US20150080958A1 - Compression-distraction spinal fixation system - Google Patents
Compression-distraction spinal fixation system Download PDFInfo
- Publication number
- US20150080958A1 US20150080958A1 US14/489,405 US201414489405A US2015080958A1 US 20150080958 A1 US20150080958 A1 US 20150080958A1 US 201414489405 A US201414489405 A US 201414489405A US 2015080958 A1 US2015080958 A1 US 2015080958A1
- Authority
- US
- United States
- Prior art keywords
- pawl
- screw
- rod
- head
- bone screw
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/70—Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
- A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
- A61B17/7002—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
- A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
- A61B17/7002—Longitudinal elements, e.g. rods
- A61B17/7014—Longitudinal elements, e.g. rods with means for adjusting the distance between two screws or hooks
-
- 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
- A61B17/7035—Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
- A61B17/7037—Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other wherein pivoting is blocked when the rod is clamped
-
- 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
- A61B17/7079—Tools requiring anchors to be already mounted on an implanted longitudinal or transverse element, e.g. where said element guides the anchor motion
-
- 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
- A61B17/7004—Longitudinal elements, e.g. rods with a cross-section which varies along its length
- A61B17/7005—Parts of the longitudinal elements, e.g. their ends, being specially adapted to fit in the screw or hook heads
-
- 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
- A61B2017/681—Alignment, compression, or distraction mechanisms
Definitions
- the present technology relates to an implant for surgical treatment of the spine, and methods for stabilizing a spine using the implants. More particularly, the present technology provides compression-distraction spinal fixation systems that include screw-rod constructs.
- Anterior, posterior and lateral spinal fixation is commonly used for the treatment of degenerative disease, trauma, deformity, and oncological processes.
- the current state of the art includes the placement of rigid bone screws into the posterior arch, pedicles or vertebral bodies of adjacent spinal segments. These bone screws are then connected to each other by rigid metal rods in order to stabilize the spine and enable progressive bony fusion.
- Such bone screw-rod constructs have gained prominence due to their superior biomechanical stability relative to alternate fixation techniques, such as wiring, etc., as well as the benefits provided by three column fixation of the spine.
- Such systems have been made more versatile in recent years with the advent of polyaxial screw head technology, which allows more complex construct placement and screw connections. While current screw-rod systems are ideal for fixating motion segments in the spine in neutral position, certain situations call for the application of compressive or distractive forces in order to improve spinal balance and to aid in spinal fusion.
- spine surgeons After placing this instrumentation, spine surgeons typically apply compressive forces manually between adjacent screws in order to increase lordosis for improved sagittal balance, or to compress upon an interbody graft in order to improve fusion. Alternatively, surgeons may wish to apply distractive forces between adjacent screws in order to improve access to the disc space for discectomy or interbody graft placement, or to affect deformity correction. Due to the smooth, cylindrical rod design, current spinal fixation systems do not provide or allow for the maintenance of compressive or distractive forces. Instead, one surgeon must provide manual compression between two screws while a second surgeon attempts to tighten the rod in place at each fixation point. This technique is both cumbersome and technically challenging.
- the present technology relates to compression-distraction spinal fixation systems that include screw-rod constructs that include a ratcheting mechanism.
- a compression-distraction spinal fixation system includes at least one bone screw, and a toothed rod connected to the at least one bone screw.
- the at least one bone screw can include a threaded shaft, a screw head, a set screw, and a pawl.
- the toothed rod can have a plurality of ratchet teeth that receive the pawl of the at least one bone screw.
- a method of performing compression-distraction spinal fixation includes attaching a first bone screw to a first bony portion of a patient's spine, and placing a toothed rod in the screw head of the first bone screw.
- the first bone screw can include a threaded shaft that attaches the first bone screw to the first bony portion, a screw head, a set screw, and a pawl.
- the toothed rod can include ratchet teeth.
- the method can also include orienting the pawl of the first bone screw to engage the ratchet teeth of the toothed rod, and ratcheting the bone screw along the length of the toothed rod.
- FIG. 1 illustrates one example of a prior art screw-rod construct.
- FIG. 3 illustrates an exploded view of the example of FIG. 2 .
- FIG. 4 illustrates a screw of the example of FIG. 2 in a first orientation.
- FIG. 6 illustrates a screw of the example of FIG. 2 in a sectioned view with an enlarged region to illustrate the ratchet and pawl mechanism.
- FIG. 7 illustrates a second example of a screw-rod construct of the present technology in a first orientation.
- FIG. 8 illustrates a screw of the example of FIG. 7 in a second, or reversed, orientation.
- FIG. 9 illustrates a third example of a screw-rod construct of the present technology in a first orientation.
- FIG. 10 illustrates a screw of the example of FIG. 9 in a second, or reversed, orientation.
- FIG. 11 illustrates an exploded view of a screw of the example of FIG. 9 .
- FIG. 12 illustrates a fourth example of a screw-rod construct of the present technology in a first orientation.
- FIG. 13 illustrates a screw of the example of FIG. 12 in a second, or reversed, orientation.
- FIG. 14 illustrates a fifth example of a screw-rod construct of the present technology in a first orientation.
- FIG. 15 shows an exploded view of the screw of the example of FIG. 14 .
- FIG. 16 illustrates a cross sectional view of the screw of the example of FIG. 14 .
- FIG. 17 illustrates a sixth example of a screw-rod construct of the present technology in a first orientation.
- FIG. 18 illustrates an exploded view of the screw of the example of FIG. 17 .
- FIG. 19 illustrates a sectioned view of one example of teeth on a rod of the present technology having triangular ratchet teeth cut into the rod.
- FIG. 20 illustrates a sectioned view of a second example of teeth on a rod of the present technology having sawtooth ratchet teeth cut into the rod.
- FIG. 21 illustrates a sectioned view of a third example of teeth on a rod of the present technology having spaced ratchet teeth cut into the rod.
- FIG. 22 illustrates a sectioned view of a fourth example of teeth on a rod of the present technology having square ratchet teeth cut into the rod.
- FIG. 23 illustrates a sectioned view of a fifth example of teeth on a rod of the present technology having a helical coil sintered, welded, soldered, bonded or otherwise attached to the rod.
- FIG. 24 illustrates a sectioned view of a sixth example of teeth on a rod of the present technology having helical threads cut into the rod.
- FIG. 25 illustrates a perspective view of one example of a rod of the present technology having ratchet teeth cut straight across the rod.
- FIG. 26 illustrates a sectioned view of the example of a rod illustrated in FIG. 25 .
- FIG. 27 illustrates a perspective view of a second example of a rod of the present technology having ratchet teeth cut radially on the rod.
- FIG. 28 illustrates a sectioned view of the example of a rod illustrated in FIG. 27 .
- FIG. 29 illustrates a seventh example of a screw-rod construct of the present technology.
- FIG. 30 illustrates a sectioned view of the screw-rod construct illustrated in FIG. 29 .
- FIG. 32 illustrates an exploded view of the screw-rod construct illustrated in FIG. 31 .
- FIG. 33 illustrates a sectioned view of the screw-rod construct illustrated in FIG. 31 .
- the present technology relates to compression-distraction spinal fixation systems that include screw-rod constructs. More particularly, the present technology provides a rod and screws that incorporate a ratchet and pawl mechanism for imposition of compression and distraction forces on the spinal column
- compression-distraction spinal fixation systems described herein can allow a single surgeon the ability to apply compressive or distractive forces as desired between adjacent spinal levels in a seamless and efficient manner.
- the unique ratcheting mechanism provided in compression-distraction spinal fixation systems of the present technology which in at least some examples can integrate into existing bone-screw rod technology, regional forces can be maintained segmentally or across the entirety of a given spinal construct, avoiding the cumbersome technique of compression/distraction that is inherent to traditional screw-rod systems.
- the compression-distraction spinal fixation systems of the present technology can add to a spine surgeon's armamentarium in the treatment of complex spinal disease.
