Correlation between anal sphincter defects and anal incontinence following obstetric sphincter tears: assessment using scoring systems for sonographic classification of defects.

OBJECTIVE

To determine if there is a correlation between the sonographic extent of anal sphincter defects revealed by three-dimensional endoanal sonography (EAUS) and the degree of anal incontinence following primary repair of obstetric sphincter tears.

METHODS

This was a follow-up study of women who had suffered anal sphincter tearing during vaginal delivery at Aalesund Hospital between January 2002 and July 2004. Incontinence was assessed by St Mark's score. The anal canal was assessed with three-dimensional endoanal sonography (EAUS). Sphincter defects were classified according to the Starck score and our new EAUS defect score. The EAUS images were interpreted by an observer blinded to other patient data.

RESULTS

Sixty-one women were included in this study. Incontinence was reported by 32 (52%) women at a median of 21 (range, 9-35) months after delivery. Three-dimensional EAUS datasets were obtained in 55 women. There was a significant correlation between St Mark's score and our EAUS defect score (P = 0.034), and correlation approached but did not reach significance between St Mark's score and the Starck score (P = 0.053). There was a strong correlation between our EAUS defect score and the Starck score (P < 0.001).

CONCLUSIONS

There is a positive correlation between the extent of sphincter defects and the degree of anal incontinence following primary repair of obstetric sphincter tears. Our findings highlight the importance of adequate reconstruction of the anal sphincters during primary repair.