Bartłomiej Szczodry A, B, E, F, Michał Kotlarski B, E, F, Paweł Chomicki D, F, Danuta Samolczyk-Wanyura A, F. Abstract.

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1 238 B. Szczodry et al. Clinical Case Dent. Med. Probl. 2013, 50, 2, ISSN X Copyright by Wroclaw Medical University and Polish Dental Society Bartłomiej Szczodry A, B, E, F, Michał Kotlarski B, E, F, Paweł Chomicki D, F, Danuta Samolczyk-Wanyura A, F The Application of Computed Tomography with Cone-Shaped Radiation in Maxillofacial Surgery in the Group of Patients with Fractures in the Facial Part of the Skull Preliminary Report Zastosowanie tomografii komputerowej z wiązką promieniowania w kształcie stożka u pacjentów ze złamaniami w obrębie części twarzowej czaszki doniesienie wstępne Clinic for Cranio-Maxillofacial Surgery, Oral Surgery and Implantology, Medical University of Warsaw, Poland A concept; B data collection; C statistics; D data interpretation; E writing/editing the text; F compiling the bibliography Abstract Background. Volumetric tomography (computed tomography with cone-shaped radiation CBCT) is used more and more often in the clinical practice. The biggest advantage of this form of diagnostics is very good quality of the scanned images. CBCT enables us to create precise images of teeth structure, bones of jaw and lower jaw in the form of thin sections, multi-surface reconstructions and 3D reconstructions. Computed tomography has proved to be a very helpful diagnostic tool in the maxillofacial surgery. Objectives. The aim of this paper is to present application of computed tomography with cone-shaped radiation in maxillofacial surgery in the group of patients with fractures in the facial part of the skull. Material and Methods. This dissertation was created on the basis of both review of already existing theses and CBCT tomography research performed on the patients of Clinic for Cranio-Maxillofacial Surgery, Oral Surgery and Implantology, Medical University of Warsaw with fractures in the area of facial part of the skull. CBCT examination was performed using apparatus New Tom 3G (Model QR-DVT 9000). Results. Computed tomography examination with cone-shaped radiation enables a precise illustration of fractures in the area of upper and lower part of the face. All the essential pieces of information about construction and threedimension location of structures have been collected. These data turned out to be extremely valuable in the case of dislocation of facial bones structures after injury. Conclusions. Computed tomography with cone-shaped radiation enables proper diagnostics and medical treatment monitoring. Detailed planning of treatment based on images without distortions helps to reduce the length of surgeries and lowers invasiveness, which is crucial in the practice of a surgeon (Dent. Med. Probl. 2013, 50, 2, ). Key words: computed tomography, CBCT. Streszczenie Wprowadzenie. Tomografia komputerowa z wiązką promieniowania w kształcie stożka (CBCT) znajduje coraz szersze zastosowanie w praktyce klinicznej. Za rosnącą popularnością tej formy diagnostyki przemawia bardzo dobra jakość obrazowania badanych struktur. CBCT pozwala na dokładne zobrazowanie twardych struktur zębów, kości szczęk i żuchwy w formie cienkich przekrojów, rekonstrukcji wielopłaszczyznowej oraz rekonstrukcji 3D. W chirurgii szczękowo-twarzowej tomografia komputerowa jest bardzo pomocnym narzędziem diagnostycznym, które znalazło szerokie zastosowanie między innymi u chorych po urazach. Cel pracy. Przedstawienie możliwości wykorzystania CBCT w diagnostyce złamań u chorych po urazach twarzowej części czaszki. Materiały i metody. W pracy wykorzystano badania CBCT wykonane u wybranych pacjentów ze złamaniami w obrębie twarzowej części czaszki leczonych w Klinice Chirurgii Czaszkowo-Szczękowo-Twarzowej, Chirurgii

2 CBCT in Maxillofacial Surgery 239 Jamy Ustnej i Implantologii WUM. Na podstawie otrzymanych wyników i przeglądu piśmiennictwa oceniono przydatność badania w diagnostyce złamań twarzowej części czaszki. Badanie CBCT zostało wykonane za pomocą aparatu New Tom 3G (Model QR-DVT 9000). Wyniki. Wykonane badania tomografii komputerowej z wiązką promieniowania w kształcie stożka pozwoliły w precyzyjny sposób zobrazować złamania w obrębie górnego i dolnego masywu twarzy. Uzyskano niezbędne informacje o budowie i lokalizacji przestrzennej struktur objętych obrazowaniem. W przypadku przemieszczeń struktur kostnych twarzoczaszki u pacjentów po urazie informacje te okazały się niezwykle przydatne w planowaniu postępowania leczniczego. Wnioski. Tomografia komputerowa z wiązką promieniowania w kształcie stożka daje niespotykane dotąd możliwości diagnostyki i monitorowania wyników leczenia, a co za tym idzie prawidłowego leczenia schorzeń związanych z obszarem części twarzowej czaszki. Szczegółowe planowanie leczenia na podstawie pozbawionego zniekształceń obrazu skraca czas zabiegów i zmniejsza ich inwazyjność (Dent. Med. Probl. 