Optimization of Ultrasonic Bone Scalpel Technique for Safe Redo Sternotomy: An Ex Vivo Study

P0146 

Abstract Submission 

Yuta Tsuchida (1), Riya Gandhi (2), Narutoshi Hibino (3)

(1) University of Chicago, Chicago, IL, (2) the university of chicago, chicago, IL, (3) Advocate Children's Hospital, Chicago, IL

Yuta Tsuchida    -  Contact Me
University of Chicago

Riya Gandhi    -  Contact Me
the university of chicago

*Narutoshi Hibino    -  Contact Me
Advocate Children's Hospital

Yuta Tsuchida    -  Contact Me
University of Chicago

Objective
The ultrasonic bone scalpel (BS) is increasingly applied in spinal and orthopedic surgery because its blunt, high-frequency vibrating blade selectively cuts bone while sparing soft tissues such as nerves and vessels. Recently, BS has been introduced for redo sternotomy in cardiac surgery, as it can safely separate the sternum from adhered cardiac tissues and great vessels. However, the high-frequency vibration of the blade generates heat, posing a potential risk of thermal injury to tissues adherent to the sternum. The optimal power settings and operative technique for safe use in redo sternotomy have not been established. This study aimed to determine the appropriate power levels and handling techniques for safe BS use during redo sternotomy using an ex vivo sheep heart model.

Methods
Whole sheep hearts were harvested, and ventricular tissue blocks were prepared. Samples were divided into two groups according to blade handling technique: (1) Holding - the blade kept stationary on the tissue, and (2) Quick touch - rapid, light, repetitive contact. Each technique was tested at three power levels (40, 60, and 100). The extent of tissue injury was assessed macroscopically by measuring the area of visible damage and histologically by evaluating thermal injury depth.

Results
Macroscopic analysis showed no visible scar or thermal injury in the quick touch group, even at high power. In contrast, the holding group demonstrated clear scar formation, which increased proportionally with power level. Histological examination confirmed that thermal injury depth correlated with power in the holding group but was absent in the quick touch group.

Conclusion
During redo sternotomy, the ultrasonic bone scalpel offers a significant advantage over conventional sternal saws by reducing the risk of injury to cardiac tissues and great vessels. Although excessive power or prolonged contact can cause thermal injury, using the quick touch technique-brief, repetitive blade contact-maintains safety even at high power. When applied properly, BS is a useful and safe device for minimizing cardiac and vascular injury during redo sternotomy.

Innovations: New devices or novel approaches, preclinical or clinical