Correction of Orbital Roof Fractures



Correction of Orbital Roof Fractures


Samita Sally Goyal

John N. Jensen





DEFINITION



  • Orbital roof fractures may occur in isolation but more often are a part of a larger pattern of traumatic injury.


  • Classification1:



    • Nondisplaced fractures


    • Isolated blow-in fractures



      • Orbital roof displaced inferiorly into orbit


      • No involvement of supraorbital rim or frontal sinus


      • Due to sudden increased intracranial pressure and shift of the cranium and intracranial contents; usually associated with severe brain injury


      • Leads to decreased volume of orbit and possible displacement of globe


      • Most likely injury type to require surgical intervention


    • Isolated blow-up (blow-out) fractures



      • Orbital roof displaced superiorly into anterior cranial fossa


      • No involvement of supraorbital rim


      • Due to increase in intraorbital pressure, hydraulic force, or shear strain


      • Leads to increased volume of orbit


    • Roof (blow up or blow in) fracture including supraorbital rim


ANATOMY



  • The orbital roof is thin, slightly concave bone that separates orbital contents and the anterior cranial fossa.


  • It may include the lateral extent of the floor of the frontal sinus


  • Consists primarily of the orbital plate of the frontal bone; lesser (posterior) contribution is from the greater and lesser wings of the sphenoid bone (FIG 1)


  • The endocranial surface is characterized by multiple ridges and thin bone that may have a role in fracture patterns.


  • The orbital surface is smooth and thin and includes the lacrimal fossa, a depression in the anterolateral orbital roof that contains the lacrimal gland.


  • The supraorbital rim confers rigidity to the superior orbit.


  • Structures in proximity to the orbital roof include the following:



    • Orbital septum


    • Lacrimal gland


    • Superior rectus muscle


    • Superior oblique muscle


    • Levator palpebrae superioris muscle


    • Supraorbital and supratrochlear nerves


    • Superior division of the oculomotor nerve


    • Globe


PATHOGENESIS



  • Orbital roof fractures make up 1% to 9% of all facial fractures.


  • Likely to have craniofacial, intracranial, ophthalmic, or other bodily injuries (isolated orbital roof fractures in adults are rare)


  • In adults, most commonly seen in men 20 to 40 years of age (89%-93%).2


  • More commonly seen in pediatric patients under 7 years of age3:



    • Children older than 7 years are more likely to sustain orbital floor fractures.


    • Young children have a high cranium:orbit ratio, incompletely pneumatized frontal sinus makes less likely shock absorption than in older children/adults; in high-energy impact situations, energy is more efficiently transmitted through the orbital roof.


  • Most commonly due to high-energy impact injuries to the face


  • Etiology



    • Motor vehicle crash (high energy): higher risk of comminution3


    • Fall: more likely linear pattern3


    • Assault


  • Commonly seen at the junction of middle and medial thirds of orbital roof






    FIG 1 • Submental view of orbital skeletal anatomy demonstrating that the majority of the roof is frontal bone.



  • Concomitant facial fractures2:



    • Frontal sinus (95%)


    • Orbital rims (60%)


    • Naso-orbital-ethmoidal region (33%)


    • Orbital wall fractures (33%)


    • Le Fort fractures (27%)


    • Also associated with fractures of the cribriform plate, lateral orbital wall, squamous portion of the temporal bone, and planum sphenoidale


  • Concomitant soft tissue injuries: 25% of all fractures involving orbit have ocular injuries.4


NATURAL HISTORY



  • In pediatric fractures, orbital roof fractures may develop into growing fractures3:



    • Growing skull fractures—cranial fracture combined with dural tear and brain herniation in a growing brain—can lead to progression of osseous defect with growth.5


    • Frontal and parietal regions more commonly affected


    • More likely to be seen in children less than 3 years of age (period of rapid brain growth)


    • Suspect risk for development into growing fracture if imaging suggests herniation of intracranial contents into orbital region


  • Isolated orbital roof “blow-in” fractures may autoreduce with resolution of cerebral edema if the dura is reasonably intact and apposed to the bone.6


PATIENT HISTORY AND PHYSICAL FINDINGS



  • History



    • Blunt or penetrating facial trauma


    • Diplopia


    • Eye pain


    • Diminished visual acuity


    • Blindness


  • Physical findings



    • Superior orbital rim contour deformity


    • Periorbital or conjunctival ecchymosis and edema


    • Epiphora


    • Hypesthesia/paresthesia of supraorbital and/or supratrochlear nerves






      FIG 2 • Comminuted orbital roof/frontal sinus fracture with rim involvement in a 19-year-old following blunt force trauma (baseball). The patient had a ptotic upper lid secondary to inferior displacement of orbital roof (indicted by leader in (A)). B. 3D CT scan demonstrating the comminuted fracture.


    • Orbital emphysema


    • Soft tissue lacerations


    • Enophthalmos/hyperglobus (blow-out fracture)


    • Exophthalmos/hypoglobus/proptosis (blow-in fracture)


    • Extraocular muscle entrapment or imbalance (superior rectus muscle) with disconjugate gaze


    • Blepharoptosis due to injury to the levator palpebrae


    • Afferent pupillary defect


  • Neurological comorbidity



    • Dural injury with cerebrospinal fluid (CSF) leak (clear rhinorrhea)


    • Intracranial hemorrhage


    • Pneumocephalus (implies dural disruption)


    • Meningitis


    • Brain injury


  • Ophthalmic comorbidity



    • Optic nerve compression or laceration


    • Detached retina


    • Retrobulbar hematoma


    • Globe rupture


    • Ptosis or lagophthalmos


    • Intraorbital foreign bodies


    • Extraocular motor nerve palsies


    • Orbital encephalocele/intrusion


IMAGING



  • Standard of care imaging modality: thin-slice (1 mm) computed tomography (CT) scan1:



    • Axial, coronal, and sagittal views essential to provide complete assessment of degree of displacement and impact on surrounding structure.


    • 3D views not essential, but can be helpful in badly displaced/comminuted fractures, especially if utilizing a limited access approach


    • Advantages: rapid, available, provides ability to assess intracranial content/injury


  • Magnetic resonance imaging (MRI): impractical as it is an insensitive exam of the bone and some foreign objects; contraindicated in situations where metallic foreign objects (bullet fragments) may be present in soft tissues (FIG 2).







FIG 2 (Continued) • C. 3D CT bird’s eye view of the fracture. D. Soft tissue envelope demonstrating the depressed eyebrow associated with the fracture.


NONOPERATIVE MANAGEMENT

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Nov 24, 2019 | Posted by in Craniofacial surgery | Comments Off on Correction of Orbital Roof Fractures

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