Anorectal continence and defecation reflex tests: pilot study

Anal incontinence and/or constipation are debilitating conditions that affect a
substantial portion of the general population. Evaluation of the
neurophysiological function of the anorectum is important to diagnose the
condition and to determine treatment strategy.

Current tests to evaluate the neurofysiologic function of the anorectum consist
of electrofysiologic tests and manometric tests. These tests are time-consuming
and are not always correlated with the clinical symptoms. Also, active
co-operation by the patient is required, which is difficult when the patients
are young children.

With our novel method, the receptors in the anal canal can be stimulated
whilst measuring pressure in the anal canal and the rectum. In this manner, the
neurophysiologic assessment of the anorectum can be performed in less time,
with greater accuracy and with less burden on the patient.

Before testing the novel method in patients, it needs to be tested in healthy
human volunteers to validate the method and to compare it to current tests.

1. To investigate whether we are able to initiate and measure the continence
and defecation reflex in healthy human volunteers with our new method.
2. To compare the results of these measurements with those of existing
techniques.
3. To investigate whether the left and right reflex pathway function with or
without cross linking.

All volunteers will be seated on a toilet seat as they undergo the following
measurements (in chronological order):

a. Anal electrosensibility test (standard clinical test)
A small catheter with electrodes will be inserted into the anal canal and on
every cm the anal sensitivity will be measured (The minimal stimulation been
felt by the person)4.

b. The continence reflex test (novel test, see further on in this section)
On different levels left or right in the anal canal the surface will be
stimulated and simultaneous the anal pressure on different levels will be
recorded.

c. The defecation reflex test (novel test, see further on in this section)
On different levels left or right in the anal canal the surface will be
stimulated and simultaneous the anal and rectal pressure on different levels
will be recorded.

d. Left and right anorectal reflex tests (novel test, see further on in this
section).
The left or right side of the anal canal will be selectively stimulated whilst
pressures in the anal canal and rectum are measured.

e. Sphincter pressure test (standard clinical test)
During relaxation, squeeze and push action of the patient anal and rectal
pressure will be measured.

f. Balloon retention test (standard clinical test)
A balloon will be inserted into the rectum and slowly (1 ml/second) filled with
water of 37*C water. Patients are asked to mention when they do feel rectal
filling sensations until maximal tolerable pressure, then the balloon will be
deflated rapidly. During this simulating solid stool in the rectum the
pressures in the anal canal and the rectum will be recorded.

g. Rectal infusion test (standard clinical test)
Without a balloon water of 37*C will be inserted slowly (1 ml/second) in the
rectum. Fecal continence for liquid stool be tested. A healthy person can
easily keep 1,5 liter into the rectum without incontinence. During this filling
pressures in the anal canal and the rectum are recorded.

The novel method combines two existing methods which do not carry any risks.
Therefore, there is no risk to the participants.

The burden of participation consists of elektrodes and a small balloon being
placed in the anal canal during one session of two hours. This may be felt as
an unusual sensation. Also, some discomfort of the anal region may be felt up
to 15 minutes after the study has ended.