Anatomical and Technical Limitations of a Rabbit Median Sternotomy Model for Translational Mediastinal Adhesion Research

Background/Objectives: Experimental animal models are fundamental to developing and translating strategies for preventing postoperative mediastinal adhesions. Rabbits are widely used in adhesion research; however, the anatomical and technical suitability of the rabbit median sternotomy model for reproducing conditions relevant to human redo sternotomy remains incompletely characterized. This study aimed to characterize the rabbit sternum and assess the feasibility and translational suitability of the rabbit median sternotomy model for mediastinal adhesion research. Methods: An acute, non-survival observational feasibility study was performed in two adult female New Zealand White rabbits. Median sternotomy was performed using 22 cm surgical scissors with ball-tipped blades, following a previously described technique with a technical modification. Macroscopic assessments included sternal morphology, the technical feasibility of midline division, pleural and peritoneal integrity, the apparent adequacy of the remaining sternal bone for re-approximation, and the relationships between the sternum and underlying mediastinal structures. Sternal closure was not attempted. Results: The rabbit sternum exhibited a narrow, highly segmented, and flexible configuration, with an elongated xiphoid process extending beyond the thoracic cavity. Median sternotomy proved technically challenging because of the limited width of the sternum. During the procedure, the surgical scissors deviated laterally, resulting in fragmentation of the sternal segments. Under the surgical conditions evaluated in this study, macroscopic assessment indicated that the remaining sternal bone was insufficient to permit stable re-approximation comparable to that required in humans; therefore, no closure attempt was made. Conclusions: These characteristics limited reproduction of the retrosternal conditions encountered during human median sternotomy. In this two-animal feasibility assessment, the rabbit median sternotomy model demonstrated anatomical and technical limitations that may reduce its translational fidelity for studies specifically intended to reproduce the retrosternal conditions of human redo sternotomy.