Consistency and sealing of advanced bipolar tissue sealers

Edward G Chekan , Mark A Davison, David W Singleton, John Z Mennone, Piet Hinoul Ethicon, Inc., Cincinnati, OH, USA Objectives: The aim of this study was to evaluate two commonly used advanced bipolar devices (ENSEAL® G2 Tissue Sealers and LigaSure™ Blunt Tip) for compression uniformity, vessel sealing strength, and consistency in bench-top analyses. Methods: Compression analysis was performed with a foam pad/sensor apparatus inserted between closed jaws of the instruments. Average pressures (psi) were recorded across the entire inside surface of the jaws, and over the distal one-third of jaws. To test vessel sealing strength, ex vivo pig carotid arteries were sealed and transected and left and right (sealed) halves of vessels were subjected to burst pressure testing. The maximum bursting pressures of each half of vessels were averaged to obtain single data points for analysis. The absence or presence of tissue sticking to device jaws was noted for each transected vessel. Results: Statistically higher average compression values were found for ENSEAL® instruments (curved jaw and straight jaw) compared to LigaSure™, P<0.05. Moreover, the ENSEAL® devices retained full compression at the distal end of jaws. Significantly higher and more consistent median burst pressures were noted for ENSEAL® devices relative to LigaSure™ through 52 firings of each device (P<0.05). LigaSure™ showed a significant reduction in median burst pressure for the final three firings (cycles 50–52) versus the first three firings (cycles 1–3), P=0.027. Tissue sticking was noted for 1.39% and 13.3% of vessels transected with ENSEAL® and LigaSure™, respectively. Conclusion: In bench-top testing, ENSEAL® G2 sealers produced more uniform compression, stronger and more consistent vessel sealing, and reduced tissue sticking relative to LigaSure™. Keywords: ENSEAL, sealing, burst pressure, laparoscopic, compression, LigaSur

Immune cell populations and cytokine production in spleen and mesenteric lymph nodes after laparoscopic surgery versus conventional laparotomy in mice

PURPOSE: There is evidence that open as well as minimally invasive abdominal surgery impair post-operative innate and acquired immune function. To compare the impact of these approaches as well as the one of different peritoneal gas exposures on immune function, we investigated cellular as well as cytokine-based immune parameters in mesenteric lymph nodes and the spleen postoperatively. METHODS: Mice (n = 26) were randomly assigned to the 4 study groups: (1) sham controls undergoing anesthesia alone, (2) laparotomy, and (3) air, or (4) carbon dioxide pneumoperitoneum. Mice were sacrificed 48 h after the intervention, and their spleens and mesenteric lymph nodes were harvested. Cytokine production (TNF-α, IL-6, IL-10, and IFN-γ), splenic T cell subpopulations (cytotoxic T cells, T helper cells, and regulatory T cells) were analyzed. RESULTS: TNF-α production of splenocytes 16 h after ex vivo lipopolysaccharides (LPS) stimulation was significantly increased in the laparotomy group compared to all other groups. In contrast, TNF-α production of lymph node cells and IL-6 production of splenocytes after ex vivo LPS stimulation did not differ significantly between the groups. The numbers of regulatory T cells (Treg) in the spleen differed between groups. A significant reduction in Treg cell frequency was detected in the CO(2) insufflation group compared to the laparotomy and the air insufflation group. CONCLUSION: Our findings demonstrate a distinct difference in immune effector functions and cellular composition of the spleen with regard to splenic TNF-α production and increased numbers of Treg cells in the spleen. These findings are in line with a higher peritoneal inflammatory status consequent to peritoneal air rather than CO(2) exposure. Treg turned out to be key modulators of postoperative dysfunction of acquired immunity