Endometrial histology after electrocoagulation using different power settings

To study endometrial histology after electrocoagulation in an in vitro model using 50 watts (W) and 100 W of coagulation current and determine the depth of endometrial destruction and survival, if any, of glands beneath this zone.

Twenty fresh uteri of similar weights and dimensions were obtained from patients undergoing hysterectomy for benign disease. Specimens were bivalved into anterior and posterior walls and each wall divided in half. Endometrial electrocoagulation was carried out with a 5-mm probe at 50 W and 100 W applied to anterior and posterior quarters of the specimen, respectively. The adjacent untreated endometrial surfaces served as controls. Specimens were formalin-fixed, embedded in paraffin, and sections stained with hematoxylin and eosin.

The number and morphology of the endometrial glands were counted and classified manually for each section and compared between each power setting and controls.

Histologic examination revealed morphologically normal glands in all specimens beneath the zone of destruction regardless of power setting. Both power settings produced significant focal and diffuse glandular and stromal destruction when compared with controls. Significant differences were noted in the number of normal glands after treatment with 50 W (71.33 glands +/- 76.44 [mean +/- SD]), 100 W (21.11 +/- 35.71) and untreated controls (240.16 +/- 110.81). Tissue destruction increased with increasing power, and there were significant differences in the percentage of morphologically normal, surviving glands between 50 W (11.7% +/- 11.4% [mean +/- SD]) and 100 W (4.9% +/- 10.9%).

These data suggest that electrocoagulation may result in a variable degree of endometrial destruction dependent on power. Viable glands and stroma may survive beneath the zone of destruction regardless of power. Such variations in endometrial insult in an in vitro model may explain, in part, the variable clinical results of endometrial electrocoagulation. The survival of glands beneath the zone of destruction in this model raises the theoretical concern for occult malignant changes and leaves open to question the exact role and mode of hormonal therapy during the menopause after endometrial ablation.