Polyaxial bone screw with lateral connector

#The present invention relates generally to an apparatus for internal fixation of the spine and, more specifically relates to a polyaxial screw body including a lateral connector integral with the screw body and useful for connecting the screw body to other components of a pelvic fixation device.

#Certain spinal conditions, including a fracture of a vertebra and a herniated disc, indicate treatment by spinal immobilization. Several methods of spinal joint immobilization are known, including surgical fusion and the attachment of pins and bone plates to the affected vertebras. One known device is a bone interface anchor inserted into at least two spaced-apart vertebras, with a stabilization rod interconnecting the two or more anchors to stabilize the vertebras spanned by the anchors.

#During surgical implantation of these prior art stabilization systems, the surgical site is crowded with tissue masses, sponges, and other surgical implements that obstruct access to the anchors. A challenge with current polyaxial screw systems is that lateral connectors typically provide fixation between stabilization rods and a pelvic screw in a spinal construct. However, at the S1-L5 junction, it can be exceedingly difficult or impossible to attach an S1 pedicle screw, L5 pedicle screw, and a lateral connector to a stabilization rod due to special limitations present at the S1-L5 junction. It has been demonstrated that the integrity of the spinal construct is decreased if either the S1 or the L5 pedicle screw is not used. The present invention combines a polyaxial screw body with a lateral connector in a single device that ensures that all necessary fixation points can be achieved in a spinal construct at the S1-L5 junction.

#FIG. 1A is a perspective view of an embodiment of a polyaxial screw body.

#FIG. 1B is an elevational view of the polyaxial screw body of FIG. 1A.

#FIG. 1C is an elevational view of another embodiment of a polyaxial screw body.

#As used herein, the term “longitudinal” refers to a direction oriented generally parallel to an imaginary centerline of a lumen disposed through a body member, as further described herein below. The terms “lateral” and “transverse” refer to being oriented generally in any direction other than parallel to longitudinal.

#Continuing with FIG. 5, a polyaxial pedicle screw 108 of the current invention is attached to the other pedicle of the L5 vertebra. In contrast to the conventional polyaxial pedicle screw 106, the polyaxial pedicle screw 108 of the current invention includes a lateral connector 116 extending integrally therefrom. The integrally extending lateral connector 116 facilitates a proper connection between the stabilization rod 110b and the polyaxial pedicle screw 104 via the polyaxial pedicle screw 108.

#An embodiment of an improved polyaxial screw body 300 comprises a body member 301 and a lateral connector 302 extending integrally from the body member 301, as illustrated in FIGS. 1A and 1B. In one embodiment, the body member 301 includes a side wall 303 that defines a lumen 305 disposed longitudinally through the body member 301 and having first and second ends proximate first and second ends 307, 309 of the body member 301. In this embodiment, a pedicle screw 311 may extend from the lumen 305 through an opening 313 at the second end of the lumen 305. The opening 313 includes an interior surface disposed in the side wall 303 thereabout. The interior surface is adapted to accommodate a head portion of the pedicle screw 311. In one embodiment, the opening 313 includes a curvilinear interior surface disposed in the wall 303 thereabout. The curvilinear interior surface may be adapted to accommodate a head portion, for example, a spherical head portion of a pedicle screw 311. An example of a body member 301 that may be useful in the present invention is disclosed in Purcell et al., U.S. Pat. No. 7,377,923, which is incorporated by reference in its entirety herein.