Patent Application
20070173827
The present application is directed to devices and methods for attaching a rod to a member, and more specifically, to connectors and methods providing multiple degrees of freedom for attaching a rod to a member.
The spine is divided into four regions comprising the cervical, thoracic, lumbar, and sacrococcygeal regions. The cervical region includes the top seven vertebral members identified as C1-C7. The thoracic region includes the next twelve vertebral members identified as T1-T12. The lumbar region includes five vertebral members L1-L5. The sacrococcygeal region includes nine fused vertebral members that form the sacrum and the coccyx. The vertebral members of the spine are aligned in a curved configuration that includes a cervical curve, thoracic curve, and lumbosacral curve.
A rod may be implanted to support and position a vertebral member in one or more of these regions. The rod extends along a section of the spine and is connected to the vertebral member with one or more anchors. The rod may have a curved configuration to conform to the curvature and contour of the spine.
An anchor is inserted into the vertebral member to connect the rod. Because the rod anchor cannot directly receive the anchor, a connector connects the rod to the anchor. The connector includes a first attachment that connects to the rod, and a second attachment that connects with the anchor. It is often difficult for the connector to accommodate both the rod and the anchor. The vertebral member may have a variably contoured surface that results in the rod and the anchor each being positioned at a variety of angular orientations.
Rods may be used in other medical applications, such as treatment of orthopedic traumas. In one embodiment, rods are internally situated within the patient and should be anchored with an internal fixation device. In other embodiments, rods may be externally situated and require external fixation devices to anchor and locate the rod.
The present application is directed to devices and methods for attaching a rod to an anchor. The device may include a connector housing having a first channel sized to receive the rod and a second channel sized to receive the anchor. A contact member may be sized to at least partially extend within the second channel. Insertion of the anchor into the second channel may cause the contact member to extend through an opening in the connector housing and into the first channel. The contact member may contact the rod and attach it to the connector housing. A fastening member may operatively connect the anchor to the connector housing. The contact member may accommodate the anchor at a variety of angular orientations within the connector housing.
The present application is directed to connectors and methods of connecting a rod with an anchor. In one embodiment, the connector includes a housing that extends between the rod and the anchor. The connector may include adjustable elements that accommodate the anchor and rod at a variety of different angular orientations. In one embodiment, the connectors and methods are useful for attaching a rod to a vertebral member. The connectors and methods may also be used in other embodiments, such as treatment of orthopedic trauma applications. The connectors and methods may be applicable internally within the body, or for external fixation.
One embodiment of a connector 10 is illustrated in
Housing 20 further includes a second channel 75 for attachment with the anchor 200. In one embodiment, the second channel 75 is substantially transverse to the orientation of the first channel 25 that houses the rod 100. In the embodiment illustrated in
In one embodiment, the cavities 21, 23 extend into the housing and connect together at a neck 22 such as illustrated in the embodiments of
In one embodiment, the first and second channels 25, 75 are positioned within the housing 20 in an overlapping substantially transverse configuration. This overlap forms an opening 24 sized for a portion of the contact member 40 to extend through (as will be explained in detail below). Opening 24 may be positioned at a variety of depths within the housing 20 between the first and second faces 26, 27. In one embodiment, the first cavity 21 extends into the channel 25 forming an opening 24.
Contact member 40 is sized and positioned within the first cavity 21. A first edge 41 may be urged towards the neck 22, and a second edge 42 may be urged towards the first face 26. In one embodiment, member 40 is positioned completely within the first cavity 21 (i.e., the length of the member 40 is less than a length of the cavity 21 causing the second edge 42 of the contact member 40 to be positioned inward of the first face 26). In another embodiment, the member 40 extends outward from the first cavity 21.
In one embodiment, the contact member 40 includes a partially convex shape. This may include the entirety of the contact member 40 being convex, or a limited section being convex. One embodiment features the contact member 40 having a spherical shape. In one embodiment as illustrated in
In one embodiment, a collet 50 extends over the anchor 200 and within the aperture 43 of the contact member 40. In one embodiment as illustrated in
The second section 52 includes a flared configuration that enlarges outward away from the first section 51. The flared configuration may be formed from substantially straight or curved sidewalls. Slits 53 may extend through a portion or entirety of the second section 52 to provide flexibility. Slits 53 may further extend into the first section 51. An interior section 54 extends through the collet 50 and is sized to receive the anchor 200.
In one embodiment in a vertebral application, a variety of different anchors 200 may attach the rod 100 to the vertebral member. In one embodiment, anchor 200 includes a non-threaded first section 201 and a threaded second section 202. The non-threaded section 201 may extend along the length of the anchor 200 a variety of distances. In one embodiment as illustrated in
Rod 100 may have a variety of lengths. In one embodiment used in a vertebral application, rod 100 includes a length to extend along the spine and support one or more vertebral members. Rod 100 may include a variety of cross-sectional shapes, sizes, and materials depending upon the context of use. In one embodiment as illustrated in
Fastening member 30 includes a threaded aperture 31 that attaches with the threads 55 on the collet 50. In one embodiment, the fastening member 30 is positioned on the second face 27 of the housing 20 when connected with the collet 50. In one embodiment, a flange 32 extends radially outward from the aperture 31 and includes a width to extend over the second cavity 23. In one embodiment, fastening member 30 is a nut having a polygonal head with a threaded interior.
