Learning curve for transanal endoscopic microsurgery: a single-center experience
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Transanal endoscopic microsurgery (TEM) was first published by the late Professor Buess in 1983. The procedure initially had a slow acceptance due to its perceived difficulty, the cost of the equipment, and limited indications. However, the widespread adoption of laparoscopic colorectal surgery provided an impetus to increase the penetration of the platform. The purpose of this study was to evaluate the TEM learning curve (LC).
After institutional review board approval, all patients who underwent TEM, from November 2005 to October 2008 were identified from a prospective database. The operations were performed by a single, board-certified colorectal surgeon (DRS), after learning the technique from Professor Buess. Patient, operative, and postoperative variables were obtained by retrospective chart review. Rates of excision in minutes per cm2 of tissue were calculated. The CUSUM method was used to plot the LC. Variables were compared using χ 2 and Student’s t test. A p < 0.05 was considered significant.
Twenty-three patients underwent TEM (median age 61 years, 69.5 % male). Mean operative time was 130.5 (range 39–254) min, and the mean specimen size was 16.6 (7.4–42) cm2. Average rate of excision (ARE) was 8.9 min/cm2. A stabilization of the LC was observed after the first four cases, showing an ARE of 13.8 min/cm2 for the first four cases versus 7.9 min/cm2 for the last 19 cases (p = 0.001). An additional rising and leveling of the LC was observed after the first 10 cases, when an increasing number of lesions located cephalad to 8 cm from the dentate line were being resected (lesions above 8 cm in the first 10 cases: 20 % vs. last 13 cases: 61 %; p = 0.04).
The ARE significantly declined after the first four cases. The LC for TEM is associated with a significant decrease in operative time after four cases.
KeywordsLearning curve Transanal endoscopic microsurgery Single center Rectal cancer Rectal tumor Recurrence Dysplasia Adenocarcinoma
Andrew Vorenberg: Davinci Surgery, Intuitive Surgical. Steven Wexner receives consulting fees and royalties from Karl Storz Endoscopy. Antonio Maya, Myrian Oviedo, Giovanna DaSilva, and Dana Sands have no conflicts of interest or financial ties to disclose.
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