A biomechanical evaluation of wired sternal fixation augmented with a bio-active adhesive using full coverage and spot welds

The use of bio-adhesives in sternal fixation aims to mitigate complications commonly associated with median sternotomy, which can lead to significant morbidity and mortality rates. Bio-adhesives are recognized for enhancing sternal fixation and limiting hemisterna displacement. This study evaluates the effectiveness of glass polyalkenoate cements (GPCs) derived from a novel BT101 glass in conjunction with a new spot weld application technique. Finite element analysis (FEA) was used to predict the minimum GPC adhesive coverage necessary to prevent pathological displacement of the hemisterna. Three sternal fixation models with varying GPC adhesive coverage 50%, 62.5%, and 75% were developed in SolidWorks and analyzed in Ansys software. The simulations applied a breathing load of 500 N and a wiring clamping force of 1000 N to replicate experimental conditions. The FEA results demonstrated a 21.4% reduction in directional displacement of the sternum with full adhesive coverage compared to traditional wire-only fixation. The maximum directional deformation for 50%, 62.5%, 75%, and 100% of adhesive coverage are 1.576 ± 0.232 mm, 1.281 ± 0.182, 0.999 ± 0.0262, and 0.29 ± 0.28, respectively, all of which are below the pathological displacement threshold of 2.0 mm. The findings indicate that increased adhesive coverage correlates with reduced sternal displacement. Consequently, the study recommends using wired sternal fixation enhanced with 75% GPC spot welds to minimize hemisterna displacement, potentially enhancing ossification and bone healing, and improve vascularization between the sternal halves at the spaces between adhesive spots. Thus, the development of the sternal fixation finite element model could be useful in parallel with the experimental analysis.