The aim of this single-center prospective observational trial is to study the influence of physical and psychological factors on the intensity of pain syndrome after anorectal interventions and to determine the association between the physiological pain threshold before surgery and the level of pain syndrome after anorectal surgery. Participants undergoing surgical treatment for anorectal diseases will be asked to complete the questionnaires before and after surgery, all information will be collected to identify risk factors for severe pain syndrome after surgery. The pain threshold test will be conducted to determine the association with pain after surgery.

This study is a single-center prospective observational study conducted on the basis of the surgical department of the Medical Research and Educational Center of Lomonosov Moscow State University (MREC MSU). Patients, who have been diagnosed with one of the benign anorectal diseases (hemorrhoidal disease of stage 2-4, anal fissure that does not respond to conservative treatment, rectal and rectovaginal fistulas, post-traumatic other types of the anal incontinence) and are intended for surgical treatment (open/closed hemorrhoidectomy with or without Ligasure, excision of the anal fissure, excision of the rectal or rectovaginal fistula with or without segmental proctoplasty, sphincterolevatoroplasty or other options for anal sphincter reconstruction) are potential participants in the study. In case of meeting the inclusion criteria and after signing a voluntary informed consent to participate by the patient all the necessary information about the participating patient was entered into an electronic database. Prior to surgery the patient is asked to fill out questionnaires in written or electronic form to collect the following information:

• demographic data: gender, age, BMI, length of smoking and smoking index
• clinical data: symptoms of the disease, in case of pain - pain assessment according to the visual analog scale (VAS), duration of the disease, analgesics intake, previous interventions in the anorectal region, disease recurrences, the day of the menstrual cycle for women, duration of the menstrual cycle, hormonal medication intake, a previously experienced the new coronavirus infection (COVID infection-19), the duration of the COVID-19 infection
• psycho-emotional status: questionnaires to identify anxiety and depression
• A scale for assessing the degree of disability due to pain After the completion of the preoperative assessment, the participating doctor conducts a test to determine the pain threshold for pressure pain: a sphygmomanometer cuff is put on the non-working arm in a sitting position, and then inflated to 250 mm Hg and then the patient assesses the pain according to the VAS scale. If there is a sharp severe pain before the cuff is inflated to 250 mm Hg, the test ends, the test result is regarded as the maximum (10 points according to the VAS scale). All results are entered by the research doctor into the database.

All patients included in the study are scheduled to undergo appropriate surgical intervention under spinal anesthesia (SMA), performed according to the standard procedure. Next, the appropriate surgical treatment is performed. In case of changes in the type of anesthesia and the volume of the operation that do not meet the stated inclusion criteria, the patient is excluded from the study. Intraoperative data are also entered to the database: the final diagnosis, the type of surgical treatment, in the case of hemorrhoidectomy - the number of removed hemorrhoids.

After waking up in the ward, the researcher provides the patient-participant with a written or electronic form of a postoperative monitoring questionnaire, including parameters for assessing:

• the severity of pain at rest (at the peak and after taking the analgesic) and pain during defecation on the VAS scale for 15 days after surgery
• the frequency of administration and the number of analgesics taken, including narcotic, within 7 days after surgery
• scale of the degree of disability assessment due to pain (Pain Disability Index) for evaluation on the 7th and 30th day after surgery
• questionnaires to determine anxiety and depression for evaluation on the 7th and 30th day after surgery In the postoperative period, patients undergo analgesia according to the scheme: 1000 mg of acetaminophen every 12 hours, 30 mg / m of ketorol every 8 hours. In case of ineffectiveness of the standard anesthesia regimen and the pain syndrome about 7-10 points according to VAS, 100 mg of tramadol is administered intramuscularly to the patient. If it is necessary (after excision of the fistula, sphincterolevatoroplasty), the debridement is performed at least 1 time a day. All patients are remotely monitored 30 days after surgery to collect postoperative data, and if there are any remaining symptoms or complaints, they are invited to the clinic for examination. If the patient does not come to the appointment, the researcher contacts him by all available means (phone or email) to clarify all the necessary data for the study. If the researcher fails to contact the patient, the patient is considered lost for follow-up and is excluded from the study.

The primary endpoint is to determine the relationship between the preoperative pain threshold level and the intensity of the postoperative pain syndrome.

Secondary endpoints include identifying predictors of the development of moderate and severe pain syndrome (pain level 5-10 points according to VAS) among physical, clinical and psychological factors, as well as determining the correlation between the severity of pain syndrome and the level of anxiety and depression after surgery.

Inclusion Criteria:

• Patients over 18 years old
• Diagnosed benign anorectal disease requiring surgical treatment: hemorrhoidal disease of stage 2-4, anal fissure that does not respond to conservative treatment, rectal and rectovaginal fistulas with or without drainage ligature, post-traumatic failure of the anal sphincter, as well as other types of failure of the anal sphincter.
• One of the planned interventions: open/closed hemorrhoidectomy with or without Ligasure, excision of the anal fissure, excision of the rectum or rectovaginal fistula of the rectum with or without segmental proctoplasty, sphincterolevatoroplasty or other options for reconstruction of the anal sphincter.
• Indications for planned surgical treatment
• Absence of other diseases that cause pain syndrome.
• I, II class of anesthetic risk according to ASA classification
• Voluntary signing by the participant of an informed consent for surgical treatment and participation in a clinical trial.

Exclusion Criteria:

• The chronic pain syndrome unrelated to the main proctological disease, exacerbation of concomitant diseases with pain syndrome

  • Chronic or prolonged use of medications, including narcotic drugs, with analgesic effect for other diseases.
  • Patients who have contraindications or technical impossibility of performing subarachnoid anesthesia or the full standard volume of surgery for the corresponding disease.
  • The presence of previously diagnosed mental and neurological disorders.
  • Patients who refused to participate at any time before the end of the study, as well as patients who did not pass the final postoperative monitoring (1 month after the intervention).
  • Pregnant women
  • Complicated course of the postoperative period

Our clinic specializes only in the adult population

Patients over 18 years of age, who have been diagnosed with one of the benign anorectal diseases (hemorrhoidal disease of stage 2-4, anal fissure that does not respond to conservative treatment, rectal and rectovaginal fistulas, post-traumatic other types of the anal incontinence) and are intended for surgical treatment (open/closed hemorrhoidectomy with or without Ligasure, excision of the anal fissure, excision of the rectal or rectovaginal fistula with or without segmental proctoplasty, sphincterolevatoroplasty or other options for anal sphincter reconstruction) are potential participants in the study.