Patent Application
20100087873
The present application is directed to connectors for attaching an elongated member to a bone, and more particularly, to a connector with a receiver having a cut-out section for inserting an anchor into the receiver.
Elongated members are used in various surgical applications, such as treatment of fractures. Another context is in the surgical treatment of spinal disorders such as degenerative disc disease, disc herniations, scoliosis or other curvature abnormalities, and fractures. Treatment of these spinal disorders may use different types of surgical treatments. In some cases, spinal fusion is indicated to inhibit relative motion between vertebral members. In other cases, dynamic implants are used to preserve motion between vertebral members. For either type of surgical treatment, elongated members may be attached to the exterior of two or more vertebral members, whether it is at a posterior, anterior, or lateral side of the vertebral members. In other embodiments, elongated members are attached to the vertebral members without the use of dynamic implants or spinal fusion.
Elongated members may provide a stable, rigid column that encourages bones to fuse after spinal-fusion surgery. Further, the elongated members may redirect stresses over a wider area away from a damaged or defective region. Also, rigid elongated members may restore the spine to its proper alignment. In some cases, flexible elongated members may be appropriate. Flexible elongated members may provide other advantages, such as increasing loading on interbody constructs, decreasing stress transfer to adjacent vertebral members while bone-graft healing takes place, and generally balancing strength with flexibility.
The elongated members are secured to one or more vertebra through connectors. The connectors include a receiver that receives the elongated member, and an anchor to anchor into the vertebra. The receiver and anchor should be constructed in a manner to allow for these elements to be connected together in an effective manner.
The present application is directed to connectors for attaching an elongated member to a bone. The connectors may include a receiver that is attached to an anchor. The receiver may include a base and outwardly-extending arms that form a channel to receive the elongated member. The base may include an opening that extends into a receptacle. The opening may include a first section in an inferior side of the receiver, and a cut-out in a lateral side. During attachment, the anchor may be positioned relative to the receiver such that a head of the anchor may be inserted into the first section and a shaft of the anchor may be inserted into a second section. After insertion, the anchor is rotated to move the shaft out of the cut-out while the head remains in the receptacle. A wedge is then attached to the receiver over the cut-out to prevent the anchor from escaping.
The various aspects of the various embodiments may be used alone or in any combination, as is desired.
The present application is directed to connectors for attaching an elongated member to a bone.
The receiver 20 may include a generally cylindrical shape with a curved exterior surface and a pair of opposing arms 23 that extend outward from a base 22. The arms 23 may include threaded sections 25 that engage with the fastener 60. The threaded sections 25 may be positioned on an interior surface of the arms 23 as illustrated in
The base 22 includes a superior side 26, an inferior side 27, and a sidewall 28 therebetween. A receptacle 80 is positioned within the base 22 and is sized to receive the head 41 of the anchor 40. The superior side 26 may form a lower extent of the channel 21 and be curved to match the shape of the elongated member. The inferior side 27 may include a rounded shape to facilitate movement relative to the anchor 40.
The receptacle 80 is positioned within the base 22 and includes a width W1. As illustrated in
The opening 24 extends through the inferior side 27 of the receiver 20 and leads into the receptacle 80. The opening 24 may also be centered on the longitudinal axis LR of the receiver 20. The opening 24 includes a smaller width than the receptacle 80.
One or more recesses 82 are positioned on the inferior side 27 of the receiver 20 to allow increased angulation of the anchor 40 relative to the receiver 20 once the connector 10 is assembled. Each recess 82 includes an angled surface that angles outward away from the longitudinal axis LR a greater amount than the adjacent sections of the inferior side 27. The recesses 82 may be evenly spaced around the opening 24, such as the embodiment of
The cut-out 30 extends through the sidewall 28 of the receiver 20 and into the receptacle 80. The cut-out 30 is in communication with the opening 24 such that the cut-out 30 and opening 24 together form a single, continuous opening that leads into the receptacle 80. The cut-out 30 may include a superior side 31 and opposing lateral edges. The cut-out 30 includes a width that is greater than a width of the anchor shaft 42. The width of the cut-out 30 may also be smaller than a width of the anchor head 41. The superior edge 31 may include a curved shape that matches a shape of the shaft 42. In one embodiment, the superior edge 31 is positioned in closer proximity to the inferior side 27 of the receiver 20 than the superior side 26 of the receiver 20. Slots 32 may extend outward from the cut-out 30 and into the interior of the sidewall 28. The slots 32 may extend along one or more of the superior side 31 and lateral sides as illustrated in
The wedge 50 fits in the cut-out 30 and prevents escape of the anchor head 41. The wedge 50 may completely fill the cut-out 30, or just a partial section of the cut-out 30. As best illustrated in
Wedge 50 may further include a recess 53 that allows for additional angulation of the anchor 20. As best illustrated in
The anchor 40 includes a head 41 and a shaft 42. The head 41 includes a spherical shape with a flat top 43 that is positioned opposite from the shaft 42. As illustrated in
The fastener 60 secures the elongated member in the channel 21 of the receiver 20.
