Comparison between Sonography-based and Surgical Extent of Deep Endometriosis Using the Enzian Classification - A Prospective Diagnostic Accuracy Study.

STUDY OBJECTIVE: To compare a preoperative evaluation of deep endometriosis (DE) by transvaginal sonography (TVS) according to the Enzian classification with the intraoperatively assessed extent of DE using the Enzian system. DESIGN: Prospective diagnostic accuracy study. SETTING: Tertiary referral center for endometriosis. PATIENTS: Women undergoing TVS and surgery for DE between 2017 and 2019 (N = 195). INTERVENTIONS: Evaluation of DE lesion sizes according to the Enzian classification as evaluated by preoperative TVS compared with surgical findings. MEASUREMENTS AND MAIN RESULTS: The rate of exact concordances between preoperative TVS-based predictions of DE lesion sizes and intraoperatively assessed lesion sizes according to the Enzian classification varied depending on anatomic localizations, that is, Enzian compartments, and evaluated lesion size. The highest rate of exact concordances was found in Enzian compartment C (rectosigmoid) in which 86% of all TVS C3 lesions were confirmed as such at surgery. Enzian compartment A (vagina, rectovaginal septum) showed similar results. The rates of exact concordances were slightly lower in Enzian compartment B (uterosacral ligaments, parametria), with confirmation at surgery of 71% of TVS B2 lesions. In most cases of discordant findings, an underestimation of the lesion size by 1 severity grade was observed compared with the intraoperative findings. In Enzian compartment FB (urinary bladder), 91% of the lesions seen at TVS and 98% of cases without any lesion at TVS were confirmed surgically. TVS could detect DE preoperatively in compartments A, B, C, and FB with an overall sensitivity of 84%, 91%, 92%, and 88%, respectively, and a specificity of 85%, 73%, 95%, and 99%, respectively. CONCLUSION: TVS provides a valuable preoperative estimation of DE localization and lesion size using the Enzian classification, especially for Enzian compartments A, C, and FB. For Enzian compartment B, the exact assessment of the lesion size using the Enzian system seems to be less precise than for the other compartments.