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

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. 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. 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. 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.