|Year : 2015 | Volume
| Issue : 2 | Page : 67-69
Diagnosis of unusual mandibular split fracture with cone-beam computed tomography
Nilüfer Ersan, Mehmet Ilgüy
Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Yeditepe University, İstanbul, Turkey
|Date of Web Publication||22-May-2015|
Dr. Nilüfer Ersan
Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Yeditepe University, Bağdat Caddesi No: 238/3/A Göztepe 34728 İstanbul
Source of Support: None, Conflict of Interest: None
Mandibular fractures are relatively easy to diagnose in comparison with other craniofacial fractures. This report presents a trauma patient with an unusual split fracture in the mandibular corpus, which was missed on the panoramic radiograph; however, could be visualized with cone-beam computed tomography (CBCT). Panoramic radiograph may be misleading for accurate diagnosis of mandibular corpus fractures. We suggest that CBCT is crucial and should be mandatory for all suspected mandibular fractures in maxillofacial trauma patients.
Keywords: Cone-beam computed tomography, mandibular corpus, maxillofacial trauma, panoramic radiography, split fracture
|How to cite this article:|
Ersan N, Ilgüy M. Diagnosis of unusual mandibular split fracture with cone-beam computed tomography. J Oral Maxillofac Radiol 2015;3:67-9
|How to cite this URL:|
Ersan N, Ilgüy M. Diagnosis of unusual mandibular split fracture with cone-beam computed tomography. J Oral Maxillofac Radiol [serial online] 2015 [cited 2019 Jun 19];3:67-9. Available from: http://www.joomr.org/text.asp?2015/3/2/67/157528
| Introduction|| |
Mandible fractures constitute around 40-62% of all facial bone fractures.  These fractures are classified according to their location and mandibular corpus, which consists mandibular body, symphysis and parasymphysis region, is one of the most frequently seen fracture sites. The evaluation of trauma of the facial skeleton is based on clinical examination followed by appropriate radiographs. The detectability of corpus fractures depends on the position of the fracture line, the degree of displacement of the fracture pieces, and the imaging methods used.  Therefore, radiographically, attention should be directed to the course of the fracture lines, involved anatomic structures and the number, size, and displacement of fractured fragments. Mandibular fractures may be difficult to diagnose because of the location and anatomic characteristics of the mandible, that some fractures are not apparent when the X-ray beam is not passing through the plane of the fracture. 
Although, panoramic radiographs (orthopantomograph [OPG]) had been considered as gold standard for the identification of mandibular fractures,  the amount of information gained from conventional or digital plain radiographs is limited that three-dimensional (3D) anatomy is compressed into a 2D image, which results in superimposition. Computed tomography (CT) has replaced OPG as the gold standard for imaging of patients with suspected mandible fractures.  In cone-beam computed tomography (CBCT), the whole 3D volume of data is acquired in a single rotation of the scanner around the patient with considerable lower acquisition time, cost and radiation exposure comparing to CT scanners. 
The purpose of this case study was to illustrate the diagnostic efficacy of CBCT for accurate diagnosis of split corpus fracture in the mandible in a trauma case.
| Case Report|| |
A 33-year-old female patient had a trauma to her mandible due to a fall 2 days before her admission to our clinic. Her medical anamnesis was unremarkable. Clinical examination revealed that she had no pain and no problem with occlusion, whereas she had limited mouth opening (<40 mm). As well, she had a hematoma on the lingual side of left posterior mandible and luxation in premolar teeth. Following clinical examination, the patient was scanned with OPG (Planmeca Promax, Helsinki, Finland), which revealed no fracture in the left corpus area, but a fracture line on the right condyle [Figure 1]. Further imaging performed with CBCT scanner (Iluma, Imtec Corporation, Oberursel, Germany) showed that the fracture in the condyle region was a dislocated incomplete fracture. In addition, a second vertical dislocated incomplete split lingual cortex fracture line in the left mandibular corpus, extending lingually from the distolingual side of the third molar to the parasymphyseal region was observed [Figure 2]a-e. The fracture was fragmented in the molar region, whereas not fragmented in the parasymphyseal region [Figure 2]a. The patient was referred to the oral surgery clinic for intermaxillary fixation.
|Figure 1: Panoramic radiograph of the patient missing the split fracture of the mandible|
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|Figure 2: (a) Three-dimensional, (b and c) axial and (d and e) coronal cone-beam computed tomography images of the fracture line|
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| Discussion|| |
Mandibular fractures are relatively easy to diagnose comparing to the other craniofacial fractures.  Chayra et al. showed that 92% of the mandible fractures could be seen on OPG.  Displacement of fracture segments commonly occurs in mandibular corpus fractures as a result of the differing forces of the muscles acting upon the mandible. In our case, there was no dislocation in the fracture fragments in mandibular corpus, which made it harder to visualize the fracture lines on OPG. As well, diagnostic accuracy of OPG will be poor when the fracture line is not parallel to the X-ray beam, especially in split fractures,  as seen in our case.
Three-dimensional techniques have become increasingly important in diagnostic imaging, especially in trauma patients. Although CBCT costs more than conventional panoramic machines, it offers wider range of diagnostic options. Some CBCT scanners allow the height of the field of view to be adjusted to capture only the necessary region to be studied complying with the principles of radiation protection. However, in trauma patients, maxillofacial region should be evaluated as a whole, that targeting only on the fractures, which is visible or suspected clinically, may cause the fracture lines to be overlooked. In this case study, it was shown that OPG was not able to detect split corpus fracture of the mandible, whereas it could be visualized on CBCT images gathered with a scanner that has a large field of view.
In the literature, it was reported that 50% of mandibular fractures are seen doubly fractured.  Parasymphyseal fractures are frequently associated with fractures at other sites of the mandible. In our case, there were two separate fracture lines, one in the condylar region, and the other in the mandibular corpus region on the opposite side. Accompanying limited mouth opening might be attributed to the trismus caused by condylar fracture and the dentist might not need further imaging.
When evaluating the mandibular fractures, enough time should be taken to interpret the images in detail, in correlation with the examination findings, which is mostly not applicable in emergency departments. In our department, the dentomaxillofacial radiologists perform both clinical and radiographic examination of the patients, which leads to a better handling of the patient taking both the clinical and radiological findings into consideration.
| Conclusion|| |
This report accentuates that OPGs may be misleading for accurate diagnosis of mandibular fractures. With regard to the mandibular split corpus fractures, we suggest that CBCT is crucial and should be mandatory for all suspected mandibular fractures along with OPG in maxillofacial trauma patients.
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[Figure 1], [Figure 2]