehydrate, which may result in a degenerated disc 8 having decreased thickness. This decreased thickness may limit the ability of degenerated disc 8 to absorb shock which, if left untreated, may result in pain and/or vertebral injury.
- the abnormality when a spinal abnormality occurs, the abnormality can cause severe pain or damage to the nervous system.
- the abnormality may also severely limit movement of the spinal column.
- the abnormality may be the result of, for example, trauma, degenerative disc disease, degenerative bone disease, or the like.
- a bone fixation system includes a bone fastener, a tower including a first thread formed on an inner surface at a first end thereof, a coupling assembly connected to the bone fastener and the first end of the tower.
- the coupling assembly includes a coupling unit including a second thread formed on an inner surface at an upper portion thereof and adjoining the first thread, and a set screw including a third thread configured to mate with the first thread and the second thread.
- the coupling unit is configured to compensate a thread pitch mismatch between the first thread and the second thread.
- the bone fastener includes a polyaxial pedicle screw having a head and a screw shaft extending from the head.
- the coupling assembly further includes a cavity that receives and holds a portion of the bone fastener.
- the coupling assembly further includes a channel formed by a pair of upper inner walls of the coupling unit.
- the bone fixation device further includes a fastener connector having a portion that seats within the channel.
- the tower further includes a coupling guide formed around an inner surface at the first end portion thereof.
- the coupling unit further includes a coupling lip formed on an outer surface of an upper portion thereof that seats in the coupling guide of the tower.
- the coupling guide is formed by a recessed surface extending between an upper recess surface and a lower recess surface, the recess surface being wider than the coupling lip of the coupling unit.
- the coupling unit travels in a direction in response to a force applied by the set screw when the first thread and the second thread are misaligned.
- the third thread of the set screw mates with the second thread of the coupling unit when a thread pitch of the first thread is aligned with a thread pitch of the second thread.
- a bone fixation system includes a tower having a tower body that includes an internal tower thread, and a thread pitch compensator.
- the thread pitch compensator substantially matches the pitch of the tower thread to a pitch of a thread in a coupling body to facilitate progression of a set screw from the tower thread into and along the thread in the coupling body.
- the thread pitch compensator includes a coupling guide that holds and guides a coupling lip on the coupling body.
- the thread pitch compensator includes a tower lip.
- the thread pitch compensator includes a stop that limits travel of the coupling lip in the coupling guide.
- the coupling guide allows the coupling lip to move in either direction along a longitudinal axis of the tower.
- a bone fixation system includes a hollow shell body having an opening at a first end portion thereof, and a derotation tower that envelopes a tower of a bone fastener when inserted into the hollow shell body via the opening of the hollow shell body.
- the hollow shell body includes a grip portion having a diameter greater than that of the first end portion thereof.
- the bone fixation system further includes a crosslink unit that removably affixes to a second end portion of the hollow shell body.
- a length of the crosslink unit is adjustable.
- the crosslink unit includes a bent end portion that removably affixes to the second end portion of the hollow shell body.
- FIG. 1 illustrates a portion of a patient's spinal column
- FIG. 2 shows an example of a bone fixation system that may be implanted in a spinal column, according to the principles of the disclosure
- FIG. 3A shows an example of a bone fixation device, constructed according to the principles of the disclosure
- FIGS. 3B and 3C show enlarged views of portions of the bone fixation device in FIG. 3A ;
- FIG. 3D shows an enlarged cross-section cut view of an example of a thread pitch compensation feature in a bone fixation device, according to the principles of the disclosure
- FIG. 3E shows a bottom view of an example of a tower, constructed according to principles of the disclosure
- FIGS. 4A, 4B and 4C show enlarged views of a connection portion of the bone fixation system in FIG. 3A ;
- FIG. 5 shows an example of a derotation device, constructed according to the principles of the disclosure
- FIG. 6A shows the derotation device in FIG. 5 and a derotation tower according to the principles of the disclosure
- FIG. 6B shows the derotation device encapsulating the derotation tower in FIG. 6A ;
- FIG. 7 shows an example of a bone fixation system, including a crosslink for linking two or more derotation devices to each other, according to the principles of the disclosure
- FIG. 8A depicts an exemplary embodiment of tower bodies that incorporate one or more flexible portions
- FIG. 8B depicts an alternative embodiment of tower bodies that incorporate one or more flexible portions, including a modular tower incorporating a removable and/or reconfigurable flexible section;
- FIG. 9A depicts an exemplary interference or collision of tower bodies in a spine analog
- FIG. 9B depicts a correctly aligned fixation construct with set screw tightened
- FIG. 9C depicts a misaligned fixation construct with set screw tightened
- FIGS. 10A and 10B depict attachment of a spinal instrument having a flexible zone being attaching to a spinal fixation element
- FIGS. 11A and 11B depict another embodiment of a percutaneous spinal instrument having flexible zones in accordance with the present disclosure
- FIGS. 12A through 12C and 13A through 13F depict additional alternative embodiments of flexible regions that can be integrated into various spinal instrumentation
- FIGS. 14A through 14C depict additional alternative embodiments of flexible towers
- FIGS. 15A through 15D depict an additional embodiment of a tower body that includes a tubular body portion with an integrated detachable tip portion;
- FIGS. 16A through 16C depict another alternative embodiment of a tower body with an integrated detachable tip portion
- FIG. 17 depicts one exemplary method of removing a tubular body portion from a tip portion of a tower body
- FIGS. 18A and 18B depict front plan and cross-sectional views, respectively, of one embodiment of an exemplary fixation element incorporating a tip portion which engages with a bone fastener in the form of a polyaxial pedicle screw;
- FIG. 19A through 19D depict various views of a set screw for use with various embodiments of the present invention.
- the abnormality when a spinal abnormality occurs in the spinal column 2 , the abnormality can cause severe pain or damage to the nervous system, and the abnormality may limit movement of the spinal column.
- the abnormality may be the result of, for example, trauma, degenerative disc disease, degenerative bone disease, or the like.
- the abnormality may be treated by affixing bone fasteners (such as, for example, bone screws or hooks) to one or more vertebrae and connecting the bone fasteners to a fastener connector (such as, for example, a rod, a curved rod, a straight rod, a wire, a cross-connector rod, a cross-connector wire, or the like).
- the fastener connector may be aligned with the longitudinal axis of the spinal column 2 to immobilize the spinal segment (e.g., adjacent vertebrae 4 ) with respect to each other.
- the bone fasteners may comprise bone screws that are screwed into pedicles of vertebrae 4 and coupled to at least one fastener connector that may include an elongated rod.
- the pedicles which consist of a strong shell of cortical bone and a core of cancellous bone, provide the strongest point of attachment of a spine and, therefore, the greatest resistance against bone-metal junction failure.
- the bone fasteners may be positioned so as to traverse all three columns of the vertebrae, thereby providing ventral and dorsal stability in the spinal column 2 .
- FIG. 2 shows an example of a bone fixation system 100 that may be implanted in the spinal column 2 (shown in FIG. 1 ) of a patient's body. Once implanted in a patient's spinal column 2 , the bone fixation system 100 may properly position, stabilize and promote fusion in a portion of the spinal column 2 , such as, for example, two or more adjacent vertebrae.
- the bone fixation system 100 may comprise any number of bone fixation devices 110 and fastener connectors 120 .
- Each bone fixation device 110 may include a bone fastener assembly 200 / 300 and a tower 400 .
- the bone fixation system 100 comprises three bone fixation devices 110 and a single fastener connector 120 connecting to the bone fastener assemblies 200 / 300 of all three of the bone fixation devices 110 .
- the bone fastener assembly 200 / 300 includes a bone fastener 200 and a coupling assembly 300 , collectively referred to as bone fastener assembly 200 / 300 .
- the bone fastener 200 in the bone fixation device 110 may comprise a poly-axial pedicle screw 200 .
- FIGS. 3A to 3E show various views of the bone fixation device 110 and/or the tower 400 , according to principles of the disclosure.
- FIG. 3A shows a cross-section cut view of a non-limiting embodiment of the bone fixation device 110 , constructed according to the principles of the disclosure;
- FIG. 3B shows a top view of the bone fixation device 11 0 ;
- FIG. 3 C shows an enlarged cross-section cut view of a connection portion A of the bone fixation device 110 ;
- FIG. 3D shows an enlarged cross-section cut view of a non-limiting embodiment of a thread pitch compensator 350 in the bone fixation device 110 ;
- FIG. 3E shows an example of a receiving end of the tower 400 .
- the tower 400 has a tower body 410 that may be removably attached to the coupling assembly 300 .
- the tower body 410 may have a cylindrical or tube-like shape with a tool insertion channel 401 formed therein by the inner walls 402 of the tower body 410 .
- the tool insertion channel 401 may be used to receive and guide a tool, such as, for example, a screw driver (not shown), facilitating delivery of an end of the tool (not shown) to the bone fastener 200 (for example, the head of the polyaxial pedicle screw) and/or a set screw 370 , so as to allow manipulation (e.g., tightening or loosening) of the bone fastener 200 and/or the set screw 370 .
- the walls of the tower body 410 have a tower end 475 that may have a semi-closed (or semi-open) shape, such as, for example, a “C” shape having an open channel 403 formed in the tower body 410 .
- the channel 403 may be provided to allow a portion of a tool (not shown) being inserted in or through the tool insertion channel 401 to protrude from the tower body 410 , or to deploy or retrieve a device such as, for example, a fastener connector 120 (shown in FIG. 2 ) along the channel 401 using, for example, a rod inserter tool (not shown).
- the tool (not shown) and fastener connector 120 may be delivered along the tool insertion channel 401 of the tower body 410 , and when the tool end (not shown) is positioned in a predetermined position, the fastener connector 120 may be pivoted outward and extended from the tower body 410 (via the channel 403 ) to be seated in or inserted into the coupling assemblies 300 in the bone fixation system 100 (shown in FIG. 2 ).
- the walls of the tower body 410 may include one or more openings (or cutouts) 412 that may run along less than the entire length of the tower 400 . Alternatively, the opening (or cutout) may run along the entire length of the tower 400 .
- the tower body 410 may be a closed type (not shown) that has a closed loop all around, or an open type (not shown) that may have multiple open channels (or cutouts) 403 formed on opposite sides of the tower 400 .
- the tower body 410 may include openings (or cutouts) 412 , which may run along the entire length of the tower 400 .
- the openings (or cutouts) 412 may run along less than the entire length of the tower 400 .
- the length of one opening (or cutout) 412 may be the same as, or differ from the length of the other opening (or cutout) 412 .
- the coupling assembly 300 may include a coupling body (or unit) 310 and a set screw 370 .
- the coupling assembly 300 may further include a first (or upper) inner ring 380 and a second (or lower) inner ring 390 .
- the coupling body 310 may have a tulip-shape, or a “U”-shape at a first (or upper) end, so as to allow the fastener connector 120 (shown in FIG. 2 ) to be positioned within a channel 302 , which may be formed by upper inner walls of the coupling body 310 .
- the width of the channel 302 may be substantially the same as, or greater than the width (or diameter) of the fastener connector 120 .
- the coupling body 310 may have a cavity at its opposite (or lower) end.
- the cavity may be formed by the inner walls of the lower portion of the coupling body 310 .
- the coupling body 310 may further include a stop against which a portion of the upper surface of the upper inner ring 380 may rest.
- the coupling body 310 may further include a lip portion 312 that may protrude inward and serve as a stop to limit downward movement of the lower inner ring 390 from the cavity.
