Development of a new operating rectal tube with a side window for transanal endoscopic surgery

A single surgeon's experience with transanal endoscopic microsurgery over 20 years with 153 early cancer cases

BACKGROUND

The first author performed transanal endoscopic surgery (TEM) in 302 patients in Japan for the last 20 years, 153 of which were early rectal cancer cases. The short- and long-term outcomes of the early rectal cancer cases are herein reported.

MATERIAL AND METHODS

The original technique of TEM developed by Gerhard Buess was performed in all cases. The hospital records were reviewed to assess the clinical outcomes. A questionnaire was sent to the patients to analyze the long-term outcomes.

RESULTS

One-hundred and fifty-three early cancer cases included 115 T0 and 38 T1 lesions. Full-thickness resection was performed in 36 patients, while 117 underwent submucosal dissection. Conversion to laparoscopic low anterior resection occurred in one case. Mortality was nil. Major operative complication was noted in only one patient, who developed stenosis. Seven patients underwent immediate salvage surgery. Six patients died of recurrence of rectal cancer. Disease-free survival rate at year 5 was 93.7%.

CONCLUSIONS

Our study, one of the largest series in the world, confirms that TEM is a preferable option in the surgical treatment of T0 and T1a rectal carcinoma. As long as early cancer cases are treated, submucosal resection seems to be sufficient. When risk of recurrence is found by pathological examination, immediate salvage operation is mandatory to improve the prognosis.

Development of a shape memory alloy actuator for transanal endoscopic microsurgery

This paper describes problems in traditional transanal endoscopic microsurgery (TEM), and proposes a mechatronics approach in new design. As one of several actuation mechanisms to expose rectal cavity, a compression coil spring made of shape memory alloy (SMA) has been studied. A custom SMA spring actuator was designed to displace 12 mm with 45 N driving force. This actuator was embedded with our new TEM tubular structure and can be used to expose a rectal site up to 60 mm wide and 80 mm long. This exposure is considered to be sufficient for treating many tumors.