Hello!

This post will show the entire development, from modeling to execution of fully printed 3D objects: an edge, a cranial prosthesis and most importantly, a printed mold completely in 3D that were used in a Cranioplasty surgery. It used free software - Blender - for modeling of objects.

!!!!!!!!!!!!!!!!!WARNING!!!!!!!!!!!! THIS POST CONTAINS PHOTOS OF A SURGICAL PROCEDURE. THE OBJECTIVE HERE IS JUST TO SHOW THE APPLICATION IN SURGERY OF THE FINAL PRODUCT WITH THE FULLY 3D PRINTED MOLD. SORRY ABOUT THAT!

All development work aimed to make a mold to be able to have as a final product a biocompatible cranial prosthesis to correct defects in the skull.

Already it is the thanks to the teachers of the Federal Technological University of Paraná - UTFPR Walter Mikos (the proposed work and full encouragement in the process of implementation), José Foggiatto (by the provision and counseling at work) and Dr. Francisco Araújo Jr. (by encouraging , monitoring and shared medical knowledge).

In this particular case, the victim (the patient's identity will be kept confidential) was shot in the head that hit much of the skull (side and top). The projectile left traces, as shown in the images collected from tomography.

After the incident, the patient required a correction surgery: cranioplasty. To perform a cranioplasty surgery, a prosthesis is necessary to correct the defects caused. However, this implant must be biocompatible so that the body does not suffer rejections. A prosthesis ready for deployment takes time to develop and is very expensive. Another possibility is to develop a specific mold for the patient to be able to make the prosthesis with the biocompatible material during the surgery. We used this case, PMMA (polymethyl methacrylate). Still, the mold is expensive (but is less than the price of a finished prosthesis). In Brazil, for those victims who can not afford, you need to get justice for the government to pay for the mold to be used, and the whole process takes considerable time.

For patients who fail to acquire a prosthesis or a specific mold, surgery occurs, but depends on the skill of the physician for the cranioplasty. The physician in many cases need to manually shape the prosthesis, spending time in surgery, and not acquiring the exact shape of the prosthesis to the patient.

Step 1: Data Collection and Skull Generation 3D

From the CT scan, were generated several files in the DICOM format (Digital Imaging and Communications in Medicine) and collected InVesalius 3.0 software that turns them into 3D file, in this case in .stl format. After .stl generation, the file was manipulated in Blender free software.

Step 2: Corrections in 3D Modeling

After generating the three-dimensional file, corrections were needed in 3D modeling. Blender is a free and open source software and has many features to do the job. Imported in Blender, the .stl file needed to be edited in order to simplify the mesh (required, because the file is too slow to be manipulated), correct the defects (traces were removed from the projectile and other interferences) and generate the prosthesis to fix the cavity.

Step 3: Modeling Prosthesis

From the 3D modeling, the prosthesis was generated. The objective was to achieve symmetry of the skull and avoid interference of the prosthesis with the skull of the patient, because the socket of the prosthesis needs to be well done.

Step 4: 3D Printing of the Prosthesis and the Edge

Completed the first stage in 3d modeling of the prosthesis, the work goes to the physical part. The 3D printing is necessary, it has the objective of providing a pre-result of the prosthesis and its socket on the skull edge of the patient. The 3D printing was held at NUFER (Core Prototyping and Tooling) UTFPR (Campus Curitiba) with accompanying team and the teacher José Foggiatto.

Step 5: Mold Modeling

After the analysis of the prosthesis and the printed edge and the verdict of Dr. Francisco Araújo Jr. (facebook - CRM-PR 22 942), some adjustments in shaping the prosthesis were needed to improve the outcome. From there, it created the mold to make the final prosthesis in bone cement (PMMA). Again software Blender was used, and the result can be seen on the images.

Approximately 50 hours were spent in the 3D modeling work (skull correction, edge, prosthesis modeling and modeling of the mold).

Step 6: 3D Printing Mold

After modeling the Blender were generated new G-code files to perform the 3D print of the mold. With the support of NUFER (UTFPR), the mold was printed, totaling 12 hours of printing, approximately.

Step 7: Sterilisation and Cranioplasty

After completion of the printing, the mold and the edge were sent for sterilization and subsequently for surgery. The surgery took place on 05.20.2016 in HUEC (Evangelical University Hospital of Curitiba) under Dr. Francisco procedure and his team. The cranioplasty lasted approximately 2 hours in total. In the process, the doctor mixed ingredients to make the dough orthopedic bone cement (PMMA). To achieve a good consistency, the dough was placed in the mold to make the final prosthesis as a result. After 15 minutes in the mold, the prosthesis was removed and finally implanted in the patient. From the fitting the prosthesis in the skull fixation, was performed with titanium plates and screws. The cranioplasty was successful, resulting in the prosthesis made from fully printed in 3D mold.

Again, 3D printing has helped in improving the lives of those most in need.

Thank you so much!