A surgical access system for accessing a surgical target site within a spine includes a retractor and an elongated element. The retractor has a closed configuration defining a lumen with an internal circumference, and an open configuration in which the internal circumference, at least at the distal end of the retractor, is enlarged relative to said closed configuration. The open configuration creates and maintains an operative corridor to said target site. The elongated element is releasably coupled to an interior wall of the retractor and has an extension extending distal of the distal end of the retractor into the surgical target site. When coupled to the retractor, the elongated element covers a body structure at the target site without blocking access to the operative corridor.