2013, 50, 2, ). Słowa kluczowe: tomografia komputerowa, CBCT. Conventional RTG images used in diagnostics of fractures in the area of facial part of the skull (PA image of jaw, diagonal image of jaw, PA image of skull, image of paranasal sinuses according to Waters, even orthopantomogram) are two-dimensional images of anatomical structures. This limits the diagnostics of facial structures of the skull that is three-dimensional. Very precise image of bones structures is extremely important in the diagnostics and planning of medical treatment, as they may be moved or twisted to incorrect positions. Illustrating anatomical structures that are able to reconstruct a 3D image based on sections detected while moving the lamp around the patient s head enables us to assess the location of sliver of bones in 3 dimensions. Thanks to computed tomography, a surgeon is in a position to define the direction of a fracture, presence of slivers and moving free bones parts [1, 2]. Using all these pieces of information, a surgeon can plan the surgery in a better way, taking into account the scope of the operation, surgical access, estimated length of surgery, raw materials consumption [3]. Computed tomography with cone-shaped radiation CBCT is a significant progress in illustrating facial structures of the skull. It is an alternative, and in some areas e.g. in surgery it almost completely squeezed out traditional spiral tomography. The main difference between those tomographies is the shape of the bundle of the rays. In traditional spiral tomography the bundle of rays resembles the shape of a fan and goes into a linear detector, whereas in cone-shaped tomography, the bundle of rays has the shape of a cone and the detector is two-dimensional, which allows us to scan bigger surfaces in a shorter time [4]. In traditional spiral tomography, a Rentgen lamp and detector move around the patient s head, collecting the data in the form of following layers that are then reconstructed into 3D [1, 2, 4, 5]. CBCT allows us to get a highquality image based on scanning after only 1 revolution around a patient s head. The examination is shorter, the dose of radiation is minimized and additionally, there is a lower risk of the patient moving during the scanning, which would worsen the quality of the images. According to various authors the dose of radiation generated by CBCT apparatuses is in the range from 13 μsv to even 269 μsv [1, 6]. Radiation dose generated by cone tomography is just several per cent of the dose from medical tomographs, where the absorbed radiation amounts to 2100 μsv [5, 7]. Two-dimensional orthopantomogram image can create radiation of 26 μsv [5]. All the research presented in this paper was performed using the Rusing apparatus New Tom 3G (Model QR-DVT 9000), for which the effective dose for the patient is 100 μsv [6]. This means 4 times higher radiation than with a two-dimensional orthopantomogram image, but, on the other hand, 21 times lower radiation than during an examination performed using spiral tomography. Case Reports Volumetric tomography application in illustrating fractures of facial part of the skull was described in this paper on the example of apparatus New Tom 3G (Model QR-DVT 9000). The images were collected thanks to computer software on the group of patients treated in Clinic for Cranio- Maxillofacial Surgery, Oral Surgery and Implantology, Medical University of Warsaw. Case 1 Zygomatico-orbital Fracture A patient, aged 23, had an injury as a result of a hit on the left side of the surface of the cheek bone. Subconjunctival ecchymosis, swelling and bruising of eyelid and orbital area at the left side were identified during the medical examination. A withdrawal and lowering of the cheek bone along with uneven bone shape in the form of a step on the lower edge of eye socket were also identified during palpable examination. Disorder