- Compression-distraction spinal fixation systems of the present technology are more particularly described in the following examples with reference to the accompanying drawings, and are intended as illustrative only. Referring to the drawings, like numbers indicate like parts throughout the views.
- Compression-distraction spinal fixation systems of the present technology include a toothed rod and at least one bone screw of the present technology.
- compression-distraction spinal fixation systems of the present technology include a toothed rod, at least one bone screw of the present technology, and at least one conventional bone screw.
- compression-distraction spinal fixation systems of the present technology include a toothed rod, a first bone screw of the present technology, and a second bone screw of the present technology.
- the rods of compression-distraction spinal fixation systems of the present technology include ratchet teeth, which are preferably evenly spaced along a portion of the length of the rod, preferably along the entire length or substantially the entire length of the rod. Placing evenly spaced ratchet teeth along the length of the rod can allow the rod to be cut and contoured as desired in the operating room.
- precut and precontoured rods can be provided, such as for example, for short segment constructs typically spanning 2, 3, and 4 vertebral levels.
- the ratchet teeth can cover at least a portion of the outer surface, or circumference, of the rod, including but not limited to, the entire circumference of the rod, half the circumference of the rod, one third of the circumference of the rod, one quarter of the circumference of the rod, or any other suitable portion of the circumference of the rod.
- the ratchet teeth can be formed as depressions in a toothed rod, or as protrusions that extend from the toothed rod.
- Bone screws of the present technology can also include a shaft, such as a threaded shaft, that can be used to attach the bone screw to a desired bony portion of the spine. Bone screws of the present technology can further include a screw head, and a set screw.
- FIGS. 2 through 6 illustrate one example of a screw-rod construct 100 of the present technology that includes a toothed rod 102 having ratchet teeth 104 , a first bone screw 106 of the present technology and a second bone screw 108 of the present technology.
- either bone screw 106 or bone screw 108 could be replaced with a conventional bone screw, such as bone screw 10 illustrated in FIG. 1 .
- each bone screw includes a threaded shaft 110 , a screw head 112 , a set screw 114 , and a pawl 116 .
- the set screw 114 of each bone screw includes a retaining ring 118 , which retains the pawl 116 on the set screw 114 .
- the pawl 116 is preferably flexible, and includes a bend 120 and a blade 122 .
- first bone screw 106 can be inserted into a bony portion of a patient's spine, such as the posterior arch, pedicle, or vertebral body of a vertebra. Then, toothed rod 102 can be placed into a recess 134 in screw head 112 . The set screw 114 can be threaded into the screw head 112 until there is significant engagement of the pawl 116 with the ratchet teeth 104 of the toothed rod 102 . Distracting or compressing forces, depending on the orientation of the pawl 116 , can then be used to slide the first bone screw 106 , and therefore the vertebra to which it is attached, relative to toothed rod 102 .
- the blade 220 of the pawl 214 engages the ratchet teeth 204 of the toothed rod 202 .
- Rotation of the pawl 214 from a first position, as shown in FIG. 7 , to a second position, as shown in FIG. 8 , that is about 180° from the first position, can reverse the direction of travel of the bone screw 206 along the length of the toothed rod 202 .
- Pawl 318 can include a cut 316 that allows expansion of the diameter of the pawl 314 to facilitate installation of the pawl 314 onto the pawl receiving groove 318 of the screw head 310 .
- the pawl 314 can include a spring portion 320 and a blade 322 .
- the blade 322 engages the ratchet teeth 304 of the toothed rod 302 .
- the spring portion 320 can provide flexibility to the pawl 314 to allow the blade 322 to slide over the ratchet teeth 304 of the toothed rod 302 when the bone screw 306 is ratcheted along the length of the toothed rod 302 .
- Rotation of the pawl 314 from a first position, as shown in FIG. 9 , to a second position, as shown in FIG. 10 , that is about 180° from the first position, can reverse the direction of travel of the bone screw 306 along the length of the toothed rod 302 .
- the screw head 410 can include a pawl receiving groove 418 on a side of the screw head 310 , and sliding pawl 414 can be slidably received in the pawl receiving groove 418 .
- the pawl can further include a first blade 422 at one first end, and a second blade 422 (not shown) at the opposite end.
- the first blade 422 can engage the ratchet teeth 404 of the toothed rod 402 when the slidable pawl is in a first position, as shown in FIG. 12 , allowing the bone screw to ratchet along the length of the toothed rod in one direction.
- the second blade 422 which can be a mirror image of the first blade 422 , can engage the ratchet teeth 404 of the toothed rod 402 when the slidable pawl is in a second position, as shown in FIG. 13 , allowing the bone screw to ratchet along the length of the toothed rod in the opposite direction.
- a leaf spring 516 can be positioned under the rod receiving groove 518 of the screw head 510 , and can provide an upward force on the toothed rod 502 to ensure engagement of the ratchet teeth 504 and the pawl 514 .
- the leaf spring 516 can deflect out of the way and allow ratcheting of the bone screw 506 along the length of the toothed rod 502 .
- FIGS. 17 and 18 illustrate a sixth example of a screw-rod construct of the present technology, with FIG. 18 being an exploded view.
- Screw-rod construct 600 includes a toothed rod 602 having ratchet teeth 604 , and a bone screw 606 .
- the bone screw 606 has a threaded shaft 608 , a screw head 610 , a set screw 612 , and a pawl 614 .
- the pawl 614 is attached to a frame 616 that has a recess 618 .
- the recess 618 attaches to the screw head 610 , and can be lowered over the screw head 610 into alignment with the toothed rod 602 so that the pawl 614 engages the ratchet teeth 602 of the toothed rod 602 .
- the pawl 614 can be is attached to the frame 616 with a fastener 620 , such as a pin, that extends through a bore 624 in the frame 618 and can be rigidly attached to the pawl 614 due to press fit of the fastener 620 into a pawl hole 626 in the pawl 616 .
- the fastener 620 can have a hexagonal head 622 .
- plunger pawl 914 could incorporate a wire wound helical spring, a leaf spring or other resilient material.
- the anti-rotation boss 920 of the plunger pawl 914 can align with the keyway 924 of the screw head 910 to maintain alignment of plunger pawl 914 with the ratchet teeth 904 of the toothed rod 902 .
- the helical spring 918 can compress and extend to so that plunger pawl 914 maintains contact with toothed rod 902 and allows motion in one direction only.
- the application of compressive or distractive forces can be accomplished by first attaching at least one bone screw of the present technology to at least one desired bony portion of a patient's spine.
- a first bone screw can be attached to a first bony portion of a patient's spine
- a second bone screw can be attached to a second bony portion of a patient's spine.
- At least one of the bone screws, or both, can have a pawl.
- the toothed rod of the present technology can be optionally shaped by an operator, such as a surgeon, and can be attached to each bone screw.
- the bone screw having a pawl, or at least one of the bone screws having a pawl, can then be ratcheted along the length of the toothed rod to apply the desired amount of distractive or compressive force.
- each set screw can be tightened to maintain each bone screw in a fixed position relative to the toothed rod.
- the distractive or compressive force can be maintained temporarily or permanently.
- the distractive or compressive force can be used to alter the distance between bony portions of a patient's spine.
- the distance between spinal vertebrae of a patient can be altered by attaching a first bone screw to a first spinal vertebra and attaching a second bone screw to a second spinal vertebra, wherein at least the first bone screw has a pawl.
- a toothed rod can then be attached to the first and second bone screws, and the pawl of the first bone screw can be oriented to engage the ratchet teeth of the toothed rod.
- the method can then include altering the distance between the first vertebra and the second vertebra.
- a screw-rod construct of the present technology was made in accordance with the example illustrated in FIGS. 2-6 .
- the toothed rod had triangular ratchet teeth formed by cutting grooves having a 90° angle along the length of the toothed rod. The grooves were cut about 0.75 mm apart, and were cut radially in an arc that was about 60°.
- the toothed rod had an inner diameter of about 5.5 mm, and was made from Grade 23 Titanium alloy (Ti6Al4V-ELI).
