A pyloromyotomy is a surgical procedure in which an incision is made in the longitudinal and circular muscles of the pylorus. It is used to treat hypertrophic pyloric stenosis. Hypertrophied muscle is cut along the whole length until the mucosa bulges out. If the mucosa is injured, it is sutured horizontally using interrupted vicryl or silk sutures. It is also known as Ramstedt's Operation, after Conrad Ramstedt who performed the procedure in 1911. However, Harold Stiles performed the procedure first, in 1910.