Deep Endometriosis According to IDEA: Sliding Sign and Pouch of Douglas Obliteration
Sliding Sign as a Dynamic Maneuver
The key maneuver is the sliding sign, assessed by applying gentle pressure and observing whether the posterior cervical or uterine wall slides freely relative to the rectum and adjacent bowel segments. Normal (positive) sliding sign reflects preserved mobility and argues against retro-uterine space (cul-de-sac) obliteration. Absence of normal sliding raises concerns regarding adhesive disease or deep infiltrative pathology.
Both practical guidelines and literature oriented to IDEA recognize the diagnostic value of this dynamic observation. Dynamic assessment has changed the very concept of "routine" pelvic scanning.
Prediction of Pouch of Douglas Obliteration
Assessment of sliding sign is considered a method for predicting pouch of Douglas obliteration in women with suspected endometriosis using dynamic transvaginal real-time technique (Reid S. et al., Ultrasound Obstet Gynecol 2013).
Systematic IDEA Approach
A systematic approach to ultrasound evaluation of the pelvis in women with suspected endometriosis, including terminology, definitions, and measurements, is outlined in the consensus statement of the International Deep Endometriosis Analysis (IDEA) group (Guerriero S. et al., Ultrasound Obstet Gynecol 2016; 48: 318–332).
Question Mark Sign
When combined with posterior pelvic endometriosis, uterine morphology may resemble a "question mark": the uterus is tilted posteriorly, the fundus is oriented toward the posterior pelvis, and the cervix toward the bladder. This condition is characterized by a negative uterine sliding sign.
Additional Ultrasound Features (Adenomyosis)
Key findings include: small fluid collections within the myometrium representing cystic dilation of ectopic glands; indistinct endometrial-myometrial interface, often thickened, irregular, or discontinuous; echogenic lines, "buds," or "islands" beneath the endometrium indicating basal endometrial invasion.
Frequently asked questions
What does a positive sliding sign indicate?
Normal (positive) sliding sign reflects preserved mobility of the posterior uterine wall/cervix relative to the rectum and argues against pouch of Douglas obliteration.
What does absence of sliding sign suggest?
Absence of normal sliding increases suspicion for adhesions or deep infiltrative endometriosis.
How is the maneuver performed?
Gentle pressure is applied and observation is made to determine whether the posterior cervical or uterine wall slides freely relative to the rectum and adjacent bowel segments.
What is the question mark sign?
Uterine morphology resembling a question mark when combined with posterior pelvic endometriosis: fundus oriented posteriorly, cervix toward the bladder; sliding sign is negative.
Which source describes prediction of obliteration using sliding sign?
Reid S. et al. "Prediction of pouch of Douglas obliteration in women with suspected endometriosis using a new real-time dynamic transvaginal ultrasound technique: the sliding sign", Ultrasound Obstet Gynecol 2013; 41(6): 685–691.