title: Infrared thermographic profiles of vessel sealing devices on thyroid parenchyma.
abstract: BACKGROUND
  During thyroid lobectomy, division of the thyroid parenchyma has traditionally been accomplished using suture ligation. Development of hemostatic techniques in the forms of ultrasonic dissection (UD) and electronic vessel sealing (EVS) have increased the usage of these devices during thyroid operations. We sought to characterize the thermal profile of each of these devices when used to divide the parenchyma of the thyroid gland.
  
  
  METHODS
  Using a porcine model, the parenchyma of the gland was sealed by alternating application of the UD and EVS devices. In each case, the thermal activity was recorded using infrared thermal imaging. We performed multiple seals with each instrument and then compared the thermal profiles.
  
  
  RESULTS
  There was no significant difference in lateral thermal spread of EVS and UD above 39, 40 or 60°C (2.30 ± 0.31 mm versus 2.53 ± 0.47 mm, P = 0.26; 2.22 ± 0.27 mm versus 2.47 ± 0.47 mm, P = 0.22, and 1.37 ± 0.27 mm versus 1.54 ± 0.26 mm, P = 0.22). There was no significant difference in mean time above 39 or 40°C (35.1 ± 8.7 s versus 31.7 ± 9.3 s, P = 0.47 and 29.9 ± 8.1 s versus 27.3 ± 6.7 s, P = 0.50). UD reached a greater maximum temperature (179.12 ± 0.0008C versus 96.52 ± 5.6C, P ≤ 0.001) and stayed over 60°C for longer than EVS (9.5 ± 1.8 s versus 5.3 ± 0.97 , P ≤ 0.001).
  
  
  CONCLUSIONS
  The amount of lateral spread of thermal energy was not significantly different between the UD and EVS devices. However, the use of UD produced a higher maximum temperature during thyroid parenchyma sealing and remained above 60°C longer than EVS. This may translate into greater thermal injury to thyroid and surrounding tissues during division.
authors.affiliation: Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792, USA.
authors.forename: Carter T
authors.initials: CT
authors.lastname: Smith
authors.forename: Barbara
authors.initials: B
authors.lastname: Zarebczan
authors.forename: Amal
authors.initials: A
authors.lastname: Alhefdhi
authors.forename: Herbert
authors.initials: H
authors.lastname: Chen
mesh_terms: D000818:Animals; D005260:Female; D006488:Hemostasis, Surgical / Q000295:instrumentation*; D013536:Suture Techniques / Q000295:instrumentation*; D013552:Swine; D013817:Thermography / Q000379:methods*; D013961:Thyroid Gland / Q000601:surgery*; D014464:Ultrasonic Therapy / Q000379:methods