Evaluation of the Fast Fill Technique for Anal Acoustic Reflectometry (AAR) in the Incontinent Anal Sphincter

Study Overview
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Brief Summary
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Anal Acoustic Reflectometry (AAR) is a technique that has been studied in our department over the last 6 years. Sound waves pass into a balloon placed in the anal canal and are used to measure the cross-sectional area. By gradually increasing and decreasing the pressure in the balloon the investigators can measure the pressure at which the cross-sectional area starts to increase and decrease, and the anal canal starts to open and close. This assessment mimics the natural opening and closing of the anal canal and the effect of squeezing the muscles. The gold standard investigation of the anal sphincter muscles has been manometry which measures anal canal pressure at rest and during squeeze. However, it has limitations. Despite the two measurements being within the normal range, some patients can have significant faecal incontinence. This has prompted clinicians to search for a better investigation to guide the management of this condition. AAR is a reproducible and repeatable technique that has been used as a research technique in the assessment of faecal incontinence. It has been shown to correlate with symptom severity and, unlike manometry, is able to distinguish between different symptomatic subgroups with faceal incontinence. In our studies so far the investigators have increased the bag inflation pressure a step at a time which means that each study takes about 20 minutes to perform. The limitation of this method is that during the measurement of squeeze pressure the sphincter muscle is subject to fatigue. A recent study using the acoustic technique in the urethra has demonstrated a faster method of recording measurements over an 8 minute period. The investigators propose to study the fatiguability effects of this faster technique and validate the method against the existing step-wise technique and standard anal manometry. Patients will be randomised into two groups: Stepwise then fast-fill Fast-fill then stepwise

Official Title
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Evaluation of the Fast Fill Technique for Anal Acoustic Reflectometry (AAR) in the Incontinent Anal Sphincter

Conditions
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Faecal Incontinence

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: adults over 18 years have capacity to consent to the study patients with symptoms of faecal incontinence Exclusion Criteria: minors under age of 18 years old patients who lack capacity to consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Faecal Incontinence: fast-fill measurement first<br>Observational study where patients with faecal incontinence undergo two AAR measurements; one with the original step-wise technique and the second with the newer fast-fill technique. A further standard manometry measurement will be taken. 18 patients will undergo fast-fill measurement first. | |
| Faecal Incontinence: step-wise measurement first.<br>Observational study where patients with faecal incontinence undergo two AAR measurements; one with the original step-wise technique and the second with the newer fast-fill technique. A further standard manometry measurement will be taken. 18 patients will have step-wise measurement first. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Opening Pressure | Opening Pressure (Op - cm H2O) - the point at which the anal canal just begins to open | 10 minutes | 
| Opening Elastance | Opening Elastance (Oe - cm H2O/mm2) - the resistance of the anal canal to stretch | 10 minutes | 
| Closing Pressure | Closing Pressure (Cp - cm H2O) - the pressure at which the anal canal closes after a period of opening | 10 minutes | 
| Closing Elastance | Closing Elastance (Ce - cm H2O/mm2) - the ability of the anal canal to close passively after a period of stretch | 10 minutes | 
| Hysteresis | Hysteresis (%) - the energy dissipated during opeing and closing of the anal canal | 10 minutes | 
| Squeeze Opening Pressure | Squeeze opening pressure (SqOp - cm H20) - the pressure at which the anal canal just starts to open whilst the patient is voluntarily trying to keep the anal canal closed | 10 minutes | 
| Squeeze Opening Elastance | Squeeze opening elastance (Sq)e - cm H20/mm2) - the resistance of the anal canal to stretch whilst the patient is voluntarily trying to keep the anal canal closed | 10 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Manometry - Resting Pressure | anal manometry measured in cmH20 | 10 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Faecal Incontinence