Additive technology more typically associated with the aerospace industry was recently used by a cross-disciplinary team of doctors and engineers in Mexico to produce a cranial implant for the victim of a shooting.
The head scan and prosthesis model design using VISI CAD
The prosthesis was designed free of charge using Vero’s VISI CADCAM package, by designers and engineers from Vero’s Mexican reseller, VISI Series México. The team comprised Raúl Moreno, Salvador Enriquez and Elĺas Hernández. VISI Series México collaborated on the project with the Advanced Human Bioengineering Foundation for Latin America (BHA Foundation).
The original STL file of the entire head was provided by the medical team and was produced by the CT/MRI scanner. The STL file was used to 3D print an internal plastic prototype model to analyse the shape of the hole.
Working with the doctors, the prototype model was reworked to create a nicer uniform hole with no fragments. Once happy with the topology of the skull, the prototype model was scanned and imported into the VISI CAD application.
The 3D prototype model of the skull cavity and prosthetic implant
From there, a network of curves was taken from the good side on the skull and mirrored onto the left side to cover the aperture. Then a surface model of the prosthesis was created and the doctors were again consulted to help determine the ideal fixing structure and screw locations and to ensure that the model conformed to the needs and complexities of cranial anatomy.
The 3D printing of the prosthetic implant was carried out on an EOSINT M280 DMLS (Direct Metal Laser Sintering) machine
At this point, a plastic prosthesis was printed for assembly to the head prototype to check for alignment and fitting. With a design finalised, the prosthesis was sent to the USA for printing on the EOSINT M280 DMLS machine. The US-$8,000 printing costs were met by a private company in Querétaro, with the support of the BHA Foundation.
Project Director Dr Gilberto Lopez, a specialist in oral and craniofacial rehabilitation, worked with experts in neurosurgery and maxillofacial surgery, regarding the cranial implant design, and successfully prepared the surgical titanium prosthesis model.
The surgical team who performed the 4 hour operation
Commenting on the prosthesis turn it into, Elĺas Hernández said: “We worked closely with the medical team to ideal the turn it into. The holes and fixing structures all assist a purpose. It was significant that the turn it into may interact naturally with the human body, enabling fusion of bone tissue and fluid flow inside the cranial cavity. Because the prosthesis is metal, it must in addition allow for low heat dissipation around the brain.
Lasting four hours, the surgical procedure was carried out at a public hospital in the Mexican city of San Luis Potosi, by a team of neurosurgeons, maxillofacial surgery and oral rehabilitation specialists, who in addition worked free of charge”.
“A number of countries, including England, the United States, China and Spain, are already starting to use this type of technology for patients with congenital or acquired craniofacial deformities”, says Raúl Moreno, Director General at VISI Series México.
Picture taken 11 days after surgery
“The process gives the ability to design and manufacture custom prostheses quickly and safely, which are both functional and aesthetical, considerably improving the patient’s quality of life. And Mexico is now finding a position amongst the pioneers of custom titanium prostheses. The fact that a group of technicians and physicians can selflessly contribute in this way to benefit our society is a great source of pride”.
