Perineal Body Measurement Improves Evaluation of Anterior Sphincter Lesions During Endoanal Ultrasonography

“Digital delineation of the perineal body during endoanal ultrasonography improved the visualization of sphincter lesions in the majority of patients. Use of this technique improves visualization of sphincter lesions.”

This groundbreaking article transformed the way many colorectal surgeons perform endoanal examinations. By inserting a finger in the vagina and gently holding it against the posterior vaginal wall, the ability to detect external anal sphincter (EAS) defects was enhanced.”

The echogenicity of a sphincter defect in EAUS images is variable…by compressing the tissue, a different acoustic impedance is created, and a more hypoechoic image is consequently created.”

It was demonstrated that anal injuries to the EAS could be better quantified (such as distinguishing between ruptured sphincter endings and scar tissue). In addition, through the use of the perineal body method, the authors were able to identify a complete rupture of the EAS versus muscle thinning.

Further, the authors stated that it is unusual to have ambiguous findings with imaging the internal anal sphincter (IAS). A discussion of IAS thickness in patients vs. asymptomatic subjects is included.

Finally, this article presented norms for perineal body width, indicating that perineal body measurements of less than 10mm should be considered abnormal.