Perpendicular rod connector for spinal fixation device

#This invention relates to spinal fixation devices and has specific reference to a spinal rod system which connects a spinal rod to a primary fixation rod and positions the two rods at a ninety degree relationship to one another.

#It is well known in the correction of spinal deformities to affix a rod or pair of rods longitudinally to the spinal column with a plurality of spinal hooks or pedicle screws. Tension or compression force is applied to the rod between each consecutive screw or hook to correct the deformity. It is further common to cross link or interconnect the longitudinal rods to provide additional stabilization or to engage the spinous process. During the surgical procedure to connect the spinal rods to the spine, the surgeon must bend the spinal rods to conform, generally, to the curvature of the spine. Quite often this requires the surgeon to bend the rod in three dimensions. Since the rods must be connected to a pedicle screw or spinal hook, the tolerances for the bend is exacting. The bending of the rods within the tight space available and to tolerance adds a significant amount of time to an already lengthy surgery.

#The spinal rod system and perpendicular rod connector of the invention provides for a first rod to be connected by two pedicle screws transverse to the spine across a vertebra. The perpendicular connector is then connected to the first rod anywhere along the rod. The longitudinal spinal rod is then connected to the perpendicular rod connector using common connectors. The perpendicular connector is slidable along the first rod. By using the perpendicular rod connector, the amount of bending and the tolerances required is reduced as the connector may be slid along the transverse rod to accommodate the longitudinal rod. Known pedicle screws may be used with a slight bend placed in the transverse rod to accommodate the spinal column. Alternatively, the pedicle screws may be bent slightly such that a straight transverse rod may be used. By using the perpendicular rod connector and transverse rod arrangement, the amount of bending required on the longitudinal rod may be reduced to thereby shorten the entire procedure.

#FIG. 1 is a perspective view of the invention connected to a vertebra represented by a solid block and the spinal rods partially shown.

#FIG. 2 is an elevational view of the invention with the spinal rods shown in cross section.

#FIG. 3 is an elevational view of the perpendicular rod connector of the invention.

#The preferred embodiments herein disclosed are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Rather, they are chosen and described to enable others skilled in the art to utilize their teachings.

#The perpendicular rod system 10 is illustrated connected to a block 8 for illustrative purposes only. Block 8 is in place of an actual vertebra well known in the art. Perpendicular rod system 10 includes a pair of pedicle screws 12 each including a threaded shaft 14 for turning into the pedicle of the vertebra and a head 16. Head 16 of each pedicle screw 12 forms a generally C-shaped seat. A rod 18 extends between each pair of pedicle screws 12 and is connected thereto by a sleeve 22 wedged into head 16 and maintained therein by a collar 24. Sleeve 22 and collar 24 engage in a ratchet manner such that collar 24 will not slide off of sleeve 22. As illustrated in FIGS. 1 and 2, rod 20 includes a central bend to conform to the outer geometry of the vertebra just above the spinous process.

#Perpendicular rod connector 24 includes a generally C-shaped body 26 defining a central opening 28. Opening 28 accommodates a spinal rod 30 with a sleeve 22 and collar 24 for securement of the rod to the connector 24. Body 26 includes a end wall 32. A pair of arcuate projections 34 extend from opposite side edges of said end wall 32 as illustrated best in FIG. 4. A small ledge 36 is formed adjacent each projection 34 in alignment with the distal tip of each projection 34. The distance between a distal tip of a projection 34 and its corresponding land 36 is slightly smaller than the distance between the distal tip and proximal portion 38 of the projection. Projections 34 are preferably integral with body 26 and may flex a small amount. A recess 40 is formed in each side 42 of body 26.