CROSS-BRACED BILATERAL SPINAL ROD CONNECTOR

A spinal rod connector apparatus for use with spinal implantation rods and methods of securing implantation rods using a cross-braced bilateral spinal rod connector apparatus. The spinal rod connector apparatus comprises a central member having two or more extension legs. The extension legs can be of varying lengths and disposed at varying angles with respect to the monolithic central member, depending upon physiological sizing requirements. Attached to each extension leg is a connecting member capable of connecting to a bilateral spinal rod construct.

DETAILED DESCRIPTION

FIG. 1illustrates an embodiment of a spinal rod connector apparatus (10). Here, a monolithic central member (1) has four extension legs (2). By forming the central member (1) and the extension legs (2) from a monolithic biocompatible material, such as surgical stainless steel or titanium, the strength and rigidity of the connector apparatus can be increased. In addition, by eliminating a mechanical interface between the central member (1) and the extension legs (2), the potential for weakening, metal fatigue, or loosening of the interface between the central member (1) and the extension legs (2) can be reduced. This improves the effective lifetime of the device (10).

Attached to each extension leg (2) is a connecting member (3) comprising a set-screw (4) and a slot (5). Each connecting member (3) is capable of translating along the longitudinal axis of the associated extension leg (2). Further, each connecting member (3) is capable of complete rotation about the axis of the corresponding extension leg (2).

FIGS. 2-7illustrate embodiments of the connector apparatus (10) as used in a bilateral spinal rod construct. Here, each connecting member (3) is provided with a slotted opening (5) capable of receiving a spinal rod (6). InFIGS. 2-7, the connecting members (3) are engaged with the spinal rods (6), allowing the connector apparatus (10) to span the unsupported distance between the spinal rods in a cross-braced fashion. Once aligned in the desired position, each connecting members (3) can be semi-permanently locked in said position by tightening of the associated set-screw (4). As set screw (4) is tightened, it pushes against the spinal rod (6), locking it in place while simultaneously fixing the axial and longitudinal position of the connecting member (3). By utilizing one set screw (4) per connecting member (3), complexity and time required for installation of this device is reduced. The head of the set screw (4) has a recess dimensioned and sized to receive a drill bit or screwdriver so that the set screw (4) can be tightened or loosened to the locked or unlocked position, as needed by the surgeon.

FIG. 8illustrates the capability of the connecting members (3) to translate along the longitudinal axis of the extension legs (2) and rotate about the extension legs.

FIG. 9illustrates a detailed view of an embodiment of a connecting member (3) engaging with a support rod (6). The support rod (6) is inserted through the slot (5) and semi-permanently engaged in position by tightening of the set screw (4).

FIGS. 10 and 11illustrate a cross-sectional view of the inner mechanism of an embodiment of the connecting member (3) used for the extension leg (2) and support rod (6) attachment. The connecting member (3) includes a connection aperture (105) through which an extension leg (not shown) can be received. A set screw (4) is depicted at the superior end (110) of the connecting member (3). The set screw (4) also interfaces with a side of the connection aperture (105) such that the set screw (4) can be driven against an extension leg (2) by applying a torque to the set screw (4). Also depicted inFIG. 10is a compression saddle (7) that is located on an opposite side of the connection aperture (105) from the set screw (4). The compression saddle (7) interfaces with the extension leg (2) such that when a compressive force is applied to the extension leg by the set screw (4), the compression saddle (7) is driven downwards towards the slot (5). If a spinal rod (6) is located within the slot (5) (e.g., when the connecting member (3) is being attached to the spinal rod (6), the downward force of the compression saddle (7) will lock the connecting member (3) to the spinal rod (6). Thus, by driving the set screw (4) with an appropriate torque, the connecting member (3) will lock the position of the extension leg (2) with respect to the spinal rod (6) into a rigid assembly. Prior to tightening, the connecting member (3) is free to rotate about the extension leg (2) and slide along the spinal rod (6). This provides a degree of freedom for the surgeon to adjust the device to suit the specific needs of the patient. Once suitable adjustments are made, the device is tightened as described above.

FIGS. 12-13illustrate embodiments of a support rod connector apparatus with a central pivot locking mechanism. Here, the central member (1) comprises a central pivot locking mechanism (8). Further, the central member has four extension legs (2). Attached to each extension leg (2) is a connecting member (3) comprising a set-screw (4) and a slot (5). Each connecting member (3) is capable of translating along the longitudinal axis of associated extension leg (2). Further, each connecting member (3) is capable of complete rotation about the axis of the associated extension leg (2).FIG. 12illustrates that the angle (α) between the extension legs (2) is relatively small, whereasFIG. 13illustrates a relatively larger angle (β) between the extension legs (2).

FIG. 14illustrates a detail view of the central member (1), wherein the central member (1) comprises a central pivot locking mechanism (8). The central pivot locking mechanism (8) provides for ease of use when surgeons need to adjust the angles angle between the extension legs (2). The central pivot locking mechanism includes a releasable locking mechanism, such as a set screw (115). When the releasable locking mechanism (8) is released (e.g., when the set screw (115) is loosened), the angle between the extensions legs (2) can be adjusted within a range of angles, depending up the preference of the surgeon, the anatomy of the patient, or the location of existing pedicle screws along the bilateral spinal rods. According to another embodiment, each of the extension legs can be bent, turned, or otherwise adjusted to accommodate the curvature of the spine, and thus the curvature of the corresponding bilateral spinal rods.