The study of laparoscopic electrosurgical instruments on thermal effect of uterine tissues.

PURPOSE: It is to compare the thermal damage on myometrium tissue caused by five electrosurgical instruments, including monopolar forceps, bipolar forceps, PK scalpel, Ligasure and BiClamp.

METHODS

Normal myometrium in vitro was collected and electric coagulation was conducted with five electrosurgical instruments under corresponding powers. The zones of thermal injury (ZTI) in each coagulation sites were examined histologically, while the width and depth of thermal damage were measured.

RESULTS

1. There were significant differences among various groups' widths of ZTI of myometrium (P < 0.05). Ligasure produced the greatest width of ZTI, and it was statistically greater than that of PK scalpel and BiClamp (P < 0.05). While the widths of ZTI caused by monopolar and bipolar electrocoagulation lied between that of Ligasure and PK scalpel, but the differences were of no statistical significance (P > 0.05). 2. The depths of ZTI in different groups were of significant differences (P < 0.05). Both monopolar and bipolar forceps had greater depths of ZTI compared with BiClamp (P < 0.05) but not had statistical differences with Ligasure and PK scalpel (P > 0.05).

CONCLUSIONS

As for myometrium, the thermal damage is rather small in the horizontal and vertical directions when using BiClamp and PK scalpel. Ligasure places larger range of thermal damage in horizontal direction with little depth in vertical direction, which is rather safe when acting on uterine surface. Electrocoagulation was conducted with monopolar (the power is 55 W) and bipolar forceps (the power is 40 W) continuously for 3 s, whose thermal damage range is fairly safe to corpus uteri wall and fundus uteri.