A surgical device comprises an elongate shaft comprising an outer tube and an inner rod positioned in the outer tube, the outer tube and inner rod each comprising a distal end and a proximal end. An actuator is operably connected to the proximal ends of the outer tube and the inner rod. An end effector is adapted for in vivo attachment to and detachment from the distal ends of the outer tube and the inner rod, the end effector comprising a collet for locking engagement with the distal end of the inner rod. The end effector may further comprise a second collet for locking engagement with the outer tube. The surgical device may further comprise a loader comprising a collet for locking the end effector in the loader. A loader for facilitating in vivo attachment and detachment of an end effector to an instrument shaft comprises an elongate shaft having a distal end and a proximal end. A loader tube is connected to the distal end of the elongate shaft, the loader tube comprising a distal opening. A collet is positioned in the loader tube, the collet being adapted and sized to receive and engage the end effector inserted through the distal opening. The collet has a locked position relative the loader tube and an unlocked position relative the loader tube. An actuator is connected to the proximal end of the elongate shaft and is operative to select between the locked and unlocked positions.La présente invention concerne un dispositif chirurgical qui comprend un tube allongé comprenant un tube externe et une tige interne positionnée dans le tube externe, le tube externe et la tige interne comprenant chacun une extrémité distale et une extrémité proximale. Un actionneur est fonctionnellement raccordé aux extrémités proximales du tube externe et de la tige interne. Un effecteur dextrémité est adapté pour fixation à et détachement des extrémités distales du tube externe et de la tige interne in vivo, leffecteur dextrémité comprenant un collet pour emboîtement de verrouillage a
