Biomechanical porcine model of median sternotomy closure.

Background: Healing complications following median sternotomy commonly include instability, nonunion, and infection. They are associated with a high mortality rate if mediastinitis supervenes. Closure complications are best avoided by improving stability at the union, but there has thus far been no widespread agreement among surgeons about relative superiority among the available closure techniques.
Materials and Methods: A biological sternotomy closure model was developed utilizing whole porcine sterna. A special stainless-steel clamp with multiple spikes was created to reliably attach the sterna to a biomechanical testing device.
Results: Two wiring techniques, single peristernal and pericostal figure-eight, were used in 14 fresh cadaveric porcine sterna. The more rigid closure utilized single peristernal wires (P < 0.0001). There was no tissue associated with clamp spikes penetrating the specimen's layers, and there was no clamp displacement even at closure failure loads.
Conclusions: The porcine sternotomy model is a valuable tool for comparing closure techniques based on geometrical and mechanical wiring patterns. The model's low cost and easy reproducibility make it a promising first step in sternotomy closure research. The stainless-steel clamp used in the porcine model provided reliable repeat specimen fixation.