3 240 B. Szczodry et al. eyeball movement and double vision were also reported. The patient also complained about lack of sense of touch in the area of upper lip and left side of the nose. Clinical image indicated zygomatico-maxillary-orbital fracture. The patient was referred to CBCT examination in order to illustrate the fracture in the area of facia part of the skull. Based on tomography performed (Figs. 1, 2), the following were reported: fracture with dislocation of zygomatic branch. The examination enabled us to describe precisely the direction of fractures and dislocation of bones. Based on the information gathered, surgery was planned and miniplate osteosynthesis was done as a result all the bone fractions were arranged correctly. The treatment result was illustrated by CBCT examination after surgery (Figs. 3, 4). Fig. 1. Cone-beam reconstruction showing the fracture of the left zygoma bone with displaced of zygomatic branch, fracture of orbital floor, maxillary multiple fracture Ryc. 1. Tomografia z użyciem promienia w kształcie stożka (CBCT) pokazująca złamanie lewej kości jarzmowej z przemieszczeniem łuku jarzmowego, złamanie dna oczodołu, mnogie złamanie szczęki Fig. 3. Postoperative 3D cone-beam reconstruction. Stable miniplate osteosynthesis Ryc. 3. Pozabiegowe obrazowanie 3D CBCT. Stabilna osteosynteza minipłytkowa Fig. 2. Cone-beam reconstruction showing the fracture of the left zygoma bone with displaced of zygomatic branch, fracture of orbital floor, maxillary multiple fracture Ryc. 2. Tomografia z użyciem promienia w kształcie stożka (CBCT) pokazująca złamanie lewej kości jarzmowej z przemieszczeniem łuku jarzmowego, złamanie dna oczodołu, mnogie złamanie szczęki Fig. 4. Postoperative 3D cone-beam reconstruction. Stable miniplate osteosynthesis Ryc. 4. Pozabiegowe obrazowanie 3D CBCT. Stabilna osteosynteza minipłytkowa

4 CBCT in Maxillofacial Surgery 241 Case 2 Bilateral Condylar Fracture A patient, aged 35, had an injury as a result of hit at chin. No movement of upper and lower teeth was identified during clinical examination. No correct occlusion, bite open in the front section. Palpable examination: ache in the area of temporo-mandibular joints, with a tendency to intensify during movements and limited movement of head of condylar process while moving the lower jaw. After examination, it was diagnosed that the patient had a bilateral condylar fracture. The patient was referred to computed tomography with cone-shaped radiation, which proved that the initial diagnosis was correct and clearly showed the direction of fractures of condylar processes. (Fig. 5, Fig. 6). The direction of condylar process fracture on the right side goes along the lower jaw, which could seriously affect the diagnosis based on conventional RTG images. Stable miniplate osteosynthesis of condylar process of mandible on both sides was done in order to stabilize the bone fractions. The results of the treatment were illustrated by CBCT examination after surgery (Fig. 7, Fig. 8). Fig. 5. 3D cone-beam reconstruction showing the fracture of the right mandibular ramus Ryc. 5. CBCT ujawniające złamanie prawej gałęzi żuchwy Fig. 7. Postoperative 3D cone-beam reconstruction. Stable miniplate osteosynthesis of the left mandibular ramus Ryc. 7. Pozabiegowa rekonstrukcja 3D CBCT. Stabilna osteosynteza minipłytkowa lewej gałęzi żuchwy Fig. 6. 3D cone-beam reconstruction showing the fracture of the left mandibular ramus Ryc. 6. Rekonstrukcja 3D CBCT pokazująca złamanie lewej gałęzi żuchwy Fig. 8. Postoperative 3D cone-beam reconstruction. Stable miniplate osteosynthesis of the right mandibular ramus Ryc. 8. Pozabiegowa rekonstrukcja 3D CBCT. Stabilna osteosynteza minipłytkowa prawej gałęzi żuchwy

5 242 Discussion Thanks to its broad possibilities of illustrating, CBCT tomography can find broad application [5, 8 11]. The main advantages of this method are: significant reduction of X radiation compared to computer tomographs, scanning and data reconstruction speed, wider access thanks to the smaller dimensions and lower costs. Very relevant issue in jaw-facial surgery and traumatology is the size of image scanned (FOV Field of View). It is assigned to a particular CBCT apparatus or ready to set, especially in new devices. It depends on detector, geometry of projection of X radiation and collimation. While choosing the apparatus for diagnostics of injuries of facial part of the skull, it is important to take into consideration the possibility of illustrating as much tissue volume as possible. Devices currently available on the market enable us to illustrate the area of approximately 30 cm, which is enough to illustrate the facial part of the skull [2, 5, 6]. Moreover, the quality of image, ability to show sections in all surfaces and multi-surface conversion function (Multiplanar Reformating MPR) are also important. Software attached allows surgeons to do all the required measurements and to modify the captured image in order to show the most precise illustration of the structures. According to the standards of European