Ultrasonographic follow-up of infantile hypertrophic pyloric stenosis after pyloromyotomy: a controlled prospective study.

Although the ultrasonographic assessment of hypertrophic pyloric stenosis (IHPS) has become the main radiological method for this disease, our knowledge about postoperative ultrasonographic follow-up is very limited. To evaluate the ultrasonographic outcome of the pylorus, we performed ultrasonographic measurements of the pylorus in 22 children with IHPS, before and after the operation in a prospective trial. The sonograms following surgery were undertaken at the end of the 1st postoperative week and of the 1st, 3rd and 6th month postoperatively. Three main ultrasonographic parameters were used: pyloric muscle thickness (MT), pyloric diameter (PD) and pyloric length (PL). The values of the pylorus, especially the "MT" measurements, began to decrease almost by the end of the first postoperative week, and were normal by the 3rd month in the majority of cases. However, the averages of the PL and PD values never returned to normal throughout the 6 months follow-up. There was a highly significant difference between the average values of pyloric muscle thickness at admission and at the 6th month after surgery (p < 0.001). Within one month after surgery, the ultrasonographic parameters returned to the levels of those in control infants. However, except for MT, they did not return to their normal ranges. Therefore, MT is the most useful parameter for ultrasonographic postoperative evaluation if the normal ultrasonographic values, as given in the literature, are used.