Titanium Cranioplasty Implants

Staff at the Medical Physics and Bioengineering Department have been working in conjunction with Neurosurgeons from the early 1980s to make titanium plates for reconstructing skulls. We have pioneered some world-leading techniques for designing and making the custom-fitting skull plates.  Now we make these plates regularly for the CDHB and other hospitals around New Zealand.

Creating the mould 

The process starts with a CT scan and a referral from the Neurosurgeon.  Then one of our Imaging Scientists uses special software, written by MPBE, which interpolates the CT scan data to determine the best shape for the implant and ensures the curvature matches that of the surrounding skull.  This software then creates a programme for our computer controlled machining centre (CNC Mill) to machine a press mould out of solid epoxy.

Pressing the plate

The implants are made from high-quality Grade 2 titanium sheet, typically 0.5mm thick.  The flat plate is then slowly pressed in a custom-built high-pressure hydraulic press up to 3000 psi so that it perfectly matches the shape of the mould.

Creating the 3D model

The CT scan data is also converted to make a 3D model of the skull.  This is made either in the CNC mill or using one of our 3D printers.  The model allows the neurosurgeon to determine the exact size of the implant.  We then use the model to trim the implant to the size drawn by the neurosurgeon.

Finishing the plate

Feathers and screw holes are added to the perimeter of the plate, and drainage and sewing holes are added in positions determined by the neurosurgeon.  Once any sharp edges are carefully removed the plate is then chemically polished and then annodised to give a golden colour.  This colour makes the plate less visible under the scalp.

Page last reviewed: 03 October 2014