Anorectal Malformations: Clinical Guidelines

List of Abbreviations

ARM - anorectal malformations

GIT - gastrointestinal tract

ICD - International Classification of Diseases

Ultrasound — ultrasound examination

MRI — magnetic resonance imaging

CT — computed tomography

EMG - electromyography

VACTERL association is a group of combined developmental anomalies. The name is formed from the initial letters of the malformations that make up the syndrome: V (Eng. Vertebral anomalies) — vertebral anomalies, A (Eng. Anal atresia) — anal atresia, C (Eng. Cardiovascular anomalies) — cardiovascular malformations, TE (Eng. Tracheo-esophageal fistula) — tracheoesophageal fistula with esophageal atresia, R (Eng. Renal defects) — renal anomalies, L (Eng. Limb defects) — limb defects

PSARP - posterior sagittal anorectoplasty (surgical technique used to correct anorectal malformations)

GRLS - State Register of Medicines

Terms and Definitions

Anorectal malformations constitute an extensive group of congenital conditions characterized by the absence of the anus and distal rectum, ectopic anal localization, and the presence of recto-organ or external fistulas. They occur in both boys and girls and are frequently combined with other malformations of the urogenital, musculoskeletal, and cardiovascular systems.

1. Brief information on the disease or condition

1.1 Definition of the disease or condition

Anorectal malformations (ARMs) are a group of congenital diseases of the distal gastrointestinal tract (GIT), characterized by the congenital absence of the rectum and anus, frequently combined with congenital recto-organ fistulas between the digestive and urogenital systems, as well as with the perineal skin [1, 2, 3, 4].

Synonyms: anorectal anomalies; anorectal malformations.

1.2 Etiology and pathogenesis of the disease or condition (group of diseases or conditions)

The exact cause of anorectal malformations is unknown. The influence of certain factors is hypothesized:

Genetic mutations. Genes responsible for the development of anorectal atresia (WNT3A, PCSK5, TCF4, MKKS, GLI2, HOXD12, BMP4) have been described. Mutations in various genes (Shh, Gli, Bmp7, Wnt5a) leading to impaired development of the urorectal septum and the formation of anorectal malformations have been identified [5, 6, 7].

Chromosomal and gene syndromes. Anorectal anomalies can be combined with Currarino, Townes-Brocks, Ivemark, Pallister-Hall, Opitz-Frias syndromes, etc. Ultimately, underdevelopment of the cloacal membrane underlies the development of a variety of anorectal malformations [7].

ARMs are frequently combined with malformations of other organs and systems [8].

1.3 Epidemiology of the Disease or Condition

The worldwide incidence of ARMs is 1 in 5,000 newborns; 1 in 1,500 live births [9, 10].

1.4 Features of Coding the Disease or Condition

Q42.0 - Congenital absence, atresia and stenosis of rectum with fistula

Q42.1 - Congenital absence, atresia and stenosis of rectum without fistula

Q42.2 - Congenital absence, atresia and stenosis of anus with fistula

Q43.7 - Persistent cloaca

1.5 Classification of the disease or condition

When formulating a diagnosis, the 2005 Krickenbeck classification should be followed, reflecting the anatomical variant of ARM [11]:

Main group:

1. Perineal (cutaneous) fistula;

2. Rectourethral fistula (prostatic, bulbar);

3. Rectovesical fistula;

4. Vestibular fistula;

5. Cloaca;

6. Anorectal malformation without fistula;

7. Anal stenosis.

Rare variants:

1. Rectal pouch (pouch colon);

2. Rectal atresia or stenosis;

3. Rectovaginal fistula;

4. H-type fistula (H-fistula);

5. Other rare anomalies.

1.6 Clinical presentation of the disease or condition

In the vast majority of cases, the manifestation of the malformation is observed immediately after birth, when the initial examination of the newborn reveals the absence of the anal opening in the typical (anatomically normal) position [1, 2]. At a later stage (more than 12 hours after birth), the clinical picture of low intestinal obstruction joins. In boys with a rectourethral or rectovesical fistula, meconium discharge from the urethra is possible. In girls with a rectogenital fistula, meconium discharge from the genitals is observed.

2. Diagnostics, medical indications and contraindications for diagnostic methods

Criteria for establishing the diagnosis/condition: based on clinical and instrumental examination data.

Principles of diagnosis formulation:

When formulating the diagnosis, the 2005 Krickenbeck classification should be followed [11].

