Fig. 3

Ergonomic element of the LESS technique. a The surgeon stands symmetrically with the straight back and slightly forward neck to maintain equilibrium. b. Keep shoulders in an unraised, neutral anatomic position, raised from 60° to 100° with upper arm straightly. c. Right arm usually elevated higher than left arm, or in some situation both arms crossed in order to maintain the position. d. The elbow joint is flexed to form an angle of 90° to 120° between the upper arm and forearm of the main surgeon. B.E. Flexion and extension of the wrist is measured as the positive or negative angle α, separately, between the humeroradial and neutral position lines. The humeroradial line was defined by markers a on the trapezium bone of the wrist and b on the knuckle of the index finger. The neutral position line starts with marker a located on the humeroradial bone of the elbow. Shoulder abduction along the biceps muscle was pointed out with marker c. C.F. Radial and ulnar deviation were also measured by markers a and b, and the positive angle β represented the radial deviation, while the negative angle β represented the ulnar deviation. D.G. The protonation with positive angle γ and supination with negative angle γ of the forearm is measured with marker a on the knuckles of the index finger and marker c on the little finger