3D Printing New Parts For Your Skull

By Michelle Dickinson 14/03/2014


3D printed polymer structure being researched in my lab (photo credit Mengbin Ye and Amy Pit)

3D printing has had a lot of bad press recently with discussions about whether or not the recently house-passed bill extending the undetectable firearms act of 1988 should have included more legislation about 3D printed guns.  Although I think that we always need to be careful about the harm that new technologies can cause, its important to remember that 3D printing has huge potential in transforming how we design and manufacture components for science and technology applications.

I’m a big fan of 3D printing, I often use it in my research lab to create new micro-structures with complex and intricate features for biomimetics, as well as at home for fun to create personalised gifts or quirky sci-fi ornaments.

The 3D printers that most of us have provide cheap and easy access to be able to print objects using plastics such as Acrylonitrile Butadiene Styrene (ABS) and Polylactic acid (PLA).

You don’t just have to 3D print using plastics though as metals, ceramics and even biological cells have been printed to create innovative and complex structures.  It is this interaction between engineering and biology that I see as the field where the technology could have a huge impact, and the ability to tailor medical devices and implants based on an individuals need could change the way we personalise medical treatment.

Computer generated model of Stephens skull created from CT scan (the ring above his skull are the staples used to close his scalp tissue after surgery)

Computer generated model of Stephens skull created from CT scan (the ring above his skull are the staples used to close his scalp tissue after surgery)

One story that caught my eye this week was the tale of 29 year old UK resident Stephen Power who broke his cheek bones, eye sockets, upper jaw and skull in a 2012 crash. Consultant maxillofacial surgeon Adrian Sugar who treated Stephen described how they were looking for a way to correct the patients left cheek and eye socket without the risk of damaging his sight further.  Their challenge was the complexity of needing to create a new cheekbone which would fit perfectly in the right place and dealing with the thin, delicate bones around the eye socket.  In a statement from the National Health Service of Wales they described how combining the expertise from Hospital’s Maxillofacial Unit and the National Centre for Product Design and Development Research (PDR) created a 3D printing solution which pushed the boundaries of what surgeons can achieve.  To try and restore the symmetry in Stephens face, doctors used CT scans to build up a 3D computer image of his skull, which they then printed out into a 3D model.  The model allowed them to physically hold and visually see any problem areas, as well as try out different solutions to help solve the symmetry issue with Stephens face.  Once they had determined the shape and dimensions of the implant structures that needed to be built, they could practice by attaching them to the 3D skull model first so they knew it would be a perfect fit during surgery.

3D printed model of Stephens skull (purple) with 3D printed titanium implanted attached (grey)

3D printed model of Stephens skull (purple) with 3D printed titanium implanted attached (grey)

The surgery would be highly complex and precise cuts were needed to be made in the skull, however using the 3D printing technique a custom fitting cobalt chromium alloy saw guide was made which fit securely around the face of the patient and incorporated slots positioned to guide the surgeon’s movement.  This took out the guesswork associated with surgery, so that the surgeon had a template to use for every cut that needed to be made. The guide also incorporated slots in which the implants would fit, allowing the whole structure to slot together during surgery ensuring the implant was secured in the exact position.  Finally once everything was in place, the cutting guide was removed leaving the skull with the new implants in place.

The main advantage of using 3D printing for this procedure is the potential speed that these models and implants can be made.  In this example they were produced off site by a contracted company, but in the future I can foresee hospitals having specialist internal workshops in which they could scan the patients and print the required device or implant within a short time frame.  With the advancement of 3D printers and the rapid growth and uptake of the technology, the cost of creating personalised hardware will inevitably go down in time.

This is not the first story using 3D printing and biology that has caught my interest recently and the combination of engineering materials and biology continues to accelerate.  If you are interested then the new innovation of combining cells with nanoparticles to 3D print bionic ear is an interesting paper with the authors suggesting it could potentially restore or enhance human hearing.  NASA also funded project looking at 3D printing wood and spider silk for projects both here on earth and in space with suggestions of 3D printed trees becoming a reality.