STUDY DESIGN: Technical note and case series. OBJECTIVES: 3D-printed implants (3DPI) for spinal surgery are a relatively recent development. We report on our experience with the rapid creation and regulatory approval of patient-specific 3DPI for use in complex spinal reconstruction, including a novel expedited turnaround time for implant creation. METHODS: Four patients underwent placement of 3DPI to replace osseous anatomy during complex spinal reconstructions. These implants were created and used to replace patient-specific anatomy created by either en bloc tumor resection or by severe neurogenic spinal arthropathy. The surgical planning, implant creation, and postoperative outcomes are outlined. RESULTS: All patients underwent successful implantation of 3DPI, which was confirmed on postoperative imaging at most recent follow-up. The time to plan, create, obtain regulatory approval, and use the first 3DPI was 28 days. Subsequent 3DPI could be planned, approved, and used in surgery in as little as 4-5 days, which is faster than previously-published reports. Thus, a 3DPI could be generated based on osseous defects created during stage 1 of a multistage surgical plan and implanted during a subsequent stage in an especially expedited manner. CONCLUSIONS: 3DPI may be used to effectively replace patient-specific anatomy during complex spinal reconstructions, including for osseous defects that are generated after the initial surgical procedure. These 3DPI may be created, approved, and used in surgery over much faster timelines than have been previously reported. Additional cases utilizing these custom 3DPI will further elucidate their utility during complex reconstructions.