Is It Useful to Distinguish Type I and Type II Avulsions on Transperineal Ultrasound?

Levator avulsion is a risk factor for pelvic organ prolapse (POP) and treatment failure. The current gold standard for diagnosis is tomographic translabial ultrasound (TLUS) in the axial plane. Avulsion is usually described as full or partial, unilateral or bilateral. Further classification into Type I where there is a hyperechoic "connection" to the sidewall, and Type II when there is no such connection has been suggested. The objective is to compare associations between avulsion types and POP.

A retrospective study on archived datasets of 931 women seen at a tertiary urogynecological service. All had undergone a standardized interview, pelvic organ prolapse quantification (POPQ) examination and 4D TLUS. Postprocessing of archived ultrasound volume data was performed. Associations of avulsion types and POP symptoms and signs were tested.

Mean age was 57.8 years (19-94), mean body mass index (BMI) was 29.6 kg/m² (16.9-65.4). A total of 496 (53%) reported prolapse symptoms. Overall, 741 (80%) were diagnosed with significant prolapse on POPQ, 639 (66%) on imaging. Avulsion was found in 194 (21%). An assessment of avulsion type could be undertaken in 188 women. Type I avulsions were found in 136 women (15%), Type II in 52 (6%). Type II avulsion was not found to be more predictive of symptoms and signs of POP compared to Type I avulsion (all p > .017 versus all p < .001).

Type II avulsion, which is supposed to represent more severe trauma, does not seem to convey any additional risk of symptoms and/or signs of prolapse compared to Type I avulsion. It does not seem to be necessary to distinguish between these two avulsion types on transperineal ultrasound.