Notes Transanal Rectosigmoid Resection With Total Mesorectal Excision in a Large Human Cadaver Series

Dana A Telem, MD, K S Han, MD, M C Kim, MD, I Ajari, MD, D K Sohn, MD, Kevin Woods, MD, V Kapur, MD, M A Sbeih, MD, S Perretta, MD, David W Rattner, MD, Patricia Sylla, MD. Massachusetts General Hospital

Introduction: Our group has previously described successful natural orifice translumenal endoscopic surgery (NOTES) transanal endoscopic rectosigmoid resection in both a survival porcine model and a cadaveric feasibility study using the TEM platform (Transanal Endoscopic Microsurgery). We now present the largest cadaveric series to date as we continue to optimize this approach for clinical application.

Methods: Between December 2008 and September 2011, NOTES transanal endoscopic rectosigmoid resection was performed in 32 fresh human cadavers using transanal dissection alone(n=19), with transgastric endoscopic assistance (n=5) or with laparoscopic assistance(n=8). Of the 19 sole transanal dissections, 9 utilized a novel platform inserted through the TEM platform, 8 used a double channel gastroscope via the TEM platform and 2 used TEM alone. For laparoscopic assistance, 1-3 trocars were added to improve visualization or facilitate retraction. Variables including gender, body mass index(BMI), operative time, length of mobilized specimen, integrity of the mesorectum and specimen and complications were recorded. Statistical analysis was performed by unpaired t-test for quantitative and fisher exact test for categorical variables. P-values<0.05 were considered significant.

Results: Transanal rectosigmoid resection was successfully performed in all 32 cadavers. Of the 32 cadavers, 22 were male and 10 female with mean BMI of 24 kg/m². Mean operative time was 5.1 hours and mean specimen length 53cm. After the first 5 cadavers specimen length significantly improved and a trend towards decreased operative time was demonstrated(Table 1). The mesorectum was intact in 100% of specimens. A stapling device was used to divide the inferior mesenteric pedicle in 23 cadavers versus a bipolar cautery device in 9. In 9 cadavers dissection was complicated as follows: colon perforation(n=5), rectal perforation(n=2), vaginal perforation(n=1), small bowel enterotomy(n=1). Comparison of cadavers with and without complication demonstrated no significant difference by operative approach, operative time, specimen length, or BMI. Factors accompanying complication included: poor quality cadaver (n=3), prior pelvic operation (n=3), and redundant sigmoid (n=1). Comparison by operative approach demonstrated significantly increased length of specimen with laparoscopic assistance versus transgastric assistance or transanal dissection alone (67.7 vs. 45.4 vs. 48.6 cm, p=0.013), respectively. Comparison of inferior mesenteric pedicle division demonstrated both significantly decreased operative time (4.8 vs. 6 hours, p=0.024) and increased specimen length (57.7 vs. 39.6 cm, p=0.025) when a stapler was used in lieu of a bipolar cautery device. This difference persisted despite operative approach.

Conclusion:
Transanal NOTES rectosigmoid resection is feasible with demonstrated improvement in specimen length and operative time with experience and newer platforms. Division of the inferior mesenteric pedicle by stapling rather then cautery device is recommended secondary to improved specimen length and operative times. Continued development of new endoscopic and flexible-tip instruments are imperative prior to pure NOTES clinical application.