Hypertrophic pyloric stenosis (HPS) in newborns is the one of the most frequent causes of vomiting that required surgery. During long period of time, X-ray was the main method for the confirming diagnosis of HPS, however after first reports about possibilities of ultrasonography (US), this method was widely applied in clinical practice. Purpose - to summarize own experience of US applying for the diagnostic of HPS; determining advantages and disadvantages of this method of examination. Materials and methods. This study based on the US results of 93 patients with HPS and 27 children with pylorospasm that were observed and treated in Lviv regional children’s clinical hospital for 2009-2020 years. By US measured the thickness of pyloric muscle, length, front-posterior (transverse) size, and diameter of orifice of pyloric canal. Results of the study were evaluated by the statistical program StatPlus: mac, AnalystSoft Inc. (version v8). Results. The thickness of pyloric muscle and pyloric canal length are the major criteria of confirming/excluding HPS diagnosis. By the measurement of pyloric muscle thickness, it is necessary to remember that tangential position of transducer and muscles’ contraction can cause pseudo-thickening. According to the results of the study, the thickness of pyloric muscle in case of HPS was 6.4±0.3 mm (a range - 3-10 mm) and was no correlation nor with duration of illness (p=0.364) nor with age of child (p=0.534). In pylorospasm, which clinically can simulate HPS, the thickness of the pyloric muscle was 3.02±0.1 mm, what is significantly less compared to infants with HPS (Student’s t-test - 1.983; p=0.0000). Pyloric canal length in case of HPS was 22.9±0.6 mm (a range - 16-32 mm), what also was significantly differed than in case of pylorospasm - 15.8±0.5 mm (Student’s t-test - 1.998; p=0.0000). This was only indicator that clear correlated with child’s age (p=0.004) and duration of illness (p=0.006). Diameter of pyloric canal orifice and front-posterior size differed from indices in children with pylorospasm also. According to the results of ROC analysis, the best markers for the confirming diagnosis of HPS was thickness of pyloric muscle, its length, and front-posterior size, while the diameter of pyloric canal orifice shows the moderate prognostic significance. Conclusions. Ultrasonographic examination makes it possible to establish the diagnosis of HPS in newborns with a high degree of reliability. A doctor, who performs US in a child with suspected pylorostenosis, should be guided by the size of the unchanged pyloric canal and in case of its hypertrophy remember the «pitfalls» in the examination and know the ways to overcome them. 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 interests was declared by the authors.

Introduction. The typical clinical picture of acute appendicitis (AA) is absent in most of patients, that lead for the high frequency of misdiagnosis with the increase of complicated forms of AA. Due to that, it is necessary to establish the new available laboratory markers, which permitted with the high level of reliability distinguish children not only with AA, but also is appendix perforation. The question what method of appendectomy should be choose – the conventional or mini-invasive – are still under debate. Aim of the study was to summarize the results of diagnosis and treatment of AA in children with the applying of various laboratory markers, ultrasonography (US), and laparoscopy. Materials and methods. This study based on the results of surgical treatment of 3171 children with AA, which were operated during 2009–2018 years. Diagnosis was established on the data of anamnesis, results of objective and laboratory investigation. US was performed in 1183 (37.3%) of patients. Open appendectomy (OA) was performed in 2879 (90.8%) and laparoscopic (LA) – in 292 (9.2%) of patients. With the aim to evaluate the results the methods of variative statistic, determination of specificity, sensitivity, positive (PPV) and negative (NPV) predictive value, etc. were applied. Results. Among the laboratory markers, the best results for the diagnosis of AA showed the neutrophil to lymphocytes ratio (NLR) with the sensitivity – 84.9%, specificity – 67.1%, PPV – 17.8%, and NPV – 98.9%. NLR (sensitivity – 82.5%, specificity – 84%, PPV – 98.5%) and sodium blood level (sensitivity – 90.3%, specificity – 89.9%, PPV – 98.9%) had the best results for the diagnostic of perforated AA. US is the important compound of diagnostic of AA in children with the high level of sensitivity, specificity, PPV, and NPV – 93%, 85%, 86%, and 92%, correspondingly. By the frequency of complications in the early postoperative period, OA and LA had no statistically significant differences, but at follow-up after surgery, LA revealed the sufficient advantages over OA. Conclusions. Among the various laboratory markers, NLR had the better prognostic value for the diagnosis of AA and indices of plasma sodium concentration and NLR for the preoperative diagnosis of perforated appendicitis. US with the high degree of reliability allows to confirm or exclude the diagnosis of AA in children with acute abdominal syndrome. Laparoscopic appendectomy is the real alternative for conventional methods of AA treatment. Besides of the well-known advantages of mini-invasive surgery, the laparoscopic appendectomy had an advantage at the follow-up period. No conflicts of interest was declared by the authors. Key words: acute appendicitis, children, diagnostic, treatment, laparoscopy.