Complex Facial and Orbital Trauma “What you need to know, and what you need to look out for.” T. Skinner, J. Adu, A. Adams, A. Roy.

Mandibular Fractures • A traumatic force to the mandible typically produces at least two fractures, due to its half ring-like

structure. • Alveolar ridge fractures must be treated as open fractures and the patient should be commenced

on an appropriate antibiotic regimen.

Introduction

• Facial and orbital injuries are a common and serious consequence of RTCs, assaults, falls and other blunt trauma.

• The incidence of traumatic facial and orbital injuries is increasing, as the age of the general population increases.

• Facial and orbital fractures are associated with significant levels of mortality and morbidity. • CT and MRI imaging are essential for the diagnosis and treatment of facial and orbital injuries. • The aim of this poster is to review the anatomy of the facial bones, identify common fracture

patterns, and alert the reporting radiologist to specific complications related to these fractures.

Le Fort Classification • René Le Fort was a French military surgeon who, in 1901, developed his classification by applying

varying degrees of blunt force to the faces of cadavers. • A Le Fort fracture is a separation of all or a portion of the maxilla from the skull base. • Disruption of the posterior vertical maxillary buttress – at the junction of the posterior maxillary

sinus and the pterygoid plates of the sphenoid – is common to all Le Fort fractures. • Any combination of Le Fort fracture can occur.

- Le Fort I – Separation of the hard palate from the sphenoid.

- Le Fort II – A pyramidal maxillary fragment has separated from the rest of the upper mid-face and sphenoid. The fracture runs through the inferior orbital rim.

- Le Fort III – Craniofacial dissociation, complete dissociation of the face from the skull base, involving fracture through the zygomatic arch.

Putting It All Together

• A radiologist must have a comprehensive knowledge of facial fracture patterns and their sequlae. • Diagnosis, and subsequent surgical management, is vitally important to prevent serious functional

impairment, as well as cosmetic deformity. • When assessing the extent of orbital trauma the reporting radiologist must:

• Assess the bony orbit for fractures, and search for herniations of orbital contents. • Evaluate the anterior chamber and position of the lens. • Evaluate the posterior chamber, searching for bleeds, fluid collections and abnormal bodies.

References 1. Yamamoto K, Matsusue Y, Murakami K, Horita S, Sugiura T, Kirita T: Maxillofacial Fractures in Older Patients. J Oral Maxillofac Surg 69:2204-2210, 2011 2. Hooper R, Salemy S, Sze R: Diagnosis of Midface fractures with CT - What the surgeon needs to know. Radiographics 2006; 26: 783-793 3. Kubal WS: Imaging of orbital trauma, Radiographics 2008; 28: 1729-1739 4. Winegar B, Murillo H, Tantiwongkosi B: Spectrum of critical imaging findings in complex facial skeletal trauma. Radiographics 2013; 33, 3-19 5. Uzelac A, Gean A: Orbital and facial fractures. NeuroimagClin N Am 24 (2014) 407-424 Coronal image illustrating a fracture through the symphysis menti and bilateral mandibular condyle fractures.

Axial and coronal images of a comminuted orbital ethmoid fracture

3D reconstruction demonstrating a right sided Le Fort II (yellow arrow) and a left-sided Le Fort III (blue arrows)

Coronal image demonstrating bilateral fractures of the medial and lateral pterygoid plates – common to all Le Fort injuries

Coronal image and 3D reconstruction illustrating a Le Fort II fracture

Axial image demonstrating a right zygomatic complex fracture

Zygomatico Maxillary Complex (ZMC) Fractures • The ZMC is a quadripod structure – which

borders the frontal, temporal, maxilla and sphenoid bones.

• A ZMC fracture usually fractures through all four sutures of the complex.

• In very high impact trauma, Le Fort, ZMC and NOE fractures can be concomitant.

• ZMC fractures often increase orbital volume by angulation of the lateral orbit wall at the zygomaticosphenoid suture – a “blow-out” of the orbital floor. In this context, the reporting radiologist must carefully scrutinise the globe to assess its integrity.

Naso Orbito Ethmoid (NOE) Fractures • NOE fractures are classified by degree of injury to the medial canthal attachment. • The radiologist’s report should comment on the degree of comminution of the medial vertical

maxillary buttress, where the medial canthus attaches to the bones of the medial orbital rim.

• Fracture fragments within any facial sinus can act as a nidus for infection.

• A fracture in the posterior table of the frontal sinus increases the risk of CSF leak and intracranial infection.

• If patency cannot be restored the sinus must be surgically sacrificed, to reduce the risk of infection – mucocele.

Axial image of bilateral frontal sinus fractures with extension through both the inner and outer tables of the skull

Orbital Trauma

• Knowledge of the potential injuries to the eye, and their imaging correlates, is essential to making an accurate and rapid radiologic diagnosis of post-traumatic orbital injury.

• In the context of traumatic head injury, the reporting radiologist must specifically search for evidence of orbital trauma.

Coronal bone and soft tissue windows illustrating a comminuted fracture of the right orbital floor, with intraconal emphysema and entrapment of the right inferior rectus muscle

Injuries to the Lens and Intraconal Haemorrhage Blunt trauma to the eye results in deformation of the globe and typically displaces the cornea and anterior sclera posteriorly, with the globe expanding in a compensatory fashion in an equatorial direction.

Asymmetrical globe contour and loss of globe volume indicating left globe rupture, with lens subluxation

Axial image illustrating a right retrobulbar haematoma

Intraorbital Foreign Bodies

• The detection and

localization of intraorbital foreign bodies is an important task for the radiologist.

• CT is sensitive and is usually the first imaging test performed.

Left intraorbital foreign body (glass fragment), which is best appreciated on the 3D

reconstructed image

Image reproduced from: Hooper R, Salemy S, Sze R: Diagnosis of Midface fractures with CT - What the surgeon needs to know. Radiographics 2006; 26: 783-793.

The Manson Classification of NOE

Fractures:

• Type I – A single bone fragment, (with intact tendon insertion).

• Type II – Comminuted bones of the medial orbital rim, but the insertion of the medial canthal tendon is intact.

• Type III – Comminuted bones of the medial orbital rim, with lateral displacement of the medial canthal ligament.

Frontal Sinus Fracture