Defining the learning curve for Transanal Minimally Invasive Surgery (TAMIS)

Henry Schoonyoung, MD, Francisco Quinteros, MD, Beatriz Martin-Perez, MD, Lawna Hunter, BA, George Nassif, DO, Teresa deBeche-Adams, MD, Sergio Larach, MD, Matthew Albert, MD, Sam Atallah, MD. Florida Hospital.

Introduction: TAMIS is a new approach for local excision of rectal neoplasms. It is technically demanding, and the number of cases required to gain competency has not yet been established. The purpose of this study is to define the learning curve for local excision of rectal neoplasms using TAMIS.

Methods: A prospectively maintained database of patients who have undergone TAMIS between 7/2009 and 9/2013 at a single-center was retrospectively reviewed.

Results: 100 patients underwent TAMIS for local excision of rectal neoplasia over a four-year period. We divided these patients into 5 groups, (n=20 per group) in order to evaluate differences in operative times between the groups. The mean operative time for the first group of cases (n = 20) was 95.6 minutes (range 35 – 192) and for the next 4 groups combined (n=80) the mean operative time was 56.6 minutes (range 15 – 115). The difference in mean operative time between the first group and the remaining 4 groups was statistically significant (p < 0.05). Comparisons of patient characteristics (age, gender, BMI, ASA classification) and tumor characteristics (malignant versus benign disease, size, distance from anal verge) did not vary between groups. There was no difference in the incidence of post-operative complications among groups.

Conclusion: TAMIS is a new, advanced transanal platform which allows surgeons to perform high-quality local excision of rectal neoplasms. As this technique becomes increasingly adopted by surgeons, it is necessary to define a learning curve. With prerequisite training, this data reveals that the learning curve for TAMIS for local excision of rectal neoplasia is approximately 20 cases.