Transanal Endoscopic Microsurgery: colorectal surgeons’
learning curve.
RM Barendse1, MG Dijkgraaf2, UR Rolf1, AB Bijnen3, ECJ Consten4, C Hoff5, E
Dekker1, P Fockens1, WA Bemelman6 and EJR de Graaf7
1 Dept.
Of Gastroenterology and Hepatology, Academic Medical Center, Amsterdam;
Clinical Research Unit, Academic Medical Center, University of Amsterdam, Amsterdam;
3 Dept. of Surgery, Medical Center Alkmaar, Alkmaar;
4 Dept. of Surgery, Meander Medical Center, Amersfoort;
5 Dept. of Surgery, Medical Center Leeuwarden, Leeuwarden;
6 Dept. of Surgery, Academic Medical Center, Amsterdam;
7 Dept. of Surgery, IJsselland Hospital, Capelle aan den IJssel, the Netherlands
2
Transanal endoscopic microsurgery (TEM) is a key technique in minimally invasive
rectal surgery. TEM is technically demanding and various training programs exist.
However, the learning curve of colorectal surgeons who commence with TEM is
unknown. We aimed to evaluate the outcomes of colorectal surgeons’ first series of TEM
procedures and to assess whether outcomes improved with increasing experience.
The first 32 TEM procedures of 4 colorectal surgeons, who completed a dedicated TEM
training program, were analyzed. Patient, lesion and procedure characteristics were
collected. Procedures were ranked chronologically per surgeon. Multivariate regression
analysis was performed to identify independent predictors of conversion rate,
postoperative complications, recurrence, procedure time and hospitalization length.
Four colorectal surgeons performed 128 procedures (mean patient age 71  12 years,
48% males, ASA classification 1/2/3 in 30/55/9%). Rectal lesions (adenoma /
carcinoma / other in 76/20/4%, 21% recurrent lesions) had a median size of 13 cm2
(IQR 6-23). Mean distance ab ano was 6.8  4.0 cm. Lesions were located on the
posterior, anterior, left and right lateral rectal wall in 47, 20, 19 and 15%. Resections
were performed with three-dimensional (3D) stereoscope in 94 cases (73%) and 2D in
34 cases. Peritoneal breech occurred in 6 cases (5%). 86 resections (67%) were
histopathologically radical (R0) and 42 were irradical or unsure (R1/Rx). Conversion
(overall conversion rate 8%) was predicted by lesion size (OR 1,046 per cm2, 95%
confidence interval (CI) 1,016 – 1,075). Postoperative complications (14% overall, 12%
surgical) were independently associated with peritoneal breech (overall OR 7,133 (95%
CI 1,317 – 38,624), surgical OR 9,167 (95% CI 1,662 – 50,562)). Recurrence (11%) was
independently associated with 3D vs. 2D instruments (OR 0,123 (95% CI 0,035 – 0,435).
Procedure time (median 90 minutes (IQR 60-90)) was dependent upon the individual
surgeon (P<.001), lesion size (B 2,173 (95% CI 1,745 – 2,601)) and peritoneal breech (B
71,075 (95% CI 19,939 – 122,211). Hospitalization (median 5 days (IQR 4-7)) was
independently associated with patient age (B 0,129 (95% CI 0,047 – 0,211)), lesion size
(B 0,069 (95% CI 0,019 – 0,119)), distance ab ano (B 0,277 (95% CI 0,013 – 0,542)) and
peritoneal breech (B 18,137 (95% CI 11,659 – 24,615)). Chronological procedure rank
did not predict any of the outcomes.
Achieved outcomes correspond with previous literature of TEM in an early phase. As
increasing experience was not associated with improved outcomes, the learning curve of
TEM may extend beyond 32 cases in colorectal surgeons.