Auricular prosthesis positioning using virtual planning in combination with additive manufacturing

This study focused on deformed or missing auricles and their replacement with silicone prostheses which are retained by craniofacial implants. Surgeons find it difficult to accurately place the implants in relation to the missing auricle in theatre. The aim of this study was to develop patient-specific devices using additive manufacturing technologies and associated software to indicate the positions of implants and to correctly orientate the prostheses relative to the positions of the implants.

The morphology of the patient was determined using Computed-Tomography (CT) scanning and the opposite auricle was mirrored in the virtual environment through specialized software from Materialise. A positioning guide for placing the implants was developed, together with an orientation guide that orientates the prosthesis accurately in relation to the implants. The orientation guide is a new development in the field of maxillofacial prosthetics and has not been attempted before. The guides are produced in nylon through laser sintering additive manufacturing.

The accuracy of implant placements was determined and the results showed relatively accurate positioning using the guides.

Implant placement showed some deviation which can largely be attributed to improper use of the guide by the surgeon during the marking of implant positions. The orientation guide can however somewhat compensate for this to still achieve aesthetically pleasing results. Using the guides significantly reduces risk, time and cost in placing the implants and producing auricular silicone prostheses.