Experimental research: biomechanical evaluation of iliosacral screw fixation effects on sacral and iliac screw strain in lumbosacral and lumbopelvic constructs
Murat K. Atalay, Sercan Capkin, Ali I. Kilic, Mustafa Celtik, Mustafa C. KosayBackground:
The biomechanical impact of iliosacral screw fixation (ISF) on lumbosacral fixation (LSF) and lumbopelvic fixation (LPF) constructs remains unclear. This study evaluates the effects of ISF on screw strain distribution and construct stability in these fixation models.
Methods:
Sixteen ovine spine-pelvis specimens were divided into LSF and LPF groups. Biomechanical testing was performed under compressive loads of up to 400 N before and after ISF placement. Strain measurements were recorded at the distal fixation points – S1 screws in LSF and iliac screws in LPF. Baseline strain values under physiological loading conditions were compared with post-fixation strain values following ISF placement.
Results:
In the LPF model, ISF resulted in a more consistent redistribution of strain, including reductions in vertical strain magnitude and right-sided horizontal tensile strain. In the LSF model, ISF led to a significant increase in left-sided oblique strain (
Conclusion:
ISF enhances biomechanical performance, particularly in LPF constructs, by reducing screw strain and redistributing loads more effectively. These findings support its potential role in surgical decision-making for complex lumbosacral pathologies. Further human studies are required to validate these findings, given anatomical and biomechanical differences.