Thickness of Cadaveric Human Lung Tissue.

BACKGROUND: Choosing the correct surgical staple height is dependent on knowledge of specific tissue thickness and compressibility. The purpose of this study was to measure the thickness of cadaveric human lung tissue. MATERIALS AND METHODS: Between December 2012 and February 2013, whole lungs were procured from 12 donors. Inclusion criteria included negative serology, no prior thoracic surgery, and completion of measurements within 72 hours of death. Tissue thickness was measured in the anterior-to-posterior direction using a tissue measuring device (TMD) at 41 lung locations. The tissue measuring device applied a constant pressure (8 g/mm2) via a plunger for 15 seconds before reading the thickness. RESULTS: Cadaveric lung tissue thickness displayed a large variation by location and within each location. Mean thickness in the anterior-to-posterior direction ranged from 1.5 mm (right middle lobe [inferior peripheral] location) to 9.0 mm (right inferior lobe [mid-central] location). In general, the periphery of the lung lobes was thinner than the central locations (e.g., mean peripheral location thickness: 4.1 mm; mean central location thickness: 5.9 mm). The thinnest tissues among the 12 donor cadaveric lung specimens were found in the one donor with a history of severe emphysema/chronic bronchitis. Height (P = 0.012) and weight (P = 0.036) were positively correlated with tissue thickness. Additionally, after adjusting for height, cadaveric lung tissue was 3.0 mm thicker for females than males. CONCLUSIONS: Large variations of lung tissue thickness were demonstrated throughout the lung as well as within each measured location across different cadaveric specimens. Generally, peripheral locations were thinner than the central locations of the lobes. There was a strong positive correlation between thickness and height, and females had slightly thicker lung tissue than males of the same height.

Consistency and sealing of advanced bipolar tissue sealers.

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™.

Electromagnetic energy sources in surgery.

The biophysics, mechanism of actions, applications, benefits and complications of electromagnetic (EM) energy-based surgical instruments, and their current use are reviewed. Understanding the mechanism of action, tissue effects, and appropriate applications of EM devices is critical to achieving an optimal surgical outcome. Although a more diverse range of EM devices are used in human medicine, current use in veterinary medicine is limited to conventional electrosurgery and CO(2) lasers.