Current Treatment Options for U-Shaped Sacral Fractures

Introduction: U-shaped sacral fractures are defined by a transverse fracture of the sacral body and bilateral vertical fractures of the sacral bone. As there is no consensus on a single treatment paradigm in the current literature, the objective of this study is to review management options and to propose our recommended approaches for these highly unstable injuries.

Methods: Articles were identified within the PubMed database using keywords U-shaped sacral fracture, spinopelvic/lumbosacral dissociation, Denis zone 3/AOS type C fracture, sacral insufficiency fracture. Two case presentations involving operative fixation of U-shaped sacral fractures were included.

Results: Surgical fixation of U-shaped sacral fractures demonstrates improved outcomes in the setting of polytrauma compared to a nonoperative approach. Nondisplaced U-shaped sacral fractures can be stabilized with iliosacral screws in isolation. Open repair has demonstrated better neurological outcomes than minimally invasive posterior pelvic ring fixation for fractures with minimal displacement in patients with neurological deficits. For displaced Denis zone 3 and AO type C fractures, spinopelvic fixation can be accomplished with placement of S2 alar-iliac screws or using pedicle screws placed at the L4, L5, or L5, S1 vertebral pedicles in addition to a cross-linking long screw in the ileum. Triangular osteosynthesis combines lumbopelvic fixation with iliosacral screws or transiliac-transsacral screws and allows for immediate weight bearing as well as early mobilization.

Conclusion : Non-displaced and most minimally displaced U-shaped sacral fractures can be stabilized using iliosacral screws alone while displaced fractures should be corrected with spinopelvic instrumentation due to a greater degree of instability. We have observed success with placement of L4 to pelvis instrumentation involving a minimum of 4 pelvic screws. Bilateral sacral-iliac (SI)/trans-sacral screws, S1A1/S2 alar-iliac (S2AI) screws, or combinations of both allow for exceptional lumbo-pelvic stabilization. It is also feasible to substitute S1AI or S2AI in lieu of SI/trans-sacral screw for pelvic fixation.