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Application note

Successful implant surgery through virtual planning
Materialise enables optimal jaw surgery preparation and implant design
By Ing. M.M.A. Beerens1, Ing. P. Laeven1, Drs. J. Poukens2

A man who suffered from an infection of his conventional jaw implant is smiling again. He received a new, custom-fit implant that could be designed by using Mimics and 3-matic software. Withinthe framework of a European Integrated Project called Custom-Fit3, Dr. Jules Poukens performed the case study at the University Hospital of Maastricht, the Netherlands, with the assistance of IDEE4 (University of Maastricht). This case clearly illustrates that it is possible to use additive manufacturing technology for the design and insertion of implants. Additive manufacturing technology enablesfaster, more accurate, better planned implant surgeries than is possible with conventional techniques.
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Making a detailed diagnosis
The patient’s conventional jaw implant had become infected. Starting with CT-images of his mandibula, Materialise’s 3D image processing software Mimics extracted a surface model of the bone defect, which clearly displayed the extent of the infection.Planning, simulating and optimizing surgical procedures
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The combination of the CT-images and surface model of the defect can be used for other purposes besides diagnosis. Because these images give a clear picture of the complete patient anatomy, they can help the surgeon predict challenges he will meet during surgery. The insights and knowledge he gains enable him to forecast an optimal procedurefor cutting the mandibula. Another solution lies in patient-specific, intra-operative guidance systems, developed and patented by Materialise, that accurately transfer the treatment plan to the patient at the time of surgery. In this case, the surface model was used to design two cutting guides that fit the mandibula exactly.

Designing a custom-fit implant
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The infected patient CTscan of the mandibula and generated 3D model (using Mimics) Cutting guides design based on virtual planning (using 3-matic)

Conventional implants are made of relatively flexible material, which means that they can be shaped and reshaped to fit during surgery. This shaping process can take a lot of time in the operating room. Thanks to Mimics and 3-matic software, a custom implant can be designed inadvance, thus reducing the length of the surgery. The design of a custom implant involves the incorporation of scanned data. Since anatomical data are extremely complex and organic in shape, it is very difficult to develop a model from them with conventional CAD-systems. With Mimics, on the other hand, it takes only minutes to transform scanned data into a complete 3D computer model.Conventional CAD systems usually can import files that result from scanning. In order to perform operations on such data, the user must first put them through the lengthy, difficult process of reverse engineering. 3-matic software completely eliminates the reverse engineering step, allowing the user to work directly on the scanned data. Tests showed that designing a jaw implant with a conventional CAD systemtook three times longer than designing it in 3-matic. In this case, IDEE used 3-matic software to design the jaw implant. Because of the considerable time span between the moment when the patient was scanned and his actual surgery, the odds were that the infection in the bone would have spread. To compensate, the designer added extra large flanges for any additional bone that might need to beremoved. A further advantage of working with 3-matic is the ability to combine organic, scanned shapes together with engineering components (such as fixtures). For example, when designing this jaw implant, the designer could quickly create the holes to fix the implant onto the existing bone with conventional titanium screws.

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Planning translated into precision surgery
Next, the implant design...