Biomechanical comparison of bone staple fixation methods with suture material for median sternotomy closure using 3D-printed bone models

Authors: Park YG, Jo JH, Lee JK, Kim JM, Lee SJ, Kim HY
Publication: New Zealand Veterinary Journal, Volume 72, Issue 5, pp 265-274, Sep 2024
Publisher: Taylor and Francis

Animal type: Dog
Article class: Research Article

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Abstract:

Aim: To compare the biomechanical properties of three different sternal closure techniques in a 3D-printed bone model of a sternum from a 30-kg dog.

Methods: Median sternotomy was performed on a total of 90 three-dimensional (3D) copies of a polycarbonate (PC) model of a sternum, generated from the CT images of the sternum of a 30-kg German Shepherd dog. Three different methods were used to repair the sternotomies: polydioxanone suture (group PDS, n = 30), stainless steel bone staples (group SS, n = 30), and nitinol bone staples (group NS, n = 30). Each repair method was tested by applying tensile force in one of three ways (longitudinally, laterally, or torsionally) resulting in a sample size of n = 10 for each repair method-loading combination. In all experiments, the loads at 1-mm and 2-mm gap formation, failure, and the displacement at the failure point were measured.

Results: In lateral distraction and longitudinal shear tests, NS and SS staple repairs required application of significantly greater force than PDS across all displacement criteria (1 and 2 mm). NS exhibited significantly greater failure load than PDS. In torsion tests, NS required significantly greater application of force compared to SS or PDS at all displacement criteria (1 and 2 mm) and exhibited a greater failure load than PDS. In terms of displacement at failure point, PDS suture showed more displacement than SS or NS across all experiments (laterally, longitudinally, torsionally).

Conclusions: In this study, bone staples were mechanically superior to PDS suture in median sternotomy closure using 3D-printed bone model in terms of 1-mm, 2-mm displacement loads, and displacement at failure. NS had a higher failure load than PDS under lateral, longitudinal, and torsional distraction.

Clinical relevance: These study results imply that bone staples can be considered as an alternative surgical method for median sternotomy closure in dogs.

KEYWORDS: Median sternotomy, bone staple, nitinol staple, 3D print, dog

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