- the cavity may be configured to receive and hold the first (upper) inner ring 380 and the second (lower) inner ring 390 , partially or entirely within the cavity.
- the first inner ring 380 and second inner ring 390 when assembled the first inner ring 380 and second inner ring 390 may form a further cavity that holds a head portion 210 of the polyaxial pedicle screw.
- the first inner ring 380 and the second inner ring 390 are designed such that when a force is applied in the direction of the arrow 10 (e.g., a force that is substantially perpendicular to the plane of the upper surface of the inner ring 380 ), the volume of the cavity that holds the head portion 210 of the bone fastener 200 is compressed or reduced, thereby securely engaging and holding the head portion 210 of the bone fastener 200 by the inner walls of the first inner ring 380 and/or second inner ring 390 .
- the force is applied to the upper surface of the inner ring 380 by the fastener connector 120 (shown in FIG. 2 ), which may be forced to move in the direction of the arrow 10 by the set screw 370 , as the set screw 370 is turned and driven toward the first inner ring 380 .
- the design of the coupling assembly 300 is configured such that the upper inner ring 380 may transfer load from the fastener connector 120 to the top surface of the head portion 210 of the bone fastener 200 .
- the design upgrades line contact into surface contact for stable seating of the fastener connector 120 and load transfer.
- the bone fixation device 110 may include a thread pitch mismatch compensator 350 .
- the thread pitch mismatch compensator 350 includes a coupling guide 420 that receives and guides a coupling lip 355 of the coupling body 310 .
- the coupling guide 420 may be configured to receive and guide known coupling body housings, so that the tower 400 may be attached to existing bone fastener assemblies having various sizes and configurations.
- the coupling guide 420 may be formed in the inner wall 402 of the tower body 410 .
- the coupling guide 420 may have an annular shape that may be cut from, or formed in a section of the inner wall 402 of the tower body 410 .
- the coupling guide 420 may be formed in a 360° section of the inner wall 402 of the tower body 410 , formed along and around the inner wall 402 of the tower body 410 and substantially perpendicular to the longitudinal axis of the tower body 410 .
- the coupling guide 420 may be formed in less than a 360° section of the inner wall 402 , or in multiple sections of the inner wall 402 .
- the coupling guide 420 is configured to receive, hold, and guide a coupling lip 355 on the coupling body 310 , allowing the coupling lip 355 to travel in the coupling guide 420 in either direction along the longitudinal axis of the tower body 410 .
- the coupling guide 420 may include a stop 424 and a tower lip 421 that may function to limit the travel of the coupling lip 355 at each end of the coupling guide 420 .
- the stop 424 may include a wall surface that is substantially perpendicular to the longitudinal axis of the tower body 410 .
- the tower lip 421 may include a first wall 426 that has a surface that is substantially perpendicular to the longitudinal axis of the tower body 410 and faces the coupling guide 420 .
- the tower lip 421 may include a second wall 428 that may have an angled or tapered surface.
- the surface angle of the wall 428 may be, for example, between 5° and 90° with respect to the longitudinal axis of the tower body 410 , and preferably between 30° and 60°.
- the surface angle of the wall 428 may be less than 5°, or more than 90° with respect to the longitudinal axis of the tower body 410 .
- the surface of the wall 428 may be angled or tapered to allow the coupling lip 355 of the coupling body 310 to be forced by, and guided along the angled surface of the wall 428 , past an edge of the wall 426 , and allowed to be snapped into position in the coupling guide 420 .
- the tower lip 421 may be annular shaped and may be formed 360° around the inner wall 402 of the tower body 410 .
- the tower lip 421 may be less than 360° and may be formed along one or more portions of the inner wall 402 of the tower body 410 .
- the upper portion of the coupling body 310 may be configured to be compressible, thereby allowing the perimeter of the coupling lip 355 to be reduced upon application of an external inward force (e.g., a force applied in the direction of the center of the coupling lip 355 by the surface of the wall 428 ), and to expand to a default configuration in the absence of an external force (shown in FIG. 3C ).
- an external inward force e.g., a force applied in the direction of the center of the coupling lip 355 by the surface of the wall 428 .
- the bone fastener receiving end of the tower 400 may be made of a material that may flex (or stretch) satisfactorily under force and revert to a default configuration (shown in FIG. 3C ) after the force is removed.
- the force may be introduced by the outer surfaces of the coupling lip 355 when the coupling lip 355 is inserted into the coupling guide 420 .
- FIG. 3E shows an example of a bone fastener assembly receiving end of the tower 400 having a tower lip 421 formed as a pair of tower lip segments 421 ′.
- the tower lip segments 421 ′ may be positioned opposite each, with spaces 425 being left open therebetween.
- the lengths of the tower lip segments 421 ′ may be the same, or one tower lip segment 421 ′ may be longer than the other.
- the lengths of the spaces 425 may be substantial identical or different.
- the lengths of the tower lip segments 421 ′ may be substantially the same as, or less than the width of the channel 302 in the coupling body 310 .
- the coupling lip 355 may be formed as a pair of coupling lip segments provided on each of the pair of upper portions of the coupling body 310 that form the U-shape and channel 302 therebetween.
- the pair of coupling lip segments provided on the pair of upper portions of the coupling 310 may be aligned with the spaces 425 and the coupling body 310 inserted into the tower end (shown in FIG. 3E ) until upper surfaces of the coupling lip 355 contact (or nearly contact) the stop 424 of the coupling guide 420 .
- the tower body 421 (and/or coupling body 310 ) may be rotated until the coupling lip segments substantially overlap with the tower lip segments 421 ′, thereby securing the coupling lip 355 in the coupling guide 420 .
- the tower lip 421 may be configure as a single 360° thread (not shown) that may allow the coupling lip 355 to be inserted in and guided by the thread into the coupling guide 420 when the coupling body 310 (or tower body 410 ) is rotated at least one complete turn with respect to the tower body 410 (or coupling body 310 ).
- the thread maybe less than 360° or greater than 360°.
- the coupling body 310 may include one or more recessed grooves 356 .
- the groove 356 may be formed in the outer wall 311 of the coupling body 310 .
- the groove 356 may have a substantially flat, an annular, or a semi-annular shape that may be cut from, or formed in the coupling body 310 .
- at least one groove 356 may be provide in the outer wall 311 of each upper portion near the coupling lip segment that is provided at upper end of the coupling body 310 .
- the groove 356 may be formed in a 360° section of the outerwall 311 , formed along and around the entire perimeter of the outer wall 311 .
- the groove 356 may be formed substantially perpendicular to the longitudinal axis of the coupling body 310 and/or the tower body 410 .
- the groove 356 may be formed in less than a 360° section of the outer wall 311 , as discussed herein with respect to the embodiment shown in FIG. 3E .
- the groove 356 may be configured to receive, hold, and guide the tower lip 421 (or tower lip segment 421 ′), allowing the tower lip 421 to travel in either direction in the groove 356 , along the longitudinal axis of the coupling body 310 and/or tower body 410 .
- the tower lip 421 may also be permitted to travel in and along the groove 356 in a direction that is substantially perpendicular to the longitudinal axis of the coupling body 310 , such as, for example, when the coupling body 310 is rotated with respect to the tower body 410 .
- the groove 356 may include one or more walls 357 , 358 .
- the walls 357 and/or 358 may function to limit travel of the tower lip 421 in the groove 356 along the longitudinal axis of the tower body 410 .
- the wall 358 may be a portion of the coupling lip 355 , the surface of which may be formed to face the groove 356 and be substantially perpendicular to the longitudinal axis of the coupling body 310 .
- the wall 357 includes a surface that may be substantially perpendicular to the longitudinal axis of the tower body 421 and facing the groove 356 .
- FIGS. 4A, 4B and 4C show three enlarged cross-sectional cut views of the thread pitch mismatch compensator 350 at three different stages of implementation to compensate the thread pitch mismatch and misalignment that may otherwise occur between the threads 319 , 419 of the coupling assembly 300 and the tower 400 , respectively.
- FIG. 4A shows an example of a stage of implementation of the thread pitch mismatch compensator 350 , wherein thread misalignment and thread pitch mismatch between the inner surfaces of the coupling body 310 and the tower 400 . It is understood that, without the thread pitch mismatch compensator 350 , the configuration in FIG. 4A would block any further downward movement of the set screw 370 . However, the thread mismatch compensator 350 compensates for the thread pitch mismatch by allowing the coupling body 310 to move with respect to the tower body 410 (shown in FIGS. 4A-4C ) until such time as the threads 319 of the coupling body 310 are matched to the threads 379 of the set screw 370 , allowing the set screw to engage and progress along the threads 319 of the coupling body 310 .
- the coupling body 310 may be pushed and move downward by the set screw 370 .
- the coupling lip 355 may contact the surface wall of the coupling guide 420 and be guided along the coupling guide 420 , such that the threaded inner surface of the coupling body 310 does not move laterally when the coupling body 310 is pushed down by the set screw 370 .
- the coupling body 310 may be further guided by the contact 429 between the outer wall 311 and the inner wall 402 of the tower body.
- the coupling body 310 may continue to move until the threads 379 on the set screw 370 are aligned with and match the threads 319 in the coupling body 310 (shown in FIG. 4B ). After the threads 379 and 319 match, the set screw 370 may engage and proceed along the thread 319 and, thereby, inner walls of the coupling body 310 .
- the thread pitch of the threads 379 and 319 as well as the thread pitch of the threads 419 in the tower 400 , become aligned and the set screw 370 may begin to mate with the thread 319 of the coupling body 310 .
- the set screw 370 may then make a transition from the tower body 410 and into the coupling body 310 .
- the bone fixation device 110 may be constructed to compensate the thread pitch mismatch between the threads of the coupling assembly 300 and the tower 400 , which can eliminate cross threading therebetween. No additional parts are required to implement the thread pitch mismatch compensation features, and, therefore, the size and number of moving parts of the bone fixation device 110 may be minimized, thereby facilitating minimally invasive surgery (MIS) procedures. Also, the same tower 400 may be interchangeably used with bone fastener assemblies 200 / 300 having different sizes and/or configurations to form the bone fixation device 110 .
- MIS minimally invasive surgery
- a method of implanting the bone fixation system 100 (shown in FIG. 2 ), and more particularly, a plurality of bone fixation devices 110 and fastener connectors 120 will now be described.
- the patient may be placed in a prone position on a radiolucent table and draped in the usual manner.
- imaging such as, for example, fluoroscopy and preoperative imaging
- a location may be determined for each incision and the incision made.
- a targeting needle (not shown) may be inserted through the dissected tissue to the level of a target pedicle.
- the targeting needle may be tapped into the vertebral body until depth is satisfactory.
- the trajectory and depth of the targeting needle should be repeatedly confirmed using the imaging (e.g., fluoroscopy) as the needle is being inserted.
- an inner stylus (not shown) may be removed from the needle and a K-wire inserted in its place to an appropriate depth.
- the targeting needle may then be removed while carefully maintaining control of the depth of the guide wire. The foregoing steps may be repeated for each of the remaining pedicles.
- a dilator (not shown) may be inserted over the guide wire, keeping the guide wire steady in the process.
- the starter dilator tube (not shown) may be removed, leaving the second (not shown) and final dilator (not shown) in place.
- An appropriately sized cannulated tap (not shown) may be inserted over the guide wire and through the second dilator. The cannulated tap may be tapped to desired length while maintaining the position and depth of the guide wire. Imaging may be used to verify that the tap is following the trajectory of the guide wire during insertion.
