Introduction

Constipation is a – often chronic - common and prevalent gastrointestinal motility disorder Because of it, many patients have decreased daily live activities. About 30 % of the general population experiences problems with constipation during life time, with elderly people and women being mostly affected [1]. Constipation has also a huge impact on sport- and work activities. Standardization of terminology and definition of constipation have been operationalized in the Rome diagnostic criteria for constipation, the Rome IV criteria (Table 1), especially for enrolment in clinical trials [2,3]. However, so far, no widely accepted, useful definition for the clinical practice of constipation exists. Constipation has been defined as abnormal stool frequency < 3 bowel movements (BMs) per week [4]. Besides this, also other symptoms, such as excessive straining, passage of hard stool, inability to defecate at will, unproductive urges, and sensation of incomplete evacuation, occur (Table 2) [4,5].

Table 1: ROME IV criteria for functional constipation.

Table 2: Defecatory and post-defecatory symptoms of constipation.

To the best of our knowledge, few systematic reviews have investigated the effectiveness of physical therapy such as pelvic floor muscle training (PFMT), alone or in combination with biofeedback (BF), electrical stimulation (ES), rectal balloons, defecation training, behavioral training, relaxation therapy or other types of exercises. The lack of consensus on the effects of these treatments necessitated this systematic review. Therefore, this systematic review evaluated the effects of physical therapy on constipation, quality of life (QOL), and muscle strength and -relaxation in adult patients with constipation, compared with no treatment, placebo, sham, and surgery.

Assessment and evaluation

Any relevant physician should check for the presence of abdominal pain as a primary symptom (if present, consider irritative bowel syndrome (IBS) with constipation (IBS-C)) and needs to eliminate any existing red flags suggestive of organic disease (e.g., unexplained weight loss > 4.5 kg, colorectal cancer, anemia, symptoms or signs of occult blood). If present, specialized medical consultation is absolutely required. If no red flags, the cause of constipation should be evaluated as primary or secondary.

Primary (idiopathic) constipation involves IBS-C, normal-transit constipation, slow-transit constipation, defecatory or rectal evacuation disorders e.g., pelvic floor dyssynergia, anismus, descending perineum syndrome, spastic pelvic floor syndrome, paradoxical pelvic floor contraction [6].

Secondary constipation because of inadequate diet, dehydration, inadequate physical activity, use of certain medications, e.g., antidepressants, pain medication, diuretics, and neurologic conditions, e.g., CVA, MS, psychological conditions, e.g., depression, anxiety [6]. For primary (idiopathic) constipation there are 3 categories, classified as 1. normal-transit constipation (NTC; patients in this subgroup may have symptoms also indicating IBS-C) [7], slow-transit constipation (STC), and 3. anorectal outlet abnormalities (including dyssynergia and pelvic floor dysfunction [5]. These categories may also overlap (e.g., STC and pelvic floor dysfunction, NTC, and IBS-C) [5,7]. Symptoms of both chronic constipation and IBS-C as well as common co-morbidities may co-exist [8]. Symptoms of prolonged or excessive straining, feelings of incomplete evacuation, application of perineal or vaginal pressure, or direct digital evacuation of stool (including soft stool) may be indications of anorectal outlet abnormality [6]. These symptoms should be followed-up with a PFM functional assessment [9,10]. Signs of no- or insufficient perineal descent during observation and anorectal digital examination indicate pelvic floor dysfunction such as paradoxical contractions of the PFM and external anal sphincter. Medical data based on physiologic studies (colonic-transit tests, anorectal manometry, balloon expulsion tests, and defecography) can be helpful for the physical therapist before start of the physical therapeutic diagnostic consultation to further evaluate the consequences of the health problem constipation in order to determine if and to what extent physical therapy is warranted for the individual patient under assessment and evaluation [5,9]. Realistically, in most cases results of these tests are not (yet) available for the physical therapist. Frequently, they only will be performed until dietary and lifestyle changes, trials of fiber and laxatives and physical therapy have produced no improvement [5].

Physical therapy for constipation

Several conservative treatment modalities for patients with constipation exist, in many cases up to now without sufficient or convincing scientific or clinical evidence. Often based on limited data about their effect, recommendations, advise, as first-line treatments, before any specific medication is subscribed, the use of general exercises or physical activity, behavioral changes regarding fluid intake and bowel habit and – regimen. Next to this, specialized physical therapy is recommended.