2.1 Complaints and Anamnesis

Absence of the anal opening or its anatomically incorrect location, discharge of meconium from an atypical site.

The diagnosis of ARM can be suspected during antenatal diagnostics – fetal ultrasound [12]. Indirect signs may include dilatation of the colon in its distal part, appearance of dense inclusions in the lumen [13]. Detection of features in the structure of the muscle complex in the 2nd–3rd trimesters of pregnancy can help in establishing the diagnosis, but has low specificity and sensitivity [14]. The presence of a large cystic formation in the pelvic region (hydrocolpos) suggests the presence of a cloaca [15].

2.2 Physical Examination

Comment: in ARMs, the anal opening in the usual place is absent. Exceptions are rectal atresia and stenosis. After identifying an ARM (absence of the anus, incorrect location, narrowing), it is necessary to determine the clinical variant of the malformation. In boys, the median raphe of the perineum and the scrotum are inspected, paying attention to potential staining of tissues by meconium (mucus) or the presence of whitish inclusions in its projection characteristic of a fistulous tract. During the examination, the "bucket handle" sign can be detected—a skin bridge covering the fistula opening. In girls, the structure of the external genitalia is evaluated: small dimensions of the labia majora/minora, a single opening on the perineum, inability to establish the vaginal introitus are suspicious for a cloaca. If a perineal fistula is present, its diameter must be determined using catheters of various sizes or Hegar dilators. The discharge of intestinal contents and/or gas from the urethra in boys indicates the presence of a urethral or vesical fistula. If no fistula is found upon examination, the patient must be re-examined after 20–24 hours, which is sufficient for any perineal fistula to manifest [16, 17, 18].

Clinical diagnostics is possible in the presence of vestibular and perineal fistulas; in other cases, additional instrumental diagnostic methods must be used [16, 17, 18].

2.3 Laboratory Diagnostics

Specific laboratory diagnostics is absent.

2.4 Instrumental Diagnostics

All children with ARMs are indicated to undergo a set of examinations to diagnose the anatomical variant of ARM [19].

Comment: the patient is placed prone on a bolster in a position with the pelvic end elevated by 45 degrees. Pelvic radiography is performed in a lateral projection. A radiopaque marker is placed on the perineal skin. After positioning the child and before performing radiography, 3–4 minutes should elapse. It is necessary to indicate the level of the terminal rectum relative to the coccyx, and also to measure the distance from the blind end of the colon to the radiopaque marker [17].

Comment: currently, performing an irrigoscopy of the excluded segment of the large intestine (distal colostography) is preferred [20, 21, 22]. The contrast study of the excluded large intestine is performed with tight filling, meaning it is filled with a water-soluble iodine-containing radiopaque agent (iodine-containing radiopaque agents) via the distal (efferent) colostomy under fluoroscopic guidance. A radiopaque marker is placed at the area of the expected anus. The main part of the procedure is performed strictly in the lateral projection. The result is the determination of the presence or absence of a fistula into the urinary system, along with clarification of its localization.

All children with ARM are indicated for a comprehensive set of studies for the diagnosis and detection of associated malformations [19, 23].

2.5 Other Procedures

Not used.

3. Treatment, including drug and non-drug therapies, diet therapy, and pain management

General principles of treatment include surgical correction of the malformation, drug therapy, diet therapy, and the management of postoperative complications and functional disorders [1, 2, 3, 9, 19].

3.1 Medical treatment

Medical treatment includes all types of therapy aimed at stabilizing the patient in complicated disease courses, preoperative preparation, and postoperative care [1, 2, 3].

Drug therapy includes:

- perioperative antibiotic prophylaxis;

- irrigation of the large intestine (cleansing enema);

- infusion therapy;

- parenteral nutrition.

Comment. Perioperative antibiotic prophylaxis is performed during elective surgery. The antibiotic (systemic antibacterial drugs) is administered 30–60 minutes before the start of surgery. During prolonged surgery, re-administration of the antibiotic (systemic antibacterial drugs) intraoperatively may be necessary.

Postoperative antimicrobial therapy is prescribed for the treatment of infectious complications [24, 25].

• All patients with ARM in the postoperative period are recommended to undergo analgesia using epidural analgesia with ropivacaine** for patients aged 0 to 6 months at a dose of 0.2 mg/kg/h, for patients aged 6 to 12 months at a dose of 0.4 mg/kg/h, and for children aged 1–12 years at 0.4 mg/kg/h (2 mg/mL) continuously into the epidural space for up to 72 hours; for children over 12 months of age - intravenous analgesia with fentanyl** 0.005% [26, 27].

