How bilateral iliolumbar fusion increases the stability of horizontal osteosynthesis in unstable pelvic ring injuries?

Objective: In type C pelvic ring injuries, the operative stabilization of the posterior ring is absolutely indicated. There exist four different types of operative methods: iliosacral screw fixation, transsacral plate synthesis, ventral plate fixation (primarily for sacroiliac luxations), and local plate synthesis performed on the dorsal cortex of the sacrum. In our current article, we analyzed the stability of fixation methods used together with bilateral iliolumbar techniques.

Methods: We analyzed a finite element pelvic model attached to lumbar 4-5 vertebrae. By imitating a standing position on two feet, we measured the differences in tension and displacement in T1 and T2 thoracic vertebrae fractures with and without iliolumbar fusion in cases of iliosacral screw fixation, transsacral plate synthesis and KFI-H (small fragment-H) plate synthesis.

Results: The osteosynthesises reinforced via Galveston technique were rather stable; the amount of displacement measured in the fracture gap was significantly less than in the cases without iliolumbar fusion. The tension in the implants were below the allowed values, therefore they were capable of withstanding the imposed loads without permanent deformation.

Conclusions: In unilateral pelvis injuries, if a non-weight bearing status cannot be achieved on the injured side, unilateral iliolumbar fusion reinforcement is justified, since the contralateral lower limb must also be non-weight bearing due to the pelvis injury itself. In the case of the most unstable sacrum fracture--"jumper's fracture", bilateral iliolumbar fusion is necessary, in which case the patient will be able to bear weight during the early postoperative period.