Persistent levator co-activation is not associated with symptoms or bother of obstructed defecation

Introduction and hypothesis The objective was to determine whether levator contraction during Valsalva (i.e. levator co-activation), as visualised on four-dimensional translabial ultrasound (4D-TLUS), is associated with obstructed defecation (OD). Methods This was a retrospective study including patients attending a tertiary urogynecological unit. All underwent an interview, clinical examination and 4D-TLUS. Frequent straining at stool, digitation or sensation of incomplete emptying during defecation were considered symptoms of OD. Archived 4D-TLUS volumes were evaluated, blinded to all other data. Hiatal anteroposterior (AP) diameter (cm) and hiatal area (cm(2)) were measured at rest and on maximal Valsalva. Patients with anatomical explanations for OD (rectocele, enterocele and/or rectal intussusception) were excluded. Reduction of hiatal AP diameter and hiatal area on Valsalva were tested for association with symptoms of OD. Results Overall, 1,383 women attended the unit from May 2013 to July 2016. Seven hundred and eight were excluded because of rectocele (n = 645), enterocele (n = 116) or rectal intussusception (n = 41) and 10 owing to missing data, leaving 665. Mean age was 53 years (16-89), mean body mass index (BMI) 27.3 kg/m(2)(15.7-64.4). OD symptoms were reported by 368 (55.3%) patients. On imaging, a reduction in hiatal AP diameter on Valsalva was seen in 11.7% cases (78 out of 665) with a mean reduction of 3.5 mm (0.2-17). A mean reduction in hiatal area of 1.9cm(2)(0.03-14.8) on Valsalva was seen in 9.8% cases (65 out of 665). These sonographic measures of levator co-activation were not associated with OD symptoms or bother caused by them (p > 0.05). Conclusions Levator co-activation seen on TLUS is not associated with obstructed defecation.