*Corresponding author:Yamen Smadi, Center for Digestive Health and Nutrition, Arnold Palmer Hospital for Children, Orlando Health, 60 W. Gore st. Orlando, FL 32806, USA
How to cite this article: Vijay M, Jeffrey A B, Devendra I M, Shaista S S, Yamen S. Outcome of Biofeedback in the Treatment of Intractable Constipation
in Children with Dyssynergic Defecation.Adv Res Gastroentero Hepatol, 2021; 17(4): 555970. DOI: 10.19080/ARGH.2021.17.555970.
Background/Aim: We aimed to study the efficacy of biofeedback on the clinical outcome and the manometric dynamics of children with dyssynergic defecation who failed aggressive conventional treatment for constipation.
Methods: We retrospectively reviewed the medical records of all patients who had dyssynergic defecation and underwent biofeedback. All patients failed conventional treatment of constipation for at least three months before they were referred to biofeedback. Sixty-nine patients (48 males), (Mean age 10±3, range 4-17 years) with dyssynergic defecation were included. Clinical outcomes after at least nine months from the last biofeedback session were assessed and were defined as “success” if the fecal frequency is more than two per week and the fecal incontinence is less than once every 2 weeks.
Results: Forty-six patients [66.6%] reported success of treatment. Biofeedback failed in treating 23 patients [33.3%]. In the “failure group”, 17 patients [24.6%] never experienced significant improvement and 6 patients [8.7%] reported initial improvement followed by relapse. Comparison of the Pre-Biofeedback and post-biofeedback manometric dynamics revealed significant improvement in first sensation volume, urge threshold, push pressure and balloon expulsion test [p<0.01]. After treatment, balloon expulsion test was normal in 24 patients (52%) of the success group compared to 1 patient (4.3%) of the failure group [p <0.0001].
Conclusion: Biofeedback results in resolution of symptoms in majority of children with dyssynergic defecation who failed traditional management of constipation at nine-month follow up.
Functional constipation is a common disorder in children that accounts for 3% of visits to general pediatric clinics and up to 30% of visits to pediatric gastroenterologists . Dyssynergic defecation (DD) defined as paradoxical contraction or failure to relax the pelvic floor and anal muscles during defecation, is present in 35% to 63% of constipated children [2-5]. Moreover, children with dyssynergia remains more frequently constipated at long-term follow-up than the other children with constipation (61% versus 29%) . A diagnostic criteria for dyssynergic defecation was published by Dr. Rao in 2008 and has been widely used for diagnostic purposes (Table 1) .
The goal of biofeedback [BF] therapy in DD is twofold (1) to correct the dyssynergic function of the abdominal, rectal and anal sphincter muscles (i.e., to restore normal recto-anal coordination) and (2) to improve rectal sensory perception in patients with impaired rectal sensation . Biofeedback uses electrical or mechanical devices to increase the awareness of physiological functions of anal sphincter by providing the patient with visual, verbal and/or auditory information and enhances self-control on body functions . During biofeedback, patients are provided with visual graphs of their rectal pressure and also taught to relax external anal sphincter with the rise of rectal pressure .
In our tertiary institution, only those who failed conventional therapy that includes counseling, diet modification, medical treatment and behavioral therapy for at least three months are referred to BF. We aimed to study the efficacy of biofeedback on the clinical outcome and the manometric dynamics of children
with dyssynergic defecation who failed aggressive conventional
treatment for constipation.
After obtaining IRB approval, we retrospectively reviewed
the medical records of all children who underwent anorectal biofeedback for dyssynergic defecation in Arnold Palmer
hospital for Children between January 2010 and January 2014.
Constipation was defined according to Rome III criteria . Fecal
incontinence term [FI] was used to describe soiling or encopresis
events. Rao’s criteria  (Table 1) used to define dyssynergic
defecation with one modification of using a 30ml air-filled balloon
in the expulsion test.
SD: Standard Deviation; 2RAIR: Rectoanal Inhibitory Reflex
Patients who were referred for biofeedback failed aggressive
conventional treatment for constipation including stool diary,
dietary modification, scheduled toilet training, stool softeners
and laxatives for at least 3 months. Sixty-nine patients who met
inclusion criteria were included in the analysis (Table 2).
a) Children [0-18 years] who were diagnosed with DD by
anorectal manometry and underwent biofeedback for treatment.
b) Biofeedback sessions are completed at least nine months
before the chart was reviewed.
a) Organic or anatomical cause of constipation
b) Surgical intervention for constipation such as cecostomy
Biofeedback: All patients underwent standard anorectal
manometry [ARM] in the first session and rectoanal inhibitory
reflex [RAIR] was documented. The 1st sensation volume
threshold corresponds to the minimum volume felt in the rectum.
