Mechanical Test Methods for Assessing Porcine Carotid and Uterine Artery Burst Pressure Following Ex Vivo Ultrasonic Ligature Seal and Transection

A test method was developed to identify those variables important for assessing the performance of ultrasonic surgical devices in ex vivo ligature sealing of porcine carotid and uterine arteries. Ruggedness testing using a small sample size in pilot experiments was conducted using a newly developed test method in an effort to assess the usefulness of this methodology and to identify test variables that might warrant further testing. The development of this test method included the use of a custom-designed prototypic tension device for load-controlled ex vivo vessel stretching during saline perfusion and subsequent seal and transection of porcine arteries with an advanced energy surgical device. The quality of the seal was evaluated as a burst pressure (mmHg). The experimental set-up allowed for either monitoring or controlling specific test conditions, including blood vessel tension during cutting and sealing, saline infusion rate, cutting time, pressure generated in the vessel during cutting, and burst pressure. Both muscular-type uterine and elastic-type carotid arteries were investigated, since energy based devices are most frequently used on muscular-type arteries but are developed and tested using elastic-type arteries. Although confounded with the age of the animal, in the ruggedness test pilot, it was observed that porcine carotid arteries yielded a comparatively lower burst strength seal as compared to porcine uterine arteries. The data generated during ruggedness testing suggests that the artery type and saline infusion rate during transection may be important variables in ex vivo vessel seal testing.