- the pawl was also made of Grade 23 Titanium alloy (Ti6A14V-ELI), and was about 0.016 inches (0.4mm) thick.
- the blade of the pawl was about 5 mm wide.
Abstract
Compression-distraction spinal fixation systems, and methods of performing compression-distraction spinal fixation, are provided that include screw-rod constructs having a ratcheting mechanism. Bone screws of the screw-rod constructs can have a pawl that engages ratchet teeth on the rod of the screw-rod construct. The bone screw can be ratcheted along the length of the rod to apply distractive or compressive forces.
Description
- This application is a divisional application of U.S. patent application Ser. No. 12/958,304 filed Dec. 1, 2010, which claims the benefit of U.S. Provisional Application Ser. No. 61/292,215, filed on Jan. 5, 2010 and U.S. Provisional Application Ser. No. 61/383,540, filed on Sep. 16, 2010. The disclosure of each of the prior applications is considered part of and is incorporated by reference in the disclosure of this application.
- 1. Field of the Invention
- The present technology relates to an implant for surgical treatment of the spine, and methods for stabilizing a spine using the implants. More particularly, the present technology provides compression-distraction spinal fixation systems that include screw-rod constructs.
- Anterior, posterior and lateral spinal fixation is commonly used for the treatment of degenerative disease, trauma, deformity, and oncological processes. The current state of the art includes the placement of rigid bone screws into the posterior arch, pedicles or vertebral bodies of adjacent spinal segments. These bone screws are then connected to each other by rigid metal rods in order to stabilize the spine and enable progressive bony fusion. Such bone screw-rod constructs have gained prominence due to their superior biomechanical stability relative to alternate fixation techniques, such as wiring, etc., as well as the benefits provided by three column fixation of the spine. Such systems have been made more versatile in recent years with the advent of polyaxial screw head technology, which allows more complex construct placement and screw connections. While current screw-rod systems are ideal for fixating motion segments in the spine in neutral position, certain situations call for the application of compressive or distractive forces in order to improve spinal balance and to aid in spinal fusion.
- Current screw based spinal fixation systems use smooth, cylindrical metal or ceramic rods to connect screws that are anchored in bony portions of each vertebral level, such as the pedicle, lateral mass, lamina, and/or vertebral body. One example of a currently known screw based spinal fixation system is illustrated in
FIG. 1 . As shown inFIG. 1 , abone screw 10 connected to arod 12.Rod 12 is cylindrical, and has a smooth outer surface.Bone screw 10 has a screw head 14, which can have a variable angle head, as shown, or it could be a fixed angle screw.Bone screw 10 includes a threadedshaft 16 attached to the screw head 14.Bone screw 10 also includes aset screw 18 that is attached to the screw head 14.Bone screw 10 can be connected to therod 12 by attaching the bone screw to the desired bony spinal portion, sliding therod 12 onto the bone screw, and then tightening theset screw 18 to secure thebone screw 10 at a desired location on therod 12. - After placing this instrumentation, spine surgeons typically apply compressive forces manually between adjacent screws in order to increase lordosis for improved sagittal balance, or to compress upon an interbody graft in order to improve fusion. Alternatively, surgeons may wish to apply distractive forces between adjacent screws in order to improve access to the disc space for discectomy or interbody graft placement, or to affect deformity correction. Due to the smooth, cylindrical rod design, current spinal fixation systems do not provide or allow for the maintenance of compressive or distractive forces. Instead, one surgeon must provide manual compression between two screws while a second surgeon attempts to tighten the rod in place at each fixation point. This technique is both cumbersome and technically challenging.
- The present technology relates to compression-distraction spinal fixation systems that include screw-rod constructs that include a ratcheting mechanism.
- In one aspect, a compression-distraction spinal fixation system is provided that includes at least one bone screw, and a toothed rod connected to the at least one bone screw. The at least one bone screw can include a threaded shaft, a screw head, a set screw, and a pawl. The toothed rod can have a plurality of ratchet teeth that receive the pawl of the at least one bone screw.
- In another aspect, a method of performing compression-distraction spinal fixation is provided that includes attaching a first bone screw to a first bony portion of a patient's spine, and placing a toothed rod in the screw head of the first bone screw. The first bone screw can include a threaded shaft that attaches the first bone screw to the first bony portion, a screw head, a set screw, and a pawl. The toothed rod can include ratchet teeth. The method can also include orienting the pawl of the first bone screw to engage the ratchet teeth of the toothed rod, and ratcheting the bone screw along the length of the toothed rod.
- Specific examples have been chosen for purposes of illustration and description, and are shown in the accompanying drawings, forming a part of the specification.
-
FIG. 1 illustrates one example of a prior art screw-rod construct. -
FIG. 2 illustrates one example of a screw-rod construct of the present technology. -
FIG. 3 illustrates an exploded view of the example ofFIG. 2 . -
FIG. 4 illustrates a screw of the example ofFIG. 2 in a first orientation. -
FIG. 5 illustrates a screw of the example ofFIG. 2 in a second, or reversed, orientation. -
FIG. 6 illustrates a screw of the example ofFIG. 2 in a sectioned view with an enlarged region to illustrate the ratchet and pawl mechanism. -
FIG. 7 illustrates a second example of a screw-rod construct of the present technology in a first orientation. -
FIG. 8 illustrates a screw of the example ofFIG. 7 in a second, or reversed, orientation. -
FIG. 9 illustrates a third example of a screw-rod construct of the present technology in a first orientation. -
FIG. 10 illustrates a screw of the example ofFIG. 9 in a second, or reversed, orientation. -
FIG. 11 illustrates an exploded view of a screw of the example ofFIG. 9 . -
FIG. 12 illustrates a fourth example of a screw-rod construct of the present technology in a first orientation. -
FIG. 13 illustrates a screw of the example ofFIG. 12 in a second, or reversed, orientation. -
FIG. 14 illustrates a fifth example of a screw-rod construct of the present technology in a first orientation. -
FIG. 15 shows an exploded view of the screw of the example ofFIG. 14 . -
FIG. 16 illustrates a cross sectional view of the screw of the example ofFIG. 14 . -
FIG. 17 illustrates a sixth example of a screw-rod construct of the present technology in a first orientation. -
FIG. 18 illustrates an exploded view of the screw of the example ofFIG. 17 . -
FIG. 19 illustrates a sectioned view of one example of teeth on a rod of the present technology having triangular ratchet teeth cut into the rod. -
FIG. 20 illustrates a sectioned view of a second example of teeth on a rod of the present technology having sawtooth ratchet teeth cut into the rod. -
FIG. 21 illustrates a sectioned view of a third example of teeth on a rod of the present technology having spaced ratchet teeth cut into the rod. -
FIG. 22 illustrates a sectioned view of a fourth example of teeth on a rod of the present technology having square ratchet teeth cut into the rod. -
FIG. 23 illustrates a sectioned view of a fifth example of teeth on a rod of the present technology having a helical coil sintered, welded, soldered, bonded or otherwise attached to the rod. -
FIG. 24 illustrates a sectioned view of a sixth example of teeth on a rod of the present technology having helical threads cut into the rod. -
FIG. 25 illustrates a perspective view of one example of a rod of the present technology having ratchet teeth cut straight across the rod. -
FIG. 26 illustrates a sectioned view of the example of a rod illustrated inFIG. 25 . -
FIG. 27 illustrates a perspective view of a second example of a rod of the present technology having ratchet teeth cut radially on the rod. -
FIG. 28 illustrates a sectioned view of the example of a rod illustrated inFIG. 27 . -
FIG. 29 illustrates a seventh example of a screw-rod construct of the present technology. -
FIG. 30 illustrates a sectioned view of the screw-rod construct illustrated inFIG. 29 . -
FIG. 31 illustrates an eighth example of a screw-rod construct of the present technology. -
FIG. 32 illustrates an exploded view of the screw-rod construct illustrated inFIG. 31 . -
FIG. 33 illustrates a sectioned view of the screw-rod construct illustrated inFIG. 31 . - The present technology relates to compression-distraction spinal fixation systems that include screw-rod constructs. More particularly, the present technology provides a rod and screws that incorporate a ratchet and pawl mechanism for imposition of compression and distraction forces on the spinal column Preferably, compression-distraction spinal fixation systems described herein can allow a single surgeon the ability to apply compressive or distractive forces as desired between adjacent spinal levels in a seamless and efficient manner. By employing the unique ratcheting mechanism provided in compression-distraction spinal fixation systems of the present technology, which in at least some examples can integrate into existing bone-screw rod technology, regional forces can be maintained segmentally or across the entirety of a given spinal construct, avoiding the cumbersome technique of compression/distraction that is inherent to traditional screw-rod systems. Combining improvements in maintenance of regional forces with ease of application and use, the compression-distraction spinal fixation systems of the present technology can add to a spine surgeon's armamentarium in the treatment of complex spinal disease.
