The precursor to this achievement was a similar patching done last year, where 75% of a patient's skull was replaced with a 3D-printed implant made of polyetherketoneketone (PEKK, a thermoplastic).

During emergency surgery, half of Hager's skull was removed to relieve pressure on his brain. Doctors had planned to replace the skull bone once Hager recovered, but the pandemic derailed those plans.