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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Optimising balloon expulsion testing and sensory testing in patients with faecal incontinence and chronic constipation
Scientific title
Optimising balloon expulsion testing and sensory testing in patients with faecal incontinence and chronic constipation
Secondary ID [1] 294885 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Faecal incontinence 307841 0
chronic constipation 307865 0
Condition category
Condition code
Oral and Gastrointestinal 306884 306884 0 0
Other diseases of the mouth, teeth, oesophagus, digestive system including liver and colon

Study type
Description of intervention(s) / exposure
Patients referred to our Neurogastroenterology Unit who meet the diagnostic criteria of functional constipation and faecal incontinence will be asked regarding their willingness to participate in the study. Apart from the Unit’s standard protocol for ARM that the patient has been referred for, the study requires them to undergo variations in the standard BET protocol and additional sensory testing via the rapid barostat protocol.

Following informed consent, the patient will undergo standard ARM for which they have been referred for using a 7-lumen water-perfused manometry catheter. Anorectal ultrasound will be performed to assess for any defects in the internal or external sphincter. Following this, procedures relating to the study will be performed as detailed below.

Footstool testing:
Patients will undergo the BET using a commercial balloon without a footstool as per the standard BET protocol. In addition balloon expulsion will be performed two more times with two footstools of different heights (7inches and 9 inches). Hence a total of 3 BET will be completed in each patient consecutively in a randomised order.

Prior to the testing, the following parameters will be measured and recorded:
• Weight
• Height
• True leg length as determined by measuring from the anterior superior iliac spine to the tip of medial malleolus.
• Degree of hip range of motion bilaterally using a goniometer as a measure of flexibility

The patient will be escorted to a private bathroom where they will attempt to push out the balloon. The angle between the lower spine and femur will be measured using a goniometer for each BET. The time taken to expel the balloon will be noted. Furthermore, the patients will be asked to rate their urge to pass the balloon, the discomfort experienced and how easy it was to pass the balloon on visual analogue scales for each BET. This information will be recorded on a form.

Sensory testing:
This will be tested using an infinitely compliant balloon continuously injected with air in a rapid barostat protocol which has been suggested to be a more reliable measure of sensation. An infinitely compliant balloon is a bag (glad baggie) that is not fully inflated hence at the volumes tested there is no intrinsic compliance of the balloon being recorded. This is in contrast to a rubberised balloon in which there is intrinsic compliance and therefore the measurement of compliance is partly contributed to by both the rubbery balloon and the organ (rectum) being assessed.
- The patients are told to report when they first feel the sensation of the expanding balloon inside the rectum and this is recorded as the rectal sensitivity threshold.
- The balloon will continue to be filled and the patient then reports when they have the urge to defecate.
- The balloon again continues to be inflated until the patient reports when they cannot tolerate the inflation any further. This is recorded as the maximum tolerated volume.

Following this, the balloon is rapidly deflated either at time of reported maximal tolerated volume or at a maximum volume of 300mL, whichever is reached first. If the patient experiences any intolerable discomfort during the procedure, it will be terminated immediately.

This sensory assessment is identical to the method used in routine anorectal manometry with a compliant balloon, except that an infinitely compliant balloon is used.
Intervention code [1] 301199 0
Diagnosis / Prognosis
Comparator / control treatment
The results will be compared with normal values obtained from our previous study which was performed 2 years ago and involved 44 healthy volunteers from the community. The results have been stored in our unit at Royal North Shore Hospital from which a manuscript has been produced.
Control group

Primary outcome [1] 305879 0
Motor: time taken to expel balloon with and without footstool, and comparing each of the three balloons to each other. The results of these will be compared with a set of normal values determined from our previous study looking at healthy volunteers to determine which method is best at discriminating between diseased and non-diseased states.

The patient will be asked to initiate expelling the balloon and the proceduralist will use a timer to time the duration taken from point of initiation to when the patient states the balloon has been expelled.
Timepoint [1] 305879 0
Immediately after balloon expulsion testing
Secondary outcome [1] 346964 0
Sensory: comparing rectal sensation measured by a compliant compared to an infinitely compliant balloon- first sensation, urge to defecate and maximal tolerated threshold (these are a composite primary outcome). The patient will be advised to inform the proceduralist once every threshold is reached and the volume of balloon inflation at each point will subsequently be recorded
Timepoint [1] 346964 0
During sensation testing.

