3D Printing

Reconstructing Cranium Reconstructions’ Evolution with 3D Printing

Just last July 10th (2013) Stratasys sent out a newsletter to update readers on the condition of a 12 year old boy (at the time) whose skull was reconstructed by using an implant modelled through 3D printing. The child, who had sustained a grave injury, is now 18 and has fully recovered. Using 3D printing was fundamental because it allowed to create an implant that could expand with his skull bones as they grew with the boy’s age. This happened back in 2007 so I started asking myself exactly how old is the use of 3D printing in cranial reconstructions? What is the state of 3D printed crania and which have been the major milestones reached in these past years?

layerwise 3D printing cranial surgery

For the wider general public (which includes myself as well), the first big news on a 3D printed implant was last year’s replacement of 75% of a patient’s skull by using the Osteofab technology developed by Connecticut based Oxford Performance Materials. That marked the first 3D printed polymer (OXPEKK-IG) implant to pass the standards of the FDA. Unlike the Stratasys’ case in 2007, doctors no longer needed to model the implant before producing it subtractively in another material but could manufacture and produce it directly through SLS to implant it as is.

At the beginning of 2014 that record was superseded by a 22 year old woman who had her entire  cranium (which is the upper part of the skull and does not include the facial skeleton) replaced with a 3D printed implant through surgery. This time the University Medical Center in Utrecht used a transparent polymer implant produced by Australian company Anatomics, which was attached with titanium clasps and screws.

As much as the polymer based implants hold great promise, judging by LayerWise’s website, using AM to create fully anatomical metal CMF (Cranial and MaxilloFacial) implant is quite radical. The European company, which focuses exclusively on producing metal parts through AM, says that standard titanium mini-plates and mesh plates, commonly used to treat fractures and cranial or facial deformities, have drawbacks.

By producing CMF implants using metal additive manufacturing technologies, LayerWise is able to create fully anatomical shapes, either as a standard implant or as a patient-specific solution. The implants can be made either deformable (pure titanium) or rigid (titanium alloys), depending on the required application.

In fact just last week we reported on a Trabecular Titanium cranial implant performed in Argentina, the first of its kind. Trabecular Titanium is an innovative multi-planar structure based on hexagonal cells that resembles the porous structure of the trabecular bone. It thus allows the natural bone to grow into it, making it part of itself. The technology has been developed by Lima Corporation and is produced principally by using Arcam’s metal EBM technology (though SLS can also be adopted).

This list is only going to grow. As is the case in many other manufacturing industries, the plate geometries that are available through traditional methods limit the possibilities of fully anatomical reconstructions as well as pre-operative planning and shaping of the implants. 3D printing can make skull implants more “personalized” and there are few things that are more personal than your own head.