HISTOLOGIC CHARACTERISTICS OF LAPAROSCOPIC ARGON BEAM COAGULATION

Study Objectives. To describe histologic effects of laparoscopic argon beam coagulation and determine the extent of tissue necrosis at vario us power settings and exposure times. Design. Prospective experimental analysis (Canadian Task Force classification II-1). Setting. Universi ty animal laboratory. Subjects. Adult female domestic pigs. Interventi ons. Various power settings (40, 60, 80 W) at increasing exposure time s (1, 3, 5 sec) were used during laparoscopic application of argon bea m coagulation to different tissues (uterine horn, bladder, ureter, kid ney, bowel, liver). Animals were sacrificed within 1 hour of coagulati on fbr histologic tissue preparation. Measurements and Main Results. H istologic measurements of both depth and lateral extent of electrosurg ical tissue effects (mm +/- SD) were ascertained and evaluated statist ically by one-way repeated measures ana lysis oi variance. Depth oi ti ssue necrosis was confined to I mm or less in uterine horn, bladder, a nd ureter. Even at highest power settings, bowel had tissue necrosis n o greater than 2 mm. Both liver and kidney shelved a deeper histologic effect (4-5 mm). The lateral extent oi tissue necrosis ranged from 2 mm (ureter) to 15 mm (liver). Conclusion. Laparoscopic argon beam coag ulation results in tissue effects that are dependent on both low power setting and duration of application, as well as on electrical and phy sical characteristics of target tissue. Thermal tissue penetration can be expected to be less than 2 mm in bowel, bladder, and ureter, and l ess than 5 mm in kidney and liver, even at 5 seconds of exposure time and at a power setting as high as 80 W. As with all thermal modalities used for hemostasis and tissue coagulation, laparoscopic argon beam c oagulation can be performed safely as long as the potential for inadve rtent thermal injury is understood.