Obstructed spinopelvic fixation in the setting of a triangular titanium sacroiliac fusion implant: a case description

Achieving lumbosacral fusion through spinopelvic fixation is an important and challenging aspect of spinal deformity surgery. Numerous instrumentation techniques are available, with iliac screws and S2-alar-iliac (SRAI) screws being most commonly used today. However, the increasing popularity of minimally invasive sacroiliac (SI) fusion as a common procedure performed for SI joint pain presents a distinct challenge in complex adult deformity cases requiring iliac screw fixation. We report a case of a 71-year-old female with a longstanding history of spinal deformity status-post T11-L5 fusion and a subsequent right-sided SI joint fusion who presented with sagittal imbalance. The SI joint fusion implant obstructed the pathway for spinopelvic fixation. Spinopelvic fixation was achieved by burring a pathway through the SI joint implant. The increasing popularity of minimally invasive SI fusion as a common procedure performed for SI joint pain presents a distinct challenge in complex adult deformity cases requiring iliac screw fixation. This is the first report in the literature describing a technique for spinopelvic fixation in the setting of screw obstruction due to an instrumented SI joint.