- Compression-distraction spinal fixation systems of the present technology are more particularly described in the following examples with reference to the accompanying drawings, and are intended as illustrative only. Referring to the drawings, like numbers indicate like parts throughout the views. Compression-distraction spinal fixation systems of the present technology include a toothed rod and at least one bone screw of the present technology. In some examples, compression-distraction spinal fixation systems of the present technology include a toothed rod, at least one bone screw of the present technology, and at least one conventional bone screw. In other examples, compression-distraction spinal fixation systems of the present technology include a toothed rod, a first bone screw of the present technology, and a second bone screw of the present technology.
- As used in the description herein, and throughout the claims that follow, the meaning of “ratcheting the bone screw along the length of the toothed rod” means that the position of the bone screw is changed with respect to its original position along the length of the toothed rod due to movement of the bone screw, movement of the rod, or movement of both the bone screw and the rod. As used in the description herein, and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
- The rods of compression-distraction spinal fixation systems of the present technology include ratchet teeth, which are preferably evenly spaced along a portion of the length of the rod, preferably along the entire length or substantially the entire length of the rod. Placing evenly spaced ratchet teeth along the length of the rod can allow the rod to be cut and contoured as desired in the operating room. In some examples, precut and precontoured rods can be provided, such as for example, for short segment constructs typically spanning 2, 3, and 4 vertebral levels. The ratchet teeth can cover at least a portion of the outer surface, or circumference, of the rod, including but not limited to, the entire circumference of the rod, half the circumference of the rod, one third of the circumference of the rod, one quarter of the circumference of the rod, or any other suitable portion of the circumference of the rod. The ratchet teeth can be formed as depressions in a toothed rod, or as protrusions that extend from the toothed rod. Toothed rods of the present technology can be made from any suitable material, including but not limited to a biocompatible metal, such as titanium, titanium alloy, stainless steel or cobalt chromium; a biocompatible polymer, such as PEEK; a composite material such as carbon fiber; or a biocompatible metal coated with another biocompatible metal or biocompatible polymer. In at least some examples, the inner diameter of the toothed rods, which is the diameter of the rod not including the height of the ratchet teeth, can be the same as the diameters that are currently used with known smooth rods, which can provide the same mechanical strength as currently known rods.
- Bone screws of the present technology can also be made from any suitable material, including but not limited to a biocompatible metal, such as titanium, titanium alloy, stainless steel or cobalt chrome; a biocompatible polymer, such as PEEK; a composite material such as carbon fiber; or a combination of these. Bone screws of the present technology include a pawl that can engage the teeth on the toothed rod to provide a ratcheting mechanism. The pawl engages at least one ratchet tooth at a location on the toothed rod, and can allow unidirectional ratcheting of the bone screw on the rod to maintain either a compressive or distractive force as desired. In some examples, pawls are flexible, while in others they are rigid. Some of the examples described herein include reversible pawls, meaning that the pawl can be adjusted to allow ratcheting in either direction along the length of the toothed rod, depending on the orientation of the pawl. In other examples, however, pawls that are not reversible, and that provide ratcheting in only a single direction, are also provided. Bone screws of the present technology can also include a shaft, such as a threaded shaft, that can be used to attach the bone screw to a desired bony portion of the spine. Bone screws of the present technology can further include a screw head, and a set screw.
-
FIGS. 2 through 6 illustrate one example of a screw-rod construct 100 of the present technology that includes atoothed rod 102 havingratchet teeth 104, afirst bone screw 106 of the present technology and asecond bone screw 108 of the present technology. In an alternative example, eitherbone screw 106 orbone screw 108 could be replaced with a conventional bone screw, such asbone screw 10 illustrated inFIG. 1 . In the illustrated example ofFIG. 2 , each bone screw includes a threadedshaft 110, ascrew head 112, aset screw 114, and apawl 116. Theset screw 114 of each bone screw includes a retainingring 118, which retains thepawl 116 on theset screw 114. Thepawl 116 is preferably flexible, and includes abend 120 and ablade 122. - When the
toothed rod 102 is slidably connected to thefirst bone screw 106 and thesecond bone screw 108. Theblade 122 of eachpawl 116 of each bone screw engages at least one tooth of theratchet teeth 104 ontoothed rod 102. Thefirst bone screw 106 can be ratcheted along thetoothed rod 102 in the direction indicated by arrow A, but the engagement of theblade 122 of thefirst bone screw 106 with theratchet teeth 104 of thetoothed rod 102 can prevent movement of thefirst bone screw 106 in the opposite direction. Likewise, thesecond bone screw 108 can be ratcheted along thetoothed rod 102 in the direction indicated by arrow B, but the engagement of theblade 122 of thesecond bone screw 108 with theratchet teeth 104 of thetoothed rod 102 can prevent movement of thesecond bone screw 108 in the opposite direction. -
FIG. 3 shows an exploded view of thefirst bone screw 106, which further illustrates the attachment of thepawl 116 to theset screw 114. As illustrated, the retainingring 118 is a circular, flexible piece of material with acut portion 124 to allow expansion of the diameter of the retainingring 118. Theset screw 114 has acircular boss 128 that includes a retainingring groove 130, and a threadedportion 132. Thepawl 116 has acircular bore 126 that communicates with thecircular boss 128 on theset screw 114. Thepawl 116 slides over thecircular boss 128 and the retainingring 118 is captured in a retainingring groove 130 to attach thepawl 116 to theset screw 114 without restraining the rotation of thepawl 116. - In use,
first bone screw 106 can be inserted into a bony portion of a patient's spine, such as the posterior arch, pedicle, or vertebral body of a vertebra. Then,toothed rod 102 can be placed into arecess 134 inscrew head 112. Theset screw 114 can be threaded into thescrew head 112 until there is significant engagement of thepawl 116 with theratchet teeth 104 of thetoothed rod 102. Distracting or compressing forces, depending on the orientation of thepawl 116, can then be used to slide thefirst bone screw 106, and therefore the vertebra to which it is attached, relative totoothed rod 102. -
FIG. 4 illustrates that rotation of thepawl 116 in the direction of the arrow C can reverse the direction of travel offirst bone screw 106 by changing to the orientation shown inFIG. 5 . Thepawl 116 is rotatable from a first position, as shown inFIG. 4 , to a second position, as shown inFIG. 5 , that is about 180° from the first position. Thepawl 116 can include a lockingboss 136, which can prevent inadvertent rotation of thepawl 116. The lockingboss 136 can allow rotation of thepawl 116 when theset screw 114 is loosened an amount sufficient for the lockingboss 136 to clear thescrew head 112. After thefirst bone screw 106 has been moved alongtoothed rod 102 to a desired location, theset screw 114 can be tightened to rigidly secure thescrew head 112 to thetoothed rod 102.FIG. 6 shows a sectioned view of thefirst bone screw 106 with an enlargement to further illustrate the elements of thefirst bone screw 106 as described above. -
