Kazunori Shibao, MD, PhD, FACS, Fumi Joden, MD, Yasuhiro Adachi, MD, Yuzan Kudo, MD, Takehide Tajima, MD, Kohi Shiro, MD, Nobutaka Matayoshi, MD, Ryota Murayama, MD, Norihiro Sato, MD, PhD, Keiji Hirata, MD, PhD. Univetsity of Occupational and Environmental Health
Background: Ultrasonic technology uses high-frequency mechanical vibration to combine cutting and coagulating. It results in precise dissection with less bleeding in various surgical procedures, including laparoscopic gastrectomy (LG). However, thermal injury caused by ultrasonic shears can lead to fatal complications in LG. Thus, it is important to safely manage the blade temperature of ultrasonic shears. There are two handling techniques for ultrasonic shears: the short-pitch technique and the full-pitch technique. The short-pitch technique is a technique to fire the shears with blades closed when a small amount of tissue is present in the distal 1/4 of the blade. This technique is appropriate for precise dissection including lymph node dissection in LG. The full-pitch technique allows for the dissection of tissue using the entire ultrasonic shear blade, which is applicable for fast and rough cutting. Many reports have demonstrated the thermal profile using ultrasonic shears. However, no report has focused on the thermal profile difference in device handling, which provides valuable information for actual clinical usage. In this study, we examined the blade temperature using the two different techniques and evaluated the safety of ultrasonic shears.
Methods: Using an ex vivo benchtop, the safety of the short-pitch and full-pitch techniques was compared with respect to the blade temperature using an infrared camera. The cutting speed and the blade temperature were measured during and after continuous dissection of a defined length of muscle (10 cm in length) under an axial tension of 20 g on the muscle with maximum power mode (Harmonic scarpel, Ethicon). The time required for the temperature to decrease to 60°C after activation was also recorded. The lateral thermal spread was assessed by infrared camera.
Results: Ex vivo tests of the short-pitch technique demonstrated significantly higher blade temperatures, longer times for returning to baseline, and wider lateral thermal spread than the full-pitch technique after the completion of cutting 10 cm (341±28.3°C and 211±6.6°C, respectively, P<0.001; 77±4.1 seconds and 35±2.1 seconds, respectively, P<0.001; 2.4±0.6 mm and 1.8±0.5 mm, respectively, P<0.001).
Conclusion: Although the short-pitch technique enables us to ensure precise lymph node dissection in LG, continuous dissection using the short-pitch technique increases thermal injury during surgery. Careful attention should therefore be paid to prevent thermal injury by ultrasonic shears during surgery.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 79937
Program Number: P423
Presentation Session: Poster (Non CME)
Presentation Type: Poster