LoR CGoE 5Level of Recommendation C (Grade of Evidence - 5)

Comments: in the absence of contraindications, performing an epidural block for postoperative analgesia (epidural analgesia) is possible. A ropivacaine** solution is used for pain relief [26].

Opioid intravenous analgesia is used for postoperative pain relief. For intravenous analgesia in children over 12 months of age, fentanyl** 0.005% solution (N01AH01) is used. The duration of postoperative pain relief is determined by ongoing pain and intestinal paresis [26, 27].

• All patients with ARM in the postoperative period are recommended to receive infusion therapy and parenteral nutrition according to standard methods [26].

LoR CGoE 5Level of Recommendation C (Grade of Evidence - 5)

3.2 Non-drug treatment

Comment. To administer cleansing enemas, a catheter must be used, which is inserted into the rectum. After the enema is given, the catheter is disconnected so that gas and stool can escape.

3.3 Dietary therapy

Comment: in the postoperative period, an enteral pause of up to 4–5 days is maintained in the absence of an intestinal stoma. In patients with an intestinal stoma, enteral feeding is resumed in the absence of complications on the day following surgery.

Infants are prescribed feeding: breast milk, or a specialized infant formula/medical nutrition product for young children. Complementary foods are introduced upon normalization of stool, with a gradual expansion of the diet [2].

3.4 Surgical treatment

Comment. The type of surgery and the method of its execution are determined depending on the type of malformation. Fundamentally, it is necessary to determine whether surgical treatment (proctoplasty and/or anoplasty) can be performed in a single stage, or if a protective colostomy is required, followed by surgical treatment of the anorectal malformation at a later date [29]. This decision must be made within 24 hours of birth [1, 2, 3, 30].

3.4.1 Creation of a protective intestinal stoma (protective colostomy, protective ileostomy)

Colostomy in patients with ARM relieves intestinal obstruction and prevents infection of the urinary tract and the perineal surgical wound from intestinal contents [1, 2, 3, 31].

• For the prevention of complications, preventive colostomy / preventive ileostomy is recommended for all patients with APR combined with:

  - rectourethral (bulbar, prostatic) fistula;

  - rectovesical fistula;

  - rectal atresia and stenosis;

  - cloaca;

  - anorectal malformation without fistula;

  - perineal fistula in boys and vestibular fistula in girls when there is no prior experience in surgical treatment of these ARM variants;

  - inability to clarify the ARM variant;

  - severe concomitant diseases requiring primary surgical or non-surgical treatment, or prolonged patient stabilization (critical congenital heart disease, low birth weight, multiple congenital malformations, etc.) [2].

LoR CGoE 5Level of Recommendation C (Grade of Evidence - 5)

Comment: the protective colostomy is placed at the level of the transition from the descending colon to the sigmoid colon. It is important to separate the proximal and distal ends of the stoma with a skin "bridge" so that the proximal (functional) end of the stoma is covered by the ostomy bag without affecting its distal end [2, 3, 31].

When performing a protective colostomy at the level of the descending-sigmoid junction, an oblique incision is made in the left iliac region. The length of the incision must be sufficient to allow the sigmoid colon to be easily eventrated from the surgical wound. The level of bowel division should be determined so that the proximal end of the colostomy can be fixed to the anterior abdominal wall without tension. The distal end is closed along the incision, forming a small stoma with a diameter of 4–5 mm. Both ends of the stoma are fixed to the parietal peritoneum, aponeurosis, and skin [2].

3.4.2 Main stage of surgical treatment

The type and method of anorectal reconstruction are determined based on the variant of the malformation [33, 34]. In any case, the goal of surgical treatment is to divide the rectourethral fistula, if present, mobilize the distal colon, and form a "neoanus" [1, 2, 3, 31, 35].

3.4.3 Postoperative anal bougienage

The goal of surgical treatment for this type of malformation is to divide the rectocutaneous fistula, mobilize the rectum, and reposition it into the center of the anal dimple [2, 36, 37].

