Computed-Tomography of maxillofacial fractures: What do surgeons want to know?

Computed-Tomography of maxillofacial fractures: What do surgeons want to know? Poster No.: C-0968 Congress: ECR 2016 Type: Educational Exhibit Authors: A. Ammar, M. Jrad, I. KASRAOUI, A. Zoubli, H. Mizouni ; 1 1 2 2 3 2 2 3 Sfax/TN, Tunis/TN, BIZERTA, BI/TN Keywords: Head and neck, CT, Computer Applications-3D, Trauma DOI: 10.1594/ecr2016/C-0968 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 23

Learning objectives To highlight the key imaging features that are critical for therapeutic management of the most common maxillofacial fractures. Background Maxillofacial fractures are commonly encountered in radiological practices. Their management and surgical treatment can present one of the most difficult undertakings for the maxillofacial surgeon. Computed-Tomography with multiplanar reformations and 3-D volume-rendering postprocessing is the imaging technique of choice in maxillofacial trauma providing necessary details for the emergency evaluation of facial injuries [1, 2]. Several systems of classification exist for the imaging evaluation of maxillofacial fractures, but besides the identification and classification of fractures, the radiologist must also recognize pertinent details that guide between a conservative or surgical management. Findings and procedure details The facial bones are bones surrounding the mouth and nose and contributing to the orbits; they include 14 bones: the paired maxillae, zygomatic, nasal, lacrimal, palatine, and nasal conchae; and the unpaired vomer and mandible ( Fig. 1 on page 12 ). Page 2 of 23

Fig. 1: Facial bones References: Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. The facial skeleton can be conceptualized as a series of buttresses: four transverse and four paired vertical buttresses ( Fig. 2 on page 13 ). Page 3 of 23

Fig. 2: Facial buttresses References: Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. The buttresses represent areas of relative increased bone thickness that support both the functional units and the form of the face in an optimal relation, and interface with the skull base or cranium as a stable reference. Disruption of the facial buttresses can alter normal function and change facial dimensions, necessitating surgical fixation for restoration. In order to plan exposure of the facial buttresses and restore them accurately, the surgeon must have a thorough preoperative understanding of the degree and nature of their damage. High-resolution multidetector computed tomography (CT) often provides the detail necessary for preoperative assessment of facial injuries. It is crucial to expose the results by 2D multiplanar reformations in bone and soft tissue windowing and 3D volume rendering (VR). Indeed the surgeon doesn't operate on a report without imaging. Page 4 of 23

Also, in complex maxillofacial fractures, it is important to distinguish those that have direct surgical relevance. To highlight the key imaging features that are critical for therapeutic management of the most common maxillofacial fractures, we developed a checklist to be verified for each fracture group. Nasal bone fractures ( Fig. 3 on page 14 ): Regarding fractures of the nasal bones, the report must indicate if there is a comminution or displacement and associated fracture or hematoma of the nasal septum [2, 3]. This is to prevent nasal obstructive symptoms. Fig. 3: Nasal fractures: (A) Axial and (B) Sagittal CT reformations in bone windowing. (C) Axial and (D) coronal CT reformation in soft tissue windowing. (E) 3D VR reconstruction. Bilateral comminuted fracture of the nasal bones (arrows). There is an associated fracture (small dotted arrows) and hematoma of the nasal septum (arrowheads). Page 5 of 23

References: Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Complex Naso-Ethmoi#do-Maxillo-Fronto-Orbital fracture (CNEMFO) ( Fig. 4 on page 15 ): For the complex naso-ethmoi#do-maxillo-fronto-orbital fracture, it must be mentioned comminution of the medial orbital rim, coronal distance between the two lacrimal fossae, lacrimal duct injury, nasofrontal duct disruption, fracture of the posterior table of frontal sinus and/or the cribriform plate, and associated intracranial abnormalities including pneumocephalus. This is to prevent respectively avulsion of the medial canthus, diplopia, dacryocystitis, frontal mucocele, CSF leakage and anosmia [4, 5]. CNEMFO fracture may be incomplete and concerns only the maxillo-orbito-ethmoidal or naso-orbito-ethmoidal (NOE) complex. Fig. 4: CNEMFO fracture: (A, B) Coronal, (C, D) axial and (E) sagittal CT reformations in bone windowing. (F) 3D VR reconstruction. Central complex midface fracture combining: Factures of posterior and anterior tables of the right frontal sinus (arrowheads) with disjunction between the frontal process of the maxilla, the nasal process of the frontal and right nasal bone (black arrows). The medial orbital rim is not comminuted (star) and the distance between the two lacrimal fossae (A) is 28 mm (normal < 35mm). Injury of the nasolacrimal and nasofrontal ducts without disruption (curved arrow). Loss of substance of the cribriform plate (small dotted arrows). Pneumocephalus (white arrow). References: Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Page 6 of 23

