The Role of Three-Dimensional Endoanal Ultrasound in Preoperative Evaluation of Anorectal Diseases

Abstract

Three-dimensional endoanal ultrasound (3D EAUS) has increased its application in colo- proctology, both in pre- or in post-operative settings, since it provides more detailed information about anorectal anatomy and function. Perianal fistula complex, internal opening location and fistula tract relation with anal canal muscles are easily viewed on 3D EAUS. Moreover, hemorrhoidectomy, sphincterotomy and transanal rectal excisions hold potential in damaging anal sphincters and should be taken into account by the surgeon. Likewise, 3D EAUS has also a significant role in staging locoregional anal and rectal tumors with comparable accuracy to pelvic magnetic resonance imaging (MRI), particularly in regard to T staging in early lesions and tumor response after neoadjuvant therapy. Finally, patients with pelvic floor dysfunction or pelvic organ prolapse (POP) may benefit from 3D EAUS dynamic evaluation in order to rule out an occult sphincter defect or to unveil unsuspected anatomical multi-compartment dysfunction. Therefore, this review will address the current role of 3D EAUS as a valuable tool in modern colorec - tal surgical practice, highlighting its application in evaluating benign anorectal diseases, anal canal and rectal tumors and evacuation disorders, namely echodefecography.