Levator ani muscle avulsion in patients with pelvic floor dysfunction - Does it help in understanding pelvic organ prolapse?

Introduction: Levator ani muscle (LAM) lesions are an important factor in the development of female pelvic organ prolapse (POP).

Objective: To determine the prevalence of LAM avulsion by transperineal ultrasound. The second outcome is to evaluate the association between complete avulsion and the type, degree, and number of POP compartments involved.

Materials And Methods: This was a retrospective cohort study performed in a tertiary hospital that included patients with pelvic floor dysfunction evaluated from January 2016 to March 2020. The presence of LAM avulsion was diagnosed by 3D/4D pelvic floor transperineal ultrasound. We identified women with POP, and they were classified according to the POP-Q system. The association between complete avulsion and the type, degree and number of compartments were calculated using generalized logit models.

Results: 848 women were included in the analysis. A complete LAM avulsion was found in 195 patients (23 %). Patients with complete avulsion were 4.7 (CI: 1.98-11.5) times more likely to have POP than patients with partial avulsion. The anterior compartment was the most frequently affected (n = 605, 25.8 %). Women with severe stage POP were 3.13 times (CI: 1.90-5.16) more likely to have bilateral complete LAM avulsion than women with mild prolapse. Patients with three-compartment POP were 2.75 times (CI: 1.53-4.94) more likely to have unilateral complete LAM avulsion than women with POP in one compartment.

Conclusion: The prevalence of LAM avulsion is high in patients with urogynecological symptoms. Patients with complete LAM avulsion are at greater risk of developing POP and have a more advanced stage of prolapse and involvement of multiple compartments.