FIGS. 7 and 8 illustrate a second example of a screw-rod construct of the present technology. Screw-rod construct 200 as shown inFIGS. 7 and 8 includes atoothed rod 202 havingratchet teeth 204, and abone screw 206. Thebone screw 206 has a threadedshaft 208, ascrew head 210, aset screw 212, and apawl 214. Thepawl 214 can be rotatably mounted to a side of thescrew head 210 by afastener 216, such as a pin. Thepawl 214 includes abend 218 and ablade 220. Theblade 220 of thepawl 214 engages theratchet teeth 204 of thetoothed rod 202. Rotation of thepawl 214 from a first position, as shown inFIG. 7 , to a second position, as shown inFIG. 8 , that is about 180° from the first position, can reverse the direction of travel of thebone screw 206 along the length of thetoothed rod 202. -
FIGS. 9 through 11 illustrate a third example of a screw-rod construct of the present technology, withFIG. 11 showing an exploded view. Screw-rod construct 300 as shown inFIGS. 9 through 11 includes atoothed rod 302 havingratchet teeth 304, and abone screw 306. Thebone screw 306 has a threadedshaft 308, ascrew head 310 having apawl receiving groove 318, aset screw 312, and apawl 314. Thepawl 314 is a clip-on pawl that can be connected to thescrew head 310 by being received by thepawl receiving groove 318 of thescrew head 310.Pawl 318 can include acut 316 that allows expansion of the diameter of thepawl 314 to facilitate installation of thepawl 314 onto thepawl receiving groove 318 of thescrew head 310. Thepawl 314 can include aspring portion 320 and ablade 322. Theblade 322 engages theratchet teeth 304 of thetoothed rod 302. Thespring portion 320 can provide flexibility to thepawl 314 to allow theblade 322 to slide over theratchet teeth 304 of thetoothed rod 302 when thebone screw 306 is ratcheted along the length of thetoothed rod 302. Rotation of thepawl 314 from a first position, as shown inFIG. 9 , to a second position, as shown inFIG. 10 , that is about 180° from the first position, can reverse the direction of travel of thebone screw 306 along the length of thetoothed rod 302. -
FIGS. 12 and 13 illustrate a fourth example of a screw-rod construct of the present technology. Screw-rod construct 400 as shown includes atoothed rod 402 havingratchet teeth 404, and abone screw 406. Thebone screw 406 has a threadedshaft 408, ascrew head 410, aset screw 412, and a slidingpawl 414. The slidingpawl 414 can be slidably attached to thescrew head 410 with afastener 416, such as a pin. Thepawl 414 can also include afastener groove 420, and the fastener can extend through the fastener groove to slidably attach thepawl 414 to thescrew head 410. Thescrew head 410 can include apawl receiving groove 418 on a side of thescrew head 310, and slidingpawl 414 can be slidably received in thepawl receiving groove 418. The pawl can further include afirst blade 422 at one first end, and a second blade 422 (not shown) at the opposite end. Thefirst blade 422 can engage theratchet teeth 404 of thetoothed rod 402 when the slidable pawl is in a first position, as shown inFIG. 12 , allowing the bone screw to ratchet along the length of the toothed rod in one direction. Thesecond blade 422, which can be a mirror image of thefirst blade 422, can engage theratchet teeth 404 of thetoothed rod 402 when the slidable pawl is in a second position, as shown inFIG. 13 , allowing the bone screw to ratchet along the length of the toothed rod in the opposite direction. -
FIGS. 14 through 16 illustrate a fifth example of a screw-rod construct of the present technology, withFIG. 15 being an exploded view andFIG. 16 being a cross-sectional view. Screw-rod construct 500 includes atoothed rod 502 havingratchet teeth 504, and abone screw 506. Thebone screw 506 has a threadedshaft 508, ascrew head 510, aset screw 512, and apawl 514. Thepawl 514 can be a raised boss on the bottom surface of theset screw 512 that engages theratchet teeth 504 of thetoothed rod 502. Aleaf spring 516 can be positioned under therod receiving groove 518 of thescrew head 510, and can provide an upward force on thetoothed rod 502 to ensure engagement of theratchet teeth 504 and thepawl 514. When horizontal force is exerted in the direction of arrow D, theleaf spring 516 can deflect out of the way and allow ratcheting of thebone screw 506 along the length of thetoothed rod 502. -
FIGS. 17 and 18 illustrate a sixth example of a screw-rod construct of the present technology, withFIG. 18 being an exploded view. Screw-rod construct 600 includes atoothed rod 602 havingratchet teeth 604, and abone screw 606. Thebone screw 606 has a threadedshaft 608, ascrew head 610, aset screw 612, and apawl 614. Thepawl 614 is attached to aframe 616 that has arecess 618. Therecess 618 attaches to thescrew head 610, and can be lowered over thescrew head 610 into alignment with thetoothed rod 602 so that thepawl 614 engages theratchet teeth 602 of thetoothed rod 602. Thepawl 614 can be is attached to theframe 616 with afastener 620, such as a pin, that extends through abore 624 in theframe 618 and can be rigidly attached to thepawl 614 due to press fit of thefastener 620 into apawl hole 626 in thepawl 616. As illustrated, thefastener 620 can have ahexagonal head 622. Aspring 628 can be attached to theframe 618 by aspring fastener 630, and can exert an inward force on thepawl 614 to maintain engagement of thepawl 614 with theratchet teeth 602. To disengage thepawl 614 from theratchet teeth 602, an operator can rotate thehexagonal head 622 of thefastener 618 clockwise. -
FIGS. 19 through 24 illustrate examples of ratchet teeth that can be formed on atoothed rod 700 of the present technology. The ratchet teeth can be formed on thetoothed rod 700 in any suitable manner, such as by being cut, pressed, rolled, forged, molded or otherwise formed. In one example,toothed rod 700 having ratchet teeth can be fabricted in a molding operation such as MIM (Metal Injection Molding). In other examples, ratchet teeth can be formed by waterjet cutting, EDM (Electrical Discharge Machining), etching, or ECM (Electrochemical Machining).FIG. 19 showstoothed rod 700 havingtriangular teeth 702.FIG. 20 showstoothed rod 700 havingsaw teeth 704.FIG. 21 showstoothed rod 700 havingtriangular teeth 706 in a staggered pattern, wherein theratchet teeth 706 are separated by an offset R.FIG. 22 showstoothed rod 700 having squaredteeth 708.FIG. 23 showstoothed rod 700 having ratchet teeth formed by a helical piece ofmaterial 710 that is wrapped around and secured to thetoothed rod 700. The helical piece ofmaterial 710 can be secured to the toothed rod in any suitable manner, including, for example, being sintered, welded, soldered, or bonded.FIG. 24 toothed rod 700 having ratchet teeth formed byhelical threads 712.Helical threads 712 can be formed in any suitable manner, including being cut intotoothed rod 700, or being formed by a thread rolling operation which could increase the fatigue life oftoothed rod 700. -
FIGS. 25 and 26 illustratetoothed rod 700 havingtriangular teeth 714 formed straight, meaning on a linear path, across an outer surface of thetoothed rod 700.FIGS. 26 and 27 illustratetoothed rod 700 havingtriangular teeth 714 formed radially, meaning on a non-linear, arcuate path, across an outer surface of thetoothed rod 700. -
FIGS. 29 and 30 illustrate a seventh example of a screw-rod construct of the present technology, withFIG. 30 being sectioned view. Screw-rod construct 800 includes atoothed rod 802 havingratchet teeth 804, and abone screw 806. Thebone screw 806 has a threadedshaft 808, ascrew head 810, aset screw 812, and apawl 814. Thepawl 814 is a toggle pawl located in a side of thescrew head 810. Thetoggle pawl 814 is housed within arecess 816 in the side of thescrew head 810. Thetoggle pawl 814 is attached to thescrew head 810, preferably at the center of thetoggle pawl 814, by afastener 818, such as a pin. Thetoggle pawl 814 can rotate about the fastener, from a first position, as shown inFIG. 30 , to a second position that has an orientation opposite that of the first position, thus allowing thebone screw 806 to be ratcheted along the length of thetoothed rod 802 in a first or second direction, respectively. Thetoggle pawl 814 can be spring-loaded, or can have sufficient friction to allow it to be rotated from the first position to the second position by manual force exerted by an operator. - Previously described are pawls which flex or rotate, however it should be understood that a pawl may also translate linearly away from toothed rod and return to contact with toothed rod under the action of a spring such as a helical spring, a leaf spring, a machined spring, or any elastic resilient material.
