The use of ultrasonography in infantile hypertrophic pyloric stenosis: does the patient's age and weight affect pyloric size and pyloric ratio?

AIMS We aimed to obtain pyloric measurements of our patients with infantile hypertrophic pyloric stenosis (IHPS) using ultrasonography (US) and to evaluate the correlations between age, weight and pyloric size, pyloric ratio (PR). MATERIAL AND METHODS We designed a retrospective study including 20 term infants with surgically proven IHPS and studied the ultrasonographically obtained pyloric muscle thickness (PMT), pyloric diameter (width) (PD), pyloric length (PL) and PR (PMT/PD) to determine if there were statistically significant associations between patient age/weight and pyloric measurements. RESULTS The mean age of the infants was 38.7+/-17.3 days (range, 9-76 days) and their mean weight was 3688.5+/-772.7 g (range, 2810-6000 g), at referral. Mean PMT was 4.98+/-1.04 mm (range, 3.5-6.8 mm). Mean PD was 14.04+/-2.39 mm (range, 10-18 mm). Mean PL was 22.16+/-4.02 mm (range, 16-31.5 mm) and mean PR was 0.35+/-0.04 (range, 0.29-0.42). The correlation between age and PMT (r=0.654, p<0.05) and the correlation between age and PD (r=0.747, p <0.05) were significant. Age and weight were not significantly correlated with PR (p>0.05). CONCLUSIONS The PMT and PD are age dependent parameters. The PR is age and weight independent and therefore, when combined with PMT, PD and PL, it can be useful in the diagnosis of IHPS in infants with early onset disease and/or in those with a lower weight.