CClinicalTrials.gg
CompletedNCT02782377Updated Dec 2, 2020Results posted

Evaluation of the Rectal Reflex Using Anal Acoustic Reflectometry

An observational study in Pelvic Floor Dysfunction, sponsored by Manchester University NHS Foundation Trust. Completed at 1 site in United Kingdom. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2020-12-02.

Sponsored by Manchester University NHS Foundation Trust · Observational

Study type
Observational
Model
Cohort
Time perspective
Prospective
Enrollment
40
Ages
18 Years and older
Sex
All
01

Study summary

Anal Acoustic Reflectometry (AAR) is a reliable and reproducible 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. In previous studies AAR has shown promise in the assessment of faecal incontinence and, that unlike manometry, it has been able to distinguish between different types of incontinence.

The Recto-anal Inhibitory Reflex (RAIR) is a normal response when the rectum fills with faeces, fluid or air, whereby there is a change in the pressures within the anal canal to determine the type of contents. This can be absent or altered in patients who have difficulty in opening their bowels. The RAIR is currently measured by anal manometry using a 4.9mm catheter, resulting in an anal canal which is already partially opened prior to the measurement, and potentially distorted.

AAR is considered a catheter free technique as the balloon has a cross-sectional area of only 0.4mm2 when collapsed. The investigators propose to measure the RAIR using a 1.7mm diameter catheter alongside the AAR balloon to determine the effect that its placement has on the recorded parameters of AAR. This aims to improve our understanding of the opening and closing of the anal canal in response to distension of the rectum.

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Conditions studied

  • Pelvic Floor Dysfunction

Keywords

  • Faecal Incontinence
  • Obstructive Defaecation
  • Rectal Prolapse
03

In context

Lead sponsor

Manchester University NHS Foundation Trust is the lead sponsor of 135 studies on the registry; 27 are open to participants now.

Counted across the registry records on this site, refreshed daily.

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Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No
Sampling method
Non-probability sample

Study population

Patients presenting to the pelvic floor clinic and neurogastroenterology with symptoms of pelvic floor dysfunction

Inclusion criteria

  1. Adults over 18 years old
  2. Have capacity to consent to the study
  3. Patients with pelvic floor dysfunction.

Exclusion criteria

Exclusion Criteria:

  1. Minors under the age of 18 years old
  2. Patients who lack capacity to consent
  3. Patients with known rectal tumours and proctitis
  4. Asymptomatic patients
05

Study design

Observational model
Cohort
Time perspective
Prospective
Enrollment
40 participants (actual)
Patient registry
No

Groups and cohorts

  • Pelvic Floor Dysfunction

    Observational study where patients with pelvic floor dysfunction undergo three AAR measurements. One at baseline, one with the catheter alongside and a third with the rectal balloon inflated. No intervention is performed Note, that initial inclusion of Squeeze parameters was detailed in error, these were not compared in this study and were compared in previous study

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What researchers measure

Primary outcomes

  1. Opening Pressure

    Measurements of differences in Opening pressure (Op - cm H2O) as measured by the AAR catheter. These measurements are taken at baseline with the rectal balloon collapsed (Pre-RAIR) and after inflation of 100mls air into rectal balloon (Post-RAIR).

    Time frame: during single study visit- measurement taken prior to balloon inflation and post balloon inflation

  2. Opening Elastance

    Measurements of differences in Opening Elastance (Oe - cm H2O/mm2) as measured by the AAR catheter. These measurements are taken at baseline with the rectal balloon collapsed (Pre-RAIR) and after inflation of 100mls air into rectal balloon (Post-RAIR).

    Time frame: during single study visit- measurement taken prior to balloon inflation and post balloon inflation

  3. Closing Pressure

    Measurements of differences in Closing Pressure (Cp - cm H2O) as measured by the AAR catheter. These measurements are taken at baseline with the rectal balloon collapsed (Pre-RAIR) and after inflation of 100mls air into rectal balloon (Post-RAIR).

