Clin Surg | Volume 5, Issue 1 | Research Article | Open Access

Accuracy of Clinical Diagnosis of Anal Sphincter Defect: Clinical Evaluation vs. 3 Dimensional Transperineal Ultrasound

Federica Capanna1,2*, Christian Haslinger1 and Josef Wisser1

1Division of Obstetrics, University Hospital of Zürich, Switzerland
2Division of Obstetrics and Gynecology, University Hospital of Geneva, Switzerland

*Correspondance to: Federica Capanna 

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Background: Obstetric Anal Sphincter Injuries (OASIS) are common and an important factor in the etiology of anal incontinence. Objective: The objective of this study was to evaluate, classify and compare the agreement of clinically diagnosed third-degree sphincter tears with 3D-Transperineal Ultrasound (3D-TPUS) realized within 3 to 7 days post-delivery. Design: This is a retrospective observational study. Settings: The study examined 8779 women who delivery by vaginal way 119 (1.35%) of those had a primary repair of third-degree perineal tear. Patients: 119 patients with third-degree obstetric anal sphincter tears were diagnosed and treated, 85 of those underwent a 3D-TPUS examination 3 to 7 days postpartum. Main outcome measures: We compared the proportion of third-degree perineal tears, classified with the clinical examination as Grade 3a+b and Grade 3c, with the 3D-TPUS. Results: In 16 patients with clinically diagnosed third-degree perineal tears Grade a and b, the ultrasound examination confirmed the lesion of the External Anal Sphincter (EAS) muscle, but in 9 patients (56% of the cases) we found a lesion of the Internal Anal Sphincter (IAS) muscle, missed by clinical examination. In the remaining 69 patients with the third-degree perineal tears Grade c, the ultrasound examination confirmed both lesions (EAS and IAS muscles) in 56 women, but in 13 patients (19% of the cases) defects of the IAS muscle could not be confirmed by the ultrasound. Limitations: Our study design did not allow detecting occult anal sphincter lesions because we did not examine an unselected group of women after vaginal delivery. Conclusion: There was moderate agreement regarding diagnosis of perineal tears Grade 3a+b and Grade 3c between ultrasound and clinical examination, so a combined use of clinical and ultrasound knowledge can improve the possibility to find a gold standard in the diagnosis of OASIS.


Perineum; Ultrasound; Urogynecology; Incontinence


Capanna F, Haslinger C, Wisser J. Accuracy of Clinical Diagnosis of Anal Sphincter Defect: Clinical Evaluation vs. 3 Dimensional Transperineal Ultrasound. Clin Surg. 2020; 5: 2743..

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