Ultrasound measurements in hypertrophic pyloric stenosis: don't let the numbers fool you.

They found that pathologic limits were 3 mm for pyloric muscle thickness, 15 mm for pyloric length, 11 mm for pyloric diameter, and 12 mL for pyloric volume. Additionally, they concluded that muscle thickness was the most discriminating factor. However, clinical experience has led us to question the applicability of these findings to infants of varying ages and weights. We postulated that infants with smaller weights and/or ages who had HPS may have had pyloric measurements that were within the normal accepted range (ie, measurements that by current standards are not diagnostic of HPS). This study was aimed at determining whether preoperative pyloric measurements correlated with weight and age in patients with surgically proven HPS. Methods The study design was a retrospective chart review. The institutional review board at our institution approved this study. Data from a single institution over a five-year period (2005 to 2020) were reviewed. Patients were identified by diagnosis codes indicating that they had HPS. Operative reports were reviewed to verify the diagnosis. Demographic data on admission for surgery were collected about individual patients. These included sex, age (postgestational age in weeks), weight (in kilograms), and duration of hospital admission. The muscle wall thickness and length of the pyloric channel (both in centimeters), as documented on the ultrasound report, were obtained for each patient. Patients who did not have pyloric ultrasound measurements recorded or who did not have pyloric stenosis at the time of operation were excluded. Pearson correlation analysis was used to determine if there were statistically significant associations between the fol lowing combinations of factors: patient age and pyloric muscle thickness, patient weight and pyloric muscle thickness, age and pyloric length, and weight and pyloric length. A linear regression analysis also was performed to analyze these relationships. Pyloric length and muscle thickness were the dependent variables, and weight and age were the independent variables.