Apparatus and devices for percutaneously extending an existing spinal construct

#The present disclosure contemplates devices and instrumentation for extending an existing spinal construct, and more particularly to procedures for achieving such extension minimally invasively, and preferably percutaneously.

#An emerging trend in spinal fixation is an increased incidence of adjacent disc degeneration subsequent to a previous fixation or fusion. This subsequent degeneration often requires fixation or fusion of additional levels of the spine. It is common in current techniques to expose the entire prior construct to access all of the existing bone fasteners to permit removal of the connecting member spanning the fasteners. The connecting member is removed and replaced with a longer member, such as a rod, to engage an additional bone fastener added at the new levels to be instrumented.

#This exposure of the prior fixation construct disrupts the existing construct complicating and lengthening the surgical procedure for adding the additional level of fixation. Such techniques are particularly problematic for a fixation construct spanning three or more vertebral levels. As such, there is a need for a device and method that facilitates the addition of further levels of fixation.

#FIG. 1 is a side elevation view of a portion of a patient's spine showing instrumentation disclosed herein to extend an existing ipsilateral spinal construct.

#FIG. 2 is an enlarged perspective view of the existing spinal construct and inline extension of FIG. 1.

#FIG. 3 is a top plan view of the existing spinal construct and inline extension of FIG. 1.

#For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the invention is thereby intended. It is further understood that the present invention includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the invention as would normally occur to one skilled in the art to which this invention pertains.

#Referring to FIGS. 1 and 2, an apparatus 10 is shown for extending an existing spinal construct 12 by adding an additional spinal construct 14 so as to increase the level of spinal fixation in a patient having previously undergone spinal fusion or other spinal surgery. The apparatus 10 generally comprises a rod connector extension assembly 16, a spinal implant extension assembly 18 and an access port 20. Rod connector extension assembly 16 includes a rod connector introducer 21 and a rod connector 22 comprising an elongate additional spinal rod 24 serving as a connecting element, as will be described. Spinal implant extension assembly 18 comprises an additional spinal implant 26 and an elongate extension 28 releasably coupled thereto. As illustrated, the existing spinal construct 12 as well as the additional spinal construct 14 are located ipsilaterly in the spine in this particular arrangement. As will be described in more detail below, rod connector introducer 21 comprises an elongate extension 30 releasably attached to the rod connector 22. Each of extension 28 and access port 20 is sized and of length to be accessible outside the patient's skin. The patient's skin or fascia is depicted as a phantom line S for illustrative purposes only, with the understanding that the level of the fascia relative to the fixation location on the spine will vary from patient to patient. Spinal construct 12 is an existing spinal construct in the sense that it has been installed prior to the installation of the additional spinal construct 14 which means that existing spinal construct 12 may have been placed in a previous surgical procedure or may be placed during the same surgical procedure as, but prior to, additional spinal construct 14.

#Turning to FIG. 2, further details of the additional spinal construct 14 and the existing spinal construct 12 are described. The existing spinal construct 12 comprises at least two previously implanted bone engaging implants 34 and 36 each of which is engaged respectively to a corresponding vertebra 38 and 40. Implants 34 and 36 are interconnected by an existing spinal rod 42 extending ipsilaterally therebetween. Existing spinal rod 42 includes an interconnecting portion 42a between implants 34 and 36 and an extending portion 42b projecting outwardly beyond implant 34, although extending portion 42b may also project in the opposite direction beyond implant 36. As shown, each of implants 34, 36 is a polyaxial pedicle screw having a lower threaded fastener portion 44, 46 for threaded engagement respectively in a pedicle of vertebra 38 and a pedicle of vertebra 40. Each implant 34, 36 includes a respective upper portion defining a yoke 48, 50 each yoke having a respective threaded slot 52, 54 for receipt of the existing spinal rod 42 therein. Set screws 55 and 57 respectively secure the existing spinal rod 42 to the implants 34 and 36.