Abstract: A coupled pair of retractors which are coupled at the distal end to allow the handles at the proximal end to be urged apart to increase the distance between handles to allow for direct line of sight to the surgical site while also allowing the use of curved tools and curved access to the surgical site. A cannula with a cross section taken perpendicular to a straight portion of the cannula that increases between the proximal end of the cannula and the distal end of the cannula allows for direct line of sight to the surgical site while also allowing the use of curved tools and curved access to the surgical site. These tools may be used in a postero-lateral approach from an incision in the back to a target position adjacent to the spine.

Abstract: A system for accessing a spine from a curved postero-lateral approach may include a curved cannula positioned along a curved path from an opening in the skin to a location proximate the spine. The location may be at the L4-L5 vertebral level, and the curved path may lie in a plane oblique to the transverse, coronal and sagittal planes of the spine, and avoid the iliac crest. A targeting post may be inserted adjacent the spine to determine the location, and a guide member may be inserted to establish the curved path. A micrometer assembly may adjust a cephalad-caudal displacement between the post and the guide member. One or more intermediate cannulas may be inserted over the guide member to dilate tissues prior to insertion of the main cannula. An interbody device may be implanted into an intervertebral space through the cannula.