Abstract: The invention refers to an implant device (10) for treating an orbital floor fracture. The implant device (10) is foldable in a first direction between a folded state and an unfolded state and is plastically extendible in a second direction from an unextended state to an extended state. In the extended state, the implant device (10) has an extension in the second direction that is longer than a length in the unextended state and equal to or greater than an aperture distance of a human maxillary sinus in an anterior-posterior direction. The invention further refers to a related implantation tool, to a related implantation system for treating orbital blow fractures and to a corresponding implantation method.