Endometriosis is the presence of endometrial tissue outside the endometrium and the myometrium. The most common locations being the ovaries and the pelvic peritoneum, followed by deep infiltrating sites.
Deep infiltrating endometriosis is the presence of endometrial implants, fibrosis and muscular hyperplasia under the peritoneum, and can involve the uterosacral ligaments, the rectosigmoid colon, the vagina and the bladder.
Deeply infiltrating endometriosis( DIE) constitutes a major concern for the gynaecologist in view of the greater severity of symptoms associated with this form of the disease, and its therapeutic complexity. Physical examination has a very limited ability to diagnose and quantify DIE. Symptoms of DIE involving the bowel vary greatly, ranging from asymptomatic women with extensive rectal involvement to patients with severe dysmenorrhea and dyschezia .
Treatment strategies include hormonal preparations or surgical excision of endometriotic nodules. However, pre-surgical staging of DIE is crucial for planning appropriate surgical intervention.
Preoperative diagnosis of infiltrative disease can now be made with good rates of sensitivity and specificity using a targeted transvaginal ultrasound examination, thus permitting the most appropriate surgical management to be followed in each case 1,2
All patients undergoing this specific ultrasound examination are submitted to bowel preparation with a mild laxative (Dulcolax fluid solution or tablet) taken orally on the eve of the examination, and receive a simple rectal enema consisting of 133 ml of Fleet enema approximately 1 hour prior to the examination2. This preparation is required to eliminate faecal residues and any gases present in the rectosigmoid immediately prior the scan. The medication is over the counter medication at a cost of less than $10.
Each ultrasound examination is interpreted and documented in real time by one of the SUFW subspecialists in gynaecological imaging. Routine analysis of the uterus and ovaries is included, as well as detailed assessment of the peritoneal surface covering the vesicouterine pouch, the pouch of Douglas, the bowel (rectum, sigmoid colon up to 30cm from the anal verge), the uterosacral ligaments, posterior vaginal fornix, and the rectovaginal septum. The process is facilitated by the prior bowel preparation, which allows all the loops of the bowel to be examined in detail, a procedure that would be impossible if air or faecal residues were degrading the ultrasound beam.
If there are endometriotic nodules in the vagina or adjacent structures, ultrasound gel may be inserted into the vagina and this will define whether the nodules are infiltrating the parietal layers of the vagina or whether they are simply adherent.
Bladder involvement is evaluated by identifying hypoechoic, irregular, nodular formations, with or without cysts, in the vesico-uterine pouch. Infiltration of the muscle layer or the bladder mucosa is investigated.
At all of these sites the likelihood of adherence is assessed by moving the transducer backwards and forwards to assess whether the structures slip smoothly over each other.
When thick blocks of tissue, nodular formations, or irregular-shaped, hypoechoic, retractable lesions are found in this area, including the uterosacral ligament, pouch of Douglas, and vagina, the specialist also looks for signs of adhesion to adjacent structures and measures the longitudinal and anteroposterior diameters of the lesions.
This type of ultrasound helps define the optimal treatment type and, if a surgical procedure is indicated, what type of surgery should be performed. Information provided includes:
1. Analysis of the size of bowel lesions
2. Definition of the number of rectal and sigmoid lesions, up to at least 30 cm from the anal verge
3. Identification of the bowel layers affected by each lesion.
4. The distance between the lower lesion and the anal verge
Preoperative planning for the individual patient is fundamental to defining optimal management, discussing alternative therapies with the patient, indicating bowel preparation, and scheduling a multidisciplinary team approach when necessary.
This new procedure for imaging DIE is currently provided by Drs Sashi Siva and Patricia Lai at Sydney Ultrasound for Women. Women undergoing such specialised examinations at SUFW can expect and will receive the highest quality expert opinion to help guide their management. The doctors at Sydney Ultrasound for Women are all accredited subspecialists of the Royal Australian and New Zealand College of Obstetricians and Gynaecologists. Trainees are not involved in the assessment and delivery of patients at SUFW, although our doctors are involved in training registrars and subspecialist Fellows at the major teaching hospitals. Women can also expect that at the completion of each imaging study, the findings will be sympathetically discussed with them prior to leaving our practices.