Contemporary applications of transanal endoscopic microsurgery: Technical innovations and limitations

Purpose: Transanal endoscopic microsurgery (TEM) is a minimally invasive procedure used to transanally excise select benign and malignant tumors of the rectum. In properly selected patients, TEM can provide for decreased postoperative morbidity without compromising oncologic outcome. This report summarizes the recent literature concerning TEM, comprehensively analyzes the authors' experience with TEM, and describes recent technical innovations and indications. Patients and Methods: Thirty-two consecutive patients scheduled for TEM were identified from our prospectively maintained colorectal service database. Clinicopathologic factors, postoperative complications, and oncologic outcomes were analyzed for all patients. In addition, a PubMed literature search was performed with use of the key words "transanal endoscopic microsurgery," "TEM;" "rectal tumor," and "rectal cancer." Results: Transanal endoscopic microsurgery was performed for rectal adenocarcinoma (n = 17; 53%), adenoma (n = 12; 38%), and carcinoid tumors (n = 3; 9%). Median tumor location was 9 cm from the anal verge (range, 3-15 cm). Of the 32 attempted TEM procedures, 27 (84%) were completed. Reasons for inability to complete TEM included narrow rectal lumen or contour of bony pelvis prohibiting passage of the operating proctoscope into the upper rectum and inability to maintain the proctoscope in the rectal lumen with carbon dioxide insufflation because of the distal location of the tumor. Innovations used in the excision of rectal tumors via TEM included the use of the harmonic scalpel, closure of the rectal defect with an extracorporeal slip knot, and a hybrid approach incorporating TEM and traditional transanal techniques. Conclusion: Transanal endoscopic microsurgery provides for low morbidity and does not appear to impair oncologic outcome in properly selected patients.