Dynamic 2-dimensional transperineal ultrasound evaluation in labor room as a screening tool for anal sphincter injuries and anal incontinence in primiparous women

Abstract Background Early repair of obstetric anal sphincter injuries is crucial in the prevention of anal incontinence, but the diagnostic accuracy of the clinical examination after delivery is poor. Endoanal ultrasound is now regarded as the gold standard for diagnosing anal sphincter injuries and it improves the diagnosis of these lacerations. Four-dimensional transperineal ultrasound have been proposed as an effective and less invasive alternative to endoanal ultrasound in the diagnosis of anal sphincter injuries. Objective to evaluate the feasibility and accuracy of the assessment of anal sphincter contraction by dynamic two-dimensional transperineal ultrasound (2D-TPUS) immediately after delivery and its correlation with anal incontinence at four months follow up. Study Design A non-consecutive series of nulliparous women with low-risk singleton term pregnancies were recruited in labor room after vaginal delivery for the purpose of this study from January 2017 to July 2017. All enrolled patients had a clinical examination of the perineum by the caregiver and repeated by an experienced research fellow. For each patient a further dynamic 2D-TPUS were carried out. Before the perineal repair women were asked to contract the anal sphincter during two-dimensional transperineal ultrasound and they were divided in two groups according to the sonographic findings: women with sonographic evidence of anal sphincter contraction (Group A) and women with no evidence of contraction at ultrasound (Group B). A follow-up examination of anal sphincter integrity with four-dimensional transperineal ultrasound (4D-TPUS) was carried out 4 months after delivery. At this time the levator ani integrity was evaluated as well using four-dimensional transperineal ultrasound, as previously described. Results Over the study period 69 women were enrolled. In 55 women (80%) there was evidence of proper anal sphincter contraction (Group A), while in 14 cases (20%) it was not possible to identify anal sphincter contraction using dynamic two-dimensional transperineal ultrasound (Group B), while obstetric anal sphincter injuries (OASIS) detected through clinical examination were significantly more frequent in Group B than in Group A (13/14, 93% vs. 7/55, 12%, p Conclusion Dynamic two-dimensional transperineal ultrasound is a feasible technique and a useful supporting tool for the assessment of anal sphincter integrity in labor room prior to suturing. Anal incontinence at 4 months follow up is more frequent among women with no evidence of anal sphincter contraction at dynamic two-dimensional transperineal ultrasound after delivery.