Design and Manufacturing of a Custom Skull Implant

Problem statement: Cranioplasty is defined as a neurosurgical procedure to cover an injured bone in the skull. This procedure is carried out in order to protect and restore intracranial structures and to restore the appearance and psychological stability of the patient. Advances in medical imaging, such as MRI and CT, have allowed the 3D reconstruction of anatomical structures for several medical applications, including the design of custom-made implants. This study describes the methodology used to design a custom-made cranial implant for a 13-year-old patient who suffered a lesion in the left frontoparietal region of the skull caused by a fall. Approach: The design of the implant was based on the 3D reconstruction of the skull of the patient, obtained by a CT scan, using Rapid Form® 2006. Once the preliminary design was completed, 3D models of the injured region of the skull and of the implant were fabricated in a Rapid Prototyping (RP) machine using Fused Deposition Modeling Technology (FDM) with the purpose of functionally and dimensionally validating the implant. Subsequently, the implant was fabricated using a 1.2-mm-thick Titanium Alloy (Ti6Al4V) plate. Results: The prosthesis was successfully implanted. The surgical time was 85% shorter than that for the same type of surgery in which standard commercial implants and titanium meshes are used. This decrease in surgery time is primarily the result of eliminating the need for trial and error procedures to achieve a good fit for the implant. Finally, the appearance of the patient was restored, allowing the patient to safely perform daily activities. Conclusion: The use of 3D reconstruction techniques from medical images reduces the possibility of errors during surgery, improves fit and provides better implant stability. The use of 3D models designed in RP proved to be an effective practice in the design process.