Extirpated uterine endometrial cryoablation with ultrasound visualization

Study Objective. To determine the efficacy of cryoablation of the uterus monitored by ultrasound. Design. Observational research (Canadian Task Force classification II-2). Setting, Clinic laboratory. Subjects. Eight uteri obtained after hysterectomy. Intervention. The uteri were subjected to freeze and thaw cycles in a 37 degrees C water bath. Ultrasound was used to monitor the advancing ice front and ice ball diameter. Measurements and Main Results. Specimens were sectioned and stained with tetrazolium red to determine the region of nonviable tissue. The maximum average ice ball diameter as measured by ultrasound was 33.2 mm (range 29.1-35.4 mm). The average maximum diameter of nonviable tissue region was 24 mm (range 21.4-28.4 mm), with depth of tissue destruction ranging from 6 to 12 mm. Conclusion. Cryosurgery at temperatures below -90 degrees C achieves excellent destruction of uterine tissue and complete destruction of endometrium. Ultrasound can be used to monitor freezing.