With the change of people’s dietary structure and the influence of various psychological and social factors, constipation has become one of the important factors affecting the quality of life of modern people. From epidemiological data, functional constipation (FC) accounts for about 5% of the population with a history of constipation. The mechanism of functional constipation is complex and the treatment is quite difficult.
Long-term laxative use is not only ineffective, but also prone to laxative enteropathy and colonic melanosis, and surgical treatment has postoperative complications such as diarrhea, fecal incontinence and even recurrence. The emerging biofeedback therapy has the advantages of simplicity, non-invasive, no side effects, easy to tolerate, low treatment cost, and outpatient treatment, thus opening up a new way of constipation treatment.
1.Biofeedback
Biofeedback therapy was first created in the 1960s, and is a combination of relaxation therapy and biofeedback technology. In fact, it is a kind of treatment and training method to learn to control one’s own involuntary visceral function by means of self suggestion and self-hypnosis.
In the process of biofeedback therapy, electronic instruments are used to record physiological functions (such as electromyography, electroencephalogram, skin temperature, heart rate, blood pressure, etc.) that are not conscious under normal conditions in the human body. And converted into perceptible sound, light and other feedback signals, so that the subject according to the feedback signal to learn to regulate their own internal organs and other bodily functions, to achieve the purpose of disease prevention and treatment.
The main clinical applications are in the treatment of hypertension, constipation, fecal incontinence, neurological headaches and other diseases. Biofeedback modalities mainly include: electromyography-mediated biofeedback, pressure measurement-mediated biofeedback, and other biofeedback.
Biofeedback therapy has been studied abroad for decades and is an acceptable and effective treatment of choice for functional defecation abnormalities.
In 1985, surgeons in Europe and the United States reached a consensus that patients should first be trained to relax the anal sphincter using a myoelectric biofeedback system to treat constipation, and that surgical procedures were the only way to deal with these “outlet obstruction” abnormal anal sphincter contractions in the past. At the same time, the same training and self-regulation can be used for those cases of fecal incontinence caused by a relaxed anal sphincter, which can also be used to strengthen the pelvic floor muscles and cure fecal incontinence. It is also very effective in children with congenital anal atresia who have post-surgical incontinence. A great deal of experience has been gained in this area.
In the last decade, behavioral therapy research in gastroenterology has developed considerably, which may be attributed to the increasing influence of biofeedback techniques in this field, especially in some developed countries, where biofeedback training is widely used as a routine method for the treatment of gastrointestinal dysfunction, such as fecal incontinence, irritable bowel syndrome, and especially for the treatment of patients with outlet obstruction type constipation.
2.Constipation
According to the criteria of Rome III, constipation is defined as
① difficulty in defecation, hard stool, reduced frequency of defecation or a sense of incomplete defecation;
② complete defecation <3 times per week, defecation volume <35g per day;
③Prolonged total gastrointestinal or colonic transit time. The gastrointestinal transit status is recommended to be judged by the internationally accepted Bristol stool typing, and those who meet the criteria for constipation are mostly Bristol type I~II.
Constipation is a common symptom that seriously affects people’s quality of life and is closely associated with the occurrence of diseases such as colon cancer, breast disease progeria and dementia. According to etiology, it can be divided into functional and organic constipation. In the United States, constipation is the main complaint of more than 2.5 million visits, and a random, stratified survey of people aged 18 to 70 years in Beijing, China, showed that the prevalence of chronic constipation is 6.07%, while other surveys of people aged 6 years or older confirmed that the prevalence is 7.3% to 20.39%, with a significant increase in prevalence with age.
Therefore, early prevention and reasonable treatment will greatly reduce the burden on society and improve people’s quality of life.
(1) Pathophysiological mechanism of constipation
Constipation mainly refers to dry stools, difficulty in defecation or a feeling of incompleteness. It is mostly caused by the disturbance of the defecation reflex process. The defecation reflex is not only a non-conscious reflex activity, but also controlled by the higher central consciousness of the brain. The defecation reflex is the entry of feces into the rectum, which causes mechanical dilatation of the rectum and an increase in intra-rectal pressure, and through the internal reflex of the rectal wall, the tone of the internal sphincter decreases and the pressure of the anal canal decreases. The pelvic floor muscles and external sphincter muscles reflexively contract to prevent fecal incontinence.
