The Accurate Free-hand Placement of S2 Alar Iliac (S2AI) Screw

Achieving an osseous fusion across the lumbosacral spine is still challenging in spine surgery. For the long multisegmental fusion surgery, it is crucial to build a robust and substantial foundation, which sometimes necessitates the distal spinal fixation to the pelvis. The pelvic fixation technique involves advancing the screw through the alar, thereby providing more purchase across the sacroiliac joint and into the ilium. The S2 alar iliac screws can obtain immediate stability and proper biomechanical strength of constructs. Here we demonstrated our experience of how to place the S2 alar iliac screw accurately as well as some pitfalls and pearls of this technique.