Evaluation of sternum closure methods by means of a nonlinear finite element analysis

Abstract

The main purpose of this study is to develop a validated three-dimensional finite element model of sternum closure techniques. For this aim, the finite element method analysis results of three closure methods were compared with experimental test results. Also, three more closure techniques are simulated numerically to study the effect of the number of wires used in the manubrium and xiphoid regions. A three-dimensional model of polyurethane sternum foam was created based on computed tomography images. Six different closure techniques using steel wire, steel bands and ZipFix bands were modeled on the sternum and transferred into a three-dimensional finite element model. The sternum was modeled as an isotropic bilinear-elasto-plastic material, and nonlinear contact conditions were applied. The models were analyzed under lateral distraction loading, and load-displacement curves were obtained from displacements at the incision line. Allowable loads and stiffness values of the methods were evaluated from these curves. The results showed the importance of the including material as well as geometric nonlinearities in the simulations to obtain realistic results from the numerical analyses. Also, the analyses showed that closures that include steel or ZipFix bands are superior to conventional wiring, and addition of a single wire at the manubrium and xiphoid regions significantly improved the efficiency of the closure techniques.

Review of Biomechanical Studies and Finite Element Modeling of Sternal Closure Using Bio-Active Adhesives

“…The adaptive FEA is composed of two refinements types, regular refinement and local refinement [79]. Orhan and Ozyazicioglu [83] specified in their FEA of sternal closure that refining the mesh would improve the accuracy of the computation.…”

“…It is strongly recommended that skewness be less than 45 degrees. In the nonlinear FEA of a sternal closure, Orhan and Ozyazicioglu [83] used the skewness parameter to check the mesh quality. The fourth quality parameter is the Jacobian, which helps to identify distortion in the element.…”

Orthopedic Principles to Facilitate Enhanced Recovery After Cardiac Surgery

“…In support of this idea, PEEK-based cable ties have been shown, in engineering studies, to have equivalent or better static-loading strength, fatigue strength, and resistance to bone cutthrough compared with stainless-steel surgical wire. 42,43 A commercially available polymer sternal cable-tie system has been evaluated in several studies, with mixed results. 41,[44][45][46][47] A retrospective comparison of 95 sternotomies closed with polymer cable ties versus 498 closed with transverse, interrupted figure-of-8 stainless-steel wires found no difference in superficial or DSWI between groups.…”

“…48 Independent criticism of these conflicting studies has noted that both are limited by lack of definition/standardization of wiring technique, different choice of outcomes, and biases in study design and reporting. 49,50 Given further conflicting results in biomechanical studies comparing conventional versus figure-of-8 wire cerclage, polymer cable ties, and steel bands, 42,43 higher-quality data are required before definitive conclusions can be reached about the appropriate role of polymer cable ties in the sternal closure toolkit. Of key importance, despite their proposed advantages over wires and bands, polymer cable ties also do not provide orthopedic stabilization of the osteotomy and are not considered rigid fixation.…”

Review of Biomechanical Studies and Finite Element Modeling of Sternal Closure Using Bio-Active Adhesives

“…The load values required for different sternal closure techniques to reach a rupture displacement of 2.0 mm[83].…”