Obstetrical ballooning and avulsion of levator ani muscle after vaginal delivery: a literature review

Abstract

Link of Video Abstract: https://youtu.be/TWDe9uP4QX8 The levator ani muscle (LAM) is thought to be of central importance concerning pelvic organ support. 10-30% of women experience overstretched or 'ballooning' of the levator hiatus, sometimes followed by detachment or 'avulsion' of the muscle from its insertion. Both ballooning and avulsion of the LAM can occur by itself or co-exist at the same time. This literature review was conducted on multiple databases from previous studies, to help clinicians better understand the ballooning and avulsion phenomenon, thus making early diagnosis possible for earlier prolapse prevention for the patients. LAM avulsion can be diagnosed clinically using digital palpation or using imaging modalities such as ultrasound and magnetic resonance imaging (MRI). During maximal contraction (or at rest) using ultrasound, levator avulsion is indicated through a levator-urethra gap (LUG) diameter > 2.5 cm. MRI is considered highly sensitive, but it requires a higher cost and an experienced radiologist. Hiatal ballooning can be diagnosed by clinical examination based on the sum of Genital hiatus and Perineal body (Gh+Pb) and imaging with 2D, 3D, or 4D ultrasound during the Valsava maneuver. Ballooning is diagnosed clinically if Gh+Pb > 7 cm, by 2D imaging of levator hiatal anteroposterior (LHAP) diameter ≥ 6 cm, and by 3D/4D imaging of the hiatal area ≥ 25 cm2. Physiotherapeutic treatment and pelvic floor muscle (PFM) exercises can be used to treat ballooning and LAM avulsion to avoid urogynecological sequelae. There is some evidence to prevent this condition, including vitamin D consumption, epidural analgesia, kegel exercise, and vaginal dilator. PFM strength, posterior vaginal wall support, and ultrasound evidence of LAM tear can be used as potential indicators to predict pelvic floor injury. Since ballooning and avulsion of the LAM have lifelong morbidity and are not often identified early by clinicians, further research is still needed.