FIGS. 31 through 33 illustrate one example of a screw-rod construct of the present technology having such a linearly translating pawl, withFIG. 32 being an exploded view, andFIG. 33 being a sectioned view. Screw-rod construct 900 includes atoothed rod 902 havingratchet teeth 904, and abone screw 906. Thebone screw 906 has a threadedshaft 908, ascrew head 910, aset screw 912, and apawl 914. Thepawl 914 is attached to a side of thescrew head 910, and can be located in a screw head bore 922 that has akeyway 924. Thepawl 914 is a plunger pawl, havingteeth 916, ablind hole 926, ahelical cut 918, and ananti-rotation boss 920. Helical cut 918 allowsplunger pawl 914 to compress like a helical spring. In lieu ofhelical cut 918,plunger pawl 914 could incorporate a wire wound helical spring, a leaf spring or other resilient material. Theanti-rotation boss 920 of theplunger pawl 914 can align with thekeyway 924 of thescrew head 910 to maintain alignment ofplunger pawl 914 with theratchet teeth 904 of thetoothed rod 902. As thebone screw 900 is ratcheted along the length of thetoothed rod 902, thehelical spring 918 can compress and extend to so thatplunger pawl 914 maintains contact withtoothed rod 902 and allows motion in one direction only. - Screw-rod constructs including at least one bone screw of the present technology and at least one rod of the present technology can allow compressive or distractive forces to be applied sequentially across each level of a given construct as desired.
- In at least one example, the application of compressive or distractive forces can be accomplished by first attaching at least one bone screw of the present technology to at least one desired bony portion of a patient's spine. In one example a first bone screw can be attached to a first bony portion of a patient's spine, and a second bone screw can be attached to a second bony portion of a patient's spine. At least one of the bone screws, or both, can have a pawl. The toothed rod of the present technology can be optionally shaped by an operator, such as a surgeon, and can be attached to each bone screw. In some examples, the toothed rod can be attached to each bone screw by placing the toothed rod in the screw head of the first bone screw and in the screw head of the second bone screw, and then placing a first set screw on the screw head of the first screw and a second set screw on the screw head of the second screw to maintain the toothed rod in the screw head of each bone screw. The pawl of the at least one bone screw having a pawl can be oriented to engage the ratchet teeth of the toothed rod. In some examples, the pawl can be oriented to engage the ratchet teeth of the toothed rod in a first position or a second position, for the application of either distractive or compressive forces as desired. The bone screw having a pawl, or at least one of the bone screws having a pawl, can then be ratcheted along the length of the toothed rod to apply the desired amount of distractive or compressive force. Once the desired amount of distractive or compressive force is achieved, each set screw can be tightened to maintain each bone screw in a fixed position relative to the toothed rod. The distractive or compressive force can be maintained temporarily or permanently.
- The distractive or compressive force can be used to alter the distance between bony portions of a patient's spine. For example, the distance between spinal vertebrae of a patient can be altered by attaching a first bone screw to a first spinal vertebra and attaching a second bone screw to a second spinal vertebra, wherein at least the first bone screw has a pawl. A toothed rod can then be attached to the first and second bone screws, and the pawl of the first bone screw can be oriented to engage the ratchet teeth of the toothed rod. The method can then include altering the distance between the first vertebra and the second vertebra. The distance between the first vertebra and the second vertebra can be altered by ratcheting the first bone screw a desired amount along the length of the toothed rod to apply an amount of distractive or compressive force sufficient to obtain the desired altered distance between the first vertebra and the second vertebra. The altered distance can then be maintained, temporarily or permanently, by the pawl engaging the ratchet teeth of the toothed rod.
- A screw-rod construct of the present technology was made in accordance with the example illustrated in
FIGS. 2-6 . The toothed rod had triangular ratchet teeth formed by cutting grooves having a 90° angle along the length of the toothed rod. The grooves were cut about 0.75 mm apart, and were cut radially in an arc that was about 60°. The toothed rod had an inner diameter of about 5.5 mm, and was made from Grade 23 Titanium alloy (Ti6Al4V-ELI). The pawl was also made of Grade 23 Titanium alloy (Ti6A14V-ELI), and was about 0.016 inches (0.4mm) thick. The blade of the pawl was about 5 mm wide. - From the foregoing, it will be appreciated that although specific examples have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit or scope of this disclosure. It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to particularly point out and distinctly claim the claimed subject matter.
Claims (14)
1.-19. (canceled)
20. A compression-distraction spinal fixation system comprising:
at least one bone screw having a head;
a pawl mounted to the head of the at least one bone screw; and
a toothed rod extending in a longitudinal direction and connected to the at least one bone screw, the toothed rod having a plurality of ratchet teeth,
wherein the toothed rod extends through a first side of the head,
wherein the pawl is configured to extend from the first side of the head and engage the ratchet teeth of the toothed rod at the first side of the head from which the pawl extends.
21. The compression-distraction spinal fixation system of claim 20 , wherein the toothed rod further extends through a second side of the head, wherein the pawl is movable to extend from the second side of the head and engage the ratchet teeth of the toothed rod at the second side of the head.
22. The compression-distraction spinal fixation system of claim 21 , wherein the second side of the head is about 180° from the first side of the head.
23. The compression-distraction spinal fixation system of claim 21 , wherein the pawl is connected to a side surface of the head with a fastener.
24. The compression-distraction spinal fixation system of claim 23 , wherein the pawl is rotatable between the first side and the second side of the head about an axis of the fastener.
25. The compression-distraction spinal fixation system of claim 23 , wherein the pawl is slidable along the side surface of the head and between the first side and the second side of the head.
26. The compression-distraction spinal fixation system of claim 25 , the pawl further comprising a fastener groove therethrough, wherein the fastener groove is configured to receive the fastener.
27. The compression-distraction spinal fixation system of claim 26 , wherein the fastener groove is configured to slide along the fastener when the pawl slides between the first side and the second side of the head.
28. The compression-distraction spinal fixation system of claim 20 , further comprising a set screw, wherein the head of the at least one bone screw is configured to receive the set screw therein in order to maintain the toothed rod in the head of the at least one bone screw.
29. The compression-distraction spinal fixation system of claim 28 , wherein the set screw is configured to be tightened in the head of the at least one bone screw to maintain the at least one bone screw in a fixed position relative to the toothed rod.
30. The compression-distraction spinal fixation system of claim 20 , wherein the pawl includes a blade configured to engage the ratchet teeth of the toothed rod.
31. The compression-distraction spinal fixation system of claim 20 , wherein the first side of the head defines at least a part of the perimeter of the head, and the pawl is configured to extend beyond the perimeter of the head.
