Placement of Triangular Titanium Implants Suprajacent to Pelvic Fixation Screws Reduces Pelvic Fixation Failure in Multilevel Spinal Fusion: Results of a Randomized Controlled Trial.

Abstract

BACKGROUND The purpose of this study was to determine whether placement of triangular titanium implants (TTI) suprajacent to S2-alar-iliac (S2AI) pelvic fixation screws during multilevel spinal fusion surgery for adult spine deformity reduces pelvic fixation failures. METHODS This prospective, multicenter, international, partially blinded randomized clinical trial included 222 patients scheduled for multilevel spinal fusion surgery with S2AI-based pelvic fixation. In the S2AI+TTI group, the mean age was 64.9 years, 54.1% were female, 3.7% were Hispanic, 5.5% were African American, and 1.8% were Asian. In the S2AI-alone group, the mean age was 64.8 years, 58.4% were female, 3.5% were Hispanic, 7.1% were African American, and 0.9% were Asian. Subjects were randomized to pelvic fixation using S2AI screws alone versus S2AI+TTI. Scheduled follow-up included a 24-month full-spine radiograph and a high-resolution computed tomography (CT) scan, which was independently interpreted. RESULTS The primary composite radiographic end point (S2AI screw breakage, lucency, or pullout, or posterior spinal rod breakage distal to S1) occurred less frequently in the S2AI+TTI group than in the S2AI-alone group (11.0% versus 20.4%, p = 0.0415). Except for rod-screw dissociation and rod fracture distal to S1, all components of the primary composite end point occurred less frequently in the S2AI+TTI group. TTI placement did not affect sagittal or coronal spinal alignment parameters. The rate of rod fracture throughout the spinal construct was slightly higher in the S2AI+TTI group (9.2% versus 5.3%) but the difference was not significant (p = 0.197). CONCLUSIONS Placement of TTI suprajacent to S2AI screws reduced the rate of pelvic fixation failure in patients undergoing multilevel spinal fusion with pelvic fixation. LEVEL OF EVIDENCE Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.