Comparative Study of Two Surgical Techniques for Proximal Adjacent Segment Pathology after Posterior Lumbar Interbody Fusion with Pedicle Screws: Fusion Extension using Conventional Pedicle Screw vs Cortical Bone Trajectory-Pedicle Screw (Cortical Screw)

Abstract

To present a minimally invasive surgical technique using cortical bone trajectory pedicle screws (cortical screws [CS]) for adjacent segment pathology (ASP) after lumbar fusion surgery, and to thoroughly compare postoperative outcomes of surgical techniques with either a CS or conventional pedicle screws (PS) for ASP at a 1-year follow-up. Among 59 patients who underwent surgical treatment for proximal ASP after lumbar fusion surgery, 53 patients who met the study criteria (group A, 31 patients with conventional technique using PS; group B, 22 patients with minimally invasive technique using CS) were enrolled in the study. The primary outcome measure was the fusion rate at 1 year after surgery, and secondary outcome measures included patient satisfaction, clinical outcomes, radiologic outcomes, and surgical outcomes and complications. Fusion at 1 year postsurgery was achieved by 90% of the patients in group A with PS and 91% of those in group B with CS (P > 0.99). Patient satisfaction at 1 month postsurgery (P= 0.03) and pain intensity within 1 month postsurgery (P= 0.04) were significantly better in group B compared with group A. Regarding surgical outcomes, blood loss was significantly less, operation time and length of hospital stay were significantly shorter, and the incision was significantly shorter n group B than in group A. Other clinical parameters and outcomes were similar in the 2 groups. We suggest that a minimally invasive surgical technique using CS for ASP can be a viable alternative to a conventional surgical technique using PS.