Orbital fracture repair







Table 67.1

Indications for surgery













Enophthalmos (>2 mm)
Extraocular muscle entrapment with diplopia
Hypoglobus
Oculocardiac reflex
Large floor fracture (>50%)


Table 67.2

Preoperative evaluation



















Exophthalmometry readings
Extraocular muscle movements and primary deviation
Measure globe dystopia
CT scan, axial and coronal views with thin cuts
Check infraorbital nerve sensation
Palpation for bony step off, trismus and signs of zygomaticomaxillary complex fracture (tripod)
Vital signs – heart rate, blood pressure; history of nausea/lightheadedness from oculocardiac reflex
Rule out globe injury; perform dilated fundoscopic exam


Introduction


Bony and soft tissue injury can occur with any trauma to the orbit. The clinical presentation and treatment vary, based on the cause, findings, and symptoms. Fractures comprise the majority of bone injuries. Several types of fractures involve the orbit with blow-out fractures being the most common. Other fractures include zygomaticomaxillary complex (tripod) fractures, Le Fort fractures, and nasoethmoidal fractures. Orbital apex fractures involving the optic canal may result in optic neuropathy with vision loss.


Blow-out fractures occur when an object strikes the orbital entrance. Two theories are postulated: (1) the indirect hydraulic theory in which posterior pressure in the orbit causes a blow-out; and (2) the direct buckling theory in which direct pressure along the inferior orbital rim causes deformation along the floor. Symptoms may include diplopia from entrapment of the inferior rectus muscle, enophthalmos, infraorbital nerve hypesthesia, and hypoglobus. CT imaging with axial and coronal thin cuts is essential for diagnosis, treatment and decision making in fracture repair.


Urgent indications for fracture repair include the “white-eyed” blow out fracture in children where the fracture site incarcerates the rectus muscle causing possible ischemia, and the oculocardiac reflex resulting from muscle entrapment. Other indications vary but most surgeons will repair fractures within 2 weeks if one or more of the following criteria are met: diplopia within 30° of primary gaze associated with a positive forced duction test, clinically significant enophthalmos greater than 2 mm, and a fracture size greater than 50% of the orbital floor. Repair is typically via a transconjunctival approach with complete reduction of the orbital contents from the fracture site and placement of an alloplastic implant.


Tripod fractures can also be associated with orbital floor fractures but with a different mechanism. The zygoma is fractured along the fronto-zygomatic, zygomatic-maxillary, and zygomatic-temporal suture lines with possible soft tissue entrapment.


Our preference for implant choice depends on the location and amount of enophthalmos. For isolated orbital floor fractures, our preferred implants are thin porous polyethylene sheets or nylon foil. For fractures with significant enophthalmos, thicker barrier channel porous polyethylene is used. For combined medial and floor fractures, titanium-coated porous polyethylene is useful to precisely configure the implant to fit the desired shape. The use of bare titanium mesh or absorbable floor implants may increase risk of delayed orbital restriction.


Complications include implant infection, extrusion, hemorrhage into the implant capsule, persistent hypesthesia of the infraorbital nerve, and eyelid malposition. Although excellent anatomic bony correction may be obtained, significant soft tissue injury may still be present. Residual enophthalmos, continued extraocular muscle imbalance, eyelid malposition, and traumatic ptosis all may necessitate additional surgery.




Figures 67.1A and 67.1B


Preoperative examination

Clinically significant orbital blow-out fractures present with enophthalmos and, possibly, hypoglobus, as shown in Figure 67.1A . Photographs of the nine gazes and worm’s eye views should be taken at all clinical encounters. Documentation of any diplopia, ocular motility disturbance, and hypesthesia of the infraorbital nerve should also be recorded. High-resolution CT imaging of the orbit with thin cuts in the axial, coronal, and sagittal planes is essential for preoperative planning. Figure 67.1B , left panel, shows a coronal image with a large orbital flow blow-out fracture (greater than 50%) with significant prolapse of the orbital soft tissues into the maxillary sinus. Figure 67.1B , right panel, is a sagittal CT image of the same patient showing the extent of the fracture from anterior to posterior. The axial images give the least amount of information of the orbital floor but better images of lateral and medial walls of the orbit.




Surgical Technique





Figure 67.2


Intraoperative forced ductions

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May 16, 2019 | Posted by in Reconstructive surgery | Comments Off on Orbital fracture repair
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