Besides PFM training, physical therapy for constipation includes use of BF, behavioral therapy, and ES. BF and ES stimulation are often used for patients with outlet obstruction or functional defecation disorders [11]. BF supports PFM and anal sphincter muscle training by converting intracavity electronic signals or pressure, captured with a small intra-rectal balloon or electronic probe to a computer screen which makes it possible for the patient to see (and/or hear) if and to what extent the pelvic floor is used adequately during PFM contractions and relaxations during physical activities [9]. It can be used to train patients to relax their PFM while straining and to coordinate relaxation and pushing to achieve defecation. BF may be helpful in patients with symptoms or physical examination findings that suggest pelvic floor dysfunction, or for those in whom conservative therapies have failed and who have diagnostic test results indicative of this disorder [5,12,13].

Physical therapy for (chronic) constipation aims to improve or restore normal bowel function and relieve symptoms such as abnormal or excessive straining during defecation, bloating, and feelings of incomplete evacuation. Together with physical therapy in patients with STC and some patients with NTC laxatives or promotility agents may be used [6]. In case of pelvic floor dyssynergia the physical therapist specialist may offer PFMT with BF, alone or in combination with prescribed medication, to stimulate coordination, timing and selective contractions/relaxation of the PFM including the external anal sphincter [5,14].

If there is no known secondary cause of constipation, also the latest International Consultation on Incontinence generally recommends physical therapy as first-line therapy [15], involving also general regular exercise, increased fluid intake, and bowel habit training [14]. This in the light of who will benefit still largely is unknown, since only limited clinical trial data supporting the effectiveness of such approaches are available. Camilleri and Bharucha [12] proposed targeted therapy for chronic constipation: physical therapy (PFMT with BF how to coordinate abdominal and PFM in order to increase intra-abdominal pressure while keeping the PFM relaxed during evacuation) for outlet dysfunction and evacuation disorders, and pharmacological treatment for constipation not associated with outlet dysfunction. The authors stated that BF therapy involving coordinated functional activity of abdominal muscles and relaxation of the PFM during evacuation of stool is the treatment of choice for functional defecation disorders. More high-quality scientific studies to identify those patients who will benefit and who will not, particularly when evaluated in patients with chronic constipation, is urgently needed [5]. Johanson indicated that ritualizing bowel habits may also help some patients [6]. He made his recommendation on the basis of observations that most patients without constipation have a regular pattern of defecation and that certain activities (e.g. waking and eating) stimulate colonic activity [14]. So far, no prospective study to warrant this recommendation has been performed [16].

Materials and Methods

This investigation was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) [17] statement and the JBI methodology for systematic reviews. We searched the Cochrane Incontinence Group Specialized Trials Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PreMEDLINE, EMBASE, ClinicalTrials.gov (a register of clinical trials and handsearching of journals and conference proceedings (from 1990 to December 2023). We also searched other electronic and non-electronic bibliographic databases and the reference lists of the included studies as well as contacting researchers in the field to identify other relevant trials. Selection criteria were randomized controlled trials with full reports in English, German, French, Portuguese or Dutch reporting on PFMT, behavioral therapy BF or ES as conservative treatment in adults with constipation.

For our data collection and analysis the two review authors (BB and MS) independently assessed all the identified trials for eligibility. To assess the quality of trials we used the PEDro scale [18]. This scale assesses quality based on the presence or absence of design features thought to influence validity, including true concealed randomization, blinding of participants and assessors, adequate follow-up and intention-to-treat analysis (see Table 4). So, risk of bias was assessed using this scale for determining bias. Disagreements were resolved by discussion, and a third reviewer was involved in the case of no consensus. Data were analyzed using Cochrane methods. Data extraction and management of the included studies was performed independently by the two review authors (BB and MS ) using a standardized form. Any disagreement was resolved by discussion or by consulting a third party. Where there was insufficient information regarding the primary outcome in the published reports, study authors were contacted. For data entry, performed by BB, Review Manager software (RevMan 5.4) was used. Processing of the included data of trials was according to the Cochrane Handbook for Systematic Reviews of Interventions [19].

Results

Totally, 23 citations were identified, 9 studies remained for the screening process. Finally, only 6 RCTs met our study selection criteria. The characteristics of the 6 included RCTs are detailed in Table 3.

