In a method of treating the spine of a patient, a fusion device is implanted via an anterior approach in an interbody space between at least two of a first vertebra, a second vertebra and a third vertebra. An access device is inserted into the patient with the access device in a first configuration having a first cross-sectional area at a distal portion thereof. The access device is actuated to a second configuration having an enlarged cross-sectional area at the distal portion thereof such that the distal portion extends across at least a portion of each of the three adjacent vertebrae. A multi-level procedure is performed through the access device across the at least three adjacent vertebrae.