[Standardized development of transanal endoscopic microsurgery].

Transanal endoscopic microsurgery (TEM) is currently the only one-port system in endoscopic surgery, which a direct endoluminal approach can lead to the target organ through a natural opening of human body. TEM has been applied in colorectal surgery for over 3 decades. Compared with radical surgery, TEM has the advantages, such as quicker recovery, shorter hospital stay and fewer complications. One perfect TEM surgical system, which mainly consists of three parts, namely peculiar rectoscope for surgery, special surgical instruments and imaging system, is the foundation of standardized development of TEM. Accurate preoperative evaluation and staging is the key for good outcomes in TEM technology. In addition to digital examination of rectum, rigid sigmoidoscopy(or rectoscopy) should be routinely performed to confirm the location of the lesion and record it in a "time-in-clock" form. For lesions with undetermined nature, biopsy should be performed. For patients with rectal tumor, pelvic MRI examination can be used on the basis of routine endorectal ultrasonography (ERUS). Endoluminal suture is the challenge for standardized development of TEM, especially for those with large intestinal wall defects. Professional training is required to master suture technique. In 2016, the consensus of experts on TEM technology was formulated by TEM Study Group of Colorectal Cancer Specialty Committee of Chinese Anticancer Association. The recommended surgical indications for TEM include (1)rectal adenoma; (2)early rectal cancer with good histopathological features; (3)extended resection of locally malignant polyps by colonoscopy; (4)other rectal tumors suitable for local resection; (5)benign stricture or anastomotic stricture of the rectum; (6)repair of anastomotic leakage after low anterior resection of rectum; (7)diagnosis of rectal hemorrhage; (8)biopsy of rectum and surrounding lesions; (9)repair of rectovaginal fistula or mucosal flap transposition of the internal mouth of anal fistula; (10)treatment of rectal foreign body. With the maturity of TEM technology, the indication of TEM continues to expand. Nowadays, TEM is applicable to rectal neuroendocrine tumor or gastrointestinal stromal tumor resection, as well as rectovaginal fistula repair. It can even serve as a "bottom-up" operation platform for transanal total mesorectal excision (taTME). This article introduces the standardization of TEM, its current indications, novel implications, and future perspectives, expecting that TEM will be further popularized and healthily developed in China.