Evaluation of the Rectal Reflex Using Anal Acoustic Reflectometry

NHS Foundation Trust

Status: Completed

Conditions: Pelvic Floor Dysfunction

Study type: Observational

Funder types: Other

Identifiers

NCT02782377

2016GA002

Details and patient eligibility

About

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.

Enrollment: 40 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

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

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

Trial design

40 participants in 1 patient group

Pelvic Floor Dysfunction

Description:

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