The collet 50 and inserted anchor 200 are further positioned within the aperture 43 of the contact member 40. When inserted into the first cavity 21, the contact member 40 seats against the interior sidewalls of the first cavity 21. This positioning further causes the contact member 40 to extend through the opening 24 and into contact with the rod 100. This contact between the contact member 40 maintains the rod 100 fixedly connected to the housing 20.
One embodiment features a vertebral application. The method of connecting the rod 100 and anchor 200 comprises initially mounting the anchor 200 to a vertebral member. The anchor 200 is mounted at a location in proximity to the vertebral rod 100. The threaded section 202 seats within the vertebral member with the non-threaded section 201 extending outward from the vertebral member. The rod 100 is inserted into the channel 25 within the housing 20, and the housing 20 is moved along the length of the rod 100 to a point in proximity to the anchor 200.
The collet 50 is connected to the anchor 200 by inserting the first section 201 that extends out from the vertebral member into the interior section 54 of the collet 50. In one embodiment, collet 50 is inserted onto the anchor 200 with the top end of the first section 201 being substantially aligned with a top edge of the collet first section 51. In another embodiment, collet 50 is inserted over the anchor 200 to a lesser extent. The contact member 40 is then inserted onto the collet 50 and anchor 200. Specifically, aperture 43 of the contact member 40 is placed over the collet first section 51 and anchor 200. In one embodiment, collet 50 can be inserted into the aperture 43 until the second edge 42 contacts the flared second section 52.
The collet 50 and anchor 200 are then inserted into the housing 20. Specifically, the collet first section 51 is inserted through the second channel 75 including the first cavity 21, neck 22, and second cavity 23 until the first section 51 extends outward above the second face 27 of the housing 20. Fastening member 30 is then connected to the collet first section 51. In one embodiment, the threaded aperture 31 of the fastening member 30 engages the threads 55 on the first section 51 of the collet 50.
As the collet first section 51 is inserted through the housing 20, the contact member 40 is moved into the interior of the first cavity 21. This movement may be caused by manually inserting the first section 51 through the housing 20, and/or by threadingly engaging the fastening member 30 onto the collet 50. In another embodiment, a ratcheting mechanism moves the collet 50 into the channel 75. This embodiment may lock the collet 50 within the channel 75 and include a release clip to loosen the collet 50. Movement of the contact member 40 into the first cavity 21 causes the contact member 40 to move through the opening 24 and contact the rod 100. The contact member 40 may move into the first cavity 21 until it seats against the inner surfaces of the cavity 21, until it is prevented from further movement because of contact with the rod 100, or both. In one embodiment as illustrated in
In one embodiment, the flared second section 52 compresses inward as the collet 50 moves through the contact member 40. This compression may further lock the collet 50 to the contact member 40, and lock the collet 50 to the anchor 200.
In one embodiment as illustrated in
In one embodiment as illustrated in
In one embodiment as illustrated in
In one embodiment, the collet 50 is maintained on the anchor 200 by a compressive force applied by the collet 50. In one embodiment, the collet 50 is constructed of a flexible material that stretches during insertion of the anchor 200 and applies a holding force. In another embodiment, insertion of the contact member 40 onto the flared section 52 of the collet 50 causes the flared section 52 to move inward and exert a compressive force onto the anchor 200.
In one embodiment, contact member 40 is constructed of a rigid material. In another embodiment, contact member 40 is constructed of a resilient material that elastically deforms when locked against the rod 100.
Contact member 40 mounts onto the anchor 200. In one embodiment, an aperture 43 having a substantially constant width extends through the contact member 40. Slits 45 may be formed in the contact member 40. In one embodiment, the first end 201 of the anchor 200 includes a tapered width that grows towards the threaded section 202.
Use of the embodiment of
Contact member 40 includes a variety of shapes. In the embodiment of
The first and second channels 25, 75 may extend through the housing 20 at a variety of different positions. In one embodiment, the first channel 25 that receives the rod 100 is substantially perpendicular to the second channel 75 that receives the anchor 200. In one embodiment, a second opening (not illustrated) extends between the first and second channels 25, 75. In one embodiment, the openings are spaced apart within the housing 20. In one embodiment, the first opening 24 is positioned within the first cavity 21 and a second opening is positioned within the second cavity 23. In one embodiment, multiple openings are positioned within a single cavity 21, 23.
In one embodiment, channel 75 is symmetrical such that the connector can be assembled from either direction. In one embodiment, channel 75 includes two symmetrically formed convex surfaces with substantially equivalent internal geometric features.
Spatially relative terms such as “under”, “below”, “lower”, “over”, “upper”, 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.
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 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.