- the correct size and/or configuration of the bone fastener assembly 200 / 300 may be selected for the particular procedure.
- a universal tower 400 may be attached to the bone fastener assembly 200 / 300 to form the bone fixation device 110 .
- An advantage of using a universal tower 400 according to the principles of the disclosure is that only a single size of tower 400 could be stocked for various sizes and/or configurations of bone fastener assemblies 200 / 300 (such as, for example, polyaxial pedicle screw assemblies).
- the tower 400 is bone fastener assembly-agnostic.
- the tower 400 may be used with different sizes and/or configurations of bone fastener assemblies 200 / 300 (such as, for example, generic pedicle screw assembly housings), including bone fastener assemblies 200 / 300 to be used for MIS or reduction procedures.
- bone fastener assemblies 200 / 300 such as, for example, generic pedicle screw assembly housings
- the bone fixation device 110 may be assembled using the selected bone fastener assembly 200 / 300 with the tower 400 constructed according to the principles of the disclosure.
- the bone fastener assembly 200 / 300 may be pushed into the receiving end of the tower body 410 (portion A in FIG. 3A ), such that the coupling lip 355 of the coupling body 310 is forced to compress under force of the angled wall 428 until it passes an edge of the wall 426 , at which point the coupling lip 355 will be in the coupling guide 420 and may snap to its default configuration (shown in FIG. 3C ).
- the tower body 410 may be made of a material that may permit the tower body 410 to flex, so as to facilitate insertion of the coupling lip 355 past the tower lip 421 and into the coupling guide 420 . In this latter regard, the coupling body 310 need not be flexible.
- one or more of the tower bodies 800 may incorporate one or more flexible portions 810 , which in various embodiments may comprise a section or subsection of a tower body that has been “weakened” or otherwise rendered more flexible (i.e., by machining and/or material removal, for example) than other portions of the tower body 800 .
- a series of slit cut patterns 820 or similar features can be made along one or more regions of the tower wall structure, such as along the middle region of the tower as shown in FIG. 8A , where a center of curvature of the flexible section can exist.
- a desired center of curvature (or a distance from the rod to the center of the slit pattern) can range from 50 mm to 250 mm.
- the tower element may be continuous, or may comprise two or more (i.e., a series) individual interlocking sections, desirably with a modular feature 830 for engaging directly with a top portion of a pedicle screw housing, including attachment to a low top pedicle screw housing in some embodiments.
- the tower bodies can include one or a plurality of flexible portions 840 , including flexible portions of differing lengths, sizes and/or positions, if desired.
- the flexible portions can include a modular segment, which can be attached to a desired portion of the tower at virtually any position along its length (not shown).
- tower collision or other tool interference can be a common occurrence due to a variety of factors, including the natural anatomy, anatomical variations between patients, injury and/or spinal degradation, and desired rod curvature and/or pedicle screw placements, which can make it difficult for a surgeon to engage subsequent instruments for compression and/or distraction.
- Tower collision can also be exacerbated where a curved spinal rod is used to match and/or correct lordotic anatomy, potentially presenting the surgeon with a challenging rod insertion and/or alignment as well as significantly limiting the amount of “real estate” available to accommodate additional surgical instrumentation.
- tower collision and/or interference can inhibit proper screw placement and/or cause “false” set screw tightening (see gap 900 of FIG. 9C ), where the construct may be misaligned and cause the set screw to cross-thread and/or prematurely lock. Such occurrence can eventually result in loosening and/or failure of the spinal construct during spinal motion and/or the patient's healing process.
- the present invention can allow proximal portions of the tower to be displaced in a desired direction and/or orientation while the remaining distal portion(s) of the tower can be attached and/or remain connected to the fixation screw in a desired manner.
- This arrangement desirably prevents and/or reduces the opportunity for collision and/or interference between adjacent towers, which often occurs when patient concavity of the spine is steep (i.e., small radius), making the tall tower exceed the radius of the curvature of the spine. As shown in FIG.
- the tower housing can be rendered flexible in one or more regions by forming slit cut patterns or any other form of material removal, which on one exemplary embodiment can be made along the tower's middle region near where the center of the curvature meets.
- This creation of a flexible zone can be integrated into any percutaneous pedicle screws with high towers or it would apply to any modular reduction tower or similar element (see FIGS. 10A and 10B ).
- FIGS. 11A and 11B depict an alternative embodiment of rigidity reducing cuts 1100 provided on upstanding leg portions 1110 of a minimally invasive screw assembly 1120 .
- portions of the assembly 1120 can be flexed in a desired direction while continuing to provide an access path through the patient's tissues in a desired manner.
- the flexible section could comprise a section of weaker material, such as a different and/or softer material that the remainder of the assembly, or the flexible section could comprise a portion of reduced cross-section or different design of the same material that potentially leads to an increased flexibility and/or greater ductility.
- FIGS. 12A through 12C and 13A through 13F depict additional alternative embodiments of flexible regions that can be formed in various spinal instrumentation.
- the flexible region can be designed to provide a full 360 degrees of flexion about the longitudinal axis of the tool, while other embodiments might provide flexion along only one or more axis, while inhibiting flexion along other axes.
- the flexion slits may completely encircle the too, or may be provided only about a portion of the circumference of the tool, such as less than 180 degrees and/or less than 90 degrees and/or less than 45 degrees of the circumference of the tool.
- the bone fixation device 110 may be assembled by holding the base of the bone fastener 200 in one hand, and a portion of the tower body 410 at the receiving end of the tower 400 (portion A, shown in FIG. 3A ) in the other hand, aligning the coupling lip segments of the coupling body 310 with the spaces 425 in the tower 400 , pushing the coupling body 310 into the receiving end of the tower body 410 (portion A in FIG. 3A ) and past the tower lip segments 421 ′, and, when properly inserted, turning one or both of the tower body 410 and coupling body 310 with respect to each until the coupling lip segments substantially overlap with the tower lip segments 421 ′.
- a cannulated bone screw driver assembly (not shown) may be inserted in the tool channel 401 .
- the screw driver (not shown) may be inserted through the tool channel 401 to the head of the bone fastener 200 , at which point the screw driver (not shown) may be manipulated to properly seat the male (or female) end of the head of the screw driver (not shown) in the female (or male) end of the bone fastener 200 .
- an outer sleeve (not shown) of the screw driver may be rotated to tighten the screw driver with respect to the tower body 410 .
- the cannulated bone fastener 200 may then be placed over the guide K-wire and slid through the final dilator to the pedicle. Once the bone fastener 200 reaches the vertebral body, the guide wire may be removed and the bone fastener 200 advanced to the desired depth by rotating the screw driver (not shown).
- the cannulated screw driver (not shown) and the final dilator may be removed at this point.
- the above process may be repeated for each of the target pedicles.
- rod measurement calipers may be used as is known in the art.
- the towers 400 in the bone fixation system e.g., shown in FIG. 2
- the towers 400 in the bone fixation system may be aligned such that the channels 302 of the coupling assemblies 300 are aligned.
- the open channel(s) 403 and/or slots 412 may be aligned.
- the appropriate fastener connector 120 may be selected together with an appropriate inserter tool (not shown, such as, e.g., an offset left rod inserter, an offset right rod inserter, an in-line rod inserter, or the like).
- the inserter tool (not shown) may be inserted in and guided through the tool channel 401 to a predetermined position in the tower body, at which point the fastener connector 120 may be deployed and placed in the channel 302 of each of the aligned coupling bodies 310 .
- the inserter tool (not shown) may be delivered to the fastener connector 120 installation site(s) external to any tower 400 .
- standard reduction e.g., derotation device 500 (described below), standard rod pushers (not shown), supplemental reduction (e.g., using parallel reducers (not shown))
- supplemental reduction e.g., using parallel reducers (not shown)
- a set screw 370 may be placed on a set screw starter tool (not shown), and the set screw starter tool (not shown) with set screw 370 may be inserted in and down the tower body 410 until it reaches the upper surface of the coupling body 310 , as seen in FIG. 4A .
- Final tightening of the set screws 370 may be carried out by using a counter torque tube holder tool (not shown) to hold the top of the tower 400 , and turning the set screw tightening tool (not shown). As seen in FIG.
- the set screw 370 will push down on the upper surface of the coupling body 310 and rotate until the pitch of the threading 379 matches that of the threading 319 in the coupling body 310 , at which point the set screw 370 will engage and progress downward into the threading 319 in the coupling body 310 (shown in FIG. 4C ).
- the bone fasteners 200 should be inserted with some good force and within the confines of the vertebra, because the pedicle should be a strong pedicle and should hold the bone fastener 200 well, since this is a fastener that is going to hold the vertebra in place while the fusion is taking place. After each bone fastener 200 is secured in place, the bone fasteners 200 may be tested by running a small current through the fasteners to determine whether the fastener may irritate a nerve. The process may be repeated for each of the other fasteners.
- FIG. 5 shows an example of a derotation device 500 , constructed according to the principles of the disclosure.
- the derotation device 500 may be used for derotation (e.g., en bloc derotation, segmental derotation, etc.), deformity correction (e.g., rib hump correction, etc.), translation, and the like.
- the derotation device 500 may include a reinforced cannulated shell.
- the derotation device 500 may be configured to slide over and at least partially encapsulate a modular derotation tower 600 (e.g., tower 400 of the bone fastening device 110 shown in FIGS. 2 and 3A ).
- the derotation device 500 may have an elongated shaped housing with a hollow body structure to receive the derotation tower 600 .
- the derotation device 500 may have an opening at a narrow tip end 510 , into which the derotation tower 600 may be inserted.
- the derotation device 500 may also include a locking mechanism, such as, for example, sliding lock 512 or the like, which may fix the tower 600 once inserted into the derotation device 500 .
- the derotation device 500 may also include a grip portion 520 , which may have a larger diameter than the narrow tip end 510 .
- the larger grip portion 520 may increase the rotational torque, thereby allowing the derotation device 500 to function as a torque sleeve.
- a crosslink unit 700 may be used to fix two or more derotation devices 500 A, 500 B at a desired distance therebetween.
- the crosslink unit 700 may have an elongated body 710 having two bent ends 712 A, 712 B.
- the bent ends 712 A, 712 B may attach to the derotation devices 500 A, 500 B, respectively.
- the body 710 may have a pair of set screws 720 A, 720 B.
- the derotation devices 500 A, 500 B may include a screw hole 530 (not shown in FIG. 7 ) near the top end portion thereof Referring to FIG.
- the derotation device 500 A may be placed to contact an inner bent surface of the bent end 712 A, and then the set screw 720 A may be screwed into the screw hole 530 of the derotation device 500 A, which may fix the derotation device 500 A to the bent end 712 A of the crosslink unit 700 .
- the derotation device 500 B may be fixed to the opposite bent end 7126 of the crosslink unit 700 in a similar manner.
- a length of the crosslink unit 700 may be adjustable.
- the body part 710 may be divided into two parts: first body part 710 A and second body part 710 B, which are fixed to each other by a set screw 712 .
- the set screw 712 may be unscrewed to disengage the first and second body parts 710 A, 710 B from each other. Then first and second body parts 710 A, 710 B may then be pulled away from each other or pushed toward each other to increase or decrease the length of the body 710 , respectively.
- the set screw 712 may be screwed to fix the first and second body parts 710 A, 710 B together.
- the bone fixation (or stabilization) system 100 may be configured for use in, for example, anterior approach and discectomy applications.
