Small Animal Laparoscopy and Thoracoscopy. Группа авторов

for single‐use raises the questions of the effectiveness of sterility and ability to perform safe and effective seals. Kuvaldina et al. [27] evaluated the number of uses, cleaning, and resterilization cycles with low temperature hydrogen peroxide sterilization for two LigaSure handpieces intended for open surgery. Based on the rate of vascular seal failure, they recommend discarding the Small Jaw handpiece after 9 cycles and the Impact handpiece after 16 cycles. Another study found the LigaSure Atlas handpiece formed an effective seal after 15 uses and resterilization cycles with ethylene oxide [26]. Gardeweg et al. [25] compared the reuse and resterilization of LigaSure, Caiman, and marSeal handpieces with a low temperature steaming process with formaldehyde as an active agent and found that LigaSure, Caiman, and marSeal devices all performed reliable seals after multiple uses and sterilizations except for one Caiman handpiece. Five cycles of sterilization were performed in this study. Performance and microbiological safety of the LigaSure 5 mm Maryland handpiece were evaluated after multiple uses and resterilization cycles by Valenzano et al. [31] Eleven of 12 handpieces failed to activate when the jaws were closed, and the activation button was depressed after a mean of 7.7 cycles. In this study, each handpiece was initially washed in tap water and a 2% enzymatic cleaner solution. The jaws of the instrument were soaked in the 2% enzymatic cleaner solution for five minutes and then scrubbed with a sponge and metal brush and air‐dried. The handpiece was pouch packaged and sterilized with a low‐temperature hydrogen peroxide sterilization unit. Using this protocol for cleaning and sterilization, no handpieces had positive cultures [31]. The 3‐mm JustRight^TM vessel sealant device from Bolder Surgical was evaluated for multiple uses and resterilization cycles and was considered safe for use for up to nine reuse and resterilization cycles [32].

Table 5.2 Various energy devices and their capabilities.

Energy device (manufacturer)	Monopolar	Bipolar	Tissue sealing	Ultrasonic dissector
Force triad (Valley Lab, Boulder, CO)	✓	✓	✓
Ethicon Gen11 generator (Ethicon, Cincinnati, OH)			✓	✓
Sonicision (Covidien, North Haven, CT)				✓
Altrus (Conmed, Utica NY)			✓
Ultracision (Ethicon, Cincinnati, OH)				✓
Autosonix (Covidien North Haven, CT)				✓
Thunderbeat (Olympus, Center Valley, PA)			✓	✓
JustRight^TM JR 100 (Bolder Surgical Louisville, CO)			✓
Caiman Lektrafuse RF generator (Aesculap, Tuttlingen, Germany)			✓

Ultrasonic Dissector

      Ultrasound waves are sound waves with a frequency above the upper limit of human hearing (>20 kHz). Sound wave energy used in surgical devices typically occurs at frequencies of 23–55 kHz. Ultrasonic surgical devices are capable of cutting, desiccation, protein coagulation, and cavitation (a hybrid form of vaporization facilitating dissection). The advantage of this form of energy is that an electrical circuit is not required, which eliminates the risk of direct and indirect coupling injuries that may occur in laparoscopy, as well as neural stimulation, which can result in cardiac and respiratory arrest.

      An ultrasonic generator delivers an alternating polarity electrical current that is modulated by the generator, directed through the transducer, and converted to sound energy. This conversion of current into sound energy occurs as the piezoelectric current is directed through a series of stacked ceramic plates within the transducer. The vibration of the ceramic plates at 55 500 times per second produces sound waves or harmonic frequency, which generates mechanical energy. Sound energy propagates down the shaft of the instrument to the tip, leading to axial displacement of the instrument tip. An increase in power on the generator leads to an increase in axial displacement of the instrument tip, leading to an increased cutting rate.

Ultrasonic energy devices generate minimal heat and, therefore, very little lateral thermal spread (<1.5 mm). Despite generating minimal thermal spread, these devices store heat in the blade even after deactivation, and care must be taken to prevent inadvertent tissue injury to surrounding visceral tissue immediately after activation. Most ultrasonic energy devices can seal vessels up to 3 mm in diameter. Table 5.2 lists various currently available ultrasonic dissectors as well as tissue fusion devices.

      A study by Newcomb et al. [17] compared vessel sealing in a porcine model with electrosurgical and ultrasonic devices. They found that vessel sealant devices had the highest mean burst pressures compared with ultrasonic dissectors. More seal failures were seen overall with the ultrasonic dissector than with the vessel sealant devices. However, for vessels 2–3 mm in diameter, the ultrasonic dissector did not have any seal failures, but the vessel sealant devices did. This study emphasizes the fact that ultrasonic dissectors consistently seal vessels less than 3 mm but perform inconsistently with larger vessel diameters.

Medtronic introduced a new generation of Sonicision, a cordless, curved jaw ultrasonic dissection system (Figure 5.11). The intensity of the ultrasonic energy is controlled by the operator with a dual‐mode energy button, where a half depression is indicated with slower dissection when increased hemostasis is desired and a complete depression of the dual‐energy mode button leads to faster dissection. In contrast to other ultrasonic devices, Sonicision is approved for use with vessels up to and including 5 mm in diameter. This device has an autoclavable generator that can be used up to 150 times. The rechargeable battery is designed for 200 uses. The ultrasonic dissector is designed for single use, but resterilization is common in veterinary medicine. No studies currently exist on the safety of resterilization of the ultrasonic dissector. The authors have currently resterilized the ultrasonic dissector greater than ten times using hydrogen peroxide sterilization and have not experienced any known failures or infections due to device reuse and resterilization.

Figure 5.11 Sonicision is a cordless ultrasonic dissector that is approved for sealing vessels up to 5 mm in diameter.

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