Surgical instrument and actuating movement transmitting device therefor

A surgical instrument, such as a surgical stapling instrument (1), comprises a tissue manipulating portion (2) which is intended to be introduced in the body of a patient, a handle portion (3) with an actuating mechanism (7) adapted to generate actuating movements for the actuation of the tissue manipulating portion (2) and comprising at least a pair of rotary output members (33; 40) and an actuating transmission device (5, 5'; 6, 6') connecting the actuating mechanism (7) of the handle portion (3) to the tissue manipulating portion (2) and comprising at least one pair of rotary rods (17, 17'; 19, 19') for transmitting rotational actuating movements from the pair of rotary output members (33; 40) to the tissue manipulating portion (2). The actuating mechanism (7) comprises synchronization means (31, 32, 32'; 38, 39, 39') which link the movements of the two rotary output members (33; 40) of the pair of rotary output members such that they counter-rotate at substantially the same speed.