Faecal incontinence (FI) is characterized by involuntary loss of rectal content through the anal canal. FI is psychologically and socially debilitating problem that can dramatically affect patient's quality of life, often in otherwise healthy individual. FI can occur as a result of obstetric sphincter injury, surgery, irradiation, anorectal malformations as well as neurological, connective tissue or endocrine disorders. Currently management options for these patients are limited, partly due to the fact that control of defaecation and continence is multifactorial but also due to the fact that FI is difficult to identify the exact cause of patients' incontinence.

Current assessment of patients with FI include endoscopic assessment to rule out intraluminal organic cause for patients' symptoms, endoanal ultrasound scan / MRI to assess their pelvic floor anatomy and anorectal manometry to assess anorectal function. Anorectal manometry is a simple test to perform but Anorectal manometry is susceptible to measurement artifacts, with a high inter-individual variation with significant overlap between healthy asymptomatic and symptomatic patients with FI. Harris et al in 1966 suggested that the anal sphincter's resistance to distension that may be of importance for sphincter competence, not how tight anal sphincter can squeeze.

Endoluminal Functional Lumen Imaging Probe (EndoFLIP©) is a novel technology used to measure the dimensions and function of a hollow organ. Limited publication so far has shown that EndoFLIP© provides a new way of assessing anal sphincter competence. The study is to assess the use of EndoFLIP© to assess anal sphincter function in Hong Kong population. Firstly to evaluate whether age has an effect on the distensibility of the anal sphincter and its function and secondly to compare between symptomatic patients with faecal incontinence and asymptomatic healthy subjects.

For Asymptomatic Group:

Inclusion Criteria: adults over 30 with no history of faecal incontinence, who are able to give consent.

Exclusion Criteria: Patients with history of gastrointestinal disease on medication or neurological disorder with bowel symptoms, anorectal surgery or previous bowel resection. Patients who are not willing to undergo the specified tests in this study. Pregnant women.

For Faecally Incontinent Group:

Inclusion Criteria: Adults over 30 with history of faecal incontinence for over 3months, who are able to give consent.

Exclusion Criteria: Patients who are not willing to undergo the specified tests in this study. Pregnant women and patients who has had anorectal surgery or bowel resection.