Three-dimensional endoanal ultrasonography of external anal sphincter defects in patients with faecal incontinence: Correlation with symptoms and manometry

Aim Anal sphincter anatomy on two-dimensional endoanal -ultrasonography (EUS) does not always correlate with the clinical data. The purpose of this study was to determine whether three-dimensional (3D) measurements yield a better correlation. Method The study group included consecutive patients who underwent 3D EUS for faecal incontinence over a 2-year period. The medical charts were reviewed for Cleveland Clinic Foundation Fecal Incontinence (CCF-FI) score and manometric pressures. Endoanal ultrasonographic images were reviewed for the presence of an external anal sphincter (EAS) defect and its extent, as determined by the radial angle, length in the sagittal plane and percentage volume deficit. Correlational analyses were performed between the clinical and imaging data. Results Sixty-one patients of median age 53years (range 15-82) were evaluated. Thirty-two patients had either a complete (17) or partial (15) EAS defect, and 29 patients had an intact sphincter. The CCF-FI scores were similar in patients with and without an EAS defect (12.5±5.6 and 11.4±5.5, respectively). The intact-sphincter group had a significantly greater EAS length (3±0.4 vs 2±0.62cm, P=0.02) and higher mean maximal squeeze pressure (MMSP; 99.7±52.6 vs 66.9±52.9mmHg, P= 0.009). There were no statistically significant correlations between MMSP, CCF-FI score and EAS status on 3D EUS. Mean percentage volume of the defect was similar in patients with complete and partial tears (14.5±5.5 and 17.5± 7.2%, P=0.25) and showed no correlation with physiological tests or symptom scores. Conclusion Improvements in external anal sphincter imaging have not yielded a better association with the clinical findings. The lack of clinical differences between patients with different EAS tears may reflect their similar volumetric defects.