Dr. Loris Trenti, specialist in General Surgery, explains what an endoanal ultrasound is, how this technique is performed and how to prepare for it.
Endoanal ultrasound consists of the exploration, by means of ultrasound, of the anus, the rectum (final part of the large intestine) and its neighboring structures. This exploration helps to complete the study of fistulas, anal abscesses, tumors of the anorectal region, anal pain and fecal incontinence among others.
How does it benefit you?
It allows to know the ultrasound characteristics of lesions located in the wall of the anal canal and rectum, neighboring structures and muscles of the anus. This allows us to know the depth of a lesion, if it affects neighboring structures and, in the case of the anal sphincter muscles, if there is any alteration or rupture. It is also essential in the preoperative study of anal fistula surgery because it allows the assessment of the relationship between the fistula tracts and the anal sphincters.
What preparation is needed for an endoanal ultrasound?
In some cases it is necessary to apply a small enema (lavativa – Micralax) about 3-4 hours before the test.
It is not necessary to come to the test accompanied. Once the test has been performed, you can resume your normal daily activities.
How is the endoanal ultrasound performed?
It is performed with a very thin rigid probe that is inserted through the anus about 3-5 cm. The insertion of the probe is done in a comfortable position, lying on the left side, and the test lasts about 10-15 minutes.
No medication is usually applied, except in some cases in which it may be necessary to introduce oxygenated water diluted with saline into perianal fistulous orifices to improve the study of fistulas.
What effect will endoanal ultrasound have on you?
It is usually well tolerated, although there is variability from one patient to another. The introduction of the probe may cause temporary discomfort or a sensation of desire to defecate. Once the scan has been performed, normal daily activity can be resumed.