At the same time. The pressure of feces on the pelvic floor stimulates the defecation receptors and impulses the cerebral cortex to produce the urge to defecate, if the environment allows. If the environment allows, the reflex contraction of the pelvic floor and external sphincter can be consciously released and defecation can be completed with the assistance of other muscles and abdominal pressure. Physiology believes that the body has the function of self-regulation and maintenance of the homeostasis of the body’s internal environment in the subcortical centers of the non-conscious layer, and biofeedback is based on the theory of operating conditioned reflexes, so. The relationship between defecation reflex and constipation is the pathophysiological basis of biofeedback treatment of constipation.
(2) Diagnostic criteria and typing of functional constipation
After excluding constipation caused by organic diseases, functional constipation can be determined according to the Rome III criteria: symptoms have been present for at least 6 months prior to diagnosis, and the symptoms in the last 3 months have the following characteristics: (1) two or more of the following points must be met: (1) at least 25% of bowel movements are strained; (2) at least 25% of bowel movements are lumpy or hard; (3) at least 25% of bowel movements have a sense of incompleteness; (4) at least 25% of bowel movements have an anal rectal obstruction/obstruction; ⑤ at least 25% of the bowel movements required manual assistance (e.g., finger-assisted defecation, pelvic floor support); ⑥ <3 bowel movements per week; (2) little to no loose stools without the use of light laxatives; and (3) insufficient evidence to diagnose IBS.
The types of constipation were classified into 3 types according to the functional and dynamic characteristics of the intestine and anorectum that cause constipation, namely slowtransitconstipation (STC), outletobstructiveconstipation (ooc), and mixedconstipation ( STC is constipation in which the intestinal contents are retained in the colon or the colon passes slowly due to colonic dysmotility, also known as colonic weakness, which is the most common type of FC, characterized clinically by a reduced number of bowel movements (<3 times/week), no bowel movement, difficult defecation and hard stool (Bristol grade 1-2).
The first choice of treatment is prokinetic agents; OOC is related to normal colonic transmission function, but due to uncoordinated anal sphincter function or abnormal rectal reflex sensory threshold for defecation. Patients often complain of straining to defecate, a feeling of incomplete defecation, low defecation volume, hard stool texture or formed soft stool. It is common in children, women and the elderly, and biofeedback training is an option for treatment; MC is characterized by slow colonic transmission and abnormal anorectal sensory function or dynamics, or both, and treatment varies from person to person.
(3) Diagnosis of constipation
Attention should be paid to history taking to determine the possible etiology. Through a detailed history, the doctor should know what the patient’s “constipation” refers to, what are the accompanying symptoms and triggering factors, etc., and make a preliminary determination of the type and severity of constipation. According to etiology, constipation can be divided into functional and organic, the latter being caused by organic lesions originating from the intestinal canal, such as tumors or muscular or neurological lesions, as well as abnormal intestinal movements caused by systemic or metabolic diseases, which should be easy to diagnose clinically.
In the case of functional constipation, the etiology and predisposing factors are more complex, and diet is not the only factor; many patients commonly complain that fiber supplementation does not improve their symptoms.
There are many factors that influence the defecation process leading to constipation, including mental and psychological factors, as well as stress and laxative abuse, in addition to the amount of food eaten and a low-fiber diet. Recent studies on neurogastroenterology suggest that brain-gut axis and neurological disorders are involved in the development of STC, and studies have also observed a decrease in the number of interstitialcellsofCajal (ICC) interstitial cells, which are the intercolonic muscle or submucosal gastrointestinal motor pacing cells, with ultrastructural abnormalities in patients with this type of constipation.
More recent studies have applied fluorescence in situ hybridization techniques to find abnormalities of chromosomes 1, 8, 17 and XY in some patients with STC.
(4) Diagnostic process
In patients with chronic constipation, attention should first be paid to the presence of alarm symptoms (e.g., wasting, anemia, bloody stools, abdominal cramps, abdominal masses, etc.) and evidence of the presence of other organic pathologies throughout the body. In patients over 40 years of age with a history of chronic constipation and worsening symptoms within a short period of time, colonoscopy should be performed to exclude the possibility of organic pathologies such as colon tumors. In patients with chronic laxative abuse, colonoscopy can determine whether there is a cathartic colon. Barium enucleation can be helpful in the diagnosis of congenital megacolon.
If outlet obstruction type constipation is suspected, anal fingering and defecography are mandatory. Intestinal tube dynamics testing is optional when necessary.
3.Biofeedback and chronic constipation treatment
(1) the principle and method of biofeedback treatment of constipation
Biofeedback treatment of constipation is through manometry and electromyography equipment, so that patients can intuitively perceive the functional state of their pelvic floor muscles during defecation, and learn how to relax the pelvic floor muscles during defecation, while increasing intra-abdominal pressure to achieve the purpose of defecation. Before the treatment, patients should be explained in detail the normal anatomy and physiological functions of human colon, rectum, anus and pelvic floor muscles as well as the normal defecation mechanism.
Then, after connecting the therapeutic instrument to the patient, explain the meaning of the curve displayed by the instrument to the patient and point out the abnormalities of breath-holding and forceful defecation in the patient’s resting state, patiently tell the patient how to regulate the stretching and contraction of the sphincter, encourage him/her to try, and encourage him/her once he/she has the right words. Finally, the patient should practice on his own without the help of the physician and in front of the instrument until three consecutive normal bowel movements occur.
Of course, the efficacy of biofeedback is linked to the improvement of symptoms and mental health and quality of life of the constipated patient, and the patient’s compliance with the treatment and the ability to complete the course of treatment are also the main factors affecting the efficacy, independent of whether other pelvic floor pathologies are combined.
(2) Clinical application
Biofeedback is applied to outlet obstruction constipation caused by pelvic floor dysfunction
The outlet obstruction type of constipation is caused by the disorder of the external anal sphincter. Reduced rectal sensitivity, weakened recto-anal reflex and abnormal recto-anal tube dynamics can all lead to constipation. Biofeedback therapy is a training method to correct this uncoordinated defecation behavior and is mainly used to treat outlet-obstructive constipation caused by anal sphincter disorders and contradictory contractions of the pelvic floor and external anal sphincter muscles during defecation: many reports have been made nationally and internationally, and constipation affects the healthy lives of approximately 45,000 people in the United States. Patients are mainly women and the elderly, and data show that about 50% of patients are caused by pelvic floor dysfunction.
The efficacy of selective application of biofeedback for pelvic floor dysfunction has been observed to be positive. Overseas, Battaglia et al. observed 24 cases of epileptics. In the 1-year observation, biofeedback was effective for 50% of patients with pelvic floor dysfunction and 20% of patients with slow transmission type, and the observation results showed that biofeedback has long-term effect on patients with pelvic floor dysfunction, while slow transmission type only has short-term effect at most.
In China, Chen Yanmin et al. observed 32 patients with functional constipation pelvic floor muscle dysfunction and performed rectal electrical and pelvic floor electrical assessments, all of which showed contradictory movements of the anterior oblique abdominal muscle – pelvic floor muscle, and the contraction amplitude was significantly reduced. Biofeedback was chosen to treat the boils 2 to 3 times a week for 1 month. After biofeedback treatment, the number of voluntary bowel movements per week in constipated patients increased from 0.8±0.3 before treatment to 3.8±1.1, and among them, l0 patients were followed up for 1 year, and the number of bowel movements per week returned to normal in 8 cases.
Analysis of the paradoxical contraction during defecation in pelvic floor dysfunction is not a muscle malfunction or a continuous spasm of an abnormal muscle, but a malfunction of the overall reflexive relaxation of the transverse pelvic floor muscle. It can be recognized that patients with functional constipation pelvic floor muscle dysfunction have abnormal anorectal dynamics with paradoxical movements of the anterior oblique abdominal muscle and pelvic floor muscle, and biofeedback treatment improves the function of the pelvic floor muscle.
Application of biofeedback in slow transmission constipation
Patients with slow-transmission constipation demonstrated using isotope and manometry that the pressure in the intestinal lumen did not increase after meals in some patients, and 24-h manometry showed that group motility was reduced. Based on the ability of biofeedback to increase brain innervated bowel activity, many believe that it is also effective in the treatment of slow-transmission constipation.
Abroad, Emmanuel et al. observed 49 patients. It was shown that the effect of biofeedback treatment was greater than that of the pelvic floor, and that the successful outcome of biofeedback treatment was associated with an increase in cerebral innervation of bowel activity and an increase in the ability to transmit smoothly, and that this effect was only on the bowel, with no effect on cardiovascular autoregulation. From the above analysis, it is clear that bioreversal therapy for slow-transmission constipation is effective.
In conclusion, electromyography-guided biofeedback training for the treatment of defecation disorders due to abnormal rectal-anal dynamics is a new medical model. It has been reported abroad to have a high success rate and efficiency, and is more economical than other therapies. At present, only a few medical institutions in China have this technology.
Initial clinical applications and results have been encouraging. Although the application of this technique is now well established, there are no uniform indicators for the observation of treatment in the national population, such as efficacy, duration, indications, and contraindications. The next research direction is to strengthen the multicenter and collaborative observation of large samples and to explore a better treatment plan suitable for the characteristics of our population.