A knot is tied externally, which is then pushed down into the mucosa with the knot pusher (as shown in the Figure below), thus ligating the artery. The Doppler sound disappears as soon as the ligation is successfully performed. The suture is cut with scissors inside of the instrument. After completion of the ligation, a second assessment with the HAL Doppler system should confirm disappearance of sound. Thereby, successfully ligating branches of the superior rectal artery.