Crown 70 is configured to be positioned in the receiver 20 and includes an annular shape with a central opening 71. When positioned in the receiver 20, the opening 71 aligns with the second opening 29 to provide access to the attachment structure 44 of the anchor 40. Crown 70 includes a superior surface 73 and an inferior surface 74. The surfaces 73, 74 may be flat, or may include one or more undulations. Crown 70 may include a shoulder 74 that corresponds with the notches 81 in the receptacle 80 as illustrated in
One or more biasing members 89 may extend into the receptacle 80 as illustrated in
The biasing members 89 are each positioned in a cavity 88 formed in an interior wall of the receiver 20. The cavities 88 and biasing members 89 may be positioned at different locations around the receiver 20. In one embodiment, the cavities 88 and biasing members 89 are positioned opposite from a non-recessed section of the receiver 20. Also, the cavities 88 and biasing members 89 may be positioned above one or more of the recesses 82. The cavities 88 are positioned for the biasing members 89 to contact against the rounded section of the head 41, and not to contact against the flat top 43. Contact against the flat top 43 may prevent the anchor 40 from rotating back to a centered position with the longitudinal axis LA of the anchor 40 aligned with a longitudinal axis LR of the receiver 20.
The number of cavities 88 and biasing members 89 may vary. In one embodiment, two cavities and biasing members 89 are positioned about 120 degrees apart. In another embodiment, a single cavity and biasing member 89 is positioned in the receiver 20. One or more cavities and biasing members 89 may also be positioned on the wedge 50.
Once the head 41 is in the receptacle 80, the anchor 40 is rotated relative to the receiver 20 such that the axes LA, LR are in closer alignment. In one embodiment as illustrated in
To prevent the anchor 40 from escaping from the receiver 20, the wedge 50 is attached to the receiver 20. In one embodiment, the wedge 50 is placed below the receiver 20 and inserted through the inferior side 27 and moved upwardly into the cut-out 30. This direction of insertion seats the flange 54 of the wedge 50. In one embodiment as illustrated in
Once positioned relative to the cut-out 30, the wedge 50 is attached to the receiver 20. The attachment may be preformed by spot welding, adhesives, mechanical fasteners, and various other methods. Once attached, the wedge 50 prevents the head 41 from escaping out of the receptacle 80. The wedge 50 is sized to reduce the remaining size of the opening 24 to be less than that of the head 41. The remaining opening 24 may be symmetrical or non-symmetrical. After the wedge 50 is attached to the receiver 20, the anchor 40 may still be movable relative to the receiver 20 to allow adjustment of the angular position of the anchor 40.
The connector 10 may be used in a variety of contexts to attach an elongated member to a bone. Examples include but are not limited to attaching a vertebral rod to a vertebra and attaching a rod to a fractured femur.
The receiver 20 and wedge 50 may be formed from a variety of materials including but not limited to titanium, stainless steel, carbon fiber, and polyetheretherketone (PEEK). The receiver 20 and wedge 50 may be formed from the same or different materials.
Spatially relative terms such as “inferior”, “superior”, “lower”, “over”, and the like, are used for ease of description to explain the positioning of one element relative to a second element. These terms are intended to encompass different orientations of the device in addition to different orientations than those depicted in the figures. Further, terms such as “first”, “second”, and the like, are also used to describe various elements, regions, sections, etc and are also not intended to be limiting. Like terms refer to like elements throughout the description.
As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.
The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. The wedge 50 may be smaller than the size of the cut-out such that it does not extend completely across the cut-out 30. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.