- an individual derotation device(s) 500 may be manipulated by a surgeon's hand, to allow for rotational and/or axial adjustment of the derotation device(s) 500 .
- FIGS. 14A through 14C depict additional embodiments of tower bodies 1400 , 1430 and 1460 which can incorporate flexible regions 1405 , 1435 and 1465 as described herein.
- the towers 1400 and 1460 can further include a single proximal bridge 1410 , or a pair of proximal bridges 1470 (or various other numbers and/or locations of bridges, including three, four or more bridges and/or pairs of bridges), which can desirably increase the strength and stability of the tower during use, including during alignment of the fixation elements and/or flexion of the towers.
- FIGS. 15A through 15D depict one exemplary embodiment of a tower body 1500 that includes a tubular body portion 1510 with an integrated tip portion 1520 .
- the tube body 1510 can include a flexible section (not shown) along virtually any portion of its length, which may include flexible sections at different points along each wall of the tube body, if desired.
- the tube body 1510 also can include one or more bridge portions 1525 .
- the integrated tip portion 1520 is attached to the tube body at a reduced diameter section 1530 , which desirably forms a “weakened” and/or frangible link between the tube body 1510 and the tip portion 1520 .
- this arrangement will allow the tip portion 1520 to be separated from the tube body 1510 at a desired point in the surgery, with the tip portion capable of function as a polyaxial or other type head of the pedicle screw assembly.
- FIGS. 16A through 16C depict another exemplary embodiment of a tower body 1600 that includes a tubular body portion 1610 with an integrated tip portion 1620 , along with a single bridge portion 1625 .
- the tube body 1610 can include a flexible section (not shown) along virtually any portion of its length, which may include flexible sections at different points along each wall of the tube body, if desired.
- FIG. 17 depicts one exemplary method of removing a tubular body portion 1710 from a tip portion 1720 of a tower body 1700 .
- the bridge portion 1725 of the tower body 1700 can be severed (“A”) by a metal cutter 1790 or other surgical tool, and the individual sections 1740 and 1745 of the body portion 1710 can be flexed (“B”) and/or otherwise displaced, which desirably stresses, “works” and/or breaks the frangible link 1750 (“C”), leaving the tip portion 1720 within the anatomy while allowing the individual sections 1740 and/or 1745 to be removed.
- a tubular tool or surgical pliers can be utilized to flex a portion of the individual sections 1740 and/or 1745 below the flexible section to break the frangible link in a desired manner.
- FIGS. 18A and 18B depict front plan and cross-sectional views, respectively, of one embodiment of an exemplary fixation element 1800 incorporating a tip portion 1810 which engages with a bone fastener in the form of a polyaxial pedicle screw 1820 .
- the tip portion 1810 When fully assembled, the tip portion 1810 holds a head portion 1830 of the polyaxial pedicle screw, which can be sandwiched between a first inner ring 1840 and a second inner ring 1850 , with the inner rings designed and positioned such that when a force is applied in a downward direction by a set screw 1890 (e.g., a force that is substantially perpendicular to the plane of the upper surface of the inner ring), the volume of the cavity that holds the head portion 1830 of the bone fastener and/or a fixation rod 1880 is compressed or reduced, thereby securely engaging and holding the head portion 1830 of the bone fastener and the rod 1880 by the inner walls of the tip portion 1810 and the rings.
- a set screw 1890 e.g., a force that is substantially perpendicular to the plane of the upper surface of the inner ring
- FIG. 19A through 19D depict various views of a set screw 1900 for use with various embodiments of the present invention.
- the set screw 1900 can include a central body 1910 with externally positioned threads 1920 .
- the threads can include a sawtooth or reverse thread pattern, as well as square threads and/or other thread designs to desirably reduce and/or obviate splay of the tip portion, if desired.
- Devices that are in communication with each other need not be in continuous communication with each other, unless expressly specified otherwise.
- devices that are in communication with each other may communicate directly or indirectly through one or more intermediaries.
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Abstract
Description
- This application is a continuation-in-part of Utility patent application Ser. No. 15/335,026 filed Oct. 26, 2016, titled “Modular Rod Reduction Tower and Related Methods,” which claims priority to and benefit thereof from U.S. Provisional Patent Application No. 62/247,183 filed Oct. 27, 2015, titled “MODULAR DEROTATION TOWER WITH ROD REDUCTION SLEEVE,” and U.S. Provisional Patent Application No. 62/257,124, filed Nov. 18, 2015, titled “MODULAR ROD REDUCTION TOWER WITH THREAD PITCH COMPENSATION FEATURE AND METHODS OF USE,” all of which are hereby incorporated herein by reference in their entireties.
- This application further claims priority to and the benefit of U.S. Provisional Patent Application No. 62/758,120 filed Nov. 9, 2018, titled “Flexible MIS Tower,” which is also hereby incorporated herein by reference in its entirety.
- The present disclosure relates to a bone stabilization system and method, and more particularly to a bone stabilization system and method for implanting within a body of a patient.
- In mammals, the spinal (or vertebral) column is one of the most important parts. The spinal column provides the main support necessary for mammals to stand, bend, and twist.
- In humans, the spinal column is generally formed by individual interlocking vertebrae, which are classified into five segments, including (from head to tail) a cervical segment (vertebrae CI-C7), a thoracic segment (vertebrae TI-TI2), a lumbar segment (vertebrae LI-L5), a sacrum segment (vertebrae SI-S5), and coccyx segment (vertebrate Col-CoS). The cervical segment forms the neck, supports the head and neck, and allows for nodding, shaking and other movements of the head. The thoracic segment attaches to ribs to form the ribcage. The lumbar segment carries most of the weight of the upper body and provides a stable center of gravity during movement. The sacrum and coccyx make up the back walls of the pelvis.
- Intervertebral discs are located between each of the movable vertebra. Each intervertebral disc typically includes a thick outer layer called the disc annulus, which includes a crisscrossing fibrous structure, and a disc nucleus, which is a soft gel-like structure located at the center of the disc. The intervertebral discs function to absorb force and allow for pivotal movement of adjacent vertebra with respect to each other.
- In the vertebral column, the vertebrae increase in size as they progress from the cervical segment to the sacrum segment, becoming smaller in the coccyx. At maturity, the five sacral vertebrae typically fuse into one large bone, the sacrum, with no intervertebral discs. The last three to five coccygeal vertebrae (typically four) form the coccyx (or tailbone). Like the sacrum, the coccyx does not have any intervertebral discs.
- Each vertebra is an irregular bone that varies in size according to its placement in the spinal column, spinal loading, posture and pathology. While the basic configuration of vertebrae varies, every vertebra has a body that consists of a large anterior middle portion called the centrum and a posterior vertebral arch called the neural arch. The upper and lower surfaces of the vertebra body give attachment to intervertebral discs. The posterior part of a vertebra forms a vertebral arch that typically consists of two pedicles, two laminae, and seven processes. The laminae give attachment to the ligament flava, and the pedicles have a shape that forms vertebral notches to form the intervertebral foramina when the vertebrae articulate. The foramina are the entry and exit passageways for spinal nerves. The body of the vertebra and the vertical arch form the vertebral foramen, which is a large, central opening that accommodates the spinal canal that encloses and protects the spinal cord.
- The body of each vertebra is composed of cancellous bone that is covered by a thin coating of cortical bone. The cancellous bone is a spongy type of osseous tissue, and the cortical bone is a hard and dense type of osseous tissue. The vertebral arch and processes have thicker coverings of cortical bone.
- The upper and lower surfaces of the vertebra body are flattened and rough. These surfaces are the vertebral endplates that are in direct contact with the intervertebral discs. The endplates are formed from a thickened layer of cancellous bone, with the top layer being denser. The endplates contain adjacent discs and evenly spread applied loads. The end plates also provide anchorage for the collagen fibers of the disc.
-
FIG. 1 shows a portion of a patient'sspinal column 2, includingvertebra 4 andintervertebral discs 6. Eachdisc 6 forms a fibrocartilaginous joint betweenadjacent vertebrae 4, allowing relative movement betweenadjacent vertebrae 4. Beyond enabling relative motion betweenadjacent vertebrae 4, eachdisc 6 acts as a shock absorber for thespinal column 2. - As noted earlier, each
disc 6 comprises a fibrous exterior surrounding an inner gel-like center which cooperate to distribute pressure evenly across eachdisc 6, thereby preventing the development of stress concentrations that might otherwise damage and/or impairvertebrae 4 ofspinal column 2.Discs 6 are, however, subject to various injuries and/or disorders which may interfere with a disc's ability to adequately distribute pressure and protectvertebrae 4. For example, disc herniation, degeneration, and infection ofdiscs 6 may result in insufficient disc thickness and/or support to absorb and/or distribute forces imparted tospinal column 2. Disc degeneration, for example, may result when the inner gel-like center begins to dehydrate, which may result in adegenerated disc 8 having decreased thickness. This decreased thickness may limit the ability of degenerateddisc 8 to absorb shock which, if left untreated, may result in pain and/or vertebral injury. - Thus, when a spinal abnormality occurs, the abnormality can cause severe pain or damage to the nervous system. The abnormality may also severely limit movement of the spinal column. The abnormality may be the result of, for example, trauma, degenerative disc disease, degenerative bone disease, or the like.
- There exists an unfulfilled need for improved bone stabilization devices, associated systems, and methodologies related thereto. Since recovery from spinal surgery is typically a long and arduous process that places severe restrictions on patient mobility, a continuing need exists for systems and methodologies that improve patient recovery and reduce recovery time after surgery.
- According to an aspect of the disclosure, a bone fixation system includes a bone fastener, a tower including a first thread formed on an inner surface at a first end thereof, a coupling assembly connected to the bone fastener and the first end of the tower. The coupling assembly includes a coupling unit including a second thread formed on an inner surface at an upper portion thereof and adjoining the first thread, and a set screw including a third thread configured to mate with the first thread and the second thread. The coupling unit is configured to compensate a thread pitch mismatch between the first thread and the second thread.
- The bone fastener includes a polyaxial pedicle screw having a head and a screw shaft extending from the head.
- The coupling assembly further includes a cavity that receives and holds a portion of the bone fastener.
- The coupling assembly further includes a channel formed by a pair of upper inner walls of the coupling unit.
- The bone fixation device further includes a fastener connector having a portion that seats within the channel.
- The tower further includes a coupling guide formed around an inner surface at the first end portion thereof.
- The coupling unit further includes a coupling lip formed on an outer surface of an upper portion thereof that seats in the coupling guide of the tower.
- The coupling guide is formed by a recessed surface extending between an upper recess surface and a lower recess surface, the recess surface being wider than the coupling lip of the coupling unit.
- The coupling unit travels in a direction in response to a force applied by the set screw when the first thread and the second thread are misaligned.
- The third thread of the set screw mates with the second thread of the coupling unit when a thread pitch of the first thread is aligned with a thread pitch of the second thread.
- According to another aspect of the disclosure, a bone fixation system includes a tower having a tower body that includes an internal tower thread, and a thread pitch compensator. The thread pitch compensator substantially matches the pitch of the tower thread to a pitch of a thread in a coupling body to facilitate progression of a set screw from the tower thread into and along the thread in the coupling body.
- The thread pitch compensator includes a coupling guide that holds and guides a coupling lip on the coupling body.
- The thread pitch compensator includes a tower lip.
- The thread pitch compensator includes a stop that limits travel of the coupling lip in the coupling guide.
- The coupling guide allows the coupling lip to move in either direction along a longitudinal axis of the tower.
