Transvaginal ultrasound for "rectosigmoid endometriosis" diagnosis: Is bowel preparation necessary?

Bowel preparation does not increase the diagnostic accuracy of transvaginal ultrasound in the diagnosis of rectosigmoid endometriosis.

Key Points

Highlights:

• This prospective study in a tertiary center evaluates whether bowel preparation makes a difference in diagnostic performance of transvaginal ultrasound (TVS) to detect rectosigmoid endometriosis.
• The authors concluded that there is no difference in the diagnosis of rectosigmoid endometriosis between patients with or without bowel preparation.

Importance:

• Bowel preparation, which is an uncomfortable procedure for the patients, is not necessary for the diagnosis of rectosigmoid endometriosis in experienced hands, as it does not increase the diagnostic performance.

What’s done here?

• 262 patients referred to the tertiary center because of pain symptoms and/or suspicion of endometriosis included in this prospective study.
• Patients were evaluated twice with TVS with and without bowel preparation and then underwent laparoscopic surgery were included.
• The patients with a previous colorectal endometriosis diagnosis, previous intestinal surgery, previous hysterectomy or bilateral ovariectomy, or to whom TVS could not be performed were excluded.
• All patients were evaluated with TVS without bowel preparation, then they were asked to come for a second examination for TVS and with bowel preparation performed by another gynecologist.
• Ultrasonographic examinations were performed by two gynecologists experienced in the ultrasonographic diagnosis of endometriosis. They were blinded about the patients’ vaginal examinations and only informed about clinical history. During the ultrasonographic examination, vagina or rectum was not distended with contrast medium.  
• The diagnosis of endometriosis was confirmed by histopathological examinations, and McNemar’s test was used to detect the diagnostic accuracy of TVS with or without bowel preparation.

Key results: 

• Out of 262 women included, 118 (45%) had rectosigmoid endometriosis at surgery whereas 136 (51.9%) had endometriosis without rectosigmoid involvement. 
• The ultrasonographic examination with or without bowel preparation was successfully completed in all included patients.
• No difference was detected in the diagnostic performance of TVS with or without bowel preparation in the diagnosis of rectosigmoid endometriosis, submucosal infiltration, and multifocal disease in patients with ultrasonographically diagnosed rectosigmoid endometriosis.

 Strengths and Limitations

• The prospective design, the sample size, performance of TVS by blinded ultrasonographers, the optimal bowel preparation using a standardized protocol represent the strength of this study.
• The study performed in a population with a high prevalence of rectosigmoid endometriosis. Experienced sonographers evaluated the patients, bowel preparation may change the diagnostic performance of TVS in less experienced hands. The surgeons were not blinded to the ultrasonographic findings of the patients. Lastly, all included women were resistant to hormonal treatment options. Therefore, the results of the study could not be applied to the patients who do not require surgical treatment.  

Lay Summary

Rectosigmoid endometriosis is a severe form of deep endometriosis. Women having rectosigmoid endometriosis present with pain and several intestinal complains such as constipation, diarrhea, intestinal cramping, abdominal bloating, feeling of incomplete evacuation, the passage of mucus and rectal bleeding during the menstrual period.

Transvaginal ultrasound (TVS) is the first line diagnostic method for the detection of rectosigmoid endometriosis. This non-invasive method is also cheaper, easier to tolerate than other methods such as rectal endoscopic sonography, magnetic resonance imaging. Some clinicians prefer bowel preparation prior to TVS to improve the diagnostic performance in the diagnosis of rectosigmoid endometriosis.

Ferrero et al, a group of scientists from Italy, published a prospective study titled as “Transvaginal ultrasonography with or without bowel preparation in the diagnosis of rectosigmoid endometriosis: prospective study” in the medical journal  Ultrasound in Obstetrics and Gynecology. The authors investigated whether there is a benefit of bowel preparation prior to TVS in the diagnosis of rectosigmoid endometriosis.

All included patients were evaluated by one gynecologist experienced in the ultrasonographic diagnosis of endometriosis performing TVS without bowel preparation during the first examination. Then patients were invited for a second TVS with bowel preparation performed by another experienced gynecologist within 1 week to 3 months after the first examination. Both of them were blinded to the patients’ vaginal examinations and only informed about their clinical history. All visible endometriotic lesions located in the rectosigmoid region were excised during the laparoscopic surgery by one of the following techniques: shaving, discoid resection or segmental resection.

Definitive diagnosis was made by the histopathological examination of specimens excised during the laparoscopic surgery. They found no significant difference in the diagnostic accuracy of TVS with or without bowel preparation in diagnosing rectosigmoid endometriosis.

Authors emphasized that the patients with suspicion of rectosigmoid endometriosis may be evaluated with TVS without the need to prepare bowel. “Bowel preparation does not provide additional benefit in the diagnosis of rectosigmoid endometriosis” they added.    

Research Source: https://www.ncbi.nlm.nih.gov/pubmed/30079504