Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
2001-09-12
2004-06-08
Shaver, Kevin (Department: 3732)
Surgery
Instruments
Orthopedic instrumentation
Reexamination Certificate
active
06746449
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to spinal fixation systems for correction of spinal deformities or injuries, and embodiments of the invention relate to an instrument for moving a vertebra or vertebrae to a desired position.
2. Description of Related Art
Spinal disorders, degenerative conditions, or trauma may result in a need to correct or stabilize the spine of a patient. A variety of spinal fixation systems may be used to correct and/or stabilize a spine. A spinal fixation system may be classified as an anterior, lateral, or posterior system according to a position of the system relative to the spine. Anterior and lateral spinal fixation systems usually include short structures that support only a few adjacent vertebral bodies of a spine. Several anterior and lateral spinal fixation systems may be coupled to vertebral bodies to correct and/or stabilize a large portion of the spine. Posterior stabilization systems often include pairs of vertically aligned rods for stabilizing both short and long segments of a spine.
A posterior spinal fixation system may include a pair of bendable rods that are contoured and longitudinally disposed adjacent to vertebral bodies of a spine. Rods used in a fixation system are typically circular in cross section, although rods having non-circular cross sections may also be used. The rods may be attached to vertebral bodies of the spine by a plurality of fixation elements. The fixation elements may be hooks and/or bone screws. Transverse connectors may be used to join the pair of spinal rods together. Transverse connectors may stabilize and provide rigidity to a spinal fixation system.
A fixation element may include a connector that attaches the fixation element to a spinal rod. One type of connector includes an opening that snaps onto a spinal rod. When a spinal rod is positioned in the opening of a connector, a fastener, such as a bolt or a locking plate, may securely attach the connector to the fixation element. The fastener may inhibit motion of the spinal rod relative to the fixation element. U.S. Pat. No. 6,132,430 issued to Wagner, which is incorporated by reference as if fully set forth herein, describes fixation elements wherein fixation element connectors are configured to snap onto spinal rods. Other types of fixation elements may also be used in a spinal fixation system. Fixation elements may include, but are not limited to, the fixation elements shown and described in U.S. Pat. Nos. 4,763,644; 4,805,602; 4,887,596; 4,950,269; 5,129,388; 5,961,518; 5,989,250; 5,997,539; and 6,063,089; each of these patents being incorporated by reference as if fully set forth herein.
A spinal rod may be attached to one or more vertebrae during a posterior spinal fixation procedure. A vertebra or vertebrae that are not in desired positions may be moved during a spinal fixation procedure. A fixation element may be attached to a vertebra that needs to be moved. A translation instrument may be used to draw the fixation element and the spinal rod together. A fastener may then be attached to the fixation element to join the rod and the element together.
A translation device that may be used to join a fixation element and a spinal rod together is the Universal Spinal System Rod Introduction Pliers from Synthes Spine (Paoli, Pa.). One of the jaws of the pliers has a hollow barrel. The other jaw is a rod contactor. The pliers are used with a holder that threadably attaches to a fixation element. After attaching the holder to the fixation element, the holder is inserted into the hollow barrel. Grips of the pliers are squeezed together by a user to cause the rod contactor to rotate and contact a spinal rod. Continued squeezing of the grips forces the rod and the fixation element together so that the rod may be positioned within an opening of the fixation element. A user of the translation device must adjust the position of the holder within the barrel to ensure that the rod is positioned within the fixation element when the grips of the translation device are closed together. Proper alignment of the translation device may be difficult to achieve during use of the translation instrument. A user may have to manually adjust the vertical position of the fixation element while simultaneously translating the fixation element and the rod together.
U.S. Pat. No. 5,020,519 to Hayes et al., which is incorporated by reference as if fully set forth herein, describes a device that may be used to introduce a rod into an opening in a spinal implant. The system includes a one-piece tool that clamps a spinal implant and aligns a rod with an opening in the spinal implant. The device may be used to reduce the vertical offset between the rod and the implant. The spinal implant must be maintained in the correct position in the translation device while threading the rod into place between the jaws.
SUMMARY OF THE INVENTION
A translation instrument may be used to move a vertebra or vertebrae to a desired position. A spinal rod may be attached to vertebral bodies by fixation elements. An adjacent fixation element may be attached to an out-of-position vertebra. It may be desirable to move the spinal rod and the adjacent fixation element together so that the vertebra is placed in a desired position relative to adjacent vertebrae. Securing the fixation element to the spinal rod may allow for proper alignment of vertebral bodies of a spinal column.
A translation instrument may be used to move the spinal rod and the adjacent fixation element together. The translation instrument may simultaneously translate the fixation element towards the rod and adjust the vertical height of the fixation element relative to the rod so that the rod is positioned within a rod opening of the fixation element. A guide of the translation instrument may engage the fixation element or an extension member coupled to the fixation element. The guide may ensure that the spinal rod is properly positioned relative to a fixation element when the translation instrument is used.
A fixation element may be coupled to a vertebral body whose position is to be adjusted. A fixation element may be, but is not limited to, a bone screw or a hook. A holder may be coupled to the fixation element. The holder may include an attachment mechanism, a shaft, and a guide. The attachment mechanism may securely attach the holder to the fixation element. The shaft may allow the holder to be coupled to a positioner of a translation instrument. The holder guide may be a protrusion that extends from a side of the shaft.
A translation instrument may include a positioner, an arm, and an actuator. A positioner may couple a fixation element holder to the translation instrument. In an embodiment, the positioner may allow the holder to move axially relative to the translation instrument.
An arm of a translation instrument may be pivotally coupled to an actuator of the translation instrument. The actuator may be a pair of lever arms or grips that are pivotally coupled together. When the grips are grasped and moved towards each other, the arm may move towards a holder placed within a positioner of the translation instrument. The arm may include a guide configured to mate with a guide of the holder. The arm may also include a rod engager. In an embodiment, the rod engager may be an indentation or groove in a body of the arm that contacts and holds a rod. The arm guide contacts the holder guide during use to adjust a position of the translation instrument relative to a fixation element. Grasping and moving the grips towards each other may rotate the arm so that the rod engager contacts a rod. Moving the grips closer together may bring the rod and the fixation element together. The holder guide may interact with the arm guide as the grips are moved towards each other. Contact of the holder guide with the arm guide may adjust a position of the translation instrument relative to the fixation element so that the rod and a rod opening of the fixation element may be brought together. After the rod is
Cottle William A.
Jones Robert J.
Loveless Eric
Priddy Michael B.
Shaver Kevin
Spinal Concepts Inc.
Vrioni Beth A.
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