PROGNOSTIC FACTORS OF THE POSTOPERATIVE VOMITING IN CASE OF HYPERTROPHIC PYLORIC-STENOSIS

From January 1986 to February 1994, 198 children were operated on for hypertrophic pyloric stenosis (HPS). Postoperative follow-up have been carried out in 194 cases. The children were divided into two groups: group A (n = 134; 69.1%): without any postoperative diet troubles (n = 52) or simple regurgitations (n = 82), and group B (n = 60; 30.9%) pr esenting more significant vomiting requiring medical treatment (n = 52 ) or a prolongation of parenteral nutrition (n = 8). A retrospective s tudy of the different factors which can possibly explain this postoper ative vomiting, was carried out. The criteria having an influence are: the age (44.5 days in group A; 35.7 days in group B; p < 0.001) the w eight at the time of the operation (3921 g in group A; 3647 g in group B; p = 0.01) the thickness of the pylorus at the pre-operative ultras ound scan (5.2 mm in group A; 4.7 mm in group B; p < 0.015). The other studied criteria (prematurity, birth weight, delay in diagnosis, weig ht loss, hydroelectrolytic abnormalities, surgical approach way - subc ostal or umbilical -, surgical difficulties and operation duration) ar e not statistically significant. The young age (and therefore the low weight) at the time of the pyloromyotomy can easily explain the post-o perative vomiting through the physiological immaturity of the lower sp hincter of the esophagus. It is more paradoxical to note that these di fficulties are all the more frequent because the pyloric tumor is less thick at the ultrasound scan. But this criterion is also directly rel ated to the child's age (average thickness of 4.5 mm before the age of one month and 5.8 mm after the age of two months; p < 0.0001). These data suggest the importance of systematic medical treatment to prevent postoperative vomiting in high-risk children, in order to decrease ho spital stay (4.14 days in group A; 5.20 days in group B; p < 0.0001).