- According to yet another aspect of the disclosure, a bone fixation system includes a hollow shell body having an opening at a first end portion thereof, and a derotation tower that envelopes a tower of a bone fastener when inserted into the hollow shell body via the opening of the hollow shell body.
- The hollow shell body includes a grip portion having a diameter greater than that of the first end portion thereof.
- The bone fixation system further includes a crosslink unit that removably affixes to a second end portion of the hollow shell body.
- A length of the crosslink unit is adjustable.
- The crosslink unit includes a bent end portion that removably affixes to the second end portion of the hollow shell body.
- Additional features, advantages, and embodiments of the disclosure may be set forth or apparent from consideration of the detailed description and drawings. Moreover, it is to be understood that both the foregoing summary of the disclosure and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the disclosure as claimed.
- The accompanying drawings, which are included to provide a further understanding of the disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the detailed description serve to help explain the principles of the disclosure. No attempt is made to show structural details of the disclosure in more detail than may be necessary for a fundamental understanding of the disclosure and the various ways in which it may be practiced. In the drawings:
-
FIG. 1 illustrates a portion of a patient's spinal column; -
FIG. 2 shows an example of a bone fixation system that may be implanted in a spinal column, according to the principles of the disclosure; -
FIG. 3A shows an example of a bone fixation device, constructed according to the principles of the disclosure; -
FIGS. 3B and 3C show enlarged views of portions of the bone fixation device inFIG. 3A ; -
FIG. 3D shows an enlarged cross-section cut view of an example of a thread pitch compensation feature in a bone fixation device, according to the principles of the disclosure; -
FIG. 3E shows a bottom view of an example of a tower, constructed according to principles of the disclosure; -
FIGS. 4A, 4B and 4C show enlarged views of a connection portion of the bone fixation system inFIG. 3A ; -
FIG. 5 shows an example of a derotation device, constructed according to the principles of the disclosure; -
FIG. 6A shows the derotation device inFIG. 5 and a derotation tower according to the principles of the disclosure; -
FIG. 6B shows the derotation device encapsulating the derotation tower inFIG. 6A ; -
FIG. 7 shows an example of a bone fixation system, including a crosslink for linking two or more derotation devices to each other, according to the principles of the disclosure; -
FIG. 8A depicts an exemplary embodiment of tower bodies that incorporate one or more flexible portions; -
FIG. 8B depicts an alternative embodiment of tower bodies that incorporate one or more flexible portions, including a modular tower incorporating a removable and/or reconfigurable flexible section; -
FIG. 9A depicts an exemplary interference or collision of tower bodies in a spine analog; -
FIG. 9B depicts a correctly aligned fixation construct with set screw tightened; -
FIG. 9C depicts a misaligned fixation construct with set screw tightened; -
FIGS. 10A and 10B depict attachment of a spinal instrument having a flexible zone being attaching to a spinal fixation element; -
FIGS. 11A and 11B depict another embodiment of a percutaneous spinal instrument having flexible zones in accordance with the present disclosure; -
FIGS. 12A through 12C and 13A through 13F depict additional alternative embodiments of flexible regions that can be integrated into various spinal instrumentation; -
FIGS. 14A through 14C depict additional alternative embodiments of flexible towers; -
FIGS. 15A through 15D depict an additional embodiment of a tower body that includes a tubular body portion with an integrated detachable tip portion; -
FIGS. 16A through 16C depict another alternative embodiment of a tower body with an integrated detachable tip portion; -
FIG. 17 depicts one exemplary method of removing a tubular body portion from a tip portion of a tower body; -
FIGS. 18A and 18B depict front plan and cross-sectional views, respectively, of one embodiment of an exemplary fixation element incorporating a tip portion which engages with a bone fastener in the form of a polyaxial pedicle screw; and -
FIG. 19A through 19D depict various views of a set screw for use with various embodiments of the present invention. - The present disclosure is further described in the detailed description that follows.
- The disclosure and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and examples that are described and/or illustrated in the accompanying drawings and detailed in the following description. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale, and features of one embodiment may be employed with other embodiments as the skilled artisan would recognize, even if not explicitly stated herein. Descriptions of well-known components and processing techniques may be omitted so as to not unnecessarily obscure the embodiments of the disclosure. The examples used herein are intended merely to facilitate an understanding of ways in which the disclosure may be practiced and to further enable those of skill in the art to practice the embodiments of the disclosure. Accordingly, the examples and embodiments herein should not be construed as limiting the scope of the disclosure. Moreover, it is noted that like reference numerals represent similar parts throughout the several views of the drawings.
- Referring to
FIG. 1 , when a spinal abnormality occurs in thespinal column 2, the abnormality can cause severe pain or damage to the nervous system, and the abnormality may limit movement of the spinal column. As noted earlier, the abnormality may be the result of, for example, trauma, degenerative disc disease, degenerative bone disease, or the like. - According to an aspect of the disclosure, the abnormality may be treated by affixing bone fasteners (such as, for example, bone screws or hooks) to one or more vertebrae and connecting the bone fasteners to a fastener connector (such as, for example, a rod, a curved rod, a straight rod, a wire, a cross-connector rod, a cross-connector wire, or the like). The fastener connector may be aligned with the longitudinal axis of the
spinal column 2 to immobilize the spinal segment (e.g., adjacent vertebrae 4) with respect to each other. For instance, the bone fasteners may comprise bone screws that are screwed into pedicles ofvertebrae 4 and coupled to at least one fastener connector that may include an elongated rod. The pedicles, which consist of a strong shell of cortical bone and a core of cancellous bone, provide the strongest point of attachment of a spine and, therefore, the greatest resistance against bone-metal junction failure. The bone fasteners may be positioned so as to traverse all three columns of the vertebrae, thereby providing ventral and dorsal stability in thespinal column 2. -
FIG. 2 shows an example of abone fixation system 100 that may be implanted in the spinal column 2 (shown inFIG. 1 ) of a patient's body. Once implanted in a patient'sspinal column 2, thebone fixation system 100 may properly position, stabilize and promote fusion in a portion of thespinal column 2, such as, for example, two or more adjacent vertebrae. Thebone fixation system 100 may comprise any number ofbone fixation devices 110 andfastener connectors 120. Eachbone fixation device 110 may include abone fastener assembly 200/300 and atower 400.FIG. 2 shows one non-limiting embodiment wherein thebone fixation system 100 comprises threebone fixation devices 110 and asingle fastener connector 120 connecting to thebone fastener assemblies 200/300 of all three of thebone fixation devices 110. Thebone fastener assembly 200/300 includes abone fastener 200 and acoupling assembly 300, collectively referred to asbone fastener assembly 200/300. According a non-limiting embodiment, thebone fastener 200 in thebone fixation device 110 may comprise a poly-axial pedicle screw 200. -
FIGS. 3A to 3E show various views of thebone fixation device 110 and/or thetower 400, according to principles of the disclosure.FIG. 3A shows a cross-section cut view of a non-limiting embodiment of thebone fixation device 110, constructed according to the principles of the disclosure;FIG. 3B shows a top view of the bone fixation device 11 0;FIG. 3 C shows an enlarged cross-section cut view of a connection portion A of thebone fixation device 110;FIG. 3D shows an enlarged cross-section cut view of a non-limiting embodiment of athread pitch compensator 350 in thebone fixation device 110; andFIG. 3E shows an example of a receiving end of thetower 400. - Referring to
FIG. 3A , thetower 400 has atower body 410 that may be removably attached to thecoupling assembly 300. Thetower body 410 may have a cylindrical or tube-like shape with atool insertion channel 401 formed therein by theinner walls 402 of thetower body 410. Thetool insertion channel 401 may be used to receive and guide a tool, such as, for example, a screw driver (not shown), facilitating delivery of an end of the tool (not shown) to the bone fastener 200 (for example, the head of the polyaxial pedicle screw) and/or aset screw 370, so as to allow manipulation (e.g., tightening or loosening) of thebone fastener 200 and/or theset screw 370. - As seen in
FIG. 3B , when viewed from above, the walls of thetower body 410 have atower end 475 that may have a semi-closed (or semi-open) shape, such as, for example, a “C” shape having anopen channel 403 formed in thetower body 410. Thechannel 403 may be provided to allow a portion of a tool (not shown) being inserted in or through thetool insertion channel 401 to protrude from thetower body 410, or to deploy or retrieve a device such as, for example, a fastener connector 120 (shown inFIG. 2 ) along thechannel 401 using, for example, a rod inserter tool (not shown). For instance, the tool (not shown) andfastener connector 120 may be delivered along thetool insertion channel 401 of thetower body 410, and when the tool end (not shown) is positioned in a predetermined position, thefastener connector 120 may be pivoted outward and extended from the tower body 410 (via the channel 403) to be seated in or inserted into thecoupling assemblies 300 in the bone fixation system 100 (shown inFIG. 2 ). The walls of thetower body 410 may include one or more openings (or cutouts) 412 that may run along less than the entire length of thetower 400. Alternatively, the opening (or cutout) may run along the entire length of thetower 400. - Alternatively, the
tower body 410 may be a closed type (not shown) that has a closed loop all around, or an open type (not shown) that may have multiple open channels (or cutouts) 403 formed on opposite sides of thetower 400. Thetower body 410 may include openings (or cutouts) 412, which may run along the entire length of thetower 400. Alternatively, the openings (or cutouts) 412 may run along less than the entire length of thetower 400. The length of one opening (or cutout) 412 may be the same as, or differ from the length of the other opening (or cutout) 412. - As seen in
FIG. 3C , thecoupling assembly 300 may include a coupling body (or unit) 310 and aset screw 370. Thecoupling assembly 300 may further include a first (or upper)inner ring 380 and a second (or lower)inner ring 390. Thecoupling body 310 may have a tulip-shape, or a “U”-shape at a first (or upper) end, so as to allow the fastener connector 120 (shown inFIG. 2 ) to be positioned within achannel 302, which may be formed by upper inner walls of thecoupling body 310. The width of thechannel 302 may be substantially the same as, or greater than the width (or diameter) of thefastener connector 120. - The
coupling body 310 may have a cavity at its opposite (or lower) end. The cavity may be formed by the inner walls of the lower portion of thecoupling body 310. Thecoupling body 310 may further include a stop against which a portion of the upper surface of the upperinner ring 380 may rest. Thecoupling body 310 may further include alip portion 312 that may protrude inward and serve as a stop to limit downward movement of the lowerinner ring 390 from the cavity. The cavity may be configured to receive and hold the first (upper)inner ring 380 and the second (lower)inner ring 390, partially or entirely within the cavity. - In the embodiment where the
