PURPOSE: Anal sphincter anatomy, as measured by 2D endoanal ultrasound (EUS), does not always correlate with clinical data. The purpose of this study was to determine if more detailed 3D measurements correlate with symptom scores and manometry.
Methods: 3D EUS studies and charts of patients with fecal incontinence (FI) were reviewed by two observers for external anal sphincter (EAS) length and for the presence of a sphincter defect and its extent (measured by the radial angle, length in the sagittal plane, and the volume percentage). Measurements were correlated to manometric pressures, and the Cleveland Clinic Foundation Fecal Incontinence (CCF-FI) score.
Results: 61 patients, median age 53 years (15-82), were evaluated. 29 patients had either complete (17) or partial (15) EAS defect and 32 patients had an intact sphincter complex. CCF-FI scores were similar in patients with and without EAS defects (12.5 +/- 5.6 and 11.4 +/- 5.5 respectively). EAS length was significantly longer (2cm +/- 0.62 vs.3cm +/- 0.4, p=0.02) and mean maximal squeeze pressure (MMSP) was significantly higher (66.9 mmHg +/- 52.9 vs. 99.7 mmHg +/- 52.6, p=0.009) in patients with intact sphincters than those with any defect. Partial and complete EAS tears had similar volumetric defects (14.5% +/- 5.5 and 17.5% +/- 7.2, p= 0.25) and showed no correlations with physiologic tests or symptom scores. There was a statistically significant pressure difference between areas of sphincter with and without defect within patients with partial defects (56 +/- 23.4 mmHg and 76 +/- 31.6 mmHg, p=0.02), and a significant correlation between % volume deficit and the pressure difference(r= 0.60, p=0.05).
Conclusions: Improvements in anal sphincter imaging correlates with pressure measurements within anal sphincters with partial defects, but not with symptom scores or by manometric pressures differences between partial and complete EAS injuries. This lack of differences may reflect similar volumetric defects.