Optimal port locations for endoscopic intracorporeal knotting.

Port location is crucial for endoscopic manipulations. The aim of the study was to investigate the influence of manipulation, azimuth, and elevation angles of instruments on endoscopic intracorporeal knotting. The standard task was tying a surgeon's knot. Manipulation angles of 30 degrees , 45 degrees , 60 degrees , 75 degrees , and 90 degrees with equal and unequal azimuth angles and elevation angles of 0 degrees , 30 degrees , and 60 degrees were investigated. The endpoints were the execution time and parameters of knot analysis. The execution time was shorter with 60 degrees than with either 90 degrees or 30 degrees manipulation angles (p < 0.0001 and p < 0. 01). Equal azimuth angles resulted in a shorter execution time than wide unequal angles (p < 0.001). A combination of 60 degrees manipulation angle with 60 degrees elevation angle had the shortest execution time (p < 0.001) and highest performance quality score (p < 0.02). A range of 45 degrees -75 degrees manipulation angles with equal azimuth angles is recommended. As the manipulation angle increases, the elevation angle has to increase accordingly.