Stereolithography In Maxillofacial Surgery

Stereolithography in Maxillofacial Surgery Prof. C. Tyrnofyeyev, Prof. O. Gorobets; Kyiv Medical Academy of Postgraduate Education named after P.L. Shupik

Introduction At the beginning of the 1970s Computerized Tomography evolved into medical practice. It was a completely new diagnostic method allowing the visualization of the connections between the isolated organs and tissues in normal or pathological conditions. CT took a strong position in the diagnostics of the maxillofacial area. In the last years, modern technology appeared for the creation of prototypes of the human skeleton using the data obtained from CT and MRI. One of the most famous is stereolithography. The basic principle of this method is the slice-by-slice building of the 3D model with exactly the same size and shape of the human body parts. Aim of analysis To determine the diagnostic possibilities of stereolithography for diseases and traumas in the maxillofacial area. Materials and Methods We first examined 47 patients. The standard clinical examination was done, which included Xray of the jaws in different projections and computerized tomography. Stereolithographic models of the jaws were made by Materialise in Belgium. Among the examined patients were patients with jaw tumors (ameloblastoma, osteoblastoma), tumor-like (cysts) and inflammatory (maxillary sinusitis, osteomyelitis) processes, with jaw deformations and defects, neurogenous diseases, patients with dental implants and with ankylosis of TMJ. The data obtained during the diagnostics by the stereolithography method was compared to the results obtained during X-ray imaging, computerized tomography and with the post-op results. Results of investigation Stereolithography gives the possibility to obtain info about the real size and precise location of the pathological focus in the jaw bone, the dimensions of the destruction area and its connections with the surrounding bone structures (Fig. 1, 2).

Building the colored stereolithography models permits us to see the tumor and its connections with the blood vessels and nerves. We have precisely determined the exact place of the resection of the jawbone affected by the ameloblastoma; it was also possible to choose the exact size of the titanic implant on the jaw which should be used for the restoration of the bone defect. With the stereolithography models we could determine precise size and location of tumors in the hard accessible regions of the mandible (ramus), to see the connections with the alveolar nerve in the mandible tunnel, to determine the presence or absence of the connections with the teeth, and the grade of destruction of the bone walls, as well as their connections with such anatomic formation as the mandible tunnel (Fig. 3a & b).

Stereolithographic models are also useful during differential diagnostics of malignant and nonmalignant tumors (Fig. 4).

In the inflammatory jawbones diseases, we’ve determined the level of correspondence of the sequester’s size or polyposis, revealed during the surgery, to the size of the pathological focus on the stereolithographic model and also could find the exact places of their location (Fig. 5),

In TMJ-ankylosis the stereolithographic method of investigation of the facial bones gave us the possibility to determine the grade of fusion of mandible and surrounding bone structures, which could help us to choose the correct size of the implants of TMJ, allow to reduce the risk of unforeseen situations (damages of vessels and nerves, jawbones) during bone plastic surgery and choose the correct surgery method in hyperformation and malformation of the jaws as well as the correct obturators for the closing of the maxilla defects (Fig. 6a & b). For patients with neuralgic diseases of the maxillofacial area caused by the narrowing of the bone tunnel of II and Ill branches of the trigeminus, stereolithography permits us to determine the precise location of this narrowing along the bone tunnel and to plan beforehand the access to this region. During the dental implantation, the stereolithographic model permits us to determine the location of the mandible nerve, the distance to the bottom of the maxilla sinus and nasal cavity, as well as to see the centers of regional osteoporosis. Conclusion Stereolithography is one of the modern investigational methods that obtains the 3-dimensional model of the facial skeleton bones. This method gives the possibility to clearly determine the exact location of the pathological focus and its real size, as well as to choose and plan the method of the surgery, reducing the risk of post-op complications. Stereolithography is recommended for general use in maxillofacial surgery.