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

CliniCal CaSe

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 exami-nation 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 three-dimension 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 surger-ies and lowers invasiveness, which is crucial in the practice of a surgeon (Dent. Med. Probl. 2013, 50, 2, 238–243).

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

Dent. Med. Probl. 2013, 50, 2, 238–243

Conventional RTG images used in diagnostics of fractures in the area of facial part of the skull (Pa im-age of jaw, diagonal imim-age of jaw, Pa imim-age 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-dimen-sional. Very precise image of bones’ structures is ex-tremely important in the diagnostics and planning of medical treatment, as they may be moved or twisted to incorrect positions. illustrating anatomical struc-tures 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 mov-ing free bones’ parts [1, 2]. Usmov-ing all these pieces of information, a surgeon can plan the surgery in a bet-ter way, taking into account the scope of the opera-tion, 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 to-mographies is the shape of the bundle of the rays. in traditional spiral tomography the bundle of rays re-sembles the shape of a fan and goes into a linear de-tector, whereas in cone-shaped tomography, the bun-dle of rays has the shape of a cone and the detector is two-dimensional, which allows us to scan big-ger surfaces in a shorter time [4]. in traditional spi-ral tomography, a Rentgen lamp and detector move around the patient’s head, collecting the data in the form of following layers that are then reconstruct-ed into 3D [1, 2, 4, 5]. CBCT allows us to get a high-quality image based on scanning after only 1 revo-lution around a patient’s head. The examination is shorter, the dose of radiation is minimized and ad-ditionally, there is a lower risk of the patient moving during the scanning, which would worsen the

qual-ity 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]. Radia-tion dose generated by “cone” tomography is just sev-eral 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 effec-tive dose for the patient is 100 μSv [6]. This means 4 times higher radiation than with a two-dimen-sional orthopantomogram image, but, on the oth-er hand, 21 times lowoth-er radiation than during an examination performed using spiral tomography.

Case Reports

Volumetric tomography application in illus-trating fractures of facial part of the skull was de-scribed in this paper on the example of apparatus new Tom 3G (Model QR-DVT 9000). The imag-es were collected thanks to computer software on the group of patients treated in Clinic for Cranio-Maxillofacial Surgery, Oral Surgery and implan-tology, Medical University of Warsaw.

Case 1

Zygomatico-orbital Fracture

a patient, aged 23, had an injury as a re-sult of a hit on the left side of the surface of the cheek bone. Subconjunctival ecchymosis, swell-ing and bruisswell-ing of eyelid and orbital area at the left side were identified during the medical exam-ination. 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

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

możliwo-ści 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, 238–243).

eyeball movement and double vision were also re-ported. 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-maxil-lary-orbital fracture. The patient was referred to CBCT examination in order to illustrate the frac-ture in the area of facia part of the skull. Based

on tomography performed (Figs. 1, 2), the follow-ing were reported: fracture with dislocation of zy-gomatic 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 os-teosynthesis 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 jarz-mowej z przemieszczeniem łuku jarzmowego, złamanie dna oczodołu, mnogie złamanie szczęki

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 jarz-mowej 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. 4. Postoperative 3D cone-beam reconstruction.

Stable miniplate osteosynthesis

Ryc. 4. Pozabiegowe obrazowanie 3D CBCT. Stabilna

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 cor-rect occlusion, bite open in the front section. Palpa-ble examination: ache in the area of temporo-man-dibular joints, with a tendency to intensify during movements and limited movement of head of con-dylar process while moving the lower jaw. after ex-amination, it was diagnosed that the patient had

Fig. 5. 3D cone-beam reconstruction showing the

frac-ture of the right mandibular ramus

Ryc. 5. CBCT ujawniające złamanie prawej gałęzi żuchwy

Fig. 6. 3D cone-beam reconstruction showing the

frac-ture of the left mandibular ramus

Ryc. 6. Rekonstrukcja 3D CBCT pokazująca złamanie

lewej 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. 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

a bilateral condylar fracture. The patient was re-ferred to computed tomography with cone-shaped radiation, which proved that the initial diagno-sis 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 serious-ly affect the diagnosis based on conventional RTG images. Stable miniplate osteosynthesis of condy-lar process of mandible on both sides was done in order to stabilize the bone fractions. The results of the treatment were illustrated by CBCT examina-tion after surgery (Fig. 7, Fig. 8).

Discussion

Thanks to its broad possibilities of illustrat-ing, 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 recon-struction speed, wider access thanks to the small-er dimensions and lowsmall-er costs. Vsmall-ery relevant issue in jaw-facial surgery and traumatology is the size of image scanned (FOV – Field of View). it is as-signed to a particular CBCT apparatus or ready to set, especially in new devices. it depends on detec-tor, geometry of projection of X radiation and col-limation.

While choosing the apparatus for diagnostics of injuries of facial part of the skull, it is important to take into consideration the possibility of illus-trating as much tissue volume as possible. Devices currently available on the market enable us to il-lustrate 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 conver-sion function (Multiplanar Reformating – MPR) are also important. Software attached allows sur-geons 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

Acad-emy 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

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 pre-cise images, with anatomical areas being illustrat-ed in three dimensions. Thanks to such a detailillustrat-ed illustration, tomography examinations allow sur-geons 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 fa-cial part of the skull [14, 15].

References

[1] Różyłło-Kalinowska i., Różyłło T.K.: Use of volumetric imaging in general dental diagnostics. Magazyn Sto-matol. 2009, 19, 6, 18–23 [in Polish].

[2] Różyłło-Kalinowska i., Różyłło T.K.: Możliwości obrazowania wolumetrycznego w przypadku pacjenta stom-atologicznego. TPS 2009, 3, 77–80 [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, 75–80.

[5] Maćkowiak K., Borczyk R., Pietranek K.: The use of cone-beam computed tomography in dental implantol-ogy. TPS 2010, 4, 66–70 [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, 609–625.

[7] Simon J.H.S.: Differential diagnosis of large periapical lesions using cone-beam computed tomography measure-ments and biopsy, J. endod. 2006, 32, 833–837.

[8] Bagińska J., Piszczatowski S.: applicability of different methods of computed tomography to endodontics – re-view of literature. Czas. Stomat. 2010, 63, 41–50 [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, 191–198 [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, 505–512 [in Polish].

[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, 330–333 [in Polish].

[12] Różyłło-Kalinowska i.: Basic principles for use of dental cone beam CT – consensus guidelines of the europe-an academy of Dental europe-and Maxillofacial Radiology. Magazyn Stomat. 2009, 19, 6, 12–16.

[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, 1171–1175

[14] Seth V., Kamath P., Vaidya n.: Cone beam computed tomography: third eye in diagnosis and treatment plan-ning. int. J. Orthod. Milwaukee 2012, 23, 17–22.

[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, 271–286.

Address for correspondence:

Bartłomiej Szczodry

Clinic for Cranio-Maxillofacial Surgery, Oral Surgery and implantology Medical University of Warsaw

lindleya 4 paw. 4 Str. 02-005 Warszawa Poland Tel.: +48 511 290 609 e-mail: bartszczodry@gmail.com Received: 29.03.2013 Revised: 25.04.2013 accepted: 6.05.2013

Praca wpłynęła do Redakcji: 29.03.2013 r. Po recenzji: 25.04.2013 r.