Intraobserver and interobserver agreement in the diagnosis of anal sphincter tears by postpartum endosonography.

OBJECTIVE: To evaluate intraobserver and interobserver agreement in the diagnosis of anal sphincter tears by endosonography when performed immediately postpartum by resident obstetricians. METHODS: Fifty-four primiparous women who delivered vaginally and had no anal sphincter tears (third- or fourth-degree perineal tears) diagnosed clinically were recruited. Four observers assessed photographic prints and video recordings of anal endosonography performed before the suture of the perineum. We calculated the intra- and interobserver agreement and the kappa coefficient to quantify the reliability of the diagnosis of clinically occult sphincter tears. RESULTS: The observers described sphincter tears in 13-28% of the prints, and in 7-32% of the video recordings. Intraobserver agreement was rated as substantial for prints (kappa, 0.63), and moderate for video recordings (kappa, 0.48). The interobserver agreement was fair for prints (kappa, 0.34) and moderate for video recordings (kappa, 0.42). CONCLUSION: Endosonography performed immediately postpartum to diagnose anal sphincter tears is of moderate reliability.