bone fastener 200 includes a polyaxial pedicle screw, when assembled the firstinner ring 380 and secondinner ring 390 may form a further cavity that holds ahead portion 210 of the polyaxial pedicle screw. The firstinner ring 380 and the secondinner ring 390 are designed such that when a force is applied in the direction of the arrow 10 (e.g., a force that is substantially perpendicular to the plane of the upper surface of the inner ring 380), the volume of the cavity that holds thehead portion 210 of thebone fastener 200 is compressed or reduced, thereby securely engaging and holding thehead portion 210 of thebone fastener 200 by the inner walls of the firstinner ring 380 and/or secondinner ring 390. In the example shown inFIG. 3C , the force is applied to the upper surface of theinner ring 380 by the fastener connector 120 (shown inFIG. 2 ), which may be forced to move in the direction of thearrow 10 by theset screw 370, as theset screw 370 is turned and driven toward the firstinner ring 380. The design of thecoupling assembly 300 is configured such that the upperinner ring 380 may transfer load from thefastener connector 120 to the top surface of thehead portion 210 of thebone fastener 200. The design upgrades line contact into surface contact for stable seating of thefastener connector 120 and load transfer. - Referring to
FIG. 3C andFIG. 3D , thebone fixation device 110 may include a threadpitch mismatch compensator 350. As seen inFIG. 3D , according to a non-limiting embodiment, the threadpitch mismatch compensator 350 includes acoupling guide 420 that receives and guides acoupling lip 355 of thecoupling body 310. Thecoupling guide 420 may be configured to receive and guide known coupling body housings, so that thetower 400 may be attached to existing bone fastener assemblies having various sizes and configurations. Thecoupling guide 420 may be formed in theinner wall 402 of thetower body 410. Thecoupling guide 420 may have an annular shape that may be cut from, or formed in a section of theinner wall 402 of thetower body 410. For instance, thecoupling guide 420 may be formed in a 360° section of theinner wall 402 of thetower body 410, formed along and around theinner wall 402 of thetower body 410 and substantially perpendicular to the longitudinal axis of thetower body 410. Thecoupling guide 420 may be formed in less than a 360° section of theinner wall 402, or in multiple sections of theinner wall 402. Thecoupling guide 420 is configured to receive, hold, and guide acoupling lip 355 on thecoupling body 310, allowing thecoupling lip 355 to travel in thecoupling guide 420 in either direction along the longitudinal axis of thetower body 410. - The
coupling guide 420 may include astop 424 and atower lip 421 that may function to limit the travel of thecoupling lip 355 at each end of thecoupling guide 420. Thestop 424 may include a wall surface that is substantially perpendicular to the longitudinal axis of thetower body 410. Thetower lip 421 may include afirst wall 426 that has a surface that is substantially perpendicular to the longitudinal axis of thetower body 410 and faces thecoupling guide 420. Thetower lip 421 may include asecond wall 428 that may have an angled or tapered surface. The surface angle of thewall 428 may be, for example, between 5° and 90° with respect to the longitudinal axis of thetower body 410, and preferably between 30° and 60°. The surface angle of thewall 428 may be less than 5°, or more than 90° with respect to the longitudinal axis of thetower body 410. The surface of thewall 428 may be angled or tapered to allow thecoupling lip 355 of thecoupling body 310 to be forced by, and guided along the angled surface of thewall 428, past an edge of thewall 426, and allowed to be snapped into position in thecoupling guide 420. - The
tower lip 421 may be annular shaped and may be formed 360° around theinner wall 402 of thetower body 410. Alternatively, thetower lip 421 may be less than 360° and may be formed along one or more portions of theinner wall 402 of thetower body 410. - The upper portion of the
coupling body 310, including thecoupling lip 355, may be configured to be compressible, thereby allowing the perimeter of thecoupling lip 355 to be reduced upon application of an external inward force (e.g., a force applied in the direction of the center of thecoupling lip 355 by the surface of the wall 428), and to expand to a default configuration in the absence of an external force (shown inFIG. 3C ). - Alternatively (or additionally), the bone fastener receiving end of the tower 400 (portion A, shown in
FIG. 3A ) may be made of a material that may flex (or stretch) satisfactorily under force and revert to a default configuration (shown inFIG. 3C ) after the force is removed. The force may be introduced by the outer surfaces of thecoupling lip 355 when thecoupling lip 355 is inserted into thecoupling guide 420. -
FIG. 3E shows an example of a bone fastener assembly receiving end of thetower 400 having atower lip 421 formed as a pair oftower lip segments 421′. As seen, thetower lip segments 421′ may be positioned opposite each, withspaces 425 being left open therebetween. The lengths of thetower lip segments 421′ may be the same, or onetower lip segment 421′ may be longer than the other. The lengths of thespaces 425 may be substantial identical or different. - According to a non-limiting embodiment of the
tower 400, the lengths of thetower lip segments 421′ may be substantially the same as, or less than the width of thechannel 302 in thecoupling body 310. In this embodiment, thecoupling lip 355 may be formed as a pair of coupling lip segments provided on each of the pair of upper portions of thecoupling body 310 that form the U-shape andchannel 302 therebetween. During assembly, the pair of coupling lip segments provided on the pair of upper portions of thecoupling 310 may be aligned with thespaces 425 and thecoupling body 310 inserted into the tower end (shown inFIG. 3E ) until upper surfaces of thecoupling lip 355 contact (or nearly contact) thestop 424 of thecoupling guide 420. Then, the tower body 421 (and/or coupling body 310) may be rotated until the coupling lip segments substantially overlap with thetower lip segments 421′, thereby securing thecoupling lip 355 in thecoupling guide 420. - According to a further non-limiting embodiment of the
tower 400, thetower lip 421 may be configure as a single 360° thread (not shown) that may allow thecoupling lip 355 to be inserted in and guided by the thread into thecoupling guide 420 when the coupling body 310 (or tower body 410) is rotated at least one complete turn with respect to the tower body 410 (or coupling body 310). The thread maybe less than 360° or greater than 360°. - The
coupling body 310 may include one or more recessedgrooves 356. Thegroove 356 may be formed in theouter wall 311 of thecoupling body 310. Thegroove 356 may have a substantially flat, an annular, or a semi-annular shape that may be cut from, or formed in thecoupling body 310. In a non-limiting embodiment of thecoupling body 310 having tulip (or U-shaped) upper portions, at least onegroove 356 may be provide in theouter wall 311 of each upper portion near the coupling lip segment that is provided at upper end of thecoupling body 310. - According to another non-limiting embodiment of the
coupling body 310, thegroove 356 may be formed in a 360° section of theouterwall 311, formed along and around the entire perimeter of theouter wall 311. Thegroove 356 may be formed substantially perpendicular to the longitudinal axis of thecoupling body 310 and/or thetower body 410. Thegroove 356 may be formed in less than a 360° section of theouter wall 311, as discussed herein with respect to the embodiment shown inFIG. 3E . Thegroove 356 may be configured to receive, hold, and guide the tower lip 421 (ortower lip segment 421′), allowing thetower lip 421 to travel in either direction in thegroove 356, along the longitudinal axis of thecoupling body 310 and/ortower body 410. Thetower lip 421 may also be permitted to travel in and along thegroove 356 in a direction that is substantially perpendicular to the longitudinal axis of thecoupling body 310, such as, for example, when thecoupling body 310 is rotated with respect to thetower body 410. - The
groove 356 may include one ormore walls walls 357 and/or 358 may function to limit travel of thetower lip 421 in thegroove 356 along the longitudinal axis of thetower body 410. According to a non-limiting embodiment, thewall 358 may be a portion of thecoupling lip 355, the surface of which may be formed to face thegroove 356 and be substantially perpendicular to the longitudinal axis of thecoupling body 310. Thewall 357 includes a surface that may be substantially perpendicular to the longitudinal axis of thetower body 421 and facing thegroove 356. -
FIGS. 4A, 4B and 4C show three enlarged cross-sectional cut views of the threadpitch mismatch compensator 350 at three different stages of implementation to compensate the thread pitch mismatch and misalignment that may otherwise occur between thethreads coupling assembly 300 and thetower 400, respectively. -
FIG. 4A shows an example of a stage of implementation of the threadpitch mismatch compensator 350, wherein thread misalignment and thread pitch mismatch between the inner surfaces of thecoupling body 310 and thetower 400. It is understood that, without the threadpitch mismatch compensator 350, the configuration inFIG. 4A would block any further downward movement of theset screw 370. However, thethread mismatch compensator 350 compensates for the thread pitch mismatch by allowing thecoupling body 310 to move with respect to the tower body 410 (shown inFIGS. 4A-4C ) until such time as thethreads 319 of thecoupling body 310 are matched to thethreads 379 of theset screw 370, allowing the set screw to engage and progress along thethreads 319 of thecoupling body 310. - As seen in
FIG. 4B , with thecoupling guide 420 that allows movement of thecoupling body 310 with respect to thetower body 410, when a rotational force is applied to move theset screw 370 further downward, thecoupling body 310 may be pushed and move downward by theset screw 370. Thecoupling lip 355 may contact the surface wall of thecoupling guide 420 and be guided along thecoupling guide 420, such that the threaded inner surface of thecoupling body 310 does not move laterally when thecoupling body 310 is pushed down by theset screw 370. Thecoupling body 310 may be further guided by thecontact 429 between theouter wall 311 and theinner wall 402 of the tower body. Thecoupling body 310 may continue to move until thethreads 379 on theset screw 370 are aligned with and match thethreads 319 in the coupling body 310 (shown inFIG. 4B ). After thethreads set screw 370 may engage and proceed along thethread 319 and, thereby, inner walls of thecoupling body 310. - As seen in
FIG. 4C , at some point of the rotational and downward movement ofset screw 370, the thread pitch of thethreads threads 419 in thetower 400, become aligned and theset screw 370 may begin to mate with thethread 319 of thecoupling body 310. Theset screw 370 may then make a transition from thetower body 410 and into thecoupling body 310. - Accordingly, the
bone fixation device 110 may be constructed to compensate the thread pitch mismatch between the threads of thecoupling assembly 300 and thetower 400, which can eliminate cross threading therebetween. No additional parts are required to implement the thread pitch mismatch compensation features, and, therefore, the size and number of moving parts of thebone fixation device 110 may be minimized, thereby facilitating minimally invasive surgery (MIS) procedures. Also, thesame tower 400 may be interchangeably used withbone fastener assemblies 200/300 having different sizes and/or configurations to form thebone fixation device 110. - A method of implanting the bone fixation system 100 (shown in
FIG. 2 ), and more particularly, a plurality ofbone fixation devices 110 andfastener connectors 120 will now be described. Initially, the patient may be placed in a prone position on a radiolucent table and draped in the usual manner. Using imaging, such as, for example, fluoroscopy and preoperative imaging, a location may be determined for each incision and the incision made. After the necessary incision is made, a targeting needle (not shown) may be inserted through the dissected tissue to the level of a target pedicle. After confirming that the targeting needle is properly placed and has the correct trajectory, the targeting needle may be tapped into the vertebral body until depth is satisfactory. The trajectory and depth of the targeting needle should be repeatedly confirmed using the imaging (e.g., fluoroscopy) as the needle is being inserted. - After the needle is inserted to its final position, an inner stylus (not shown) may be removed from the needle and a K-wire inserted in its place to an appropriate depth. The targeting needle may then be removed while carefully maintaining control of the depth of the guide wire. The foregoing steps may be repeated for each of the remaining pedicles.
- Next, a dilator (not shown) may be inserted over the guide wire, keeping the guide wire steady in the process. Once properly placed, the starter dilator tube (not shown) may be removed, leaving the second (not shown) and final dilator (not shown) in place. An appropriately sized cannulated tap (not shown) may be inserted over the guide wire and through the second dilator. The cannulated tap may be tapped to desired length while maintaining the position and depth of the guide wire. Imaging may be used to verify that the tap is following the trajectory of the guide wire during insertion.
