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

Completed

Conditions: Faecal Incontinence

Registration Number: NCT02782364

Lead Sponsor: Manchester University NHS Foundation Trust

Brief Summary: 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:

1. Stepwise then fast-fill

2. Fast-fill then stepwise

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 36

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

Study & Design

Study Type: OBSERVATIONAL

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Closing Pressure	10 minutes	Closing Pressure (Cp - cm H2O) - the pressure at which the anal canal closes after a period of opening
Squeeze Opening Elastance	10 minutes	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
Opening Pressure	10 minutes	Opening Pressure (Op - cm H2O) - the point at which the anal canal just begins to open
Closing Elastance	10 minutes	Closing Elastance (Ce - cm H2O/mm2) - the ability of the anal canal to close passively after a period of stretch
Hysteresis	10 minutes	Hysteresis (%) - the energy dissipated during opeing and closing of the anal canal
Opening Elastance	10 minutes	Opening Elastance (Oe - cm H2O/mm2) - the resistance of the anal canal to stretch
Squeeze Opening Pressure	10 minutes	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