Longitudinal surgical incision through the anterior wall of the pyloric canal to the level of the submucosa (tissue), to treat hypertrophic pyloric stenosis which is the narrowing of the pyloric canal due to narrowing of the pyloric canal due to muscular hypertrophy (abnormal enlargement) of the surrounding circular muscle.

Pyloric stenosis occurs more often in boys than in girls, and is rare in children older than six months because the condition is usually diagnosed by the time a child is six months old.