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238
B. Szczodry et al.
Clinical Case
Dent. Med. Probl. 2013, 50, 2, 238–243
ISSN 1644-387X
© Copyright by Wroclaw Medical University
and Polish Dental Society
Bartłomiej SzczodryA, B, E, F, Michał KotlarskiB, E, F, Paweł ChomickiD, F,
Danuta Samolczyk-WanyuraA, 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, 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
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CBCT in Maxillofacial Surgery
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, 238–243).
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 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]. 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 CranioMaxillofacial 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
240
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
B. Szczodry et al.
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. 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. 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
osteosynteza minipłytkowa
CBCT in Maxillofacial Surgery
Case 2
241
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
Fig. 7. Postoperative 3D cone-beam reconstruction. Stable
miniplate osteosynthesis of the left mandibular ramus
Ryc. 5. CBCT ujawniające złamanie prawej gałęzi żuchwy
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
Fig. 8. Postoperative 3D cone-beam reconstruction. Stable
miniplate osteosynthesis of the right mandibular ramus
Ryc. 6. Rekonstrukcja 3D CBCT pokazująca złamanie
lewej gałęzi żuchwy
Ryc. 8. Pozabiegowa rekonstrukcja 3D CBCT. Stabilna
osteosynteza minipłytkowa prawej gałęzi żuchwy
Bilateral Condylar Fracture
242
B. Szczodry et al.
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
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].
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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: [email protected]
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.
Zaakceptowano do druku: 6.05.2013 r.