THE USE OF 3D VIRTUAL PLANNING AND 3D PRINTING FOR THE TREATMENT OF FACIAL ASYMMETRY: A CASE REPORT
2.2. Operation The 3D printed surgical template was used during the bone harvesting of the anterior iliac crest where a rectangular piece of bone larger than the template was harvested, using the template to define the bone cuts. Thereafter the singlepiece bone graft was manually trimmed using the template as target model, which was afterwards grafted on the body of the left side of the mandible. The surgeon built up the mandible with the bone and fixated the different pieces with 6 mini screws
( KLS Martin, Germany) of lengths 7 and 9 mm. 2.3. Postoperative evaluation Postoperative CT was taken one month after the operation with the same settings as for the preoperative scan. The data was evaluated in the Amira software( FEI, USA). The preoperative and postoperative DICOM images were imported and the postoperative images were superimposed on the preoperative images via voxel based registration with mutual information 4 – 6( Fig. 3).
a. b. c. d.
Figure 3. a. Preoperative skull( gray). b. Postoperative skull( green). c. Postoperative skull registered onto the preoperative skull frontal view, and d. lateral view
The preoperative extension was imported into the Amira project to visualize the changes between the simulated extension and the postoperative outcome( Fig. 4). The postoperative bone was segmented and the extension was separately segmented then exported as STL files for further analysis.
A part comparison analysis between the postoperative extension and the simulated extension was done in the 3-matic software( Materialise, Leuven, Belgium) where the Euclidean distances between the surfaces were calculated( Fig. 5).
Figure 4. The simulated preoperative extension overlaid on the postoperative outcome after registration
a. b.
Figure 5. a. The postoperative mandible with the postoperative segmented extension. b. The postoperative mandible and extension with the preoperative simulated extension
158 STOMA. EDUJ( 2016) 3( 2)