    Time frame: during single study visit- measurement taken prior to balloon inflation and post balloon inflation

  4. Closing Elastance

    Measurements of differences in Closing Elastance (Ce - cm H2O/mm2) as measured by the AAR catheter. These measurements are taken at baseline with the rectal balloon collapsed (Pre-RAIR) and after inflation of 100mls air into rectal balloon (Post-RAIR).

    Time frame: during single study visit- measurement taken prior to balloon inflation and post balloon inflation

  5. Hysteresis

    Measurements of differences in Hysteresis (%) as measured by the AAR catheter. These measurements are taken at baseline with the rectal balloon collapsed (Pre-RAIR) and after inflation of 100mls air into rectal balloon (Post-RAIR). Hysteresis is the extent of energy expenditure during opening and closing of the anal canal and represents the difference between opening and closing pressure and is expressed as a percentage

    Time frame: during single study visit- measurement taken prior to balloon inflation and post balloon inflation

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Results

Posted Mar 30, 2020

Participant flow

Participant flow — Overall Study
MilestonePelvic Floor Dysfunction
Started40
Completed35
Not completed5
Withdrew: Physician decision5

Outcome measures

PrimaryOpening Pressure

Measurements of differences in Opening pressure (Op - cm H2O) as measured by the AAR catheter. These measurements are taken at baseline with the rectal balloon collapsed (Pre-RAIR) and after inflation of 100mls air into rectal balloon (Post-RAIR).

Time frame:
during single study visit- measurement taken prior to balloon inflation and post balloon inflation
Reported as:
Median · cmH2O
Opening Pressure
cmH2OPre-RairPost-RAIR
Opening Pressure34.44 (13.84 to 82.96)15.41 (0 to 50.53)
PrimaryOpening Elastance

Measurements of differences in Opening Elastance (Oe - cm H2O/mm2) as measured by the AAR catheter. These measurements are taken at baseline with the rectal balloon collapsed (Pre-RAIR) and after inflation of 100mls air into rectal balloon (Post-RAIR).

Time frame:
during single study visit- measurement taken prior to balloon inflation and post balloon inflation
Reported as:
Median · cmH2O/mm2
Opening Elastance
cmH2O/mm2Pre-RairPost-RAIR
Opening Elastance1.39 (0.74 to 2.18)1.1 (0 to 2.13)
PrimaryClosing Pressure

Measurements of differences in Closing Pressure (Cp - cm H2O) as measured by the AAR catheter. These measurements are taken at baseline with the rectal balloon collapsed (Pre-RAIR) and after inflation of 100mls air into rectal balloon (Post-RAIR).

Time frame:
during single study visit- measurement taken prior to balloon inflation and post balloon inflation
Reported as:
Median · cmH2O
Closing Pressure
cmH2OPre-RairPost-RAIR
Closing Pressure20.06 (6.01 to 55.92)8.00 (0 to 35.41)
PrimaryClosing Elastance

Measurements of differences in Closing Elastance (Ce - cm H2O/mm2) as measured by the AAR catheter. These measurements are taken at baseline with the rectal balloon collapsed (Pre-RAIR) and after inflation of 100mls air into rectal balloon (Post-RAIR).

Time frame:
during single study visit- measurement taken prior to balloon inflation and post balloon inflation
Reported as:
Median · cmH2O/mm2
Closing Elastance
cmH2O/mm2Pre-RairPost-RAIR
Closing Elastance1.31 (0.64 to 2.29)1.13 (0 to 1.73)
PrimaryHysteresis

Measurements of differences in Hysteresis (%) as measured by the AAR catheter. These measurements are taken at baseline with the rectal balloon collapsed (Pre-RAIR) and after inflation of 100mls air into rectal balloon (Post-RAIR). Hysteresis is the extent of energy expenditure during opening and closing of the anal canal and represents the difference between opening and closing pressure and is expressed as a percentage

Time frame:
during single study visit- measurement taken prior to balloon inflation and post balloon inflation
Reported as:
Median · percent
Hysteresis
percentPre-RairPost-RAIR
Hysteresis39.71 (26.2 to 56.86)39.9 (0 to 82.28)

Adverse events

Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Pelvic Floor Dysfunction0/40 (0%)0/40 (0%)0/40 (0%)

