A separable surgical guide instrument is configured to be inserted minimally invasively into a patient's soft tissue, and includes a guide body and a guide aperture that extends through the guide body. The guide body has a distal end that includes a first distal end portion and a second distal end portion that are arranged such that at least one of the first and second distal end portions is movable with respect to the other of the first and second distal end portions between 1) a closed position whereby the first and second distal end portions are concurrently insertable into a bone fixation aperture of a bone plate, and 2) an open position whereby the first distal end portion is spaced from the second distal end portion a sufficient distance such that the first and second distal end portions are not concurrently insertable into the bone fixation aperture.