Hypothesis / aims of study
Pelvic floor disorder (PFD) is an umbrella term representing a myriad of complex conditions spanning across various specialties, encompassing Urology, Gynaecology and Colorectal surgery(1). These disorders, caused by both anatomical and functional causes, have a profound impact on the patient’s overall quality of life. With manifestations such as pelvic organ prolapse, urinary incontinence, sexual dysfunction and defecatory disorders, PFDs pose a prevalent problem affecting populations worldwide, often being underdiagnosed(2,3). Globally, reports indicate that as many as 45.9% of individuals have encountered at least one of these symptoms with an alarming, estimated lifetime risk of approximately 11% to 19% requiring surgical interventions for prolapse or urinary incontinence (4–6).
Despite extensive research on PFDs, the etiology and pathophysiology remain incompletely understood, with a significant knowledge gap existing regarding the relationship between ethnicity and the anatomical variations or abnormalities observed in patients with multi-compartment PFDs.
Ethnicity is acknowledged as a significant determinant impacting anatomical differences, including the pelvic floor. A study led by Patriquin investigated the bony morphology of individuals of white and black ethnic background and reported notable ethnic variations observed in 12 of the 13 measurements taken(7). Furthermore, variabilities in soft tissue density and dimensions are also highlighted in studies employing clinical investigative modalities, such as trans-labial ultrasound and MRI(7,8). While studies have explored potential impact of ethnic variation on the development of pelvic floor disorders, none have explored inter-ethnic variation in anatomical abnormalities on pelvic floor ultrasound (PFUS) which includes transperineal (TPUS) and transvaginal ultrasound (TVUS).
We hypothesize that ethnic variation exists in anatomical abnormalities observed on TPUS and TVUS.
Study design, materials and methods
This is a single-institution, study of female patients with multi-compartment pelvic floor symptoms who underwent both transperineal and transvaginal ultrasound in a tertiary colorectal pelvic floor unit (PFU) between March 2013 and October 2023. PFU receives a mixture of both rural and urban referrals.
Patients were identified from a prospectively maintained departmental database. Data was collected from the prospective database for age and ethnicity. Consultant verified TPUS and TVUS reports were accessed through electronic patient records and data regarding anatomical and functional abnormalities was collected.
An initial 48 sub-categories of ethnicities were identified. To address the heterogeneity within the data and enhance the clarity of analysis and interpretation, they were subsequently classified into seven broader groups: White British, White other, Black British, Black other, Mixed, Other, and Asian.
Data collected for anatomical abnormalities detected on TPUS included rectocele (bulge of the rectal wall over and beyond the perineal body such that rectum herniated into the vagina), enterocoele (hyperechoic mass descending from above the rectal ampulla into the vagina or rectovaginal space), middle compartment descent (Hyperechoic mass descending from the top into the vagina or rectovaginal space) and cystocele ( graded in relation to the vagina) while anatomical abnormalities detected on anterior TVUS included bladder neck descent (distance between the position of the bladder neck during squeezing up and on maximal descent). Data collected for anatomical abnormalities on posterior TVUS included rectocele (protrusion of the anterior rectal wall with impingement onto the perineal body on posterior transvaginal scanning), intussusception (innovative method was adopted as with the Oxford Radiological Grading System), and enterocoele (small bowel between the rectum and the endovaginal probe ).
Functional parameters such as propulsion (poor propulsive effort was noted while bearing down) and coordination (poor coordination was the failure to open the anorectal angle during bearing down, rest: push ratio ≤1) were also collected for both TPUS and TVUS.
Data was analyzed after excluding missing values where a p-value <0.05 was considered significant.
Results
A total of 1625 women underwent both TPUS and TVUS to investigate multi-compartment PFDs where the mean age was 52 +/- 14 years.
Ethnicity was not documented for 775 (47.7%) patients. Of the remaining, they were classified into seven broader ethnic categories as follows: Asian (38), Black British(22), Black other (106), Mixed (24), Other (33), White British (529), and White Other (98).
Table 1 shows inter-ethnic variability in anatomical abnormalities on TPUS and TVUS
Inter-ethnic variability in anatomical abnormalities observed on TPUS
A higher prevalence of rectocele was found in Other (84.8%), White British (75.2%), and Asian (71.1%) ethnicities compared to Black-British (45.5%), and mixed ethnicity (58.3%), p-value 0.004.
A higher prevalence of enterocoele was found in Black-British (18.2%) and White-British (14.6%) ethnicities compared to Asian (2.6%) and mixed ethnicity (4.2%), p-value 0.050.
No inter-ethnic variability was observed for cystocele or middle compartment descent on TPUS.
Inter-ethnic variability in anatomical abnormalities observed on TVUS
A higher prevalence of enterocoele was found in Other (12.5%) and Black-British (9.1%) ethnicities compared to Asian (0%) and mixed ethnicity (0%), p-value 0.042.
No inter-ethnic variability was observed for rectocoele, pathological intussusception (grade III – V) and bladder neck support on TVUS.
Inter-ethnic variability in function observed on TPUS and TVUS
No inter-ethnic variability was observed for coordination and propulsion on both TPUS and TVUS. However, data was missing for 223 patients (26.2%) for propulsion and 221 patients (26.1%) for coordination on TPUS. On TVUS 221 patients (26%) did not have data recorded for propulsion and coordination.
Table 2 shows inter-ethnic variability in function on TPUS and TVUS.
Interpretation of results
• Recording ethnicity is essential to assess risk, disease severity, response to treatment and behaviour for seeking care.
• Recording function is essential to interpret results as anatomical abnormalities can be under-reported if propulsion and coordination are poor.
• Under-reporting ethnicity or under-representing minorities is not uncommon. Thus, studies lacking robust collection of data on ethnicity are not reflective of the actual population with results not being externally valid and generalizable.
• Given inter-ethnic variation in anatomical abnormalities despite no difference in function suggests there may be variations in the pathophysiology responsible for symptoms and their severity.
• Future prospective research can help clinicians identify ethnic groups in whom pathological findings on TPUS and TVUS can be predicted and aid in planning investigations and treatment accordingly.