Baseline characteristics

Age, Continuous
Age, Continuous(years)Pelvic Floor Dysfunction
Median57.5 (34 to 77)
Sex: Female, Male
Sex: Female, Male(Participants)Pelvic Floor Dysfunction
Female26
Male6
Race and Ethnicity Not Collected
Race and Ethnicity Not Collected(Participants)Pelvic Floor Dysfunction
Region of Enrollment
Region of Enrollment(participants)Pelvic Floor Dysfunction
United Kingdom32
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Study locations

1 site
  • University Hospital of South Manchester
    Manchester, Greater Manchester M23 9LT, United Kingdom
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References and documents

Publications

  • Klarskov N, Saaby ML, Lose G. A faster urethral pressure reflectometry technique for evaluating the squeezing function. Scand J Urol. 2013 Dec;47(6):529-33. doi: 10.3109/21681805.2013.776629. Epub 2013 Mar 19. PubMed 23506115 ↗
  • Hornung BR, Mitchell PJ, Carlson GL, Klarskov N, Lose G, Kiff ES. Comparative study of anal acoustic reflectometry and anal manometry in the assessment of faecal incontinence. Br J Surg. 2012 Dec;99(12):1718-24. doi: 10.1002/bjs.8943. Erratum In: Br J Surg. 2013 Jan;100(2):301. PubMed 23132420 ↗
  • Saaby ML, Klarskov N, Lose G. Urethral pressure reflectometry before and after tension-free vaginal tape. Neurourol Urodyn. 2012 Nov;31(8):1231-5. doi: 10.1002/nau.22239. Epub 2012 Mar 27. PubMed 22457059 ↗
  • Klarskov N. Urethral pressure reflectometry. A method for simultaneous measurements of pressure and cross-sectional area in the female urethra. Dan Med J. 2012 Mar;59(3):B4412. PubMed 22381095 ↗
  • Mitchell PJ, Klarskov N, Telford KJ, Hosker GL, Lose G, Kiff ES. Viscoelastic assessment of anal canal function using acoustic reflectometry: a clinically useful technique. Dis Colon Rectum. 2012 Feb;55(2):211-7. doi: 10.1097/DCR.0b013e31823b2499. PubMed 22228166 ↗
  • Mitchell PJ, Klarskov N, Telford KJ, Hosker GL, Lose G, Kiff ES. Anal acoustic reflectometry: a new reproducible technique providing physiological assessment of anal sphincter function. Dis Colon Rectum. 2011 Sep;54(9):1122-8. doi: 10.1097/DCR.0b013e318223fbcb. PubMed 21825892 ↗
  • Cheeney G, Nguyen M, Valestin J, Rao SS. Topographic and manometric characterization of the recto-anal inhibitory reflex. Neurogastroenterol Motil. 2012 Mar;24(3):e147-54. doi: 10.1111/j.1365-2982.2011.01857.x. Epub 2012 Jan 11. PubMed 22235880 ↗
  • Heywood NA, Sharma A, Kiff ES, Klarskov N, Telford KJ. Placement of a fine-bore rectal balloon catheter in the anal canal does not affect anal sphincter pressures: improving our understanding of physiological function with anal acoustic reflectometry. Colorectal Dis. 2020 Nov;22(11):1626-1631. doi: 10.1111/codi.15300. Epub 2020 Aug 30. PubMed 32770704 ↗
  • Heywood NA, Sharma A, Kiff ES, Klarskov N, Telford KJ. A novel method for measurement of the recto-anal inhibitory reflex using anal acoustic reflectometry. Colorectal Dis. 2020 Nov;22(11):1632-1641. doi: 10.1111/codi.15110. Epub 2020 Sep 23. PubMed 32367609 ↗

Individual participant data

Plan to share: No

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Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Dec 2, 2020, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT02782377
Lead sponsor
Manchester University NHS Foundation Trust
Responsible party
Sponsor
First posted
May 25, 2016
Start date
Feb 2016
Primary completion
Oct 2016
Completion
Apr 2017
Results posted
Mar 30, 2020
Last update
Dec 2, 2020

Study contacts

Karen J Telford, MBChBMDFRCS
study chair · University Hospital of South Manchester

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

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