Intraoperative navigation in the maxillofacial area based on 3D imaging obtained by a cone-beam device

The aim of this study was to evaluate intraoperative navigation in the maxillofacial area based on three-dimensional imaging obtained by a cone-beam device. Digital volume tomograms (DVT) were obtained by the prototype of GALILEOS (Sirona Dental Systems Inc., Bensheim, Germany), a newly developed, compact size, cone-beam machine with a scan volume of 15 cm × 15 cm × 15 cm. Intraoperative navigation was performed in 12 patients in three selected indications. Target detection error expressing the accuracy of DVT navigation and registration performance of specially developed methods for image-to-patient registration was estimated. Target detection error was maximally 2 mm and depended on the registration method chosen. The automatic detection rate of the fiducial markers ranged between 0.64 a nd 0.32. The preoperatively defined treatment plan was fully accomplished in 11 out of 12 cases. A favourable surgical outcome was achievable in all cases. Intraoperative complications were not observed. Intraoperative navigation based on DVT imaging can be considered as a valuable alternative to CT-based procedures. Special characteristics of the cone-beam technique, in terms of contrast resolution and the limited field-of-view size of the devices, restrict the indication spectrum and create a demand for modifications of the usual registration methods.