Role of extended transperineal ultrasound in differentiating type of midurethral slings: An exploratory study

Accurate differentiation between retropubic (RPT) and transobturator (TOT) slings is essential for guiding management of mesh-related complications. This study evaluates extended two-dimensional (2D) transperineal ultrasound (TPUS), incorporating targeted adductor compartment scanning, for sling classification, and assesses the effect of clinician experience on image interpretation.

This retrospective analysis included women attending a tertiary pelvic floor imaging clinic. In a primary analysis, original TPUS and magnetic resonance imaging (MRI) reports were compared with operative records as the reference standard. In a secondary analysis, extended 2D TPUS images were independently reviewed by four blinded clinicians with differing levels of experience to assess interobserver agreement and reproducibility.

Forty-two women were included. TPUS correctly identified all sling types with 100% accuracy (35/35; 95% CI 90.1-100.0). MRI correctly classified all cases in which a definitive sling type was reported (26/26), but six MRI examinations were non-diagnostic; when these were included, overall MRI accuracy decreased to 81.3% (26/32; 95% CI 64.7-91.1). Concordance between TPUS and MRI was 71.8% (28/39), with moderate agreement (κ=0.46; 95% CI [0.20-0.72]). In the secondary blinded review analysis, observer performance varied according to experience, with near-perfect agreement among experts and lower agreement among less experienced clinicians.

Extended 2D TPUS can accurately identify sling type in specialist practice and represents a practical first-line imaging modality. However, interpretation is operator-dependent, highlighting the importance of structured training and standardized imaging protocols.