A minimally invasive system includes a bone screw (100), and a tissue retractor (200) having a partial pathway through it. The tissue retractor is removably couplable to the bone screw. An instrument (400) has a hollow cavity (406) and is removably couplable to the tissue retractor. A drive shaft (504) for a cap (700) of the bone screw has a diameter less than a diameter of the hollow cavity. A counter- torque handle (600) has an interlock end portion (604) by means of which it can be rotatably fixed to the instrument. The interlock end portion also includes an open-ended slot having a width greater than the drive shaft diameter such that the counter- torque handle is movable to and from the assembled configuration while the drive shaft is within the hollow cavity. A removal instrument (1200) has an interface (1204) for removing the retractor from the screw.