Comment. Before surgery, a two-way Foley catheter, size Ch/Fr No. 6 or No. 8 depending on the patient's weight, is inserted into the urethra. To stimulate muscle contractions during surgery, an anesthetic stimulator (portable electrical stimulator) is used. Traction sutures are placed around the circumference of the fistula, and the rectocutaneous fistula is divided. The incision of the perineal soft tissues is continued until the posterior wall of the rectum is visualized. The rectum is mobilized in a retrograde direction to allow its free pull-through to the perineum. The operation is completed with anoplasty. If the rectocutaneous fistula opens within the anal dimple and has a large diameter, it is advisable to divide the fistula while preserving its integrity along the anterior 1/3 or 1/4 of the circumference [2, 9, 31, 36, 38, 39].

In girls with a vestibular fistula, bowel dissection must be continued until complete separation of the anterior bowel wall and the posterior vaginal wall [1, 2, 3, 40].

In boys with a perineal fistula opening onto the scrotum or penis, the fistula wall must be incised until the bowel wall is visualized. After that, traction sutures are placed and dissection is performed [2, 41].

3.4.4 Surgical treatment of patients with anal atresia and perineal fistula

The goal of surgical treatment for this type of anorectal malformation is to divide the rectourinary (rectourethral/rectovesical) fistula, mobilize the rectum, and reposition it into the center of the anal dimple [35].

Comment. Before surgery, a two-way Foley catheter, size Ch/Fr No. 6 or No. 8 depending on the patient's weight, is inserted into the urethra.

When the fistula is localized in the bulbar urethra, a posterior sagittal approach is preferred (rectal reconstruction, sacral proctoplasty). An anesthetic stimulator (portable electrical stimulator) is used to stimulate muscle contractions during surgery. Perineotomy is performed until the posterior wall of the rectum is visualized; then the rectourethral fistula must be identified, divided, and the rectum dissected in a retrograde direction until it can be freely pulled through to the perineum (rectal reconstruction). The final stage is anoplasty.

When the fistula is localized in the prostatic urethra or the bladder neck, it is advisable to use a laparoscopic approach to mobilize the rectum and perform proctoplasty (rectal reconstruction, abdominoperineal proctoplasty). Regardless of the surgical method, the procedure is completed by performing anoplasty [1, 2, 3].

3.4.5 Surgical treatment of patients with rectourethral/rectovesical fistula

A specific feature of surgical treatment for this variant of anorectal malformation is the use of a rectal dissection (mobilization) method depending on the level of atresia [2].

Comment. Before surgery, a two-way Foley catheter, size Ch/Fr No. 6-10, is inserted into the urethra depending on the patient's weight and age. The type and method of the operation are determined by the level of rectal atresia. The urethra can serve as a reference point for this.

When rectal atresia is localized at the level of the bulbar urethra, a posterior sagittal approach is preferred for rectal reconstruction. When the level of atresia is localized at the prostatic urethra or the bladder neck, it is advisable to use a laparoscopic approach to mobilize the rectum and perform the surgical procedure—rectal reconstruction. Regardless of the surgical method, the procedure is completed by performing anoplasty.

3.4.6 Surgical treatment of patients with fistula-free anorectal malformations

Rare malformations include a "rectal pouch", rectal atresia or stenosis, and other rare anomalies of anorectal malformations.

Comment. If the rectum is absent, a "neorectum" must be created. In the surgical treatment of patients with rare anorectal malformations, the principles of maximum preservation of the existing colon length and its pull-through to the perineum at the center of the anal sphincter must be followed. An anesthetic stimulator (portable electrical stimulator) is used to stimulate muscle contractions during surgery.

3.4.7 Surgical treatment of patients with rare anorectal malformations

Comment. The type and method of the operation are determined based on the length of the common channel. An anesthetic stimulator (portable electrical stimulator) is used to stimulate muscle contractions during surgery. If the length of the common channel is less than 3 cm, reconstruction can be performed via a posterior sagittal approach. Intraoperatively, a two-way Foley catheter, size Ch/Fr No. 8 or No. 10, is inserted into the bladder. The rectum must be isolated, the rectourinary fistula divided, and the rectum mobilized until it can be freely pulled through to the perineum. Then the urogenital complex is isolated and mobilized as a single unit by transecting the pubic ligaments between the symphysis and the bladder. The complex is pulled through to the perineum, and the urethra, vagina, and rectum are reconstructed. The final stage is anoplasty.

If the common channel is greater than 3 cm, the reconstructive surgery is accompanied by an abdominal (open or laparoscopic) approach. If the length of the vagina is subsequently insufficient for pull-through to the perineum, various types of vaginal reconstruction are used, including using a segment of the bowel [1, 2, 31].

