Two-dimensional Endoanal Ultrasound Scan Correlates with External Anal Sphincter Structure and Function, but not with Puborectalis

BackgroundTo investigate the relevance of two-dimensional (2D) endoanal ultrasonic (EAUS) assessment of anal sphincter and puborectalis morphology by comparison to functional measures derived from patient symptoms and anorectal physiology.MethodsThirty women (mean age 44 years, mean parity 2) with anal incontinence underwent 2D EAUS, anorectal pull-through manometry, anorectal electosensitivity and sensation to rectal distension, pelvic floor dynamometry, and completed Wexner incontinence scores. EAUS images were reported blind to physiological assessments by a single experienced observer. The external and internal sphincters, and puborectalis were measured and scored for integrity and atrophy, and correlated with symptom load (Wexner score) and physiological data.ResultsThe mean Wexner score was 10 (range 1–20). The puborectalis could not be accurately measured in 12 patients (44%) on EAUS. Anal squeeze pressure correlated with integrity of the external sphincter (r = −0.4, p = 0.02) but not integrity or atrophy of the puborectalis. There were no other significant correlations between EAUS features and patient symptom load or anorectal physiology (r range, −0.42–0.26, p > 0.05).ConclusionTwo-dimensional EAUS can define sphincter integrity, has a limited role for assessment of muscular quality but is not useful for assessment of the puborectalis.