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Method Article
Renato Rozental
1. Centro Desenvolvimento Tecnológico (CDTS), FIOCRUZ, RJ, 21040-361, Brazil. 2. Instituto de Ciências Biomédicas, CCS, Universidade Federal do Rio de Janeiro (UFRJ), RJ, 21941-902, Brazil. 3. Dept Neuroscience, Albert Einstein Coll Medicine, Bronx, NY, 10461, USA.
Corresponding Author
License:
This work is licensed under a CC BY 4.0 License. Read Full License
We present a detailed step-by-step approach for the low-cost production and surgical implantation of cranial prostheses, aimed at restoring aesthetics, cerebral protection, and facilitating neurological rehabilitation. This protocol uses combined scan computed tomography (CT) cross-sectional images, in DICOM format, along with a 3D printing (additive manufacturing) setup. The in-house developed software InVesalius®️ is an open-source tool for medical imaging manipulation. The protocol describes image acquisition (CT scanning) procedures, and image post-processing procedures such as image segmentation, surface/volume rendering, mesh generation of a 3D digital model of the cranial defect and the desired prostheses, and their preparation for use in 3D printers. Furthermore, the protocol describes a detailed powder bed fusion additive manufacturing process, known as Selective Laser Sintering (SLS), using Polyamide (PA12) as feedstock to produce a 3-piece customized printed set per patient. Each set consists of a “cranial defect printout” and a “testing prosthesis” to assemble parts for precision testing, and a cranial “prostheses mold” in 2 parts to allow for the intraoperative modeling of the final implant cast using the medical grade Poly(methyl methacrylate) (PMMA) in a time span of a few min. The entire 3D processing time, including modelling, design, production, post-processing and qualification, takes approximately 42 h. Modeling the PMMA flap with a critical thickness of 4 mm by means of Finite Element Method (FEM) assures mechanical and impact properties to be slightly weaker than the bone tissue around it, a safety design to prevent fracturing the skull after a possible subsequent episode of head injury. On a parallel track, the Protocol seeks to provide guidance in the context of equipment, manufacturing cost and troubleshooting. Customized 3D PMMA prostheses offers a reduced operating time, good biocompatibility, and great functional and aesthetic outcomes. Additionally, it offers greater than 15-fold cost advantage over the usage of other materials, including metallic parts produced by additive manufacturing.
Keywords
cranial repair, cranioplasty, 3D printing, additive manufacturing, Selective Laser Sintering (SLS), Polyamide (PA12), Poly(methyl methacrylate) (PMMA), cranial prostheses, InVesalius®️, dural tenting, seroma.
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This is a list of supplementary files associated with this preprint. Click to download.
- TABLE1RR.jpg
Table 1. Adult Routine Head CT parameters adopted from existing CT protocols (link B). 1The amount of tissue inferior and superior to the prescribed scan range that is irradiated by over ranging can vary, * lower mA values for bone structures, higher mA values to include soft tissues. 2The amount of tissue inferior and superior to the prescribed scan range that is irradiated by over ranging can vary, depending on the scanner model and how the scan is performed (pitch value, collimation, etc.). 3Collimation in CT serves to ensure good image quality and to reduce unnecessary radiation for the patient. The tube collimator is used to shape de X-ray fan beam before it penetrates the patient. Values adopted for the Brilliance 16 slice scanner (Philips) are 16 x 1.5 mm.
- TABLE2RR.jpg
Table 2. CT Imaging of Adult Head. Routine suggested image thickness and interval sets. Topogram: cranio-caudal direction.
- TABLE3RR.jpg
Table 3. 3D manufacturing: minimum requirement and recommended hardware.
- TABLE4RR.jpg
Table 4. Quantity of nodes and cranial and prosthetic elements for simulation of cranial repair.
- TABLE5RR.jpg
Table 5. Properties of materials used in the finite element simulation.
- TABLE6RR.jpg
Table 6. Understanding 3D manufacturing cost to produce cranial prostheses.
- TABLE7RR.jpg
Table 7. Troubleshooting.
- TABLE8RR.jpg
Table 8. Mean time required for each stage of the set of cranial prostheses fabrication process using 3D printed PA smoothed molds. Processes requiring human input are shown in bold, automatic/unattended processes are shown in italics.
- TABLE9RR.jpg
Table 9. Individual data listings through the cranioplasty study at HMMC and HR, for patients assisted by the Brazilian Universal Health System (SUS).
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Version History
CURRENT STATUS: Posted
Version 1
Posted 01 Apr, 2021
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Associated Publications
- The published 10.4103/sni.sni_149_18 DOI linking is not working. It can be accessed at: Surg Neurol Int 2019 Jan 15;10:1 Functional and aesthetic evaluation after cranial reconstruction with polymethyl methacrylate prostheses using low-cost 3D printing templates in patients with cranial defects secondary to decompressive craniectomies: A prospective study. Juan Pablo Borges Rodrigues Maricevich, Auricelio B Cezar-Junior, Edilson Xavier de Oliveira-Junior, Jose Arthur Morais Veras E Silva, Jorge Vicente Lopes da Silva, Amanda Amorin Nunes, Nivaldo S Almeida, Hildo Rocha Cirne Azevedo-Filho
10.4103/sni.sni_102_18
10.4103/sni.sni_149_18
An open repository of community-contributed protocols sponsored by Nature Research.
