Bilateral open sacroiliac joint fusion during adult spinal deformity surgery using triangular titanium implants: technique description and presentation of 21 cases

Abstract

OBJECTIVE Pelvic fixation enhances long constructs during deformity surgery. Subsequent loosening of iliac screws and pain at the pelvis occur in as many as 29% of patients. Concomitant sacroiliac (SI) fusion may prevent potential pain and failure. The objective of this study was to describe a novel surgical technique and a single institution’s experience using bilateral SI fusion during adult deformity surgery with S2-alar-iliac (S2AI) screws and triangular titanium rods (TTRs) placed with navigation. METHODS The authors reviewed open SI joint fusions with TTR performed between August 2019 and March 2020. All patients underwent lumbosacral fusion through a midline approach and bilateral S2AI pelvic fixation in the caudal teardrop, followed by TTR placement just proximal and cephalad to the S2AI screws using intraoperative CT imaging guidance. RESULTS Twenty-one patients were identified who received 42 TTRs, ranging in size from 7.0 × 65 mm to 7.0 × 90 mm. Three TTRs (7%) were malpositioned intraoperatively, and each was successfully repositioned during index surgery without negative sequelae. All breaches occurred in a medial and cephalad direction into the pelvis. Incremental operative time for adding TTR averaged 8 minutes and 33 seconds per implant. CONCLUSIONS Image-guided open SI joint fusion with TTR during lumbosacral fusion is technically feasible. The bony corridor for implant placement is narrower cephalad, and implants tend to deviate medially into the pelvis. Detection of malpositioned implant is aided with intraoperative CT, but this can be salvaged. A prospective randomized clinical trial is underway that will better inform the impact of this technique on patient outcomes.