Academy of DentoMaxilloFacial Radiology (EADMFR) concerning CBCT examinations, it is required to assess potential benefits for a patient in every case. Dose of radiation should be maintained at the minimum level and CBCT examination ought to ensure new pieces of information, impossible B. Szczodry et al. to obtain using traditional Rentgen images with lower dose of radiation. It is one of the main rules of a patient s radiological protection ALARA (As Low As Reasonably Achievable) [12]. Illustration techniques using tomography with bundle in the shape of a cone are being constantly improved. Nowadays, portable CBCT devices are available (xcat ENT portale CBCT system) that allow carrying out an examination during surgery or just after it to assess the treatment results. Such a solution helps to assess the results of treatment while doing the surgery and to make amendments, if needed. Some authors describe the possibility of applying such devices in reconstruction operations of the bottom of eye socket using mesh plate and autogenic transplants. Thanks to intraoperative CBCT examination, it was possible to amend the incorrect arrangement of reconstruction material, which was not possible with clinical methods [13]. Conclusions CBCT tomography is a modern diagnostic tool squeezing out conventional X-ray images in daily clinical practice. Although the dose of radiation is insignificantly higher, it is possible to get very precise images, with anatomical areas being illustrated in three dimensions. Thanks to such a detailed illustration, tomography examinations allow surgeons to specify the direction of fracture precisely, identify the presence of slivers and movement of bones parts. Volumetric illustration provides more information than conventional X-ray examination and can be used for diagnostics of fractures of facial part of the skull [14, 15]. References [1] Różyłło-Kalinowska I., Różyłło T.K.: Use of volumetric imaging in general dental diagnostics. Magazyn Stomatol. 2009, 19, 6, [in Polish]. [2] Różyłło-Kalinowska I., Różyłło T.K.: Możliwości obrazowania wolumetrycznego w przypadku pacjenta stomatologicznego. TPS 2009, 3, [in Polish]. [3] Kryst L. (red.): Chirurgia szczękowo-twarzowa. Wydawnictwo Lekarskie PZWL, Warszawa 2007, wyd. 5 (dodruk 2011). [4] Scarfe W.C., Farman A.G., Sukovic P.: Clinical applications of cone-beam computed tomography in dental practice. J. Can. Dent. Assoc. 2006, 72, [5] Maćkowiak K., Borczyk R., Pietranek K.: The use of cone-beam computed tomography in dental implantology. TPS 2010, 4, [in Polish]. [6] De Vos W., Casselman J., Swennen G.R.J.: Cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial region: A systematic review of literature. J. Oral Maxillofac. Surg. 2009, 38, [7] Simon J.H.S.: Differential diagnosis of large periapical lesions using cone-beam computed tomography measurements and biopsy, J. Endod. 2006, 32, [8] Bagińska J., Piszczatowski S.: Applicability of different methods of computed tomography to endodontics review of literature. Czas. Stomat. 2010, 63, [in Polish]. [9] Różyłło-Kalinowska I., Różyłło T.K.: Cone-Beam Computed Tomography in diagnostics of vertical dental root fracture in vitro study. Czas. Stomatol. 2010, 63, [in Polish]. [10] Postek-Stefańska L., Bednarski J., Mazur T., Borkowski L.: In vitro evaluation of matched-taper single cone ProTaper and Thermafil technique root canal obturations using digital radiography. Dent. Med. Probl. 2011, 48, [in Polish].

6 CBCT in Maxillofacial Surgery 243 [11] Owecka M., Kulczyk T.: The use of cone-beam computed tomography (CBCT) in identification of the causes of teeth eruption disturbances. Nowiny Lek. 2008, 77, [in Polish]. [12] Różyłło-Kalinowska I.: Basic principles for use of dental cone beam CT consensus guidelines of the European Academy of Dental and Maxillofacial Radiology. Magazyn Stomat. 2009, 19, 6, [13] Stuck B.A., Hulse R., Barth T.J.: Intraoperative cone beam computed tomography in the management of facial fractures. J. Oral Maxillofac. Surg. 2012, 41, [14] Seth V., Kamath P., Vaidya N.: Cone beam computed tomography: third eye in diagnosis and treatment planning. Int. J. Orthod. Milwaukee 2012, 23, [15] Kaeppler G., Mast M.: Indications for cone-beam computed tomography in the area of oral and maxillofacial surgery. Int. J. Comput. Dent. 2012, 15, Address for correspondence: Bartłomiej Szczodry Clinic for Cranio-Maxillofacial Surgery, Oral Surgery and Implantology Medical University of Warsaw Lindleya 4 paw. 4 Str Warszawa Poland Tel.: bartszczodry@gmail.com Received: Revised: Accepted: Praca wpłynęła do Redakcji: r. Po recenzji: r. Zaakceptowano do druku: r.