Early clinical results of endorectal surgery using anewly designed rectal tube with a side window

Background: Transanal endoscopic microsurgery (TEM) using the original Buess devices requires the use of a completely closed system for positive pressure gas insufflation. To simplify the setup of the system and expose the target lesion in the rectum without gas insufflation, we have developed a new operating rectal tube with a side window. Methods: The new rectal tube is a transparent cylinder measuring 40 mm in diameter with its forward end closed and a 40-mm opening on its side. When a rectal tumor is captured within the opening, it can be clearly visualized without positive gas insufflation. Under endoscopic control, the lesion is then resected and the defect is closed by suturing. Using this new system, we performed endorectal surgery on 10 patients with rectal tumors. Our series included four benign adenomas, two carcinomas in situ, two T2 cancers, and two carcinoid tumors. Results: The operation was performed successfully in all 10 cases. There were no significant operative complications and the postoperative course was excellent in all cases. Pathological analysis revealed that the surgical margins of all specimens were completely free from tumor. Conclusions: Our early clinical results suggest that the newly designed operating rectal tube with a side window simplifies the endorectal surgical procedure and facilitates the safe resection of rectal tumors < 40 mm in diameter.