Minimal criteria for the diagnosis of avulsion of the puborectalis muscle by tomographic ultrasound

Introduction and hypothesis: Puborectalis avulsion is a likely etiological factor for female pelvic organ prolapse (FPOP). We performed a study to establish minimal sonographic criteria for the diagnosis of avulsion. Methods: We analysed datasets of 764 women seen at a urogynecological service. Offline analysis of ultrasound datasets was performed blinded to patient data. Tomographic ultrasound imaging (TUI) was used to diagnose avulsion of the puborectalis muscle. Results: Logistic regression modelling of TUI data showed that complete avulsion is best diagnosed by requiring the three central tomographic slices to be abnormal. This finding was obtained in 30% of patients and was associated with symptoms and signs of FPOP (P<0.001). Lesser degrees of trauma ('partial avulsion') were not associated with symptoms or signs of pelvic floor dysfunction. Conclusions: Complete avulsion of the puborectalis muscle is best diagnosed on TUI by requiring all three central slices to be abnormal. Partial trauma seems of limited clinical relevance.