- At this point, the correct size and/or configuration of the
bone fastener assembly 200/300 (e.g., polyaxial pedicle screw assembly) may be selected for the particular procedure. - Referring to
FIGS. 3A and 3C , after the appropriately sizedbone fastener assembly 200/300 is selected for the procedure, auniversal tower 400 may be attached to thebone fastener assembly 200/300 to form thebone fixation device 110. An advantage of using auniversal tower 400 according to the principles of the disclosure is that only a single size oftower 400 could be stocked for various sizes and/or configurations ofbone fastener assemblies 200/300 (such as, for example, polyaxial pedicle screw assemblies). Thetower 400 is bone fastener assembly-agnostic. In other words, thetower 400 may be used with different sizes and/or configurations ofbone fastener assemblies 200/300 (such as, for example, generic pedicle screw assembly housings), includingbone fastener assemblies 200/300 to be used for MIS or reduction procedures. - If the
bone fixation device 110 is not preassembled, it may be assembled using the selectedbone fastener assembly 200/300 with thetower 400 constructed according to the principles of the disclosure. - Holding the base of the
bone fastener 200 in one hand, and a portion of thetower body 410 at the receiving end of the tower 400 (portion A, shown inFIG. 3A ) in the other hand, thebone fastener assembly 200/300 may be pushed into the receiving end of the tower body 410 (portion A inFIG. 3A ), such that thecoupling lip 355 of thecoupling body 310 is forced to compress under force of theangled wall 428 until it passes an edge of thewall 426, at which point thecoupling lip 355 will be in thecoupling guide 420 and may snap to its default configuration (shown inFIG. 3C ). Thetower body 410 may be made of a material that may permit thetower body 410 to flex, so as to facilitate insertion of thecoupling lip 355 past thetower lip 421 and into thecoupling guide 420. In this latter regard, thecoupling body 310 need not be flexible. - In at least one exemplary embodiment, such as depicted in
FIGS. 8A and 8B , one or more of thetower bodies 800 may incorporate one or moreflexible portions 810, which in various embodiments may comprise a section or subsection of a tower body that has been “weakened” or otherwise rendered more flexible (i.e., by machining and/or material removal, for example) than other portions of thetower body 800. To make the tower housing more flexible, a series of slit cutpatterns 820 or similar features (including other partial material removal operations) can be made along one or more regions of the tower wall structure, such as along the middle region of the tower as shown inFIG. 8A , where a center of curvature of the flexible section can exist. In at least one exemplary embodiment, a desired center of curvature (or a distance from the rod to the center of the slit pattern) can range from 50 mm to 250 mm. The tower element may be continuous, or may comprise two or more (i.e., a series) individual interlocking sections, desirably with amodular feature 830 for engaging directly with a top portion of a pedicle screw housing, including attachment to a low top pedicle screw housing in some embodiments. - As depicted in
FIG. 8B , the tower bodies can include one or a plurality offlexible portions 840, including flexible portions of differing lengths, sizes and/or positions, if desired. It some embodiments, the flexible portions can include a modular segment, which can be attached to a desired portion of the tower at virtually any position along its length (not shown). - During many surgical procedures, tower collision or other tool interference can be a common occurrence due to a variety of factors, including the natural anatomy, anatomical variations between patients, injury and/or spinal degradation, and desired rod curvature and/or pedicle screw placements, which can make it difficult for a surgeon to engage subsequent instruments for compression and/or distraction. Tower collision can also be exacerbated where a curved spinal rod is used to match and/or correct lordotic anatomy, potentially presenting the surgeon with a challenging rod insertion and/or alignment as well as significantly limiting the amount of “real estate” available to accommodate additional surgical instrumentation. In addition, tower collision and/or interference (see
FIG. 9A ) can inhibit proper screw placement and/or cause “false” set screw tightening (seegap 900 ofFIG. 9C ), where the construct may be misaligned and cause the set screw to cross-thread and/or prematurely lock. Such occurrence can eventually result in loosening and/or failure of the spinal construct during spinal motion and/or the patient's healing process. - By incorporating a flexible element in the tower that is can be capable of significant flexion (up to 360 degrees about the longitudinal axis of the tower in some embodiments), the present invention can allow proximal portions of the tower to be displaced in a desired direction and/or orientation while the remaining distal portion(s) of the tower can be attached and/or remain connected to the fixation screw in a desired manner. This arrangement desirably prevents and/or reduces the opportunity for collision and/or interference between adjacent towers, which often occurs when patient concavity of the spine is steep (i.e., small radius), making the tall tower exceed the radius of the curvature of the spine. As shown in
FIG. 9B , once the fixation elements have been implanted into the spine, upon tightening the set screw the housing desirably becomes normal (i.e., perpendicular) to the rod, with the screw immovably fixed to the housing. However, where tower collision and/or interference occurs, in some cases this interference creates a force F (represented by sideways arrows inFIG. 9C ) that inhibits and/or prevents the housing from assuming a normal orientation, allowing agap 900 or other space to exist between portions of thefixation rod 910 and theset screw 920 during screw tightening, which can allow the set screw to loosen and/or other construct to fail after tower removal and/or during patient movement. - In at least one exemplary embodiment, the tower housing can be rendered flexible in one or more regions by forming slit cut patterns or any other form of material removal, which on one exemplary embodiment can be made along the tower's middle region near where the center of the curvature meets. This creation of a flexible zone can be integrated into any percutaneous pedicle screws with high towers or it would apply to any modular reduction tower or similar element (see
FIGS. 10A and 10B ). -
FIGS. 11A and 11B depict an alternative embodiment ofrigidity reducing cuts 1100 provided onupstanding leg portions 1110 of a minimallyinvasive screw assembly 1120. In this embodiment, portions of theassembly 1120 can be flexed in a desired direction while continuing to provide an access path through the patient's tissues in a desired manner. In various alternative embodiments, the flexible section could comprise a section of weaker material, such as a different and/or softer material that the remainder of the assembly, or the flexible section could comprise a portion of reduced cross-section or different design of the same material that potentially leads to an increased flexibility and/or greater ductility. -
FIGS. 12A through 12C and 13A through 13F depict additional alternative embodiments of flexible regions that can be formed in various spinal instrumentation. If desired, the flexible region can be designed to provide a full 360 degrees of flexion about the longitudinal axis of the tool, while other embodiments might provide flexion along only one or more axis, while inhibiting flexion along other axes. In addition, the flexion slits may completely encircle the too, or may be provided only about a portion of the circumference of the tool, such as less than 180 degrees and/or less than 90 degrees and/or less than 45 degrees of the circumference of the tool. - In various of the described non-limiting embodiments of a
tower 400 having atower lip 421 that comprises multipletower lip segments 421′ (shown inFIG. 3E ), thebone fixation device 110 may be assembled by holding the base of thebone fastener 200 in one hand, and a portion of thetower body 410 at the receiving end of the tower 400 (portion A, shown inFIG. 3A ) in the other hand, aligning the coupling lip segments of thecoupling body 310 with thespaces 425 in thetower 400, pushing thecoupling body 310 into the receiving end of the tower body 410 (portion A inFIG. 3A ) and past thetower lip segments 421′, and, when properly inserted, turning one or both of thetower body 410 andcoupling body 310 with respect to each until the coupling lip segments substantially overlap with thetower lip segments 421′. - Once the
tower 400 andbone fastener assembly 200/300 are properly assembled, such as, for example, when the channel(s) 403 (if any) of thetower body 410 is aligned with thechannel 302 in thecoupling body 310, a cannulated bone screw driver assembly (not shown) may be inserted in thetool channel 401. The screw driver (not shown) may be inserted through thetool channel 401 to the head of thebone fastener 200, at which point the screw driver (not shown) may be manipulated to properly seat the male (or female) end of the head of the screw driver (not shown) in the female (or male) end of thebone fastener 200. Once the screw driver head (not shown) is properly seated, an outer sleeve (not shown) of the screw driver may be rotated to tighten the screw driver with respect to thetower body 410. The cannulatedbone fastener 200 may then be placed over the guide K-wire and slid through the final dilator to the pedicle. Once thebone fastener 200 reaches the vertebral body, the guide wire may be removed and thebone fastener 200 advanced to the desired depth by rotating the screw driver (not shown). The cannulated screw driver (not shown) and the final dilator may be removed at this point. - The above process may be repeated for each of the target pedicles.
- After two or more of the
bone fastener devices 110 have been installed, as described above, rod measurement calipers (not shown) may be used as is known in the art. Thetowers 400 in the bone fixation system (e.g., shown inFIG. 2 ) may be aligned such that thechannels 302 of thecoupling assemblies 300 are aligned. Also, the open channel(s) 403 and/orslots 412 may be aligned. Then, theappropriate fastener connector 120 may be selected together with an appropriate inserter tool (not shown, such as, e.g., an offset left rod inserter, an offset right rod inserter, an in-line rod inserter, or the like). The inserter tool (not shown) may be inserted in and guided through thetool channel 401 to a predetermined position in the tower body, at which point thefastener connector 120 may be deployed and placed in thechannel 302 of each of the alignedcoupling bodies 310. Alternatively, the inserter tool (not shown) may be delivered to thefastener connector 120 installation site(s) external to anytower 400. - If the
fastener connector 120 does not fully seat in achannel 302 of acoupling body 310, standard reduction (e.g., derotation device 500 (described below), standard rod pushers (not shown), supplemental reduction (e.g., using parallel reducers (not shown))), or the like may be used to facilitate proper positioning and seating of thefastener connector 120 with respect to thechannel 302. - After the
fastener connector 120 is properly seated in each intendedcoupling body 310, then aset screw 370 may be placed on a set screw starter tool (not shown), and the set screw starter tool (not shown) withset screw 370 may be inserted in and down thetower body 410 until it reaches the upper surface of thecoupling body 310, as seen inFIG. 4A . Final tightening of theset screws 370 may be carried out by using a counter torque tube holder tool (not shown) to hold the top of thetower 400, and turning the set screw tightening tool (not shown). As seen inFIG. 4B , if the pitch of the threading 379 does not match the pitch of the threading 319 in the coupling body, theset screw 370 will push down on the upper surface of thecoupling body 310 and rotate until the pitch of the threading 379 matches that of the threading 319 in thecoupling body 310, at which point theset screw 370 will engage and progress downward into the threading 319 in the coupling body 310 (shown inFIG. 4C ). - The
bone fasteners 200 should be inserted with some good force and within the confines of the vertebra, because the pedicle should be a strong pedicle and should hold thebone fastener 200 well, since this is a fastener that is going to hold the vertebra in place while the fusion is taking place. After eachbone fastener 200 is secured in place, thebone fasteners 200 may be tested by running a small current through the fasteners to determine whether the fastener may irritate a nerve. The process may be repeated for each of the other fasteners. -
FIG. 5 shows an example of aderotation device 500, constructed according to the principles of the disclosure. Thederotation device 500 may be used for derotation (e.g., en bloc derotation, segmental derotation, etc.), deformity correction (e.g., rib hump correction, etc.), translation, and the like. Thederotation device 500 may include a reinforced cannulated shell. - As seen in
