Stand-alone anterior interbody fusion for substitution of iliac fixation in long spinal fixation constructs

摘要

Introduction The use of distal sacral anchorage solely, in long spinal fusions, may lead to substantial complications. Extending the fixation down to the ilium and the addition of anterior column support are both used to facilitate construct stability and improve fusion rates. In the current study, we aimed to determine whether supplementation of long thoracolumbar fixation constructs with stand-alone anterior interbody fusion (ALIF) cage with embedded screws can eliminate the biomechanical need for iliac screws fixation biomechanically.Methods Seven lumbopelvic human cadavers (LI-full pelvis) were used. All specimens were tested with the following fixation constructs: bilateral Ll-Sl, bilateral Ll-Sl with unilateral iliac screw, and bilateral Ll-Sl with bilateral iliac screw. The three constructs were tested with and without the addition of stand-alone ALIF cage. We evaluated the multidirectional rigidity and the axial SI screw strain.Results The addition of an ALIF cage solely did not affect rigidity and resulted in mixed SI screw strain results. One iliac screw was superior to ALIF in rigidity and inferior in SI screws strain. Bilateral iliac fixation produced similar rigidity and lower SI screws strain than unilateral iliac fixation. When ALIF was combined with bilateral iliac screws, it resulted in equal rigidity and lower SI screws strain.Conclusion Our results do not support stand-alone ALIF cage as a substitute for iliac fixation in in long posterior lumbosacral fusion. They do support the use of stand-alone ALIF for the supplementation of bilateral iliac fixation in long lumbosacral fusions.