3.4.8 Surgical treatment of patients with cloaca

Comments. Hegar dilators are used to perform "neoanus" bougienage. The first bougienage is performed on the 10th–14th postoperative day in the absence of postoperative complications. The dilator size is gradually increased to the age-appropriate diameter.

Table 1. Age-matching and sizes of Hegar dilators [2].

3.5 Treatment of complications

Postoperative complications in the treatment of children with anorectal malformations include urethral injury, urethral "pseudodiverticulum" [55], extrasphincteric colon pull-through, surgical site infection, retraction of the pulled-through bowel, anal stenosis (coloanal anastomosis/"neoanus"), mucosal prolapse of the pulled-through bowel (rectal prolapse), fistula formation, and scarring deformity of the perianal area and perineum [2].

Comment. In surgical site infection, local treatment consists of partial suture removal and soft tissue drainage. Retraction of the brought-down bowel is detected on visual inspection of the anus. Anal stenosis occurs due to non-compliance with the prophylactic bougienage regimen and tissue tension of the brought-down bowel. Mucosal prolapse of the brought-down bowel is determined by visual inspection of the perineum and requires excision of redundant brought-down bowel tissue. In case of recurrent rectoorgan fistulas, intestinal contents or gas appear in the urine, and in female patients, discharge of intestinal contents from the pudendal cleft.

3.6 Treatment of functional disorders

Functional disorders in the postoperative period in patients with anorectal malformations are caused by the type of malformation and concomitant pathology. The prognosis for functional disorders is determined during examination prior to anorectal reconstruction.

Comment. The components of therapy for functional disorders depend on the type of disorder. The type of intestinal transit disorder is determined by the variant of the anorectal malformation and confirmed by contrast enema and/or assessment of fluoroscopic monitoring of contrast passage through the intestine. Hypomotor function (delayed intestinal transit) is characterized by a dilated rectum and sigmoid colon. Hypermotorship (accelerated intestinal transit) is characterized by a narrow, short rectum and sigmoid colon.

Comment. The main method of treating functional disorders is a cleansing enema. The volume and concentration of the enema are selected individually for each patient; the method to control adequate bowel evacuation after a cleansing enema is an abdominal plain radiograph after defecation [2]. Stimulant laxatives (ATC-A06A) are used as drug therapy for delayed transit and are selected individually based on the clinical picture [60, 61, 62, 63, 64, 65].

4. Medical Rehabilitation and Sanatorium-Resort Treatment

There are no specific rehabilitation methods for patients with anorectal malformations.

5. Prevention and Dispensary Observation

There are no specific preventive measures for anorectal malformations.

Prevention methods should be aimed at preventing postoperative complications and intestinal functional disorders [69, 70, 71].

Dispensary follow-up. Dispensary follow-up of the patient is carried out by a pediatric surgeon.

• Patients with anorectal malformations who develop complications after radical surgical treatment are recommended to be referred to a pediatric surgical inpatient facility [72, 73].

LoR CGoE 5Level of Recommendation C (Grade of Evidence - 5)

6. Organization of Medical Care

Treatment of patients with anorectal malformations is carried out in a multidisciplinary pediatric inpatient facility [73]. Care for patients with anorectal malformations is provided by pediatric surgeons and pediatric anesthesiologists-resuscitologists.

Indications for emergency hospitalization to a medical organization:

- variants of anorectal malformations requiring a protective colostomy (rectourethral and rectovesical fistula, cloaca, rare variants of malformations),

- intestinal obstruction and other conditions requiring emergency surgical intervention (fistula-free form of anorectal malformation),

- associated malformations.

Indications for planned hospitalization in a medical organization:

- variants of anorectal malformations without impaired bowel evacuation,

- rehabilitation of patients with anorectal malformations after surgery,

- correction and treatment of postoperative complications in patients with anorectal malformations.

Indications for patient discharge:

- with sustained improvement, when the patient can stay outside the hospital without detriment to health,

- if the patient needs to be transferred to another medical institution,

- upon the request of the patient or their legal representative.

7. Additional Information

The prognosis in children operated on for anorectal malformations is determined by the variant of the anorectal malformation [74, 75] and the presence of concomitant anomalies [57, 76, 77, 78]. The main problems in the long-term postoperative period after correction of anorectal malformations are chronic constipation, fecal incontinence, as well as urination disorders and erectile dysfunction [79, 80, 81, 82].

