UOG Journal Club: March 2019 Levator ani muscle morphology and function in women with obstetric anal sphincter injury I. Volløyhaug, A. Taithongchai, I. Van Gruting, A. Sultan and R. Thakar Volume 53, Issue 3, pages 410–416 Journal Club slides prepared by Dr Erkan Kalafat (UOG Editor for Trainees)

Levator ani muscle morphology and function in women with obstetric anal sphincter injury Volløyhaug et al., UOG 2019 INTRODUCTION Approximately, one out of five women will undergo surgical repair for pelvic organ prolapse during their lifetime. ~%20 Levator ani avulsion is a significant risk factor for pelvic organ prolapse which can be detected by palpation, ultrasound or MRI. However, it is controversial whether levator ani avulsion is also a risk factor for urinary or anal incontinence.

Levator ani muscle (LAM) Levator ani muscle morphology and function in women with obstetric anal sphincter injury Volløyhaug et al., UOG 2019 INTRODUCTION Obstetric anal sphincter injury (OASI) can be diagnosed after delivery via palpation whereas most levator ani avulsions are occult. Levator ani muscle (LAM) avulsion Anal sphincter injury The primary aim of this study was to estimate the prevalence of major LAM injury in women with clinically diagnosed OASI and to explore the risk factors associated with LAM injury. The secondary aim was to assess the association between LAM injury and pelvic floor muscle contraction, anal incontinence (AI) and urinary incontinence (UI) in women with OASI.

Levator ani muscle morphology and function in women with obstetric anal sphincter injury Volløyhaug et al., UOG 2019 METHODS Women referred to Croydon University Hospital between 2013 and 2015 with a clinical diagnosis of OASI were included in the study. Included women were evaluated via: Clinical history Anal incontinence- St. Mark’s incontinence score Urinary incontinence - ICIQ-UI-SF Pelvic muscle strength - Modified Oxford Scale LAM integrity – transperineal 4D ultrasound (n = 250)

Levator ani muscle morphology and function in women with obstetric anal sphincter injury Volløyhaug et al., UOG 2019 RESULTS At the time of evaluation, 88 (35.2%) women were pregnant again. The median time interval between last pregnancy and evaluation was 5 months. Two women were excluded from analysis due to artifacts in the saved image volumes (levator muscle was assessed in 248 ultrasound volumes).

Evaluated with 4D transperineal ultrasonography Levator ani muscle morphology and function in women with obstetric anal sphincter injury Volløyhaug et al., UOG 2019 RESULTS Intact LAM (177/248, 70.6%) Major LAM avulsion (73/248, 29.4%) Evaluated with 4D transperineal ultrasonography Unilateral (49/248, 19.8%) Bilateral (24/248, 9.7%)

Levator ani muscle morphology and function in women with obstetric anal sphincter injury Volløyhaug et al., UOG 2019 RESULTS Factors associated with major LAM avulsion (univariate analysis) Previous operative delivery increased significantly the odds of major LAM avulsion along with obesity in the univariate analysis P < 0.05

Factors associated with major LAM avulsion (multivariable analysis) Levator ani muscle morphology and function in women with obstetric anal sphincter injury Volløyhaug et al., UOG 2019 RESULTS Factors associated with major LAM avulsion (multivariable analysis) Previous operative delivery (forceps) and lower BMI remained as significant risk factors for major LAM avulsion. Women with previous operative delivery had 4.1 times increased odds of major LAM avulsion. One-point increase in BMI was associated with a 10% reduced risk of major LAM avulsion.

Levator ani muscle morphology and function in women with obstetric anal sphincter injury Volløyhaug et al., UOG 2019 RESULTS Women with major LAM avulsion had weaker pelvic muscle contraction in both digital and ultrasound examination. However, major LAM avulsion was not associated with an increased severity of anal or urinary incontinence symptoms.

Levator ani muscle morphology and function in women with obstetric anal sphincter injury Volløyhaug et al., UOG 2019 DISCUSSION In this study, operative vaginal delivery was associated with a four-fold higher risk of LAM injury than was normal vaginal delivery. Women with major LAM injury had weaker pelvic floor muscle contraction as assessed by palpation and on ultrasound. No association between LAM injury and AI or UI, and no association between muscle contraction and incontinence were demonstrated.

Levator ani muscle morphology and function in women with obstetric anal sphincter injury Volløyhaug et al., UOG 2019 POINTS FOR DISCUSSION The effect of major LAM avulsions on incontinence symptoms in elderly women. Possible implications of universally screening postpartum women with transperineal ultrasonography for the detection of pelvic muscle trauma. Importance of pelvic rehabilitation for women with pelvic muscle trauma.