Expandable fusion devices, systems, and methods. The expandable fusion device includes one or more integrated deployable retention spikes configured to resist expulsion of the device when installed in the intervertebral disc space. The implant may include upper and lower main endplates, an actuator assembly configured to cause an expansion in height of the upper and lower main endplates, and a sidecar assembly including a sidecar carrier, an upper carrier endplate pivotably coupled to an upper spike, and a lower carrier endplate pivotably coupled to a lower spike such that forward translation of the sidecar carrier pushes against the upper and lower carrier endplates, thereby deploying the upper and lower spikes.