Assessment of haemorrhoidal artery network using Doppler-guided haemorrhoidal artery ligation for haemorrhoids and pathogenesis implications.

The number of distal branches of the superior rectal artery that have been localized by the Doppler-guided HAL-RAR technique is lower at the posterior midline than in the other segments of the lower rectum. This is another evidence of the vascular deficiency at the posterior pole of the anal canal that might explain the pathogenesis of the anal fissure.