Orbital fractures ( Fig. 5 on page 16 ): In orbital fractures, it is necessary to look for integrity of the eyeball, muscle and/or fat incarceration, eno- or exophthalmos, damage in the infra-orbital nerve, intra-orbital bone fragments or conflicting on neurovascular structures and oculomotor muscles and intraorbital hematoma [6, 7]. Some of these lesions may indicate an urgent surgical treatment because the visual prognosis is at stake. Fig. 5: Orbital floor fracture: (A) Coronal and (B) Sagittal CT reformations in soft tissue windowing. Comminuted fracture of the orbital floor with plugging of the lower rectus muscle by a bone splinter (white arrow). This muscle is enlarged compared to the contralateral side (arrowheads). The infra orbital nerve canal is damaged (black arrow). There are also indirect signs of floor fracture: hemosinus right maxillary (star) and orbital emphysema (curved arrow). References: Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Zygomatic fractures ( Fig. 6 on page 17 ): In zygomatic fractures, the integrity of the orbital contents should always be sought and the degree of comminution or angulation can indicate surgical exposure [3, 8]. Page 7 of 23

Le-Fort fractures involve disruption of the pterygoid plates from the posterior maxilla. Once a pterygo-maxillary disjunction has been diagnosed, the remaining facial buttresses are inspected to determine the class of Le Fort fracture ( Fig. 7 on page 18 ), with possible combination of Le Fort I, II, and III. We must seek in their context an associated fracture of the hard palate compounding the functional prognosis. Fig. 7: Le Fort fractures: CT 3D VR reconstruction shows the common Le Fort fracture patterns: The Le Fort I pattern involves fractures through the inferior portions of the medial and lateral maxillary buttresses. The Le Fort II pattern involves fractures through the zygomatico-maxillary and fronto-maxillary sutures. The Le Fort III pattern involves complete craniofacial dissociation. References: Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Fig. 8 on page 18 shows an example of bilateral Le Fort fracture. Page 9 of 23

Fig. 8: Bilateral Le Fort fracture: (A,B,C) Axial and (D) frontal CT reformations in bone windowing. (E) 3D VR reconstruction. Transverse fracture of the face (Lefort II at right, Lefort I at left) associating: Fracture of the two pterygoid processes (arrowheads) and the maxillary walls (dotted arrow). Floor fracture of the right orbit (black arrow). Involvement of the right nasolacrimal duct (white arrow) and associated fracture of the left hard palate (curved arrow). References: Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Mandibular fractures [5, 10]: For mandibular fractures, one must know the articular or extra-articular fractures, displacement, bilateralism and the passage through the toothed portion and/or the inferior alveolar nerve canal. These findings guide to a functional or surgical treatment and whether antibiotherapy is necessary. Fig. 9 on page 19 illustrates the anatomy and the main lines of mandibular fracture. Page 10 of 23

Fig. 9: Mandibular anatomy and fractures: CT 3D VR reconstruction illustrating the anatomy and the main fracture lines on the left hemi-mandibule: 1: Coronoide fracture; 2: condylar fracture; 3: high subcondylar fracture; 4 low sub condylar fracture; 5: angular fracture; 6: fracture of the corpus passing through the root of the tooth 36; 7: parasymphysis fracture; 8: symphysis fracture. References: Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Fig. 10 on page 20 shows an example of bilateral complex mandibular fracture. Page 11 of 23

Fig. 10: Mandibular complex fracture: (A) Axial and (B) frontal CT reformations in bone windowing and (C, D) 3D VR reconstructions. Bilateral fracture of the corpus passing through the root of the teeth and through the inferior alveolar nerve canal (arrowheads) associated to bilateral low sub-condylar fracture with dislocation of the temporo-mandibular articulations (arrows). References: Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Images for this section: Page 12 of 23

Fig. 1: Facial bones Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Page 13 of 23

Fig. 2: Facial buttresses Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Page 14 of 23

Fig. 3: Nasal fractures: (A) Axial and (B) Sagittal CT reformations in bone windowing. (C) Axial and (D) coronal CT reformation in soft tissue windowing. (E) 3D VR reconstruction. Bilateral comminuted fracture of the nasal bones (arrows). There is an associated fracture (small dotted arrows) and hematoma of the nasal septum (arrowheads). Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Page 15 of 23