Due to flaws in methodological designs, small study groups, variability in protocols, few available RCTs, until 15 years ago we widely had to rely on little scientific evidence from systematic reviews and trials and expert expertise [20].

Table 3: RCTs on physical therapy to treat constipation.

Koutsomanis et al. [21] compared in 60 adults with constipation perianal electromyographic (EMG) BF for relaxation plus balloon defecation training versus balloon defecation training alone. The RCT found similar improvements between groups in the number of straining episodes a week 1 week after treatment. However, reviewing the data of this RCT results should be interpreted with caution because of methodological issues: the analysis apparently included people who had crossed over to alternative treatment after only two unsuccessful treatment sessions (8 people) [22]. Heymen et al. (1999) compared four methods of biofeedback for patients with constipation [23]. Thirty-six patients were prospectively, randomly assigned to one of four protocols:

1) outpatient intra-anal electromyographic biofeedback training;

2) electromyographic biofeedback training plus intrarectal balloon training;

3) electromyographic biofeedback training plus home training;

or 4) electromyographic biofeedback training, balloon training, and home training.

All 36 patients received weekly one-hour outpatient biofeedback training. Success was measured by increased unassisted bowel movements and reduction in cathartic use. In all instances patients maintained a daily log in which documentation was maintained regarding each bowel evacuation and the need for any cathartics. There was a significant improvement in outcome after all four treatment protocols for constipation; however, no significant difference was found among the treatments.

Chiarioni et al. (2006) demonstrated in a RCT of 54 patients with pelvic floor dyssynergia that BF therapy, aiming at coordinating relaxation of PFM with increase of intra-abdominal pressure by adequate use of abdominal muscles is significantly more effective than laxative use in this patient population [24]. At 6 months, 80% of patients receiving BF vs 22% of those receiving laxatives reported statistically significant symptom improvement. One RCT (77 people with chronic constipation (69 women, 8 men) compared three treatment groups: BF (relaxation, coordination PFM with abdominal muscles) versus sham versus standard treatment (including laxatives, diet, and exercise) [25]. The RCT found that BF significantly improved the rate of complete spontaneous bowel movements a week compared with sham treatment and standard treatment. BF also significantly improved global bowel satisfaction compared with sham treatment but not standard treatment at 3 months. BF significantly improved stool frequency compared with standard treatment, but not sham treatment at 3 months. The RCT also found no significant difference for BF for stool consistency or laxative consumption compared with either sham or standard treatment at 3 months [25]. Heymen et al. (2009) compared in 84 patients with dyssynergia-type constipation BF (relaxation PFM, coordination with abdominal muscles during evacuation) with diazepam or placebo [23]. All patients were trained to do PFMT to correct pelvic floor dyssynergia during 6 biweekly 1-hour sessions, but only BF patients received electromyography feedback. All other patients received pills 1-2 hours before attempting defecation. BF was superior to diazepam by intention to treat analysis. and also superior to placebo. BF patients had significantly more unassisted bowel movements at follow-up compared to placebo, with a trend favoring BF over diazepam. BF patients reduced pelvic floor electromyography during straining significantly more than diazepam patients. The authors concluded that instrumental BF is effective and essential for successful treatment of this kind of patients. In a fairly recent RCT comparing home and office BF (relaxation, coordination PFM/abdominal muscles) in patients with dyssynergic defecation (DD) (Rome III), Rao et al. (2019) included 100 patients (96 female, 50 in each treatment arm) to investigate whether home BF improves quality of life (QOL and is cost-effective when compared to office BF [26]. The authors concluded that BF therapy significantly improves QOL in patients with DD regardless of home or office setting. They also stated that home BF is a cost-effective treatment option for DD compared to office BF, and offers the potential of treating many more patients in the community.

Methodological quality

The PEDro rating score was used to classify the methodological quality of the 6 included trials (Table 4), resulting in moderate (5/10) to high (8/10) methodological quality. Also, for the treatment of constipation it should be noted that the two criteria related to blinding of the therapist and patient are almost impossible to meet in physical therapy trials.

Table 4: PEDro quality score of RCTs in systematic review of physical therapy to treat constipation.

