Is There a Difference in Hiatal Area on Straining Between Type I and II Levator Avulsions?

A distinction can be made between levator avulsions that preserve the appearance of a connection to the pelvic sidewall (type I), and those that do not (type II). We evaluated whether avulsion type affects hiatal area on straining.

This retrospective observational study used archived patient data from a tertiary urogynaecological service between 2/2019 and 12/2020. All patients underwent a standardized interview, POP-Q examination, and 4D pelvic floor ultrasound. On analysing the archived volume data, the first author assessed hiatal area on maximum straining, the second author determined avulsion type, blinded to all other data. The primary outcome was hiatal area on straining, with avulsion type as the explanatory variable.

Inter-rater reliability for hiatal area on straining showed an intraclass correlation coefficient (ICC) of 0.872. Five hundred and twenty-four archived volume data were available. Mean age was 58 years (range 20-95), mean body mass index (BMI) was 29.1 kg/m² (range 16.9-56.8), and mean parity was 3 (range 0-8). Stress and urgency urinary incontinence were reported in 387 (73.9%) women, prolapse symptoms in 267 (51%). Mean POP-Q points were Ba = -1 cm (-3 to +5), C = -5 cm (-10 to +9), and Bp = -1 cm (-3 to +3). Mean hiatal area on straining was 26.9 cm² (8.1-60 cm²). A full/complete avulsion defined as detachment of the pubococcygeous/puborectalis or 'pubovisceralis' muscle from its insertion on the inferior pubic ramus was diagnosed in 124 women (24%), with 43 (8%) bilateral. Avulsion type classification was impossible in 10 due to suboptimal image quality; in 80, we found a type I avulsion (15.3%), and in 34, a type II (6.5%). No significant difference was observed in hiatal area on straining between type I and type II avulsions (32.6 cm² [SD 8.39] vs. 33.48 cm² [SD 11.29]; P = 0.6).

Levator avulsion type does not seem to significantly affect hiatal area.