Normative Metrics of High-Resolution Anorectal Manometry With the Use of Water-perfused System in a Healthy Russian Cohort

Inclusion Criteria: * Willingness to participate in this clinical trial, confirmed by signed informed consent form. * Patients of both sexes, aged 18 to 65 years inclusive. * Permanent residence in the Russian Federation (capable citizens of Russia on the basis of a passport of a citizen of the Russian Federation). * Absence of rectal diseases, confirmed by the results of clinical and instrumental examinations * Ability to follow the instructions when high-resolution anorectal manometry procedure is performed. Exclusion Criteria: * Known diseases of the rectum on the basis of clinical and / or instrumental examination, including presence of complaints to difficulties with defecations that require manual aids or use of laxatives; * Surgical interventions on pelvic organs in history; * History of organ transplantation except for corneal transplantation and eye lens replacement surgery; * Oncology of any localization, with the exception of skin cancer in situ; * Severe concomitant pathology of any organs and systems, which, in the opinion of the researcher, makes it impossible to carry out the procedure of high-resolution anorectal manometry or if the procedure may cause the risk of worsen the patient's condition; * Absence of anamnestic, clinical and laboratory signs of alcohol abuse (abuse will be considered in case of the use of more than 30 g of pure alcohol per day by males and the use of more than 20 g of pure alcohol per day by females; * Use of illegal drugs, including history; * Use of concomitant medications that can affect the motor function of the colon (including, but not limited to: calcium channel blockers, metoclopramide, m-cholinolytics, domperidone, nitrates, tricyclic antidepressants, opiates, beta-blockers, beta-adrenomimetics, alcohol). The duration of the period of non-use of these drugs should provide sufficient time for the complete cessation of their pharmacological action, but not less than two half-life periods. * Pregnancy and breast-feeding; * Technical impossibility to insert the catheter due to the previously known or current poor tolerability of high-resolution anorectal manometry procedure or due to the presence of anatomical features that make it impossible to insert the catheter. Criteria of non-inclusion of the data to the analysis: \- Patients may choose to stop their participation in the study by withdrawal of their previously signed consent, that leads to the exclusion of their data from the analysis. The researcher should be guided by the following criteria, however, he may at any time terminate the patient's participation in the study on the basis of his own clinical judgment. Cancellation of participation in the study can be carried out on the basis of the following events: 1. Lack of the possibility to insert water-perfused catheter during high-resolution anorectal manometry procedure due to anatomical features or psychological state of the patient. 2. Incomplete high-resolution anorectal manometry procedure. 3. Presence of adverse event(s) during high-resolution anorectal manometry procedure, causing the further procedure impossible. 4. Obtaining incomplete recording of high-resolution anorectal manometry parameters for any reason. 5. Identification of the conditions described in the section "exclusion criteria" during examination of the patient.