Transanal Endoscopic Microsurgery (TEM) and Transanal Minimally Invasive Surgery (TAMIS)

Abstract

Transanal endoscopic surgery (TES) is an innovative minimally invasive approach with an ever increasing range of applications ranging from local excision of rectal neoplasms to repair of complex rectovisceral fistulas, completion proctectomy, and even transanal total mesorectal excision. Patients experience the benefits of a minimally invasive approach including shorter length of hospital stay, reduced postoperative pain and morbidity, and faster recovery relative to radical rectal resection. Well-documented advantages of this approach over traditional transanal excision include improved visualization and reach for lesions in the proximal rectum and improved capacity to complete full-thickness excision with reduced specimen fragmentation and margin positivity. TES is currently indicated for a variety of benign rectal pathologies, carefully selected early rectal cancer with low histopathological risk for lymph node metastasis, and palliation of locally advanced rectal tumors. The transanal endoscopic microsurgery (TEM) and transanal endoscopic operation (TEO) system are metal platforms with a fixed camera allowing for stability of operative and optical field that can provide transanal access to lesions up to 20 cm from the anal verge, but that afford limited range of motion due to their rigid design. Transanal minimally invasive surgery (TAMIS) platforms are shorter, more pliable, and disposable, which are compatible with standard laparoscopic equipment, but require a second operator to control the camera. Far more published data exists regarding the procedural efficacy and long-term oncologic safety of rigid TES platforms for carefully selected rectal lesions. In the absence of randomized trials directly comparing the various TES approaches, the preliminary TAMIS data published to date suggests equivalent outcomes to TEM and TEO in selected patients.