Transanal Minimally Invasive Surgery (TAMIS): Challenging the limits of traditional local excision

Danielle M Giesler, MD, Mark A Casillas, Jr., MS, MD. The University of Tennessee Graduate School of Medicine, Department of Surgery.

BACKGROUND:
Transanal endoscopic microsurgical (TEM) resection is associated with improved outcomes compared to transanal excision of rectal lesions. However, TEM equipment requires additional operative setup time, and tumor location dictates patient positioning. Transanal minimally invasive surgery (TAMIS) was first reported in 2010 as a technique for local excision of well selected rectal neoplasia. The purpose of this study was to review our initial experience with TAMIS.

METHODS:
This study is a retrospective review of prospectively maintained IRB approved database. Seven consecutive patients underwent TAMIS resection of endoscopically unresectable rectal polyps by a single colorectal surgeon in a single hospital system between August 2012 through August 2012. Demographic data, intra-operative parameters, and post-operative outcomes were assessed.

RESULTS:
Seven consecutive patients underwent TAMIS resection of rectal neoplasms all measuring greater than or equal to 3cm in maximum diameter. Demographics, neoplasm location, intra-operative and peri-operative parameters as well as final pathology are depicted in the below table. Average operative duration was 154.2 min. Length of hospitalization was averaged less one day as 3 patients went home the day of surgery. There were no conversions. Six of seven neoplasms contained high grade dysplasia (HGD). The median maximum diameter of the neoplasm was 4.8 cm with an average of 4.2 cm in this very small sample size. One HGD neoplasm contained a focus of ypT1 Sm1 rectal adenocarcinoma. One benign specimen had a positive margin. No post-operative complications occurred. All patients with HGD are followed up every 6 months with proctoscopic evaluation. There were no conversions to open. Long-term follow-up is pending.

CONCLUSIONS:
This is a report describing full thickness rectal resection utilizing TAMIS. Key instrumentation includes the angled needle tip cautery and the use of Lapra-Ty or V-lock in order to close sizable rectal defects transversely. TAMIS is a feasible and cost effective alternative to transanal endoscopic microsurgery. The learning curve is comparable to TEM as the primary surgeon only had prior experience with TEM during fellowship training. Limitations include the very small sample size in this early experience.