Trans-anal minimally invasive surgery (TAMIS) versus trans-anal endoscopic microsurgery (TEM): a comparative case-control matched-pairs analysis.

AIM: Since its introduction, transanal endoscopic microsurgery (TEM) has become the treatment of choice for rectal benign lesions not amenable to flexible endoscopic excision and for early rectal cancer. Disposable soft devices as the Trans-anal Minimally Invasive Surgery (TAMIS) are a valid alternative to non-disposable rigid trans-anal endoscopic microsurgery (TEM) platforms. The aim of the present study is to compare TEM and TAMIS in terms of incidence of R1 resection and lesion fragmentation which were combined in a composite outcome called quality resection. Perioperative complication and operative time were also investigated.

METHODS: A total of 132 patients were eligible for this study of whom 63 (47.7%) underwent TAMIS and 69 (52.3%) underwent TEM. Patients were extracted for from a prospective maintained database and groups resulted homogenous after matching using propensity score in terms of size of the lesion, height from the anal verge, position within the rectal lumen, preoperative histology, neoadjuvant treatment. A multivariate logistic and linear regression analysis was carried out using those variables that have significant independent relationship with the quality of surgical resection and operative time.

RESULTS: The incidence of R0 resection and lesion fragmentation was similar between groups. No differences were found in terms of perioperative complication. TAMIS was associated with less setup time and less operative time compared with TEM. Variables influencing quality resection at the multivariate analysis were larger lesion (> 5 cm) and ≥ T2 stage. Variables influencing operative time were surgical procedure (TEM vs TAMIS), height from the anal verge and size of the lesion.

CONCLUSION: The present study shows that TEM and TAMIS are equally effective in terms of quality of local excision and perioperative complication. TAMIS resulted less operative time consuming compared to TEM.