32. The compression-distraction spinal fixation system of claim 20 , wherein the at least one bone screw is a first bone screw, wherein the compression-distraction spinal fixation system further comprises:
a second bone screw comprising a pawl;
wherein the toothed rod is connected to both the first bone screw and the second bone screw, the pawl of the first bone screw is configured to engage the ratchet teeth of the toothed rod, and the pawl of the second bone screw is configured to engage the ratchet teeth of the toothed rod.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/489,405 US20150080958A1 (en) | 2010-01-05 | 2014-09-17 | Compression-distraction spinal fixation system |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US29221510P | 2010-01-05 | 2010-01-05 | |
US38354010P | 2010-09-16 | 2010-09-16 | |
US12/958,304 US8864800B2 (en) | 2010-01-05 | 2010-12-01 | Compression-distraction spinal fixation system |
US14/489,405 US20150080958A1 (en) | 2010-01-05 | 2014-09-17 | Compression-distraction spinal fixation system |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/958,304 Division US8864800B2 (en) | 2010-01-05 | 2010-12-01 | Compression-distraction spinal fixation system |
Publications (1)
Publication Number | Publication Date |
---|---|
US20150080958A1 true US20150080958A1 (en) | 2015-03-19 |
Family
ID=44305683
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/958,304 Expired - Fee Related US8864800B2 (en) | 2010-01-05 | 2010-12-01 | Compression-distraction spinal fixation system |
US14/489,405 Abandoned US20150080958A1 (en) | 2010-01-05 | 2014-09-17 | Compression-distraction spinal fixation system |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/958,304 Expired - Fee Related US8864800B2 (en) | 2010-01-05 | 2010-12-01 | Compression-distraction spinal fixation system |
Country Status (6)
Country | Link |
---|---|
US (2) | US8864800B2 (en) |
EP (1) | EP2521502A4 (en) |
JP (1) | JP5753195B2 (en) |
AU (1) | AU2010340232A1 (en) |
CA (1) | CA2784092A1 (en) |
WO (1) | WO2011084275A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9907582B1 (en) | 2011-04-25 | 2018-03-06 | Nuvasive, Inc. | Minimally invasive spinal fixation system and related methods |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2498696A4 (en) * | 2009-11-09 | 2014-09-03 | Applied Orthopaedics Llp | Apparatus for retaining bone |
JP5753195B2 (en) * | 2010-01-05 | 2015-07-22 | ザ・ジョンズ・ホプキンス・ユニバーシティー | Compression-distraction spinal fixation system |
US9414862B2 (en) | 2011-10-24 | 2016-08-16 | Warsaw Orthopedic, Inc. | Bone fastener for a spinal surgical system |
US20140088647A1 (en) * | 2012-09-21 | 2014-03-27 | Atlas Spine, Inc. | Minimally invasive spine surgery instruments: spinal rod with flange |
US20150297265A1 (en) * | 2014-04-22 | 2015-10-22 | Alan J. Arena | Remote Operated Adjustable Spine Device |
CN105310757A (en) * | 2015-11-28 | 2016-02-10 | 张英泽 | Adjustable and elastic outer fixing device used after fibular osteotomy |
US10194960B1 (en) | 2015-12-03 | 2019-02-05 | Nuvasive, Inc. | Spinal compression instrument and related methods |
US11051859B2 (en) * | 2016-04-27 | 2021-07-06 | Warsaw Orthopedic, Inc. | Spinal correction system and method |
US10194958B2 (en) * | 2016-04-27 | 2019-02-05 | Warsaw Othopedic, Inc. | Spinal correction system and method |
US20200060731A1 (en) * | 2017-05-11 | 2020-02-27 | Marc Evan Richelsoph | Advanced Polyaxial System and Surgical Procedure |
US10610265B1 (en) | 2017-07-31 | 2020-04-07 | K2M, Inc. | Polyaxial bone screw with increased angulation |
Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030055430A1 (en) * | 2001-09-14 | 2003-03-20 | Kim Kee D. | System and method for fusing spinal vertebrae |
US20070123865A1 (en) * | 2004-04-28 | 2007-05-31 | Fridolin Schlapfer | Device for the dynamic stabilization of bones |
US20070276371A1 (en) * | 2004-02-10 | 2007-11-29 | Baynham Bret O | Dynamic cervical plate |
US20080051788A1 (en) * | 2006-08-21 | 2008-02-28 | Schwab Frank J | System And Method For Correcting Spinal Deformity |
US20080234681A1 (en) * | 2004-02-10 | 2008-09-25 | Baynham Matthew G | Dynamic cervical plate |
US20090048601A1 (en) * | 2007-08-15 | 2009-02-19 | Forton Charles R | Mis crosslink apparatus and methods for spinal implant |
US20090099609A1 (en) * | 2007-10-11 | 2009-04-16 | Zimmer Gmbh | Bone anchor system |
US20090264933A1 (en) * | 2008-04-22 | 2009-10-22 | Warsaw Orthopedic, Inc. | Anchors for securing a rod to a vertebral member |
US20100145388A1 (en) * | 2008-12-03 | 2010-06-10 | Spartek Medical, Inc. | Low profile spinal prosthesis incorporating a bone anchor having a deflectable post and a compound spinal rod |
US20100160965A1 (en) * | 2008-12-22 | 2010-06-24 | Zimmer Spine, Inc. | Bone Anchor Assembly and Methods of Use |
US20100324600A1 (en) * | 2009-06-18 | 2010-12-23 | Ashok Biyani | Unidirectional rotatory pedicle screw and spinal deformity correction device for correction of spinal deformity in growing children |
US20110118784A1 (en) * | 2004-02-10 | 2011-05-19 | Baynham Bret O | Cervical Plate Ratchet Pedicle Screws |
US20110301646A1 (en) * | 2010-01-05 | 2011-12-08 | The Johns Hopkins University | Compression-distraction spinal fixation system |
US20110319939A1 (en) * | 2010-01-05 | 2011-12-29 | Neuraxis Technologies LLC | Compression-distraction spinal fixation system and kit |
US8777995B2 (en) * | 2008-02-07 | 2014-07-15 | K2M, Inc. | Automatic lengthening bone fixation device |
Family Cites Families (34)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4085744A (en) * | 1977-01-31 | 1978-04-25 | David Warren Lewis | Spinal column prostheses orthoses |
US4567884A (en) * | 1982-12-01 | 1986-02-04 | Edwards Charles C | Spinal hook |
US4771767A (en) * | 1986-02-03 | 1988-09-20 | Acromed Corporation | Apparatus and method for maintaining vertebrae in a desired relationship |
DE8704134U1 (en) * | 1987-03-19 | 1987-07-16 | Zielke, Klaus, Dr.Med., 3590 Bad Wildungen, De | |
US4896661A (en) * | 1988-02-05 | 1990-01-30 | Pfizer, Inc. | Multi purpose orthopedic ratcheting forceps |
US5167662A (en) * | 1992-01-24 | 1992-12-01 | Zimmer, Inc. | Temporary clamp and inserter for a posterior midline spinal clamp |
US5702395A (en) * | 1992-11-10 | 1997-12-30 | Sofamor S.N.C. | Spine osteosynthesis instrumentation for an anterior approach |
DE4425357C2 (en) * | 1994-07-18 | 1996-07-04 | Harms Juergen | Anchoring element |
US5961517A (en) * | 1994-07-18 | 1999-10-05 | Biedermann; Lutz | Anchoring member and adjustment tool therefor |
FR2734147B1 (en) * | 1995-05-19 | 1997-10-10 | Klein Jean Michel | IMPLANTABLE OSTEOSYNTHESIS DEVICE |
US5672177A (en) * | 1996-01-31 | 1997-09-30 | The General Hospital Corporation | Implantable bone distraction device |
FR2789886B1 (en) * | 1999-02-18 | 2001-07-06 | Dimso Sa | DISTRACTION / CONTRACTION DEVICE FOR A SPINAL OSTEOSYNTHESIS SYSTEM |
US20060064092A1 (en) | 2001-05-17 | 2006-03-23 | Howland Robert S | Selective axis serrated rod low profile spinal fixation system |
US7011658B2 (en) * | 2002-03-04 | 2006-03-14 | Sdgi Holdings, Inc. | Devices and methods for spinal compression and distraction |