Learn more about Protocol Exchange
Method Article
Renato Rozental
1. Centro Desenvolvimento Tecnológico (CDTS), FIOCRUZ, RJ, 21040-361, Brazil. 2. Instituto de Ciências Biomédicas, CCS, Universidade Federal do Rio de Janeiro (UFRJ), RJ, 21941-902, Brazil. 3. Dept Neuroscience, Albert Einstein Coll Medicine, Bronx, NY, 10461, USA.
Corresponding Author
Version History
CURRENT STATUS: Posted
Version 1
Posted 01 Apr, 2021
No community comments so far
Metrics
Comments: 0
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
We present a detailed step-by-step approach for the low-cost production and surgical implantation of cranial prostheses, aimed at restoring aesthetics, cerebral protection, and facilitating neurological rehabilitation. This protocol uses combined scan computed tomography (CT) cross-sectional images, in DICOM format, along with a 3D printing (additive manufacturing) setup. The in-house developed software InVesalius®️ is an open-source tool for medical imaging manipulation. The protocol describes image acquisition (CT scanning) procedures, and image post-processing procedures such as image segmentation, surface/volume rendering, mesh generation of a 3D digital model of the cranial defect and the desired prostheses, and their preparation for use in 3D printers. Furthermore, the protocol describes a detailed powder bed fusion additive manufacturing process, known as Selective Laser Sintering (SLS), using Polyamide (PA12) as feedstock to produce a 3-piece customized printed set per patient. Each set consists of a “cranial defect printout” and a “testing prosthesis” to assemble parts for precision testing, and a cranial “prostheses mold” in 2 parts to allow for the intraoperative modeling of the final implant cast using the medical grade Poly(methyl methacrylate) (PMMA) in a time span of a few min. The entire 3D processing time, including modelling, design, production, post-processing and qualification, takes approximately 42 h. Modeling the PMMA flap with a critical thickness of 4 mm by means of Finite Element Method (FEM) assures mechanical and impact properties to be slightly weaker than the bone tissue around it, a safety design to prevent fracturing the skull after a possible subsequent episode of head injury. On a parallel track, the Protocol seeks to provide guidance in the context of equipment, manufacturing cost and troubleshooting. Customized 3D PMMA prostheses offers a reduced operating time, good biocompatibility, and great functional and aesthetic outcomes. Additionally, it offers greater than 15-fold cost advantage over the usage of other materials, including metallic parts produced by additive manufacturing.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
This is a list of supplementary files associated with this preprint. Click to download.
- TABLE1RR.jpg
Table 1. Adult Routine Head CT parameters adopted from existing CT protocols (link B). 1The amount of tissue inferior and superior to the prescribed scan range that is irradiated by over ranging can vary, * lower mA values for bone structures, higher mA values to include soft tissues. 2The amount of tissue inferior and superior to the prescribed scan range that is irradiated by over ranging can vary, depending on the scanner model and how the scan is performed (pitch value, collimation, etc.). 3Collimation in CT serves to ensure good image quality and to reduce unnecessary radiation for the patient. The tube collimator is used to shape de X-ray fan beam before it penetrates the patient. Values adopted for the Brilliance 16 slice scanner (Philips) are 16 x 1.5 mm.
- TABLE2RR.jpg
Table 2. CT Imaging of Adult Head. Routine suggested image thickness and interval sets. Topogram: cranio-caudal direction.
- TABLE3RR.jpg
Table 3. 3D manufacturing: minimum requirement and recommended hardware.
- TABLE4RR.jpg
Table 4. Quantity of nodes and cranial and prosthetic elements for simulation of cranial repair.
- TABLE5RR.jpg
Table 5. Properties of materials used in the finite element simulation.
- TABLE6RR.jpg
Table 6. Understanding 3D manufacturing cost to produce cranial prostheses.
- TABLE7RR.jpg
Table 7. Troubleshooting.
- TABLE8RR.jpg
Table 8. Mean time required for each stage of the set of cranial prostheses fabrication process using 3D printed PA smoothed molds. Processes requiring human input are shown in bold, automatic/unattended processes are shown in italics.
- TABLE9RR.jpg
Table 9. Individual data listings through the cranioplasty study at HMMC and HR, for patients assisted by the Brazilian Universal Health System (SUS).
Loading...
Associated Publications
- The published 10.4103/sni.sni_149_18 DOI linking is not working. It can be accessed at: Surg Neurol Int 2019 Jan 15;10:1 Functional and aesthetic evaluation after cranial reconstruction with polymethyl methacrylate prostheses using low-cost 3D printing templates in patients with cranial defects secondary to decompressive craniectomies: A prospective study. Juan Pablo Borges Rodrigues Maricevich, Auricelio B Cezar-Junior, Edilson Xavier de Oliveira-Junior, Jose Arthur Morais Veras E Silva, Jorge Vicente Lopes da Silva, Amanda Amorin Nunes, Nivaldo S Almeida, Hildo Rocha Cirne Azevedo-Filho
10.4103/sni.sni_102_18
10.4103/sni.sni_149_18