The flying buttress construct for posterior spinopelvic fixation: a technical note

We adopted a new spinopelvic fixation system, in which iliac screws are side-to-side connected to the posterior thoracolumbar rod construct, independent of the angle between the rod and the iliac screw. Open angled parallel connectors are used to connect short iliac rods from the posterior rod construct to the iliac screws at both sides. The construct resembles in form and function an architectural Flying Buttress, or lateral support arches, used in Gothic cathedrals.Three different cases that illustrate the Flying Buttress construct for spinopelvic fixation are reported here with the clinical details, radiographic findings and surgical technique used.The Flying Buttress construct may offer an alternative surgical option for spinopelvic fixation in circumstances wherein coronal or sagittal balance cannot be achieved, for example in cases with significant residual pelvic obliquity, or in revision spinal surgery for failed lumbosacral fusion.Posterior fusion of the spine to the pelvis in paediatric and adult spine deformity poses many challenges to the spine surgeon. Spinopelvic fusion is indicated in neuromuscular scoliosis with a pelvic obliquity of more than 15 degrees, stabilizing adult fixed lumbosacral coronal plane curve, reduction of high grade spondylolisthesis, spinal pseudarthrosis (Charcot spine), surgical treatment of sacral tumours requiring (partial) sacrectomy, or as a tool to extend failed lumbosacral fixation [1-4]. A solid spinopelvic fusion can be achieved by a rigid posterior spinopelvic fixation that includes posterior lumbosacral spinal instrumentation with extension to the ilium [4].The original surgical technique of posterior spinopelvic fixation has been developed by Allen and Ferguson in the 1980s [5-7]. They introduced smooth bended iliac rods that included the posterior instrumentation and the pelvis for the treatment of idiopathic adolescent scoliosis and revision scoliosis. The rods were inserted from the posterior superior iliac spine i