FR2843538B1 (en) * | 2002-08-13 | 2005-08-12 | Frederic Fortin | DEVICE FOR DISTRACTING AND DAMPING ADJUSTABLE TO THE GROWTH OF THE RACHIS |
US6918910B2 (en) * | 2002-12-16 | 2005-07-19 | John T. Smith | Implantable distraction device |
US7942908B2 (en) * | 2005-02-02 | 2011-05-17 | Depuy Spine, Inc. | Adjustable length implant |
US7578822B2 (en) * | 2005-04-29 | 2009-08-25 | Warsaw Orthopedic, Inc. | Instrument for compression or distraction |
US8157806B2 (en) * | 2005-10-12 | 2012-04-17 | Synthes Usa, Llc | Apparatus and methods for vertebral augmentation |
ES2377671T3 (en) * | 2006-01-11 | 2012-03-29 | Biedermann Motech Gmbh | Bone anchor set |
EP2015692B1 (en) * | 2006-04-21 | 2010-10-27 | Greatbatch Medical SA | Dynamic intervertebral stabilization system |
US8317845B2 (en) * | 2007-01-19 | 2012-11-27 | Alexa Medical, Llc | Screw and method of use |
US8021396B2 (en) * | 2007-06-05 | 2011-09-20 | Spartek Medical, Inc. | Configurable dynamic spinal rod and method for dynamic stabilization of the spine |
US8177810B2 (en) * | 2007-07-17 | 2012-05-15 | Anova Corporation | Methods of annulus and ligament reconstruction using flexible devices |
US8080038B2 (en) * | 2007-08-17 | 2011-12-20 | Jmea Corporation | Dynamic stabilization device for spine |
US8308767B2 (en) * | 2007-09-19 | 2012-11-13 | Pioneer Surgical Technology, Inc. | Interlaminar stabilization system |
US20090093820A1 (en) * | 2007-10-09 | 2009-04-09 | Warsaw Orthopedic, Inc. | Adjustable spinal stabilization systems |
EP2074957B1 (en) * | 2007-12-31 | 2013-04-17 | Spinelab AG | Pedicle screw with a locking device for attaching a rod to stabilise the spine |
US20090216273A1 (en) * | 2008-02-19 | 2009-08-27 | U. S. Spinal Technologies, L.L.C. | Curved facet joint fixation assembly and associated implantation tool and method |
US8372081B1 (en) * | 2008-02-20 | 2013-02-12 | Nuvasive, Inc. | Vertebral distraction assembly and related methods |
US8211149B2 (en) * | 2008-05-12 | 2012-07-03 | Warsaw Orthopedic | Elongated members with expansion chambers for treating bony members |
GB0822507D0 (en) * | 2008-12-10 | 2009-01-14 | Karnezis Ioannis | Surgical device for correction of spinal deformities |
US20100241172A1 (en) * | 2009-03-23 | 2010-09-23 | Ashok Biyani | Pedicle screw including stationary and movable members for facilitating the surgical correction of spinal deformities |
US9561062B2 (en) * | 2012-03-19 | 2017-02-07 | Alphatec Spine, Inc. | Spondylolisthesis reduction system |
-
2010
- 2010-12-01 JP JP2012548007A patent/JP5753195B2/en not_active Expired - Fee Related
- 2010-12-01 WO PCT/US2010/058624 patent/WO2011084275A1/en active Application Filing
- 2010-12-01 US US12/958,304 patent/US8864800B2/en not_active Expired - Fee Related
- 2010-12-01 CA CA2784092A patent/CA2784092A1/en not_active Abandoned
- 2010-12-01 AU AU2010340232A patent/AU2010340232A1/en not_active Abandoned
- 2010-12-01 EP EP10842440.9A patent/EP2521502A4/en not_active Withdrawn
-
2014
- 2014-09-17 US US14/489,405 patent/US20150080958A1/en not_active Abandoned
Patent Citations (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030055430A1 (en) * | 2001-09-14 | 2003-03-20 | Kim Kee D. | System and method for fusing spinal vertebrae |
US20110118784A1 (en) * | 2004-02-10 | 2011-05-19 | Baynham Bret O | Cervical Plate Ratchet Pedicle Screws |
US20080234681A1 (en) * | 2004-02-10 | 2008-09-25 | Baynham Matthew G | Dynamic cervical plate |
US20070276371A1 (en) * | 2004-02-10 | 2007-11-29 | Baynham Bret O | Dynamic cervical plate |
US20070123865A1 (en) * | 2004-04-28 | 2007-05-31 | Fridolin Schlapfer | Device for the dynamic stabilization of bones |
US20080051788A1 (en) * | 2006-08-21 | 2008-02-28 | Schwab Frank J | System And Method For Correcting Spinal Deformity |
US8403958B2 (en) * | 2006-08-21 | 2013-03-26 | Warsaw Orthopedic, Inc. | System and method for correcting spinal deformity |
US20090048601A1 (en) * | 2007-08-15 | 2009-02-19 | Forton Charles R | Mis crosslink apparatus and methods for spinal implant |
US8608780B2 (en) * | 2007-08-15 | 2013-12-17 | Zimmer Spine, Inc. | MIS crosslink apparatus and methods for spinal implant |
US8048129B2 (en) * | 2007-08-15 | 2011-11-01 | Zimmer Spine, Inc. | MIS crosslink apparatus and methods for spinal implant |
US20100331898A1 (en) * | 2007-10-11 | 2010-12-30 | Zimmer Gmbh | Bone anchor system |
US20090099609A1 (en) * | 2007-10-11 | 2009-04-16 | Zimmer Gmbh | Bone anchor system |
US8777995B2 (en) * | 2008-02-07 | 2014-07-15 | K2M, Inc. | Automatic lengthening bone fixation device |
US20090264933A1 (en) * | 2008-04-22 | 2009-10-22 | Warsaw Orthopedic, Inc. | Anchors for securing a rod to a vertebral member |
US20100145388A1 (en) * | 2008-12-03 | 2010-06-10 | Spartek Medical, Inc. | Low profile spinal prosthesis incorporating a bone anchor having a deflectable post and a compound spinal rod |
US20100160965A1 (en) * | 2008-12-22 | 2010-06-24 | Zimmer Spine, Inc. | Bone Anchor Assembly and Methods of Use |
US20100324600A1 (en) * | 2009-06-18 | 2010-12-23 | Ashok Biyani | Unidirectional rotatory pedicle screw and spinal deformity correction device for correction of spinal deformity in growing children |
US20110319939A1 (en) * | 2010-01-05 | 2011-12-29 | Neuraxis Technologies LLC | Compression-distraction spinal fixation system and kit |
US20110301646A1 (en) * | 2010-01-05 | 2011-12-08 | The Johns Hopkins University | Compression-distraction spinal fixation system |
US8864800B2 (en) * | 2010-01-05 | 2014-10-21 | The Johns Hopkins University | Compression-distraction spinal fixation system |
US8968367B2 (en) * | 2010-01-05 | 2015-03-03 | The Johns Hopkins University | Compression-distraction spinal fixation system and kit |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9907582B1 (en) | 2011-04-25 | 2018-03-06 | Nuvasive, Inc. | Minimally invasive spinal fixation system and related methods |
US10716600B1 (en) | 2011-04-25 | 2020-07-21 | Nuvasive, Inc. | Minimally invasive spinal fixation system |
US11596453B2 (en) | 2011-04-25 | 2023-03-07 | Nuvasive, Inc. | Minimally invasive spinal fixation system |
Also Published As
Publication number | Publication date |
---|---|
JP2013516273A (en) | 2013-05-13 |
EP2521502A4 (en) | 2014-11-05 |
JP5753195B2 (en) | 2015-07-22 |
AU2010340232A1 (en) | 2012-07-05 |
US8864800B2 (en) | 2014-10-21 |
EP2521502A1 (en) | 2012-11-14 |
US20110301646A1 (en) | 2011-12-08 |
WO2011084275A1 (en) | 2011-07-14 |
CA2784092A1 (en) | 2011-07-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8864800B2 (en) | Compression-distraction spinal fixation system | |
US8968367B2 (en) | Compression-distraction spinal fixation system and kit | |
US20220022919A1 (en) | Semi-constrained Anchoring System | |
CA2674147C (en) | Spinal anchoring screw | |
US8303631B2 (en) | Systems and methods for posterior dynamic stabilization | |
US20110184468A1 (en) | Spinous process fusion plate with osteointegration insert | |
US20100137911A1 (en) | Adjustable Assembly for Correcting Spinal Abnormalities | |
US20220133359A1 (en) | Dynamic stabilization connecting member with pre-tensioned solid core member | |
AU2012200187A1 (en) | Dynamic stabilization connecting member with pre-tensioned solid core |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |