The Mechanism Study Of Biofeedback Training For Constipation

Part OneThe mechanism study of biofeedback training forconstipationObjective: It has been a history of more than 30 years since biofeedback has been used to the rehabilitation of the anorectal function. Although it has been widely accepted for the results of the technique, there has not enough studies about its mechanism. It is a complicated course of coordination of the nerves and muscles during the biofeedback training for defecation diseases, so it is reasonable to study the mechanism of anal sphincter as well as that of the mechanisms which present in the course of super-centers coordinating the spinal reflex center. Our purpose to carry out this study begins with the pathological-physiological types of constipation, and the outcomes of biofeedback for different types of constipation are discussed. The pathologic and physiologic changes of obstructive constipation in the course of biofeedback training are studied, and the electro-activity changes of the external anal sphincter present in the first and end sessions of biofeedback are discussed also. The decreasing of the potential and paradoxical activities of the external anal sphincter is paied more attention to. The coordination of the super centers to the spinal reflex center in the training of biofeedback being discussed is for the explanation of the fact that it is a comprehensive rehabilitation of the reflex and coordination mechanisms that the real function of the biofeedback is for the patients with constipation. The basic functional position locating on the spinal center of defecation reflex, the changes of the muscle EMG being the most obvious outer expression. Material and methods:Anorecatal manometry was carried out for 9 children and twenty adults with constipation. Stimulated defecation training was performed for patients with constipation coordinating their abdominal muscles and external anal sphincter,demanding the contraction of the abdominal muscles at the same time relaxing the external anal sphincter voluntarily, with the results of descending of the muscle electro-activity and avoiding the conflicted contraction of the external anal sphincter. Homework of relaxing exercises of the external anal sphincter and diary of defecation were required. The doctors need to pay more attention to the subjective senses of the patients, correcting the false maneuvers of the contraction and reflex of the anal sphincter with suitable languages in a suitable condition. Discussing the false maneuvers and the incorrect feelings with the patients, doctors can made the patients feel that the biofeedback machine is only a helpful tool for them to learn the correct maneuvers of the anal motility, not a competing one they must fight against. Then the training course will be changed from passive to an initiative one, the homework exercises will be done with more efforts and separate from the machine training to self-training quickly. Results:1. Based on the external anal sphincter's electro-activity during stimulated defecation of patients with constipation, there are four types as following,I (high electrode potential + conflict contraction), II (high electrode potential),III(conflict contraction) and IV(neither high electrode potential nor conflict contraction). The former three ones belong to the obstructive constipation. There is no significant difference of rectal initial sensation among them, which is significantly lower than the last one.2. As for the obstructive constipation, except for the conflict contraction of the integrated external anal sphincter, there is an inclination of conflict location at the lower part of the anal canal (the site of the intermediate loop of the external anal sphincter muscle complex);while for the adults, the inclination position locates at the upper part of the anal canal (the site of the top loop, composing of the deep part of external anal sphincter and puborectalis).3. The effects of the biofeedback have significant relationship with differenttypes of constipation. Obstructive constipation is the most suitable ones. The effects have no relationship with age, sex of the patients and training numbers.4. There exists significant relationship between biofeedback effects and the following characteristics, decreasing of the integrated electrode potential of the external anal sphincter complex, the decreasing of the electrode potential between the corresponding groups of the first and last training program in the state of squeeze and relax of abdominal muscles, the decreasing gradient or tendency of the electrode potential between the first and last program in the state of squeeze and relax of the abdominal muscles. And the latter two factors result in the decreasing of the integrated muscle activity.5. The effects of biofeedback have a significant connection with the change of the conflict contraction rate of the external anal sphincter complex. There will be a good result when a decreased conflict contraction of the anal sphincter is obtained.Conclusion:1. Four pathologic types of constipation can be suggested according to the studies of the manometric and electro-activity of the external anal sphincter, i.e., type I (high electro-potential + paradoxical contraction), type II (high electro-potential), type III (paradoxical contraction) and type IV (without high electro-potential without paradoxical contraction ). The first three types belong to the obstructive constipation, and the last on belongs to the slow transit constipation.2. The studies of the obastructive constipation suggest that the basic pathology of this type is the high resting electro-potential and the paradoxical contraction of the external anal sphincter based on the former.3. Biofeedback training can decrease the high resting rlectro-potential effectively and inhibit the paradoxical contraction, as makes this therapycan be used to the therapy of obstructive constipation.4. It is the foundation and strenthen of the operant conditioning that the basis of the biofeedback training participated by human being is. So it is vital for the clinicians to maitain the volition of the adults and promote the interst of the children, such as providing some material reward.5. The valuntarily controlled activity of defecation is a physiological course characteristic of the nerve-muscle coordinating highly, and the mechanism of biofeedback is to fulfill and condition that physiologic course systematically. So it is important to focus on not only the correction of the local phathophysiology, but also the continuous conditioning of the super centers to the spinal one, as is a duration determined by the disease history, may be a considerably long period.6. Biofeedback can be served as the supplementary method for the treatment of slow transit constipation.