The sensation of rectal fullness with a constant desire to defecate
corresponds with the urge volume threshold. Maximal squeeze
pressure is determined by asking the child to squeeze the sphincter
complex as tight as possible without contracting abdominal
muscles for 10 seconds. This maneuver is repeated few times. The
maximum squeeze pressure is measured as the highest pressure
during these efforts. Patients then are educated to push by asking
to contract abdominal muscles, flex knees against abdomen and
relaxing pelvic floor while intra-rectal and sphincter pressures
are recorded and the push pressure is measured. For balloon
expulsion test, the balloon is inflated with 50 ml of air and the
child then is asked to defecate in left lateral position. If this does
not occur within two minutes, 20 ml of air is withdrawn [leaving
30 ml] and the attempt is repeated. If defecation fails with 30 ml
air-filled balloon, the expulsion test is recorded as abnormal. The
physician then tries to assist defecation by applying slight traction
for training purpose. Similarly, another 15ml is withdrawn if
defecation still does not occur (leaving 15ml) and if this is still
unsuccessful the equipment is removed.
Biofeedback sessions start with explaining the anorectal
dysfunction and discuss its relevance with the patients and their
parents before approaching the treatment. Patients are next shown
anal manometry recordings displaying their anal function and are
taught through trial and error to relax the pelvic floor and anal
muscles during straining. This objective is pursued with the help
of visual feedback on pelvic floor muscle relaxation coordinated
with abdominal contraction, accompanied by continuous
encouragement from the therapist [2,7,11-15]. Patients also are
educated to practice toilet training at home by attempting a bowel
movement at least twice a day, 30 minutes after meals, and to
strain for no more than 5 minutes.
We collected our data by reviewing the electronic medical
records including clinical visit notes, phone notes and recorded
notes during biofeedback sessions. Demographic data included
age, sex and race. Clinical elements included frequency of
defecation, fecal incontinence (soiling and/or encopresis),
consistency and size of stool, pain during defecation, laxative
medications use, and associated symptoms such as abdominal
pain, appetite, and enuresis. We also recorded behavioral or
psychological disorders such as Attention Deficit Disorder (ADD),
Asperger disorder, Obsessive-Compulsive Disorder (OCD) and
autism. This was reported based on medical history. All patients
were asked to follow up with a clinic visit one month after the
biofeedback sessions are completed. Our clinic staff contacted
those who completed treatment to document long-term clinical
outcome. We collected manometric dynamics before and after BF
treatment including resting pressure, 1st sensation threshold, urge
threshold, squeeze pressure, push pressure and balloon expulsion
Clinical outcomes after at least nine months from the last BF
session were assessed and were defined as “success” if the fecal
frequency is more than two per week and the fecal incontinence is
less than once every 2 weeks. Balloon expulsion test was defined
as normal if patient can expel 30ml air-filled balloon without
assistance and abnormal if patient fails to do that with assistance.
The balloon volume was decreased to 30 ml instead of 50ml to
account for smaller size of pediatric patients.
Prevalence of clinical outcome improvement was calculated.
The effect of balloon expulsion test on clinical outcome was
measured by fisher test. T-test was used to compare manometric
dynamics before and after BF treatment. The effect of gender and
behavioral disorders as a risk factor on outcome was measured by
using fisher test.
From January 2010 till January 2014, seventy-nine patients
underwent BF treatment. Ten patients were excluded for reasons
explained in (Figure 1). Sixty-nine patients met inclusion criteria.
Patients demographic data, constipation characteristics, medical
management and baseline manometry dynamics are shown in
(Table 2). There were more male patients [n= 48, 69.6%], and the
mean age of our patient group was 10 [range 4-17 years]. Baseline
pre-BF treatment manometric dynamics revealed elevated
first sensation threshold and urge threshold and diminished
maximum push pressure (Table 2). All patients except 2 failed
30ml air-filled balloon expulsion test (n=67, 96.5%). These 2
patients were included in our study due to clinical symptoms of intractable constipation and fecal incontinence and we included
them to measure their response to biofeedback on clinical
symptom of constipation and fecal incontinence. All patients met
Rome III criteria for constipation and all patients had daily faecal
incontinence at presentation. All 69 patients underwent 3 or more
BF sessions [mean 5, range 3-10]. Average follow-up period was
11.8 months [range 9-28months].
Forty-six patients [66.66%] reported success of treatment.
Average FI frequency in the success group was once every 21 days
(range: 17-60 days) and average fecal frequency in the success
group was 3 bowel movements per week (range: 2-5 per week).
In 23 patients [33.33% of all] BF failed in treating constipation;
Among them 17 patients [24.6% of all] never experienced
significant improvement in their symptoms and 6 patients [8.7%
of all] reported initial improvement then relapsed symptoms.
Pre-BF and post-BF manometric dynamics were compared
using T-test. The comparison revealed significant improvement
in first sensation threshold, urge threshold and push pressure.
Squeeze pressures, pre and post BF, were not significantly
different. (Table 3 & Figure 2) show detailed results of the pre and
post BF dynamics. There was significant difference in all dynamics
between success and failure group (p < 0.01).
Balloon Expulsion Test: Balloon expulsion test was normal in
2 patients (2.8% of all) before BF compared to 25 patients (36% of
all) after BF (p < 0.01). After BF treatment, balloon expulsion test
was normal in 24 patients (52%) of the success group compared to
1 patient (4.3%) of the failure group [p <0.0001, CI 95%], [Relative
Risk 1.9 (1.37-2.08)].