FIGS. 6A and 6B , thederotation device 500 may be configured to slide over and at least partially encapsulate a modular derotation tower 600 (e.g.,tower 400 of thebone fastening device 110 shown inFIGS. 2 and 3A ). Thederotation device 500 may have an elongated shaped housing with a hollow body structure to receive thederotation tower 600. Thederotation device 500 may have an opening at anarrow tip end 510, into which thederotation tower 600 may be inserted. Thederotation device 500 may also include a locking mechanism, such as, for example, slidinglock 512 or the like, which may fix thetower 600 once inserted into thederotation device 500. Thederotation device 500 may also include agrip portion 520, which may have a larger diameter than thenarrow tip end 510. When manually operated with a surgeon's hand, thelarger grip portion 520 may increase the rotational torque, thereby allowing thederotation device 500 to function as a torque sleeve. - As seen in
FIG. 7 , acrosslink unit 700 may be used to fix two ormore derotation devices crosslink unit 700 may have an elongated body 710 having twobent ends derotation devices set screws FIG. 5 , thederotation devices FIG. 7 ) near the top end portion thereof Referring toFIG. 7 , thederotation device 500A may be placed to contact an inner bent surface of thebent end 712A, and then theset screw 720A may be screwed into thescrew hole 530 of thederotation device 500A, which may fix thederotation device 500A to thebent end 712A of thecrosslink unit 700. Thederotation device 500B may be fixed to the opposite bent end 7126 of thecrosslink unit 700 in a similar manner. - A length of the
crosslink unit 700 may be adjustable. For example, the body part 710 may be divided into two parts: first body part 710A and second body part 710B, which are fixed to each other by aset screw 712. To adjust the length, theset screw 712 may be unscrewed to disengage the first and second body parts 710A, 710B from each other. Then first and second body parts 710A, 710B may then be pulled away from each other or pushed toward each other to increase or decrease the length of the body 710, respectively. Once the body 710 is adjusted to a desired length, theset screw 712 may be screwed to fix the first and second body parts 710A, 710B together. - Referring to
FIGS. 3A-3E, 4A-4C, 5, 6A, 6B and 7 simultaneously, the bone fixation (or stabilization)system 100, thederotation device 500, thecrosslink unit 700 may be configured for use in, for example, anterior approach and discectomy applications. For instance, after a patient is positioned in a prone or supine position on, for example, a radiolucent operating table, the surgical area cleaned, incisions made, muscle tissue and/or organs moved to the side(s), and other common surgical procedures carried out, and thebone fixation system 100 installed as described above, an individual derotation device(s) 500 (or two ormore derotation devices 500 when connected by one or more cross link units 700) may be manipulated by a surgeon's hand, to allow for rotational and/or axial adjustment of the derotation device(s) 500. -
FIGS. 14A through 14C depict additional embodiments oftower bodies flexible regions FIGS. 14A and 14C , thetowers proximal bridge 1410, or a pair of proximal bridges 1470 (or various other numbers and/or locations of bridges, including three, four or more bridges and/or pairs of bridges), which can desirably increase the strength and stability of the tower during use, including during alignment of the fixation elements and/or flexion of the towers. -
FIGS. 15A through 15D depict one exemplary embodiment of atower body 1500 that includes atubular body portion 1510 with anintegrated tip portion 1520. If desired, thetube body 1510 can include a flexible section (not shown) along virtually any portion of its length, which may include flexible sections at different points along each wall of the tube body, if desired. Thetube body 1510 also can include one ormore bridge portions 1525. In this embodiment, theintegrated tip portion 1520 is attached to the tube body at a reduceddiameter section 1530, which desirably forms a “weakened” and/or frangible link between thetube body 1510 and thetip portion 1520. Desirably, this arrangement will allow thetip portion 1520 to be separated from thetube body 1510 at a desired point in the surgery, with the tip portion capable of function as a polyaxial or other type head of the pedicle screw assembly. -
FIGS. 16A through 16C depict another exemplary embodiment of atower body 1600 that includes atubular body portion 1610 with anintegrated tip portion 1620, along with asingle bridge portion 1625. As similarly described in combination with any of the embodiments described herein, thetube body 1610 can include a flexible section (not shown) along virtually any portion of its length, which may include flexible sections at different points along each wall of the tube body, if desired. - In various embodiments, once one or more of the individual fixation elements (i.e., the pedicle screws) are secured into the targeted anatomy in desired positions and/or orientations (which may include the placement of connecting rods and/or set screws, one or more of the tower bodies may be removed from the tip portions. For example,
FIG. 17 depicts one exemplary method of removing a tubular body portion 1710 from a tip portion 1720 of a tower body 1700. In this embodiment, the bridge portion 1725 of the tower body 1700 can be severed (“A”) by a metal cutter 1790 or other surgical tool, and the individual sections 1740 and 1745 of the body portion 1710 can be flexed (“B”) and/or otherwise displaced, which desirably stresses, “works” and/or breaks the frangible link 1750 (“C”), leaving the tip portion 1720 within the anatomy while allowing the individual sections 1740 and/or 1745 to be removed. Where a flexible section (not shown) has been incorporated into the individual sections 1740 or 1745, a tubular tool or surgical pliers can be utilized to flex a portion of the individual sections 1740 and/or 1745 below the flexible section to break the frangible link in a desired manner. -
FIGS. 18A and 18B depict front plan and cross-sectional views, respectively, of one embodiment of anexemplary fixation element 1800 incorporating atip portion 1810 which engages with a bone fastener in the form of apolyaxial pedicle screw 1820. When fully assembled, thetip portion 1810 holds ahead portion 1830 of the polyaxial pedicle screw, which can be sandwiched between a firstinner ring 1840 and a secondinner ring 1850, with the inner rings designed and positioned such that when a force is applied in a downward direction by a set screw 1890 (e.g., a force that is substantially perpendicular to the plane of the upper surface of the inner ring), the volume of the cavity that holds thehead portion 1830 of the bone fastener and/or afixation rod 1880 is compressed or reduced, thereby securely engaging and holding thehead portion 1830 of the bone fastener and therod 1880 by the inner walls of thetip portion 1810 and the rings. -
FIG. 19A through 19D depict various views of aset screw 1900 for use with various embodiments of the present invention. Theset screw 1900 can include acentral body 1910 with externally positionedthreads 1920. In various embodiments, the threads can include a sawtooth or reverse thread pattern, as well as square threads and/or other thread designs to desirably reduce and/or obviate splay of the tip portion, if desired. - The terms “including,” “comprising,” and variations thereof, as used in this disclosure, mean “including, but not limited to,” unless expressly specified otherwise.
- The terms “a,” “an,” and “the,” as used in this disclosure, means “one or more,” unless expressly specified otherwise.
- Devices that are in communication with each other need not be in continuous communication with each other, unless expressly specified otherwise. In addition, devices that are in communication with each other may communicate directly or indirectly through one or more intermediaries.
- Although process steps, method steps, or the like, may be described in a sequential order, such processes and methods may be configured to work in alternate orders. In other words, any sequence or order of steps that may be described does not necessarily indicate a requirement that the steps be performed in that order. The steps of the processes or methods described herein may be performed in any order practical. Further, some steps may be performed simultaneously.
- When a single device or article is described herein, it will be readily apparent that more than one device or article may be used in place of a single device or article. Similarly, where more than one device or article is described herein, it will be readily apparent that a single device or article may be used in place of the more than one device or article. The functionality or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality or features.
- While the disclosure has been described in terms of exemplary embodiments, those skilled in the art will recognize that the disclosure can be practiced with modifications in the spirit and scope of the appended claims. These examples are merely illustrative and are not meant to be an exhaustive list of all possible designs, embodiments, applications or modifications of the disclosure.
Claims (12)
Priority Applications (3)
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US16/512,268 US20190336182A1 (en) | 2015-10-27 | 2019-07-15 | Modular rod reduction tower and related methods |
US16/992,955 US11622795B2 (en) | 2015-10-27 | 2020-08-13 | Modular rod reduction tower and related methods |
US18/132,912 US20230240728A1 (en) | 2015-10-27 | 2023-04-10 | Modular rod reduction tower and related methods |
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US201562247183P | 2015-10-27 | 2015-10-27 | |
US201562257124P | 2015-11-18 | 2015-11-18 | |
US15/335,026 US20170112551A1 (en) | 2015-10-27 | 2016-10-26 | Modular rod reduction tower and related methods |
US201862758120P | 2018-11-09 | 2018-11-09 | |
US16/512,268 US20190336182A1 (en) | 2015-10-27 | 2019-07-15 | Modular rod reduction tower and related methods |
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US15/335,026 Continuation-In-Part US20170112551A1 (en) | 2015-10-27 | 2016-10-26 | Modular rod reduction tower and related methods |
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US16/992,955 Continuation US11622795B2 (en) | 2015-10-27 | 2020-08-13 | Modular rod reduction tower and related methods |
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US16/992,955 Active US11622795B2 (en) | 2015-10-27 | 2020-08-13 | Modular rod reduction tower and related methods |
US18/132,912 Pending US20230240728A1 (en) | 2015-10-27 | 2023-04-10 | Modular rod reduction tower and related methods |
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US18/132,912 Pending US20230240728A1 (en) | 2015-10-27 | 2023-04-10 | Modular rod reduction tower and related methods |
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Cited By (8)
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US20190059959A1 (en) * | 2017-08-29 | 2019-02-28 | Zimmer Biomet Spine, Inc. | Surgical cord tensioning devices, systems, and methods |
US20190231399A1 (en) * | 2018-01-26 | 2019-08-01 | Aesculap Ag | Spinal repositioning instrument, spinal repositioning system, and methods of using these |
US10905474B2 (en) | 2017-08-29 | 2021-02-02 | Zimmer Biomet Spine, Inc. | Surgical cord tensioning devices, systems, and methods |
US11141221B2 (en) * | 2015-11-19 | 2021-10-12 | Eos Imaging | Method of preoperative planning to correct spine misalignment of a patient |
US11439442B2 (en) | 2020-04-16 | 2022-09-13 | Warsaw Orthopedic, Inc. | Modular screw system with head locker and derotator |
WO2022237955A1 (en) * | 2021-05-10 | 2022-11-17 | Ulrich Gmbh & Co. Kg | Bone screw and sleeve remover |
WO2022241140A1 (en) * | 2021-05-12 | 2022-11-17 | Spine23 Inc. | Systems and methods for pedicle screw stabilization of spinal vertebrae |
US11617602B2 (en) | 2020-04-16 | 2023-04-04 | Medtronic, Inc. | Systems, methods of use and surgical instruments employing a secure slide lock to fasten a head |
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DE102017114273A1 (en) * | 2017-06-27 | 2018-12-27 | Silony Medical International AG | Extension device for a bone anchor |
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US8002798B2 (en) * | 2003-09-24 | 2011-08-23 | Stryker Spine | System and method for spinal implant placement |
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US7846093B2 (en) * | 2005-09-26 | 2010-12-07 | K2M, Inc. | Minimally invasive retractor and methods of use |
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US8162952B2 (en) | 2006-09-26 | 2012-04-24 | Ebi, Llc | Percutaneous instrument assembly |
US7947045B2 (en) * | 2006-10-06 | 2011-05-24 | Zimmer Spine, Inc. | Spinal stabilization system with flexible guides |
US8052720B2 (en) | 2006-11-09 | 2011-11-08 | Zimmer Spine, Inc. | Minimally invasive pedicle screw access system and associated method |
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US8137356B2 (en) * | 2008-12-29 | 2012-03-20 | Zimmer Spine, Inc. | Flexible guide for insertion of a vertebral stabilization system |
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US9707019B2 (en) | 2009-08-11 | 2017-07-18 | Zimmer Spine, Inc. | System and method for performing vertebral reduction using a sleeve |
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US20160106480A1 (en) * | 2014-07-02 | 2016-04-21 | Yue Zhou | Extension piece at screw end of pedicle screw, dilator and push rod reset lever |
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2020
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2023
- 2023-04-10 US US18/132,912 patent/US20230240728A1/en active Pending
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Also Published As
Publication number | Publication date |
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US11622795B2 (en) | 2023-04-11 |
US20200367946A1 (en) | 2020-11-26 |
US20230240728A1 (en) | 2023-08-03 |
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