Evacuation disorders (ED) affect approximately one in ten people and the symptoms increase with age (1) and are caused by  structural pelvic floor abnormality (rectocoele, intussusception, enterocoele, sigmoidocoele, and rectal prolapse), dynamic failure of evacuation in the absence of a structural abnormality (and pelvic floor muscle dyssynergia) or both (2–5). ED are initially managed by preliminary conservative measures such as lifestyle, laxatives, pelvic floor muscle re-training which helps patients learn to strengthen or relax their pelvic floor muscles to improve bowel or bladder function, and psychosocial support (6). 

Rectal irrigation is the introduction of warm tap water through the anal canal into the rectum to initiate defecation. It is recommended by the National Institute for Health and Care Excellence (NICE) in patients with ED refractory to preliminary conservative measures (7).

We determined the prevalence of rectal irrigation in patients with ED after failing preliminary conservative measures. We also determined the socio-demographic and clinical predictors of low versus high-volume rectal irrigation.

This is a single-institution study of patients with ED from a tertiary colorectal pelvic floor unit (PFU). 

Pathway in PFU 
A mixture of urban and rural referrals is received in the PFU. A multidisciplinary approach is taken to assess the patients which starts with an initial evaluation using a structured interview along with standardised questionnaires (8) in a nurse-led telephone triage assessment clinic (TTAC). Patients are then reviewed in a face-to-face bowel function clinic (BFC), where examination for the initial assessment is performed (digital rectal +/- vaginal examination in females), patients undergo retraining of pelvic floor muscles, and are provided psychosocial support. If patients' symptoms persist after 3-4 BFC sessions, then investigations such as total integrated pelvic floor ultrasound (TPUS), defecating proctogram (DP), defecating MRI and anorectal manometry (ARM) are organised as considered appropriate. Patients are then discussed in the PFU multi-disciplinary meeting (MDM) consisting of consultant surgeons, bowel specialist nurses, physiotherapists, radiologists, and clinical scientists to review symptoms, treatment offered up until that point, and investigations to plan further management which also includes starting patients on rectal irrigation. 

Data Sources and Study Variables
Data was collected from a prospectively-maintained database for socio-demographics including age, gender, ethnicity, and socio-economic status, and retrospectively from patient records for clinical factors such as presenting symptoms, findings on imaging (integrated total pelvic floor ultrasound and defecating proctogram), and type of rectal irrigation used (low versus high-volume) to manage patient symptoms between March 2013 and May 2019. Data was analyzed where a p-value <0.05 was considered significant.

A total of eight ethnicities were recorded: White British, White other, Black British, Black Caribbean, Black other, Asian, Mixed and Others. Socioeconomic status was proxied by the English Indices of Deprivation Measure 2019 (IMD)(9) which is an official measure of relative deprivation in England. The scale ranges from 1 to 10. Patients were classified by the IMD score and divided into quintiles (1-5), by combining adjacent decile groups. The lowest quintile represented the most deprived while the highest quintile represented the least deprived patients.  

The findings collected on TPUS included the presence of a rectocele and intussusception while those on DP included the presence of a pathological rectocele (>2cm) and intussusception (Grade III, Grade IV and Grade V).  Results from ARM included the presence of normal or altered rectal sensitivity (hypersensitivity or hypersensitivity).

Electronic patient records were reviewed for all patients up till the point where they were either considered treated and discharged or lost to follow-up (LTFU) where patients were marked LTFU if they missed two consecutive appointments or did not contact the department after their appointment was left open for 6 months.

After excluding patients with missing data, analysis was performed where a p-value < 0.05 was considered significant.

A total of 1617 patients with evacuation disorders were reviewed in BFC with a mean age of 53 +/- 15 years. After failing preliminary conservative treatment, 593 (36.7%) patients were started on rectal irrigation of which 516(87%) were females. The most common presenting complaint recorded was constipation (293, 49.5%).  Abnormal rectal sensation on ARM was found in 29% of patients, rectocele in 58.2% and intussusception in 39.7% on TPUS. Pathological rectocele was found in 35% and pathological intussusception in 37.5% on DP. After commencing irrigation, 48.8% of patients were lost to follow-up. 

Patients with presenting complaints of constipation (293,41.8%) were more likely to be started on rectal irrigation compared to those who presented with anal incontinence (117, 27.7%), p-value < 0.001. When comparing patients on preliminary conservative treatment versus those started on rectal irrigation, we did not find any variability in gender, socio-economic status, ethnicity, and findings on imaging such as rectocele and intussusception.

Table 1 shows the comparison of socio-demographic and clinical characteristics between patients who were started on rectal irrigation versus those who continued with preliminary conservative measures. 

Low-volume irrigation (LVRI) was started in 398 and high-volume irrigation (HVRI) in 195 patients. Age > 50 years and anal incontinence were associated with LVRI while age <50 years and constipation were associated with HVRI, p-value < 0.05. Patients on LVRI (212, 54.8%) were more likely to complete treatment and be discharged, whereas (103, 56.3%) of the patients who were started on HVRI did not complete their treatment and were lost to follow-up, p-value 0.015. There was no significant variability observed in gender, ethnicity, socioeconomic status, reporting feeling of a vaginal bulge, sensitivity on ARM,  findings on TPUS and DP between high and low-volume irrigation groups. 

Table 2 shows the comparison between the socio-demographic and clinical characteristics of patients started on LVRI and HVRI

•	One-third of patients with ED may not respond to preliminary conservative measures and need rectal irrigation.

•	Patients with constipation are more likely to be started on rectal irrigation.

•	Although there is no evidence to date if one type of irrigation has better outcomes for patients with a particular pathology or symptoms, it may be that LVRI has better outcomes in patients with anal incontinence and HVRI in patients with constipation, but future prospective research is needed to explore this.

•	There may exist an association between ethnicity as the severity of the symptoms, response to conservative management, etiology, or cultural beliefs may vary between different groups leading to variation in using rectal irrigation as a treatment. There may exist variability within socio-economic groups due to possible differences in awareness and knowledge about pelvic floor disorders, understanding, and acceptability of irrigation as a treatment. Future research is needed to explore these.

This study has shown that 36.7% of patients with ED were started on rectal irrigation with female predominance. The predictors for HVRI were presenting symptoms of constipation and age < 50 years and for LVRI symptoms of anal incontinence and age < 50 years. 

Future studies are required to find out when rectal irrigation is likely to be useful so that it can be considered early on in the treatment pathway and to help inform when to use high-volume versus low-volume irrigation so patients don’t have to switch between them.

 To improve patient-care outcomes, prospective research is needed to explore barriers to rectal irrigation such as gender, cultural beliefs, socio-economic status and ethnicity or any other factors which we haven’t appreciated or did not find significant in this study.

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