Obstetric trauma can have a profound impact on quality of life, with symptoms including urinary and faecal incontinence, constipation and pain. Symptoms are thought to be due to damage of muscles including the external and internal anal sphincters and puborectalis muscles, in addition to pudendal neuropathy (1,2). Subjective (questionnaires) and objective measures (ultrasound scans and anal manometry measurements) can be evaluated in women presenting with pelvic floor related disorders and can be used to quantify and monitor the burden of symptoms and extent of anatomical damage.
The Birmingham Bowel and Urinary Symptoms Questionnaire (BBUSQ-22) is a validated symptom questionnaire that objectively assesses faecal storage, evacuation and incontinence as well as urinary symptoms in four domains. Our aim was to assess whether findings on endoanal ultrasound (EAUS) and anal manometry (AM) correlate with patient scores obtained from these domains. 
This retrospective single centre study aims to investigate the association between symptoms of faecal incontinence (FI) and faecal evacuation (FE) with internal anal sphincter (IAS) and external anal sphincter (EAS) areas and anorectal pressures. 

Hypothesis: FI and FE symptom scores from the BBUSQ-22 correlate with EAUS and anal manometry findings.

A retrospective cohort study of women attending a Pelvic Floor Clinic with a previous obstetric sphincter injury at a tertiary urogynaecology department between February 2015 and April 2021 were identified. Women attending the pelvic floor clinic completed a BBUSQ-22 questionnaire. A history was taken and women underwent an external perineal examination followed by AM and EAUS. Anal manometry was recorded with the women supine in the left lateral position using a one-way four French (4Ch) catheter attached to a Laborie UDS transducer using Laborie UDS 120 GOBY software version 12.0. A single resting pressure was taken followed by three squeeze pressures with the best reading being recorded. 2D/3D EAUS was performed using a BK Ultrasound FlexFocus 500. 
Measurements of the IAS and EAS were performed offline. Sphincter thickness was measured at 12, 3, 6 and 9 o’clock positions and a measure of total sphincter area was also obtained. Information was recorded in an encrypted Microsoft Excel version 16.48 file with statistical analysis being performed using IBM SPSS Statistics version 27. 
Participants were categorised as having normal or abnormal FI and FE symptoms (3). This was done using the standardised analysis and coding procedures recommended by the creators of the questionnaire (3). Participants were then categorised into groups dependent on their combined symptoms: abnormal, mixed and normal. Those in the abnormal group were symptomatic for FI and FE as they scored above the cut-off score within the questionnaire. The mixed group had either abnormal FI or FE symptoms. The normal group were asymptomatic for both FI and FE, with their scores being below the recommended cut-off for clinically relevant symptoms.  Mann Whitney U and one-way ANOVA statistical tests were used to investigate for potential differences between groups. A value of p<0.05 was used as a measure of significance.

339 questionnaires were reviewed, with 11 women being excluded as they failed to complete questions 3-6. 328 women had their electronic health records searched for their delivery information and comprehensive patient data including age, parity, mode of delivery and grading of perineal tear. 224 women were excluded due to demographic data not being available, investigations not being performed or available or the dates of the questionnaire and clinic not being the same. 102 women fully completed the questionnaire and underwent AM and EAUS. 
No differences were observed between symptomatic and non-symptomatic FI and FE groups regarding the age at delivery (mean years 31.35 ± 0.53 SEM), body mass index (24.27kg/m2 ± 0.46), neonatal birth weight (3.45kg ± 0.05) and neonatal head circumference (34.14cm ± 0.25). Further patient demographics are shown in Figure 1.
64 women had normal symptoms (asymptomatic) for both FI and FE. 28 reported as having mixed symptoms. 10 suffered from abnormal FE and FI. The mean IAS diameters for asymptomatic women at the 12, 3, 6 and 9 positions were 1.43mm, 2.04mm, 1.80mm and 2.02mm respectively. The mean EAS diameters at each position were 2.47mm, 3.22mm, 2.95mm and 3.07mm. The mean IAS and EAS areas were 1.16cm2 and 2.19cm2. For the women with mixed symptoms (either FI or FE), the mean IAS diameters at the 12, 3, 6 and 9 positions were 1.49mm, 1.98mm, 1.94mm and 2.14mm. The mean EAS diameters at each position were 2.66mm, 3.22mm, 3.32mm and 3.55mm. The mean IAS and EAS areas were 1.26cm2 and 2.65cm2. Mean IAS and EAS diameters at the 12, 3, 6 and 9 o’clock positions for the women suffering from both FI and FE symptoms were 1.42mm, 1.99mm, 1.73mm, 2.08mm (IAS) and 2.11mm, 3.42mm, 3.14mm and 3.37mm (EAS). The mean IAS and EAS areas were 1.20cm2 and 2.33cm2 respectively.
Measurements of thickness and area showed good levels of inter and intra-observer reliability with an intraclass correlation coefficient for thickness of >0.7 and ICC of area >0.797.
The only statistically significant differences observed were between the mixed group and the normal group (Fig.2). The normal group had a smaller EAS area than the mixed group (2.19cm2 ± 0.07, 2.64cm2 ± 0.19 respectively, p=0.022).

We did not find any statistical associations between anorectal pressures and ultrasound measurements when comparing those with and without faecal incontinence and evacuation symptoms separately. With further analysis, those with mixed symptoms (suffering from either FI or FE symptoms) had a larger EAS area than those with normal symptoms (n=28 and n=64 respectively). These results should be interpreted with caution due to the small sample sizes. The role of pudendal nerve damage was not accounted for and this may have played a part in the symptoms. 
Larger prospective studies with age matched controls may find further differences or correlations between those with and without symptoms in the future, so further studies are warranted.

We believe this study to be the first to compare IAS and EAS areas in women with perineal tears with and without symptoms identified by the BBUSQ-22. Despite a lack of significant differences being observed between groups, the importance of endoanal ultrasound and anal manometry interpretation must not be underestimated when identifying women requiring more specialised care such as surgery or physiotherapy. Future studies should measure EAS and IAS volumes as well as areas.

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