Purpose: To compare tip temperatures of the vibrating blades of the newer-generation Harmonic Ace device and the older-generation Ultracision Harmonic Scalpel LCS-K5.
Materials and Methods: Comparison of two different harmonic scalpel blades was performed by applying them to 3-mm strips of raw chicken breast at room temperature and measuring the temperature of the tip of the vibrating blade at 0.5-second intervals using a thermocouple. Following activation, the tip was allowed to passively cool to 30°C each time before reactivation. Each device was tested at power settings of 3 and 5 after activation for 1 to 5 seconds. All measurements were performed 5 times.
Results: Compared to the older-generation Ultracision Harmonic Scalpel LCS-K5, the newer-generation Harmonic Ace was associated with higher tip temperatures at power level 5 at all times of activation (1–5 seconds), and at power level 3 at longer times of activation (3–5 seconds). The Harmonic Ace also takes longer to reach peak temperatures and can maintain blade hyperthermia for a longer period after activation for more than 3 seconds at power levels 3 and 5.
Conclusion: The newer-generation Harmonic Ace may be potentially more effective in tissue dissection, but is associated with greater increases in peak temperatures and longer blade hyperthermia periods compared to the older-generation Ultracision Harmonic Scalpel LCS-K5. The difference is greater after longer periods of activation, and this may have more potential for collateral damage, particularly to nerves and bowel.