Factors negatively affecting treatment outcomes:

- development of infectious complications [83],

- associated pathology (sacral and coccygeal pathology, spinal cord pathology) [84],

- chromosomal abnormalities and genetic pathology [76].

Criteria for Evaluating the Quality of Medical Care

References

Appendix A1. Working Group Composition

1. Aleksandr Yu. Razumovsky – MD, Professor, Corresponding Member of the Russian Academy of Sciences, Head of the Yu.F. Isakov Department of Pediatric Surgery at Pirogov Russian National Research Medical University of the Ministry of Health of Russia, Chief Pediatric Surgeon of the Moscow Healthcare Department, Chief Pediatric Surgeon of the Central Federal District of Russia, Head of the Department of Thoracic Surgery and Surgical Gastroenterology at the Filatov Children's City Clinical Hospital (Moscow), Chairman of the Presidium of the Russian Association of Pediatric Surgeons, Board Member of the Moscow Society of Surgeons, Board Member of the Society of Endoscopic Surgeons, Board Member of the Russian Society of Surgical Gastroenterologists, Member of the European Association of Pediatric Surgeons, Member of the Russian Association of Hepatobiliary Surgeons.

2. Morozov Dmitry Anatolyevich – Doctor of Medical Sciences, Professor, Director of the Yu.E. Veltishchev Research and Clinical Institute of Pediatrics and Pediatric Surgery of the Pirogov Russian National Research Medical University (Moscow), Head of the Department of Innovative Pediatrics and Pediatric Surgery of the Institute of Continuing Education and Professional Development (ICEPD), Chief Freelance Pediatric Surgeon of the Russian Ministry of Health, Deputy Chairman of the Presidium of the Russian Association of Pediatric Surgeons, Vice President of the National Medical Chamber, member of the Association of Coloproctologists of Russia, member of the European Paediatric Surgeons' Association.

3. Novozhilov Vladimir Alexandrovich – Doctor of Medical Sciences, Associate Professor, Head of the Department of Pediatric Surgery, Irkutsk State Medical University; Chief Medical Officer of the City Ivano-Matrenin Children's Clinical Hospital (Irkutsk); member of the Russian Association of Pediatric Surgeons, Chairman of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons, member of the Association of Coloproctologists of Russia, member of the Association of Surgeons of Irkutsk Region.

4. Mokrushina Olga Gennadievna – Doctor of Medical Sciences, Professor at the Department of Pediatric Surgery named after Yu.F. Isakov, Pediatric Faculty, Pirogov Russian National Research Medical University; Deputy Chief Medical Officer for Surgery, Filatov Children's City Clinical Hospital, Moscow Healthcare Department (Moscow); member of the Presidium of the Russian Association of Pediatric Surgeons, member of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons, member of the Association of Coloproctologists of Russia.

5. Shcherbakova Olga Vyacheslavovna – Doctor of Medical Sciences, Head of the Surgical Department, Federal Research and Clinical Center of Children and Adolescents of the Federal Medical-Biological Agency (Moscow); Chief Researcher at the Federal Research and Clinical Center of Children and Adolescents of the Federal Medical-Biological Agency; member of the Russian Association of Pediatric Surgeons, member of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons, member of the Association of Coloproctologists of Russia.

6. Karavaeva Svetlana Alexandrovna – Doctor of Medical Sciences, Associate Professor, Head of the Department of Pediatric Surgery, North-Western State Medical University named after I.I. Mechnikov (Saint Petersburg); member of the Presidium of the Russian Association of Pediatric Surgeons, Chairman of the Problem Commission on Neonatal Surgery, member of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons.

7. Kotin Alexey Nikolaevich – Candidate of Medical Sciences, Associate Professor at the Department of Pediatric Surgery with a Course in Anesthesiology and Intensive Care, Pavlov First Saint Petersburg State Medical University; leading operating surgeon of the Neonatal Surgery Service, Children's City Hospital – Pediatric Center of High Medical Technologies (Saint Petersburg); member of the Russian Association of Pediatric Surgeons, member of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons, member of the Association of Coloproctologists of Russia.

