Prediction of Pouch of Douglas Obliteration: Point-of-care Ultrasound Versus Pelvic Examination

Abstract

Study objective: To evaluate the point-of-care preoperative transvaginal ultrasound (TVUS) sliding sign in comparison with palpation of a nodule on digital pelvic examination for the prediction of pouch of Douglas (POD) obliteration.

Design: Analysis of data from a prospective data registry (Canadian Task Force classification II-2).

Setting: A tertiary referral center.

Patients: Women with suspected endometriosis who had preoperative pelvic examination and point-of-care TVUS followed by laparoscopic surgery between August 2015 and December 2016.

Interventions: Women were preoperatively assessed for the prediction of POD obliteration with pelvic examination for a nodule and point-of-care TVUS uterine/cervix sliding sign.

Measurements and main results: The study included 269 women, 15.2% (41/269) of whom had POD obliteration at the time of surgery. A preoperative negative sliding sign had a sensitivity of 73.2% (95% confidence interval, 57.1%-85.8%) and a specificity of 93.9% (95% CI, 89.9%-96.6%) in the prediction of POD obliteration compared with preoperative palpation of a nodule on pelvic examination, which had a sensitivity of 24.4% (95% CI, 12.4%-40.3%) and a specificity of 93.4% (95% CI, 89.4%-96.3%). The difference in sensitivity was statistically significant (McNemar test, p <.001). A negative sliding sign was also associated with longer operating times and more difficult surgery including the need for ureterolysis.

Conclusion: The point-of-care TVUS sliding sign showed significantly improved sensitivity compared with palpation of a nodule on pelvic examination for the prediction of POD obliteration. Therefore, the point-of-care TVUS sliding sign improves the preoperative assessment of POD disease and thus may lead to more optimal surgical planning in women with suspected endometriosis.

Keywords: Deep infiltrating endometriosis; Endometriosis; Pouch of Douglas obliteration; Sliding sign; Transvaginal ultrasound.