Thermal balloon endometrial ablator: a preclinical safety and effectiveness study

To evaluate the preclinical safety and efficacy of the thermal balloon endometrial ablator (TBEA).

Informed consent was taken from all patients for TBEA and hysterectomy at same sitting. TBEA was performed in vivo just before hysterectomy on 6 patients' uteri to determine uterine rupture, perforation and thermal damage to surrounding viscera and peritoneum. Temperatures in the pouch of Douglas, uterovesical peritoneum and serosa of uterus were taken by a sterile laboratory thermometer to note for any rise in temperature before, during and after the procedure. The extirpated uteri were then examined grossly for the nature and extent of thermal damage which was visible as a zone of erythema in the endomyometrium. Five extirpated uteri, 3 from the above group and 2 on whom TBEA was performed 3 months ago were histopathologically examined to study the nature and extent of damage to endomyometrial cells. A 5 mm longitudinal strip of uterus along with both the cornual ends were sectioned in such a way that it was representative of the entire uterus.

There was no evidence of uterine perforation, rupture or any damage to the surrounding viscera and peritoneum. There was no rise in temperature in most sites while TBEA was performed. The only area that felt warm was the surface of the uterus and there too the measured rise was only 1 degree C. On gross examination the zone of erythema measured 5.4 mm (mean) (range 3-9 mm). In those uteri subjected to histopathology immediately after TBEA early evidence of thermal damage was visible as hemorrhage, congestion, edema, eosinophilic infiltration and necrosis in 2 out of 3 cases. Late changes of thermal damage after TBEA were seen as basal endometrium and areas of hyalinization. The changes in general were patchy and not uniform.

TBEA is a safe device with no thermal damage to uterus and surrounding viscera. The mean zone of thermal damage in the endomyometrium is 5.4 mm. On histopathology, the early changes of thermal damage are hemorrhage, congestion, edema, eosinophilic infiltration and necrosis and the late changes are visible as areas of hyalinization and presence of basal endometrium.