The importance of pre‐operative ultrasound diagnosis of pouch of Douglas obliteration

P re-operative diagnosis of pouch of Douglas (POD) obliteration is important for several reasons. We know that pre-operative identification of POD obliteration allows for the identification of women who may be at a higher risk of having underlying bowel endometriosis. In women noted to have POD obliteration at laparoscopy, there is a three times higher risk of concurrent bowel deep infiltrating endometriosis (DIE). If POD obliteration is detected during the pre-operative transvaginal ultrasound scan (TVS) assessment, then these high risk women could then be referred to have a more detailed pelvic ultrasound performed by an advanced gynaecological sonologist/sonographer. This is important in order to identify and map posterior compartment DIE nodules that may exist in the anterior rectum, anterior recto-sigmoid, retro-cervix, vagina, rectovaginal septum, and/or uterosacral ligaments. Another reason to identify whether the POD is obliterated pre-operatively using TVS, is to provide the laparoscopic surgeon with as much information as possible in relation to what to expect at surgery. This is very important as part of the pre-operative planning stage of surgery and when the POD obliteration is secondary to the presence of underlying posterior compartment DIE, the procedure is often long and complex, requiring the skills of an advanced laparoscopic surgeon (with colorectal input, in the case of co-existing bowel endometriosis). Therefore, when POD obliteration is noted on TVS and underlying posterior compartment endometriosis is suspected, these women should be referred to an advanced laparoscopic surgeon and/or colorectal surgeon to discuss the implications of possible bowel endometriosis and expectations for surgery. By ensuring the appropriate referral of these high risk women for bowel endometriosis to an advanced laparoscopic surgeon, this may also prevent the situation where the woman undergoes two laparoscopies; i.e. the primary laparoscopy is performed by a general gynaecologist who is not able to excise the severe endometriosis and this results in the need for a second laparoscopy by an advanced laparoscopic surgeon. I truly believe that with experience, the need for this " primary diagnostic laparoscopy " can be potentially negated by the introduction of advanced gynaecological ultrasound skills to correctly identify POD obliteration in conjunction with severe posterior compartment DIE. Posterior compartment DIE is known to be associated with POD obliteration and the use of pre-operative imaging techniques to predict posterior compartment DIE have been well documented. TVS is the most commonly used imaging modality to predict posterior compartment DIE location and extent. It is …