Prediction of pouch of Douglas obliteration in women with suspected endometriosis using a new real-time dynamic transvaginal ultrasound technique: the sliding sign.

OBJECTIVE: To evaluate preoperative real-time dynamic transvaginal sonography (TVS) in the prediction of pouch of Douglas (POD) obliteration in women undergoing laparoscopy for suspected endometriosis.

METHODS: This was a multicenter prospective observational study undertaken from January 2009 to November 2011. All women with symptoms suggestive of endometriosis who were scheduled for laparoscopy underwent detailed preoperative TVS, in particular to ascertain whether the POD was obliterated. POD obliteration was assessed using a real-time TVS technique called the 'sliding sign'. Preoperative TVS sliding sign findings were then compared to gold standard laparoscopic POD findings.

RESULTS: One hundred consecutive women with preoperative TVS and laparoscopic outcomes were included in the final analysis. Mean age was 32.8 years and mean age at diagnosis of endometriosis was 27.4 years. At laparoscopy, 84/100 (84%) were found to have some form of endometriosis (73% peritoneal endometriosis, 35% ovarian endometrioma(s), 33% deep infiltrating endometriosis). At laparoscopy, 30/100 (30%) had an obliterated POD and 19/30 (63.3%) of these women also had evidence of bowel endometriosis. The sonographic sliding sign technique had an accuracy of 93.0%, sensitivity of 83.3%, specificity of 97.1%, positive predictive value of 92.6%, negative predictive value of 93.2%, positive likelihood ratio of 29.2 and negative likelihood ratio of 0.17 in the prediction of POD obliteration (P = 1.8E-16).

CONCLUSIONS: Preoperative real-time dynamic TVS evaluation using the sliding sign seems to establish with a high degree of certainty whether the POD is obliterated. Given the increased risk of deep infiltrating endometriosis in women with POD obliteration, the TVS sliding sign technique may also be useful in the identification of women who may be at a higher risk for bowel endometriosis.