Medical device locking mechanisms and related methods and systems. In some embodiments, the medical device may comprise an outer surface defining one or more fastener openings configured for receiving one or more fasteners. The one or more fasteners may comprise an upper surface configured to be engaged by a component of the locking system to prevent fastener backout. A plurality of petal structures may be configured to be selectively expanded or contracted to engage the head portion and retain the at least one fastener within the fastener opening to prevent the fastener from backing out of the fastener opening. A biasing member may selectively engage the plurality of petal structures to either expand or contract the plurality of petal structures to facilitate locking the fastener(s) in place within the device.
