Microwave endometrial ablation: does endometrial thickness or the medium for preoperative hysteroscopy affect the depth of ablation?

Objectives To determine the depth of tissue necrosis following microwave endometrial ablation (MEA) after perioperative saline hysteroscopy, and to determine the effects of varying endometrial thickness on depth and regularity of necrosis after gas hysteroscopy.

Subjects 15 premenopausal women undergoing hysterectomy for dysfunctional uterine bleeding at Aberdeen Royal Infirmary.

Methods Endometrial thickness was measured by transvaginal ultrasound scanning. After cervical dilation a hysteroscopy was performed with carbon dioxide or saline before proceeding to MEA and then hysterectomy. A vital stain was used to assess the depth and regularity of endomyometrial necrosis in the excised uterus.

Results The nitroblue tetrazolium stain was a simple and effective way of demonstrating the depth of necrosis. In this small study, saline hysteroscopy led to cornual sparing in some cases. There was no clear effect of endometrial thickness up to 8 mm with gas hysteroscopy.

Conclusions Saline hysteroscopy may affect the clinical outcome of MEA. Aspiration of residual saline may minimize any negative effect. The depth and regularity of necrosis did not seem to be affected by endometrial thicknesses of up to 8 mm after gas hysteroscopy. It seems reasonable to proceed to a clinical trial to assess the outcome of postmenstrual MEA without hormonal endometrial preparation.