Key inclusion criteria
1. Aged between 18 and 75
2. Females and males
3. English speakers
4. Meets diagnostic criteria for either faecal incontinence or chronic constipation
5. Willingness to give written informed consent
6. Willingness to comply with study
Minimum age
18 Years
Maximum age
75 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Women who are lactating or pregnant
2. Patients with a history of psychological illness or condition such as to interfere with the patient’s ability to understand the requirements of the study.

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
As there is no hypothesis to test, statistical power considerations do not apply. However, a large sample is needed to estimate the standard deviation accurately. A sample size of >100 is typically considered large enough for small random sampling variations to be smoothed out and a sample size of 150 is proposed.
For the secondary aim of sensory testing, to be able to see a difference between the sensory measurements, n=120 patients may be required to achieve a statistical power of 0.8 at the 0.05 level of significance.
We therefore plan to enrol a total of 150 patients for the study, 100 for the three way balloon and 50 for the foot stool study, giving a total of 150 of all patients.

Results between three way balloon expulsion times and balloon expulsion with or without footstool, and for comparing sensation thresholds using the two different balloons, will be assessed using McNemar’s test and described using the Kappa coefficient of concordance. However, given time taken to expel the balloon is a continuous variable, if the results are not normally distributed, then the Kruskal-Wallis test may be utilised.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 22653 0
2065 - Royal North Shore Hospital

Funding & Sponsors
Funding source category [1] 299470 0
Name [1] 299470 0
Royal North Shore Hospital (Public)
Address [1] 299470 0
Neurogastroenterology Unit
Royal North Shore Hospital
Gastroenterology Department
Reserve Road
St Leonards, NSW 2065
Country [1] 299470 0
Primary sponsor type
Government body
Northern Sydney Local Health District
Royal North Shore Hospital
Reserve Road
St Leonards, NSW 2065
Secondary sponsor category [1] 298772 0
Name [1] 298772 0
Address [1] 298772 0
Country [1] 298772 0

Ethics approval
Ethics application status
Ethics committee name [1] 300377 0
Northern Sydney Local Health District HREC
Ethics committee address [1] 300377 0
Royal North Shore Hospital
Reserve Road, St Leonards 2065
Ethics committee country [1] 300377 0
Date submitted for ethics approval [1] 300377 0
Approval date [1] 300377 0
Ethics approval number [1] 300377 0
NSLHD referece RESP/18/22

Brief summary
Chronic constipation and faecal incontinence carry significant health and economic burdens on individuals as well as the health system. Initial treatment remains conservative including medications and dietary modifications. However should these be ineffective, guidelines recommend investigating for physiological abnormalities by anorectal physiology testing including ARM and BET. The results of these are subsequently used to guide prescription of second line management including biofeedback therapy, neuromodulation and surgical interventions which when used appropriately demonstrated positive outcomes.
Given the central role of anorectal physiological testing, there remains a lack of standardisation when conducting these procedures and subsequently, we remain uncertain whether the results produced are comparable. This applies to the study protocol itself, the equipment used during testing and analysis of results. Literature has even suggested that in cases of faecal incontinence, it may be beneficial for individual units to have their own range of values for defining abnormalities.
The sensory component of defaecation, namely alterations in visceral perception and rectal compliance has also become increasing studied and tested. Determining type and degree of dysfunction in these have implications on provision of treatment. Barostat methodology is now widely used to assess sensory components of defaecation but different protocols exist, mainly with varying duration and equipment for the procedure. As a result, normal cut-offs remain unclear.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 83462 0
Dr Zhengyan Qi
Address 83462 0
Gastroenterology Department
Royal North Shore Hospital
Reserve Road, St Leonards NSW 2065
Country 83462 0
Phone 83462 0
Fax 83462 0
Email 83462 0
Contact person for public queries
Name 83463 0
Dr Allison Malcolm
Address 83463 0
Gastroenterology Department
Royal North Shore Hospital
Reserve Road, St Leonards NSW 2065
Country 83463 0
Phone 83463 0
+612 9463 2450
Fax 83463 0
Email 83463 0
Contact person for scientific queries
Name 83464 0
Dr Allison Malcolm
Address 83464 0
Gastroenterology Department
Royal North Shore Hospital,
Reserve Road
St Leonards, NSW 2065
Country 83464 0
Phone 83464 0
Fax 83464 0
Email 83464 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
Patient data will be deidentified as per ethics and only available to the investigators of this study. The coding is specific to our unit and will not be able to be interpreted by people outside of the unit.
What supporting documents are/will be available?
No other documents available
Summary results
No Results