Spinopelvic Fixation in Complex Sacral Fractures.

Abstract

Vertically unstable and complex bilateral sacral fractures are a result of high-energy mechanisms that are often associated with other injuries1-19. Vertically unstable sacral fractures result in the separation of the hemipelvis from the lumbar spine, whereas complex bilateral fractures result in a complete dissociation of the appendicular and axial skeleton. Recently, the surgical treatment algorithm for these fractures has changed, with an increasing number of surgeons advocating for the use of spinopelvic fixation or triangular osteosynthesis, a combination of spinopelvic fixation along with sacroiliac or transsacral screw fixation, to increase the stability of the construct and to allow for early weight-bearing with decreased concern for secondary displacement1-19. ### Osseous and Ligamentous Anatomy The sacrum is a rhomboid-shaped bone consisting of five fused segments that is the lowest functional section of the spinal column and acts as the keystone of the pelvic ring20. When force enters the sacrum, it propagates laterally across the sacroiliac joints into the pelvis. Because of the shape of the sacrum and the orientation of the sacroiliac joints, axial forces stabilize the sacroiliac articulation in the pelvic outlet plane; however, in the pelvic inlet plane, the osseous configuration lacks inherent stability. The interosseous ligaments and posterior sacroiliac ligaments provide the majority of the intrinsic stability. Comparatively, the sacrospinous and sacrotuberous ligaments provide the extrinsic stability21. The osseous architecture of the sacrum can be …