A retractable surgical cutting device , comprising: a handle including a handle proximal end, a handle distal end, an outer surface, and an internal space, the handle extending along a central longitudinal axis; an actuator located and movable in a first direction to a first actuator position and in a second direction to a second actuator position on the outer surface of the handle ; a sheath extending along the central longitudinal axis and including a sheath proximal end and a sheath distal end, wherein the sheath proximal end is positioned within the internal space of the handle , and wherein the sheath is configured to move in the first direction to a sheath first position, and is configured to move in a second direction to a sheath second position; a shaft at least partially positioned within the sheath and extending along the central longitudinal axis and including a shaft proximal end and a shaft distal end , wherein the shaft proximal end is connected to the interior surface of the handle and the shaft distal end includes a blade ; and a drive and locking mechanism connected to the actuator and to the sheath within the internal space of the handle , characterized in that the drive and locking mechanism is configured to move the sheath in the first direction and lock the sheath in the sheath first position in response to movement of the actuator in the second direction, and wherein the drive mechanism is configured to move the sheath in the second direction and lock the sheath in the sheath second position in response to movement of the actuator in the first direction, wherein the locking is not performed by friction, but by a positive, mechanical, locking function a handle including a handle proximal end, a handle distal end, an outer surface, and an internal space, the handle extending along a central longitudinal axis; an actuator located and movable in a first direction to a first actuator position and in a second direction to a second actuator position on the outer surface of the handle ; a sheath extending along the central longitudinal axis and including a sheath proximal end and a sheath distal end, wherein the sheath proximal end is positioned within the internal space of the handle , and wherein the sheath is configured to move in the first direction to a sheath first position, and is configured to move in a second direction to a sheath second position; a shaft at least partially positioned within the sheath and extending along the central longitudinal axis and including a shaft proximal end and a shaft distal end , wherein the shaft proximal end is connected to the interior surface of the handle and the shaft distal end includes a blade ; and a drive and locking mechanism connected to the actuator and to the sheath within the internal space of the handle , characterized in that the drive and locking mechanism is configured to move the sheath in the first direction and lock the sheath in the sheath first position in response to movement of the actuator in the second direction, and wherein the drive mechanism is configured to move the sheath in the second direction and lock the sheath in the sheath second position in response to movement of the actuator in the first direction, wherein the locking is not performed by friction, but by a positive, mechanical, locking function <EOS>