Endosonography in benign anorectal disease: an overview

Background: Endosonography may be used for diagnosing various anorectal dis orders. This review addresses its technique and clinical use in benign anor ectal disease. Methods: The English literature available on anal endosonogr aphy was reviewed. The different modalities, the endosonography technique i tself and its value in benign anorectal disease were described. Results: An al endosonography is easy to perform, has a short learning curve and causes less discomfort than routine digital examination. Anal sphincters can be c learly visualized and distinction is possible between the internal (hypoech oic) and external (hyperechoic) anal sphincters. Other pelvic floor structu res, like the puborectalis muscle, can also be visualized. Endosonography i s mostly used in the assessment of faecal incontinence; it has brought new insight into the pathophysiological mechanisms of this disorder and can sel ect patients with traumatic incontinence for sphincter repair. It has repla ced electromyographical sphincter mapping, which is a painful and time-cons uming procedure. In perianal sepsis, endosonography assists in defining fis tula tract anatomy. The use of contrast agents has significantly increased the accuracy of endosonography in the assessment of perianal fistulae. In a ddition, endosonography is an excellent alternative to expensive MRI. Besid es its use in incontinence and perianal sepsis, with anal endosonography su rgical possibilities can be evaluated in individual patients, for example, to decide whether a sphincter repair or a lateral sphincterectomy is prefer able. Finally, endosonography may occasionally identify internal sphincter myopathy in patients with intractable constipation or proctalgia. Conclusio n: Anal endosonography images the internal and external sphincters with hig h accuracy. It is easy to perform and is especially valuable in the diagnos is of anal incontinence and perianal sepsis.