8. Akselrov Mikhail Alexandrovich – Doctor of Medical Sciences, Associate Professor, Head of the Department of Pediatric Surgery with a Course in Urology and Andrology, Institute of Motherhood and Childhood, Tyumen State Medical University; Head of Pediatric Surgical Department No. 1, Regional Clinical Hospital No. 2 (Tyumen); Chief freelance pediatric surgeon of the Tyumen Region, Chairman of the Association of Pediatric Surgeons of the Tyumen Region, member of the Association of Surgeons of Russia, member of the Russian Association of Pediatric Surgeons, member of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons, member of the Association of Coloproctologists of Russia.

9. Svarich Vyacheslav Gavrilovich – Doctor of Medical Sciences, Associate Professor, Professor at the Department of Pediatric Surgical Diseases named after G.A. Bairov, Saint Petersburg State Pediatric Medical University (Saint Petersburg); member of the Russian Association of Pediatric Surgeons, member of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons, member of the Association of Coloproctologists of Russia.

10. Stepanova Nataliya Maratovna – Candidate of Medical Sciences, Associate Professor at the Department of Pediatric Surgery, Irkutsk State Medical University; Head of the Center for the Treatment of Anorectal Malformations and Pediatric Colorectal Surgery, City Ivano-Matrenin Children's Clinical Hospital (Irkutsk); member of the Russian Association of Pediatric Surgeons, member of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons, member of the Association of Coloproctologists of Russia, member of the Association of Surgeons of Irkutsk Region.

11. Gopienko Mikhail Anatolievich – Assistant at the Department of Pediatric Surgery with a Course in Anesthesiology and Intensive Care, Pavlov First Saint Petersburg State Medical University; surgeon at the Neonatal Surgery Service, Children's City Hospital – Pediatric Center of High Medical Technologies (Saint Petersburg); member of the Russian Association of Pediatric Surgeons, member of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons.

12. Okulov Evgeny Alekseevich – Candidate of Medical Sciences, Leading Researcher at the Laboratory of Scientific Foundations of Thoracoabdominal Surgery, National Medical Research Center for Children's Health (Moscow); member of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons, member of the Russian Association of Pediatric Surgeons.

13. Filippov Dmitry Vladimirovich – Candidate of Medical Sciences, Head of the Surgical Department, Children's City Hospital No. 22 (Saint Petersburg); Associate Professor at the Department of Pediatric Surgical Diseases named after G.A. Bairov, Saint Petersburg State Pediatric Medical University; member of the Russian Association of Pediatric Surgeons, member of the Problem Commission on Coloproctology of the Russian Association of Pediatric Surgeons, member of the Association of Coloproctologists of Russia.

There is no conflict of interest.

Appendix A2. Methodology for Developing Clinical Guidelines

Target audience for these clinical guidelines:

1. Pediatric surgeons;

2. Anesthesiologists-intensivists;

3. Neonatologists;

4. Pediatricians;

5. Functional diagnostics physicians;

6. Medical geneticists;

7. Bedside nurse (ward nurse);

8. Healthcare organizers (methodologist physician);

9. Medical students, residents, postgraduate students.

In these clinical guidelines, all data are ranked by level of reliability (evidence) depending on the quantity and quality of studies on the issue.

Table 1. Scale for assessing levels of evidence (LE) for diagnostic methods (diagnostic interventions)

Table 2. Scale for assessing levels of evidence (LE) for prevention, treatment, and medical rehabilitation methods, including those based on natural therapeutic factors (preventive, therapeutic, and rehabilitative interventions)

Table 3. Grading of recommendations assessment, development and evaluation (GRADE) for methods of prevention, treatment, and medical rehabilitation, including those based on natural therapeutic factors (preventive, therapeutic, and rehabilitative interventions)

Procedure for updating clinical guidelines.

The clinical guideline update mechanism provides for systematic revision at least once every three years, as well as upon the emergence of new evidence-based data regarding the diagnosis, treatment, prevention, and rehabilitation of specific diseases, or when justified additions/comments to previously approved clinical guidelines arise, but no more frequently than once every 6 months.