Gender and outcome: 33 male patients (69%) compared
to 13 female patients (56.5%) reported successful intervention
[p=0.59, CI 95%]. On the other hand, after BF treatment, 15 male
patients had positive expulsion test compared to 10 female patients
[p=0.276, CI 95%]. The above results indicate no significant effect
of gender on clinical outcome or on expulsion test.
Behavioral disorders: Behavioral disorders such as ADD,
autism and Asperger disorders, were more common in the
failure group compared to the successful group (21.7% vs. 8.6%
respectively). However, that was not statistically significant [p
0.148, CI 95%].
10-year retrospective study on 264 children with Chronic
Constipation found that >30% of patients experienced persistent
symptoms for >2 years and a prominent psychiatric burden
despite aggressive laxative therapy . These findings suggest
that better treatments are needed rather than laxatives alone, the
present standard of care , and that recognition of dyssynergic
defecation and the use of biofeedback might improve the quality
of life of children with intractable constipation.
Our experience is that biofeedback is effective most of the
time in improving both clinical and defecation dynamic outcomes
in children treated for dyssynergic defecation. In contrast to
most of the trials discussed below, which compared conventional
treatment to biofeedback, our practice is to refer patients for
biofeedback only if they fail aggressive conventional treatment,
therefore our population is different from most of studies done
before. In our study, BF was effective in treating children with DD in
two thirds of the cases and BF resulted in significant improvement
in manometric dynamics and clinical outcome correlated with
normalization of balloon expulsion test. Behavioral disorders
were more common in patients who failed to respond to treatment
but that was not statistically significant. Normal expulsion test
was significantly more common in patients who had improvement
in their symptoms [p<0.0001]. However, 48% of patients in this
group continued to fail the test despite their improved clinical
outcome. One explanation is that we perform the expulsion
test in lateral position instead of physiologic sitting position. In
contrast to Minguez et al.  who found that 9 out of 10 patients
who failed balloon expulsion test were female, our study found
that gender was not a risk factor for neither abnormal balloon
expulsion test nor clinical outcome. In adults, several randomized
trials comparing BF to either placebo or alternative strategies (e.g.,
laxatives, sham BF) reported outcomes favoring BF. The response rates in randomized control trials of BF ranged from 53% to
75% . Chiarioni et al.  conducted a literature review on
efficacy of BF for DD and concluded that functional defecation
disorder, one of the most frequent and disabling subtypes of adult
constipation, can be treated effectively with biofeedback training.
This improvement was sustained at 12 and 24 months [2,19] due
to a change in underlying pathophysiology. Moreover, biofeedback
therapy was recommended for the short-term and long-term
treatment of constipation and fecal incontinence with dyssynergic
defecation in the most recent position paper published by Rao et
However, the efficacy of BF in treating children with DD varies
in pediatric literature. In 1987, Wald et al. compared biofeedback
therapy with mineral oil in a group of 55 encopretic children;
16 of whom showed evidence of functional defecation disorder.
Although a trend toward greater improvement in the biofeedback
group was evident, the difference in success rate did not reach
significance . In another controlled study, a well-defined
pediatric population of 43 children with functional defecation
disorder was randomized to receive biofeedback therapy plus
conventional care (laxatives) or conventional treatment only. The
biofeedback group did significantly better than the conventional
one, with about half of patients showing successful symptoms
resolution at one year follow-up compared to 16% in the
conventional-care-only group. The clinical benefit was correlated
with normalization of defecation dynamics [2,22]. Similar benefits
were reported in another controlled study in pediatric population,
but the follow-up was too short (3 months) [2,23]. Another small
trial evaluating the effects of biofeedback found that all children
learned to relax the external anal sphincter after five sessions of
In contrast to the successful studies described above, the
largest randomized, controlled study in pediatric constipation
(192 children), which compared laxatives plus Electromyogram
[EMG] biofeedback therapy to laxatives alone, failed to show any
benefit from biofeedback.4 However, a criticism of this study
was that not all the subjects had functional defecation disorder.2
Twenty-one randomized trials with a total of 1371 children were
reviewed by Brazziel et al.  and published as a Cochrane review
in 2011. The authors concluded that there is no evidence that
biofeedback training adds any benefit to conventional treatment
in the management of functional faecal incontinence in children.
However, sample sizes were generally small and interventions
varied amongst trials and few outcomes were shared by trials
addressing the same comparisons.
Our study included patients with DD exclusively and excluded
other pathologies for constipation, which was necessary to study
the effect of BF on those patients. The discrepancy between
adult and pediatric literature on one hand and among pediatric
publications itself is not well explained. Furthermore, trials
studying the effect of biofeedback in dyssynergic defecation
in children are limited and other options of treatment are not well defined [11,26]. The results of our study support favorable
outcome with BF for treating children with DD if they fail
conventional management of constipation.
This is a retrospective review of children with DD who
underwent treatment with BF. Three pediatric gastroenterologists
performed manometry and BF sessions. The later might have
resulted in variation in interpreting manometry results. Thought
it is not studied in pediatrics, we think that performing the balloon
expulsion test in a lateral position might affect the results of the