Analysis of cryolesions in the uterine cervix: application techniques, extension, and failures.

Although cryosurgery is regularly used for treatment of cervical intraepithelial neoplasia (CIN), there are few data concerning freeze technique and attendant extension of the cryolesion. This study evaluated how to create cryolesions extensive enough to eradicate the CIN lesion completely. The way the extension of the cryolesion was influenced by type of probe, anatomical position in the cervix, shape of the external os, and freeze time was analyzed. Furthermore, we examined whether localization of the cryolesions corresponded with the CIN III location. Cryosurgery was applied to the cervix of 64 women the day before hysterectomy was performed for benign disease. Four types of probes were tested and freezing was done with a double freeze cycle. After extirpation of the uterus, slides were cut at the 3-, 6-, 9-, and 12-o'clock positions. With a computerized graphic tablet, the depth and linear extension of the cryolesion were measured morphometrically. After short freeze times, it appeared that an adequate lesion was present in only 67.4% of the slides. The large cone probe gave the best results; the small flat cervix probe the worst. At the 3- and 9-o'clock positions, a significantly higher percentage of inadequate lesions was found (60.8 and 65.3%, respectively). This proved to be due primarily to the extensive vascular supply at those positions. Longer freeze times gave an excellent result within all slides, even at the 3- and 9-o'clock positions. The topographic position of the cryolesion corresponded completely in all cases with that of the CIN III lesion.(ABSTRACT TRUNCATED AT 250 WORDS)