Appendix A3. Reference Materials

Related documents

These clinical guidelines were developed taking into account the following regulatory legal documents:

1. Federal Law of the Russian Federation No. 323-FZ dated November 21, 2011, "On the Fundamentals of Protecting the Health of Citizens in the Russian Federation";

2. Federal Law No. 326-FZ dated November 29, 2010, "On Compulsory Medical Insurance in the Russian Federation";

3. Order of the Russian Ministry of Health No. 203n dated April 14, 2025, "On Approval of Criteria for Assessing the Quality of Medical Care";

4. Order of the Ministry of Labor of Russia No. 374n dated July 26, 2024, "On Approval of Classifications and Criteria Used in Carrying out Medical and Social Expertise of Citizens by Federal Medical and Social Expertise Institutions";

5. Federal Law No. 178-FZ dated July 17, 1999, "On State Social Assistance".

Appendix B. Physician Action Algorithms

Appendix B1. Physician action algorithms in case of ARMs in boys

Appendix B2. Physician action algorithms in case of ARMs in girls

Appendix C. Patient Information

Anorectal malformations (ARMs) represent a broad, heterogeneous group of anomalies associated with various developmental disorders of the rectum and anus during embryogenesis. In most cases, the opening on the perineum is either completely absent or opens outside the center of the external anal sphincter muscle. In the latter case, these are so-called "external" fistulas (perineal, vestibular) through which stool can pass if the fistula diameter is sufficient. In the absence of such an external fistula in a BOY, the rectum may end blindly or, most commonly, empty into the urinary tract, forming a rectourethral (bulbar, prostatic) or rectovesical fistula. In the absence of an external fistula in a GIRL, the rectum may also end blindly, empty into the vagina via a vaginal fistula (extremely rarely), or form the most complex ARM variant – a cloaca. The causes and factors predisposing to the development of ARMs are unknown; there are no preventive methods.

It is fundamentally possible to detect ARM antenatally via ultrasound, but prenatal detection rates remain low today. In most cases, ARM in a child is first discovered shortly after birth; a thorough examination of the newborn's perineum by a physician in the delivery room plays a key role here. If ARM is suspected, the child should be transferred to a multi-profile surgical hospital, where a surgeon will perform the necessary additional examinations within the next 24 hours and develop a treatment plan. The scope of the examination is determined by the specific type of malformation and may either be limited to a perineal examination or include instrumental methods (transperineal rectal ultrasound, irrigoscopy, sacral and coccygeal radiography, fistulography, computed tomography of the abdominopelvic organs, and electromyostimulation of the pelvic floor muscles under general anesthesia). In all cases, it is also necessary to rule out other developmental malformations that are frequently combined with ARM and affect the heart, kidneys, spine, esophagus, trachea, and limbs.

For certain types of ARM, early diagnosis may be difficult; therefore, if an unusual appearance of the anus/perineum is suspected in a child of ANY age, they should undergo an appointment (examination, consultation) with a pediatric surgeon.

Treatment for ARM is exclusively surgical; this malformation is considered correctable. The general principle of surgical correction in most cases comes down to eliminating the fistula, if present, and placing the rectum in the center of the muscle complex with the formation of an opening ("neoanus") in the center of the external anal sphincter.

Various surgical techniques exist for the correction of ARM, utilizing different approaches (several types of perineal, laparotomic, or laparoscopic approaches, as well as combinations thereof). Surgical treatment can be single-stage (primarily radical) or performed in several stages, one of which is the creation of a colostomy (temporary diversion of a segment of the large intestine to the anterior abdominal wall). The decision on the optimal treatment method in each case is made by the pediatric surgeon, depending on the specific type of malformation, severity of associated anomalies, child's weight, and several other factors. In a number of cases, multiple treatment options are permissible, including regarding the optimal age for performing ARM correction. Consequently, approaches in different clinics may vary to a certain extent.

In the postoperative period, monitoring the adequacy of the diameter and sufficient elasticity of the neoanus is of great importance, which is ensured by calibrating it with special Hegar dilators (bougies). A number of delayed complications may develop (mucosal excess, cicatricial stricture of the neoanus, etc.), which may require repeat reconstructive surgeries.

To establish future function of the anus and rectum, not only maximal anatomical correction is important, but also long-term subsequent rehabilitation. Specific agents and approved universal rehabilitation programs do not exist, but regular and adequate bowel evacuation must be monitored. Most patients following ARM correction are prone to constipation, and some to fecal incontinence. The functional prognosis depends primarily on the type of ARM, the presence of spinal cord pathology, and sacral proportionality. In addition, patients with ARM are at risk for developing neurogenic bladder dysfunction.

To achieve the best treatment outcomes, long-term (lasting at least throughout childhood) regular dispensary follow-up by a pediatric surgeon is necessary, if possible in the same clinic, and optimally in the institution where the malformation correction was performed.

Appendix G. Assessment Scales, Questionnaires, and Other Evaluation Tools

None provided.