Fig. 4: CNEMFO fracture: (A, B) Coronal, (C, D) axial and (E) sagittal CT reformations in bone windowing. (F) 3D VR reconstruction. Central complex midface fracture combining: Factures of posterior and anterior tables of the right frontal sinus (arrowheads) with disjunction between the frontal process of the maxilla, the nasal process of the frontal and right nasal bone (black arrows). The medial orbital rim is not comminuted (star) and the distance between the two lacrimal fossae (A) is 28 mm (normal < 35mm). Injury of the nasolacrimal and nasofrontal ducts without disruption (curved arrow). Loss of substance of the cribriform plate (small dotted arrows). Pneumocephalus (white arrow). Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Page 16 of 23

Fig. 5: Orbital floor fracture: (A) Coronal and (B) Sagittal CT reformations in soft tissue windowing. Comminuted fracture of the orbital floor with plugging of the lower rectus muscle by a bone splinter (white arrow). This muscle is enlarged compared to the contralateral side (arrowheads). The infra orbital nerve canal is damaged (black arrow). There are also indirect signs of floor fracture: hemosinus right maxillary (star) and orbital emphysema (curved arrow). Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Page 17 of 23

Fig. 6: Disjunction fracture of the zygomatic bone: CT 3D VR reconstruction shows zygomatic disjunction fracture (arrowheads) with comminution of the zygomatic arch (dotted arrow) and impaction (solid arrow) of the zygoma. We also note in this reconstruction a fracture of the orbital floor, a fracture of the anterior wall of the maxillary sinus through the infra orbital nerve canal and a low sub-condylar mandible fracture. Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Fig. 7: Le Fort fractures: CT 3D VR reconstruction shows the common Le Fort fracture patterns: The Le Fort I pattern involves fractures through the inferior portions of the medial and lateral maxillary buttresses. The Le Fort II pattern involves fractures through the zygomatico-maxillary and fronto-maxillary sutures. The Le Fort III pattern involves complete craniofacial dissociation. Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Page 18 of 23

Fig. 9: Mandibular anatomy and fractures: CT 3D VR reconstruction illustrating the anatomy and the main fracture lines on the left hemi-mandibule: 1: Coronoide fracture; 2: condylar fracture; 3: high subcondylar fracture; 4 low sub condylar fracture; 5: angular fracture; 6: fracture of the corpus passing through the root of the tooth 36; 7: parasymphysis fracture; 8: symphysis fracture. Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Page 20 of 23

Fig. 10: Mandibular complex fracture: (A) Axial and (B) frontal CT reformations in bone windowing and (C, D) 3D VR reconstructions. Bilateral fracture of the corpus passing through the root of the teeth and through the inferior alveolar nerve canal (arrowheads) associated to bilateral low sub-condylar fracture with dislocation of the temporo-mandibular articulations (arrows). Department of Radiology, La-Rabta Hospital, Tunis / Tunisia 2015. Page 21 of 23

Conclusion Knowledge of the common patterns of injury and the salient information that can guide patient management is important to providing pertinent and clinically beneficial reports. Personal information References 1. Sung EK, Nadgir RN, Sakai O. Computed Tomographic Imaging in Head and Neck Trauma: What the Radiologist Needs to Know. Seminars in Roentgenology. 2012;47(4):320-9. 2. Mehta N, Butala P, Bernstein MP. The Imaging of Maxillofacial Trauma and its Pertinence to Surgical Intervention. Radiologic Clinics of North America. 2012;50(1):43-57. 3. Patel R, Reid RR, Poon CS. Multidetector Computed Tomography of Maxillofacial Fractures: The Key to High-Impact Radiological Reporting. Seminars in Ultrasound, CT and MRI. 2012;33(5):410-7. 4. Millet-Cénac I, Taourel P. TDM EN TRAUMATOLOGIE: Elsevier Health Sciences France; 2009. 5. Avery LL, Susarla SM, Novelline RA. Multidetector and Three-Dimensional CT Evaluation of the Patient With Maxillofacial Injury. Radiologic Clinics of North America. 2011;49(1):183-203. 6. Boswell KA. Management of Facial Fractures. Emergency Medicine Clinics of North America. 2013;31(2):539-51. 7. Lo Casto A, Priolo GD, Garufi A, Purpura P, Salerno S, La Tona G, et al. Imaging Evaluation of Facial Complex Strut Fractures. Seminars in Ultrasound, CT and MRI. 2012;33(5):396-409. 8. Kochhar A, Byrne PJ. Surgical Management of Complex Midfacial Fractures. Otolaryngologic Clinics of North America. 2013;46(5):759-78. 9. Gentile MA, Tellington AJ, Burke WJ, Jaskolka MS. Management of Midface Maxillofacial Trauma. Atlas of the Oral and Maxillofacial Surgery Clinics. 2013;21(1):69-95. Page 22 of 23

10. Ogura I, Sasaki Y, Kaneda T. Multidetector computed tomography of maxillofacial fractures. Japanese Dental Science Review. 2014;50(4):86-90. Page 23 of 23