Usefulness of computed tomography in pre-surgical evaluation of maxillo-facial pathology with rapid prototyping and surgical pre-planning by virtual reality.
OBJECTIVE
To validate a protocol for creating virtual models to be used in the construction of solid prototypes useful for the planning-simulation of maxillo-facial surgery, in particular for very complex anatomic and pathologic problems. To optimize communications between the radiology, engineering and surgical laboratories.


METHODS
We studied 16 patients with different clinical problems of the maxillo-facial district. Exams were performed with multidetector computed tomography (MDCT) and single slice computed tomography (SDCT) with axial scans and collimation of 0.5-2 mm, and reconstruction interval of 1 mm. Subsequently we performed 2D multiplanar reconstructions and 3D volume-rendering reconstructions. We exported the DICOM images to the engineering laboratory, to recognize and isolate the bony structures by software. With these data the solid prototypes were generated using stereolitography. To date, surgery has been preformed on 12 patients after simulation of the procedure on the stereolithographyc model.


RESULTS
The solid prototypes constructed in the difficult cases were sufficiently detailed despite problems related to the artefacts generated by dental fillings an d prostheses. In the remaining cases the MPR/3D images were sufficiently detailed for surgical planning. The surgical results were excellent in all patients who underwent surgery, and the surgeons were satisfied with the improvement in quality and the reduction in time required for the procedure.


CONCLUSIONS
MDCT enables rapid prototyping using solid replication, which was very helpful in maxillo-facial surgery, despite problems related to artifacts due to dental fillings and prosthesis within the acquisition field; solutions for this problem are work in progress. The protocol used for communication between the different laboratories was valid and reproducible.
Toso
Francesco
F
Istituto di Radiologia, Policlinico Universitario a Gestione Diretta, Università degli Studi di Udine, Udine. ftoso@sirm.org
Zuiani
Chiara
C
Vergendo
Maurizio
M
Salvo
Iolanda
I
Robiony
Massimo
M
Politi
Massimo
M
Bazzocchi
Massimo
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008441:Maxillary Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D019767:Maxillofacial Abnormalities / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008875:Middle Aged; D008953:Models, Anatomic; D011300:Preoperative Care; D014057:Tomography, X-Ray Computed; D014584:User-Computer Interface