Maxillo-facial fractures: diagnostic role of multiplanar and 3D TC imaging with multislice technique

The purpose of our research was to verify, in a selected series of 37 patients, not only the real validity of multislice CT employment with 2D and 3D reformatted images in pre-surgical evaluation, but also the real necessity to use this technique as elective methodological procedure for maxillo-facial fractures in emergency. Material and methods. 37 selected patients (24 males, 13 females), with age ranging from 17 to 63 years (mean age 33 years), underwent multislice CT examination at the casualty department of the hospital San Camillo of Rome, from October 2004 to March 2005. In all the patients the computed tomography was carried out with spiral technique (General Electric Light Speed - 8 crowns), using thin acquisition of 2.5 mm, with configuration of the eight detectors 8 x 1,25 or 8 x 2,25, with values of pitch equal to 1 (in some cases 1, according to thickness of the anatomical volume to appraise), with interval and thickness of retro-reconstruction respectively of 1 mm and of 1,25 mm. The parameters of exposure were: 280 mAs, 120 Kv and a time for total scanning of 10-15 sec. (for only maxillofacial structures). Results. The results of the study were: 7 out of 37 patients reproduced a facial smash, 26 out of 37 patients showed a complex fracture: 8 patients with a nasal-ethmoidalorbital fractures, 7 patients with a zygomatico-maxillary fracture, 5 patients with a nasal-maxillary fracture; 4 patients with a condylar or subcondylar fracture, 1 patient with multiple fracture of jaw, 1 patient with fracture of the orbital floor (blow out); and 4 patients showed a picture of malar fracture. On the total of the examined patients, 26 (70 %) showed solitary or multiple fractures of the orbital walls. In particular in 9 cases were found fractures of the orbital floor, of which 6 with sinking of bony fragments in the underlying maxillary sinus (blow out). The medial walls of the orbit were involved in the complex fractures in 7 cases. In 11 cases presented fractures of the orbital lateral walls. Discussion. The most important aspect emerged by this experience was the absence of patients in which the classical pattern of fracture, in accordance with the historical Le Fort classification, was reproduced faithfully, and the clean prevalence of complex fractures, that come out from the normal canons of classification. We wanted to underline the role of CT in the diagnosis in this type of fractures, and in particular of the spiral multislice technique, with axial volumetric thin acquisitions supplied with coronal/sagittal and 3D with volumetric rendering reconstructions. Conclusion. In comparison with the traditional CT examination that, in prevision of MPR and 3D reconstructions, results incompatible with the necessary time and accuracy request for emergency conditions, the spiral technique reduces drastically both the times and the radiant dose, allows to work in the phase of post-elaboration on the raw data of volumetric scanning, obtaining from the axial scans multiplanar and three-dimensional reconstructions of superior quality. Emphasis was placed also on the fact that the possibility to appraise the entity of the skeletal damages, the concomitant muscular lesions, of cerebral parenchyma and of the cervical rachis made this techniqueelective in this field. The MPR reconstructions hold particular importance because undoubtedly better underline the presence of suspected or badly definable lesions compared with axial scans and complete the diagnostic supply.