Quality of the intervention

Most of the studies treated dyssynergetic defecation. In general, the training protocols refer to PFM relaxation, coordination and adequate use together with BF, but lack sufficient information on dose-response issues, intensity of home and office training and adherence to the protocols, so it is difficult to judge the quality and adequacy of the PFMT. With EMG BF electromyographic (EMG) activity and manometry BF paradoxical increases in anal pressure during straining easily could be detected [27]. BF is specifically indicated for dyssynergetic defecation. Retraining works through teaching patients to relax the PFM and anal muscles during straining. Anal pressure may be measured by means of water-perfused catheters, solid state transducers or balloon catheters. No single technique seems superior to the others, and the choice relies on the therapist’s training and experience. Anal EMG may be recorded either by intra-anal probes or by peri-anal EMG electrodes stuck to the skin [27].

Chiarioni et al. (2006) mentioned that defective expulsion is commonly investigated by asking the patient to defecate a 50-mL water-filled rectal balloon and that patients with functional defecation disorders usually fail this test [24,27]. Chiarioni et al. (2006) indicated that behavior therapy is to first explain the anorectal dysfunction and discuss its relevance with the patient before approaching the treatment [24]. The protocols used by authors of the RCTs include training the patients on a more effective use of the abdominal muscles and instructions on diaphragmatic breathing technique to enhance the push effort. Patients are next shown anal manometry or EMG recordings displaying their anal function and are taught through trial and error to relax the PFM and anal muscles during straining. By increasing the intra-abdominal/intra-rectal pressures with synchronized relaxation of the anal sphincters using visual and verbal feedback from manometry recto-anal coordination can be improved. Visual feedback on PFM relaxation and contraction is continuously encouraged by the physical therapist. When the patient has learned to relax the PFM during straining, the visual and auditory help can be discontinued. Another kind of training is to use an air-filled balloon attached to a catheter, which is slowly withdrawn from the rectum while the patient concentrates on the evoked sensation and tries to facilitate its passage [27]. Then the patient should defecate the balloon spontaneously without any assistance. Also, it is possible to use the rectal balloon for sensory retraining in case of a hyposensitive rectum. Usually, this kind of BF training is safe, has no side-effects [28] and will last up to 6 intensive supervised sessions of 30 to 60 minutes each, provided by a well-trained and experienced physical therapist [24]. RCTs comparing different BF protocols to each other are still needed.

Discussion

BF, aiming at coordinated relaxation of PFM and adequate use of abdominal muscle to increate intra-abdominal pressure during evacuation, may have a role in people with constipation caused by obstructed defecation secondary to anismus [29] or by functional outlet obstruction [30]. BF has demonstrated efficacy in that small group of chronically constipated patients who do not respond to standard therapies and who exhibit evidence of pelvic floor dyssynergia on diagnostic testing. In fact, according to Chiarioni et al (2005) BF therapy does not benefit constipated patients without dyssynergetic defecation [31].

The American Neurogastroenterology and Motility Society (ANMS) and the European Society of Neurogastroenterology and Motility (ESNM) convened a task force to examine the indications, study performance characteristics, methodologies used and the scientific basis, noting especially the results of RCTs and the impact of BF therapy on patient reported outcomes, objective measurements and quality of life [28]. These measures were used to provide evidence-based recommendations regarding the clinical utility and efficacy of biofeedback therapy for dyssynergetic defecation, levator ani syndrome leading to constipation. Next, the ANMS and ESNM published a position paper and consensus guidelines on BF, with the aims described before, for anorectal disorders. They have stated that, based on the strength of evidence, BF is recommended for the short term and long term treatment of constipation with dyssynergetic defecation (Level I, Grade A). They indicated also that, based on ‘fair’ evidence, BF may be useful in the short-term treatment of Levator Ani Syndrome with dyssynergetic defecation (Level II, Grade B) [28].

Conclusions

Current RCT data may indicate positive effects of PFMT with BF for patients with pelvic floor dysfunction related to constipation, but more specific high-quality RCTs are needed to enrich the evidence [32].

Author contributions

Conceptualization, BB. and MS.; methodology, BB.; software, BB.; validation, BB, MS,.; formal analysis, BB.; investigation, BB.; resources, BB, MS.; data curation, BB,; writing original draft preparation, BB.; writing review and editing, BB, MS.; visualization, BB.; supervision, BB.; project administration, BB, MS.

All authors have read and agreed to the published version of the manuscript.

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