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

J Bone Joint Surg Am · Jul 16 2026 · Recent

Elder BD, Mundis G, Eastlack R, Arrigoni P, Franke J, Lee R, et al.

San Diego Spine Foundation, San Diego, California

Spine

SUMMARY — THE REDUCTIONIn a randomized trial of 222 patients, adding triangular titanium implants above S2AI pelvic screws significantly reduced pelvic fixation failure (11% vs 20.4%) in multilevel spinal fusion without affecting alignment.
Abstract, as published

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.

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