A control mechanism (100) for controlling a rod (210) having a preformed curve and at least one key, the control mechanism comprising a handle and a cannula, wherein - the handle (130) comprises a slip ring ( 131), a sliding shaft (132) and a drive shaft (133), each of which extends along a longitudinal axis (101) and comprises a central opening； wherein - the slide ring (131) is threadably connected to the slide shaft (132)； - the drive shaft (133) and the sliding shaft (132) are connected by locking means that prevent axial rotation between the drive shaft (133) and the sliding shaft (132) and that allow the shaft (133) actuator slides within sliding shaft (132)； the control mechanism being characterized in that: - the drive shaft (133) and the slip ring (131) are connected by connection means that prevent axial displacement between the drive shaft (133) and the slip ring (131) and allowing axial rotation between the drive shaft (133) and the slip ring (131)； and - the internal surface of the drive shaft (133) comprises at least one longitudinal groove or keyway configured to engage the at least one key of the rod (210)； and - the cannula is a friction reduction cannula (110) configured to receive the rod (210)； the friction reduction cannula (110) being attached to the sliding shaft (132) or the drive shaft (133).Un mecanismo (100) de control para controlar una varilla (210) que tiene una curva preformada y al menos una chaveta, comprendiendo el mecanismo de control un mango y una cánula, en el que - el mango (130) comprende un anillo deslizante (131), un árbol deslizante (132) y un árbol (133) de accionamiento, cada uno de los cuales se extiende a lo largo de un eje longitudinal (101) y comprende una abertura central； en el que - el anillo deslizante (131) está conectado de forma roscada al árbol deslizante (132)； - el árbol (133) de accionamiento y el árbol deslizante (132) están conectados por medios de bloqueo que evitan la rotación axial entre el árbol (133)
