Endosonography of the anal sphincters: incontinent and continent patients and healthy controls.

It has previously been shown that in healthy subjects anal sphincter functions as assessed by anorectal manometry and anal sphincter anatomy as measured by endoluminal ultrasound are poorly correlated. It remains to be shown, however, whether this is true for a larger series of patients with anorectal dysfunctions such as incontinence, and what is the clinical relevance of anal sonography. Anal sonography was performed in 42 consecutive patients with fecal incontinence, in 19 patients with constipation and/or anal pain, and in 15 healthy volunteers to determine anal sphincter integrity and the dorsal diameter of the internal and external anal sphincter muscles. Conventional multilumen anorectal manometry was performed in all subjects and patients to determine, among others, external and internal sphincter (EAS, IAS) performance at rest and during squeezing. It was shown that healthy subjects exhibit significantly higher muscle diameters of the IAS than both patient groups, but the EAS was similar in all groups. In 11/42 cases of incontinent patients, in 3/19 constipated patients, but in none of the controls a muscle defect of the EAS was found with sonography. Thirteen of these 14 patients were women with previous birth traumas. EAS but not IAS muscle thickness and muscle performance (squeezing and resting, respectively) were significantly correlated. Across all groups, women had smaller EAS muscle diameters than men. It is concluded, that in incontinent patients anal sonography may reveal additional information of clinical relevance in a substantial fraction of patients, and, thus, both anal manometry and anal ultrasound are of clinical value.