Ultrasonography in diagnostic of hypertrophic pyloric stenosis in children: advantages and pitfalls

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 ch