Background: The inherent tedium of intracorporeal knot tying has stimulated greater interest in energy-based and mechanical alternatives for hemostasis. Methods: Three hundred thirty-one arteries and veins were sealed by application of precisely controlled electrothermal energy and physical pressure, allowing for brief cooling in compression, in experimental animals and fresh abattoir vessels. These seals were compared for bursting strength with occlusions by ultrasonic and bipolar coagulation, surgical clips, and ligatures. Results: Ultrasonic and bipolar occlusions were significantly less likely to have burst strengths greater than 400 mmHg as compared with seals, clips, and ligatures (p < 0.001). Seal competence could be visually assessed by its translucence. Conclusions: Precise energy control with physical compression, including a brief cooldown, produces a distinctive, translucent seal of partially denatured protein that can typically be transected after a single application. These seals have bursting strengths comparable to those of clips and ligatures and resist dislodgement because they are intrinsic to the vessel wall structure.Intracorporeal knot tying and suturing are important hemostatic maneuvers that tend to define a level of advanced expertise in laparoscopic surgery. Nevertheless, their inherent tedium has spawned greater interest in energy-based and mechanical alternatives, as well as more tolerance for the cost and limitations of such devices. Electrosurgical and ultrasonic thermal energy applications are reliable for vessels up to 2 mm in diameter. Clips work for larger vessels but are subject to dislodgement, and staples are largely wasted for single-vessel application. Thinking that there was still room for innovation in the 3-to 7-mm vessel niche, we were attracted to the laser ''welding'' concept, wherein partially denatured protein, sometimes assisted by an albumin solder, was held in apposition by sutures until the layers became firmly adherent and resistant to bursting [2]. Electrosurgical energy was thought, a priori, to be more controllable, offer fewer design limitations, and prove safer and less costly to use.
Materials and methodsVariables of current, pressure, and holding time were explored in abattoir vessels, with acute burst strength as the main outcome measurement. Bursting pressures were measured using a fixture that progressively increased the volume in an occluded vessel segment to approximate increments of 100 mmHg/sec for arteries and 10 mmHg/sec for veins. The readout captured maximum pressure when the occlusion or the normal vessel wall burst, or the system reached its maximum of 900 mmHg.Once the rather narrow-peak optimum sealing parameters were defined, prototype devices were developed and tested on 3-to 7-mm-diameter vessels for seal durability in survival studies and compared acutely with existing devices, using the burst fixture. Ultrasonic coagulation was done with the vibrator's blunt or broad presentation, maintaining forceful compression until the seal severed...
