A range of Delcam’s CADCAM software, in particular the latest release of the CopyCAD Pro reverse engineering system, is being used by a group of companies in New Zealand to design and manufacture custom-made maxillofacial implants for patients suffering with tumours or major bone loss.
The overall process, which is managed by Computer Generated Implants Ltd, has improved the quality of the results and the speed of recovery.
Most of the recent cases have involved patients who have had tumours removed some time ago. Typically, the reconstructive surgery carried out at the time involved a bone graft using a shaped portion of patient’s fibula. Aesthetic outcomes were often poor and the patient also had to endure a lengthy period in a leg plaster cast while the fibula healed.
in these cases, there was little requirement to design and manufacture implants in a short time frame. However, for so-called ‘hot cases’, the priority is to dramatically shorten the overall lead time. Ideally, the surgeons would like to operate well beyond the margins of the tumour and insert the custom-made implant in the same procedure.
“We had been using Delcam’s CopyCAD and PowerSHAPE successfully for many years for the design of these types of implant,” explained a spokesman for the group. ‘The results have been good but the process required a high level of modelling skill and could take days or weeks. This was not a real problem for historic cases but we really needed to shorten the lead time for the process.
The new CopyCAD Pro release has proved much easier to use and enables us to confidently take on “hot cases’ now. It is a huge and important leap forward.”
The process used by the New Zealand group begins when patient data in either a CT or MRI scan is received. This data is converted into STL format at the Axia Design Group, using Scan IP software, and then transferred into CopyCAD Pro.
Before manufacture of the implant is commenced, the group will produce models of the skull and the implant using Axia’s Stratasys rapid prototyping machine. This enables the operation procedure to be practised in advance and ensures that there are no surprises in the operating theatre. The same additive technology is also used to produce any drilling jigs and/or cutting jigs needed by the surgeon.
The next decision concerns the manufacturing method for the implant. The more straight-forward examples can be machined directly from medical-grade titanium using five-axis machining but the more complex implants require a combination of additive manufacturing and machining.
For the additive manufacturing, the group uses the EBM solution from Arcam, while the five-axis machining is undertaken by RPM International using Delcam’s PowerMILL CAM system.
“For many years we have relied on our traditional toolmaking expertise to attract business and we continue to be very successful in this sector,” commented RPM Director, Peter Smith. “However, we recognised that we needed to diversify and medical machining is also proving very successful for us. We have recently invested in another seat of PowerMILL and a Makino machining centre to take advantage of this growth market.”