3D-printed PMMA casting molds for posterior fossa reconstruction in the surgical treatment of Chiari I malformation: technical note and illustrative cases.

OBJECTIVE: To describe a new method for cranial reconstruction after posterior fossa craniectomy in the surgical treatment of Chiari 1 malformation through a technical note and presentation of 3 illustrative cases. METHODS AND MATERIALS: A virtual surgical planning workflow was established for planning posterior fossa decompression, designing the suboccipital reconstruction, and manufacturing a 3D-printed polymethylmethacrylate (PMMA) casting mold. The casting accuracy was assessed by conducting a phantom experiment, and clinical data were provided by means of 3 illustrative cases. RESULTS: The accuracy of implant fabrication was found to be excellent, particularly when PMMA is introduced into the mold in a malleable state. In all 3 clinical cases, the implants were fabricated and positioned with success. Postoperative analysis revealed that accurate placement was achieved, with only minor deviation from the preoperative plan. CONCLUSIONS: 3D virtual surgical planning provides feasible tools for the planning of posterior fossa decompression and intraoperative fabrication of accurate patient-specific suboccipital cranioplasty.