Pulmonary sequestration is a complex malformation of the lungs, which is based on a violation of the development of their bronchopulmonary and vascular components. The multifactorial nature of morphological and functional disorders is clinically manifested by respiratory distress syndrome and heart failure with a threat of a critical outcome for a newborn child, despite the sufficient development of the respiratory system as a whole. Purpose - optimization of diagnosis and treatment of lung sequestration in children based on the study of clinical and diagnostic data, as well as the results of surgical treatment. Materials and methods. The study included 18 patients aged from 8 days to 18 years, including newborns - 6, children from 1 to 12 months - 5, from 1 to 3 years - 3, from 7 to 9 years - 2 and from 15 to 18 years - 2. Median age was 4.5 months. Research methods included evaluation of clinical symptoms, chest X-ray, contrast-enhanced CT, and angiography. Prenatal diagnosis was carried out using ultrasonography and fetal MRI. In all cases, open surgical treatment was used. Results. Intrapulmonary sequestration was diagnosed in 13 (72.2%) patients, extrapulmonary - in 5 (27.8%), p=0.082. Left-sided localization in 11 (61.1%) patients, right-sided localization in 7 (38.9%) patients, р=0.3. Associated malformations had 9 (50%) patients: polycystic (n=4) or hypoplasia (n=2) of the lung, diaphragmatic hernia (n=3), pericardial defect (n=1), thoracic dystopia of the kidney (n=2), Waardenburg syndrome (n=1), ventricular septal defect (n=1), innominate artery tracheal compression (n=1). Symptomatic course was noted in 15 (83.3%) patients, asymptomatic - in 3 (16.7%) cases (p=0.021). Main symptoms were as follows: pulmonary bleeding, hemophthisis, respiratory and hemodynamic disorders, signs of inflammation. Lobectomy (n=8), atypical segmental lung resection (n=4) and transection of aberrant vessels (n=1) were performed for intrapulmonary sequestration, and sequestrectomy (n=4) for extrapulmonary sequestration. In cases of associated diaphragmatic hernia (n=3), simultaneous diaphragmatic plasty was performed, including using a non-free pericardial flap (n=1) or a PTFE patch (n=1), and in case of innominate artery compression of the trachea, aortopexy (n=1). In 17 (94.4%) cases, a positive result of surgical treatment was noted. Postoperative complications (intrathoracic bleeding) and lethality were observed in 1 (5.6%) case. Patients were examined in the long-term period from 2 months to 30 years after surgery. Conclusions. Surgical correction of pulmonary sequestration is appropriate as the diagnosis is made, mainly in the neonatal period. Given the complexity of the pathology, especially in the presence of associated malformations, and the expediency of early correction in the neonatal period, thoracotomy access should be preferred as safer for sequential division of arterial and then venous vessels, and for atypical segmental lung resection or lobectomy, depending on peculiarities of sequester. The presence of associated defects requires simultaneous correction. In the case of associated diaphragmatic hernia, autopericardial defect plastics or a synthetic patch are appropriate as an alternative to simple suturing. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors. Keywords: congenital malformations of the lungs, lung sequestration, surgical treatment, children.

Congenital diaphragmatic hernia (CDH) occurs with a frequency of 3.5 per 10,000 live births and occurs due to a fusion disorder of the closure of the pleuroperitoneal fold and transverse septum during 8-12 weeks of gestation. In an isolated variant of this pathology, mortality is quite high and there are a number of controversial issues. Even in the best specialized prenatal intensive care centers, the mortality rate reaches 30%. The use of new technologies in the treatment of CDH has increased the survival rate of patients, however, against this background, there is an increase in surgical problems associated with CDH. Purpose - to describe the structure and incidence of reoperations in children with CDH, depending on the access, identification of the main risk factors for reoperations, pathogenetic justification of optimal surgical access. Materials and methods. A retrospective cohort study of surgical correction of CDH in 104 infants who were operated on the basis of the NCH «OKHMATDYT» during 2000-2020 was conducted. To homogenize the group and to maximally exclude selection bias in order to identify risk factors, we include a group of patients with left-sided CDH in the study. Correction of the left-sided CDH was performed through the laparotomic approach in 51 patients (61%). Thoracotomy for left-sided EDH was used in 33 (39%) patients. Results. In the study group of patients, 14 (16.7%) reoperations were performed in this group at different times of the long-term period. The indications for reoperations were: adhesive intestinal obstruction - 3 (21.5%), inc. strangulated intestinal obstruction with bowel necrosis - 2 (14%), obstruction caused by malrotation - 1 (7%), gastroesophageal reflux - 4 (29.5%), recurrent hernia - 2 (14%), pectus excavatum - 1 (7%), spleen torsion - 1 (7%). The number of reoperations in the study group during a certain observation period was slightly higher in the thoracotomy group (18% versus 14%, p=0.80). More than half of repeated interventions were associated with acute intestinal obstruction, more often after laparotomy (35.7 versus 7%; p=0.16). In this group, 5 reoperations were performed, the cause of which was intestinal obstruction, in contrast to the thoracic group, where one patient was operated for malrotation. Reoperations for recurrent diaphragmatic hernia occurred only in the thoracotomy group in one patient with agenesis of the left diaphragm dome. Early postoperative mortality was found slightly higher in the laparotomy group (27.4% versus 18.1%; p=0.167). Conclusions. The optimal method of surgical treatment of large defects and agenesis of the dome is surgical correction of the diaphragm through a thoracotomy approach using a synthetic patch and thoracalization of the abdominal cavity. The abdominal approach has a high risk of reoperations, which is associated with the development of the adhesive process and the likelihood of the formation of ventral hernias due to viscero-abdominal imbalance. The indications for the use of thoracic access and patches for plasty of the diaphragm defect should be expanded regardless of the side of the lesion and the size of the defect. The main factors determining the risk of recurrent CDH are the size of the hernial defect and the method of diaphragm correction. The research was carried out in accordance with the principles of the Helsinki declaration. The study protocol was approved by the Local ethics committee of all participating institutions. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors. Key words: congenital diaphragmatic hernia, reoperations, intestinal obstruction, gastroesophageal reflux, recurrence, malrotation, thoracatomy, laparotomy.