How custom made implants have the potential to improve surgical procedures

The recent innovation of custom made implants has the potential to improve surgical procedures. The use of PolyEther Ether Ketone (PEEK) in these implants can play a key role in preventing post-surgical infection.

Cranioplasty can be defined as the surgical repair of a defect or deformity of the skull. The function of the cranium, the top part of the skull is to house and protect the brain, and this role is of high importance due to the brain controlling many processes such as thoughts, movement, memory and speech.

Cranial implants may be needed to reconstruct the skull of a patient that has experienced incidents such as head trauma or a neurovascular accident. It is particularly important for these implants to be strong and malleable.

The innovation of custom made implants has been made possible through advances in medical imaging such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) which allow the 3D reconstruction of structures.

It is believed that the use of 3D reconstruction techniques from medical images could reduce the possibility of errors during surgery, offer an improved fit and provide better implant stability.

The surgical time is also reported to be significantly shorter for personalised implants compared to standard commercial implants. This is thought to be due to achieving a good fit for the implant first time.

Granta, a small start-up in Mexico City, are using its industrial-design background to create these custom implants.

Carlos Monroy, CEO, Granta highlighted how the company was in its infancy: “We’re starting by creating this skull implant. It is a patient-specific implant to fix and reconstruct the skull of a patient that has been suffering from a head trauma, neurovascular accident, a tumour or from being born with deformation.”

Discussing a case where Granta successfully treated a patient with a custom implant, Martin Carcaño, head of biomedical design, Granta mentioned how the implant a surgeon had originally put in to the patient had become infected just two days later. “They had to remove the implant again” stated Carcaño.

Commenting on the manufacture of the implant, Monroy explained, “it’s the easiest to design, probably most difficult to fabricate because it’s a very organic and complex shape.”

Monroy went on to talk through the process of creating a custom implant: “We receive the CT scan from the patient. From there we propose a design that may help to fix the problem, and then we 3D print a model of the skull and the implant that we are proposing.”

The next step according to Monroy is to then discuss with the doctor at this stage if this is the best option for this patient.

“We manufacture it in a five-axis Computed Numerical Control (CNC) machine. We manufacture the final implant in the biocompatible material, that then is shipped to the hospital to be sterilised”, Monroy explained. “We use material that is completely biocompatible, that is called PEEK, and it’s a material that has many properties.” PEEK is advantageous as the body will not attack this material, and therefore its use will not result in an infection.

Looking back on the procedure, Monroy said, “when they took out the implant from the sterilised bag and they put it on the skull, we all saw that it fit perfectly.”

Carcaño concluded, “when you start to design something that is so critical for a human being, I mean a part that he or she relies on to live, it is a completely different level. I was so excited to be a part of that.”