Maxillofacial Injuries


Figure 22-1. Sources of bleeding in facial trauma.



SOFT TISSUE INJURIES


Important anatomic regions of the face that must be precisely reapproximated include the vermillion border of the lip, the eyebrow, and the eyelid where even small inaccuracies in repair can become larger deformities later. Defects of up to 25% of the lip or eyelid can be closed primarily with good results. Eyelid lacerations involving the medial third must be closely evaluated to identify the punctum and canaliculus which drains into the nasolacrimal duct to the inferior meatus in the nose. Retrobulbar hematoma is a surgical emergency that must be immediately decompressed to prevent permanent vision loss. Signs include decreasing visual acuity, elevated intraocular pressure (IOP) (>40), pain, tense globe, proptosis, and often a visible hematoma on imaging. Treatment is with immediate lateral canthotomy and cantholysis for decompression (Figs. 22-3 and 22-4).13


The nasal septum and ear pinna must be checked for hematoma which can lead to cartilage necrosis (with subsequent “saddle nose deformity” or “cauliflower ear”) if not evacuated. Following drainage, a bolster should be placed to prevent reaccumulation. Any injury along the course of the facial nerve proximal to the lateral canthus should be suspect for injury to a major branch and repaired primarily (Fig. 22-5).


Injuries to the parotid gland and duct must be identified. To identify ductal injury or continuity defects, the Stenson duct orifice (best found at the papilla adjacent to the maxillary second molar) is visualized while simultaneously “milking” the parotid gland from extraorally in the direction of salivary flow. If the duct is intact, saliva should be visible flowing from the orifice into the mouth. However, lack of salivary flow does not confirm ductal injury, as flow can be minimal in multiple conditions such as dehydration or autoimmune disorders. Comparison to the contralateral or uninjured side can help in differentiating acute injury. Another maneuver that can be diagnostic is cannulating the duct using a lacrimal probe and following the path as far proximally as possible. If the duct has been transected, the probe may be visible within the facial wound. Midductal injuries require proximal and distal segment reanastamosis, usually over a catheter which is left in place for 10 to 14 days. Distal ductal injuries can be left open to the mouth with creation of a neoorifice.14,15 For intraglandular injury, the parotid capsule may be closed and a pressure dressing placed to prevent development of a sialocele (Fig. 22-6).




Figure 22-2. The patient was acutely stabilized by the trauma service (Drs DeMoya and Velmahos). A,B: Bleeding was acutely controlled by packing for the ascending pharyngeal artery, cauterization of the ethmoidal arteries, and immobilization of the midface. C: The laceration was temporarily closed.




Figure 22-3. A,B: At the initial operation, the right globe was found to be ruptured and thus exenterated. The left globe had increased intraocular pressure, was tense and had limited extraocular movements on forced duction so an emergent lateral canthotomy was performed with immediate decompression. The nasolacrimal apparatus was cannulated by the oculoplastics service and noted to be severed.


4 Fractures of the maxilla and mandible differ from other fractures because of the presence of teeth which are the most important landmark for reduction and render fractures as “open.” The goal of treatment is not only reduction, fixation, and immobilization, improved contour, and range of motion, but also restoration of occlusion. Although in the acute or emergent setting the airway should be secured by any means necessary, when planning definitive treatment, the requirement for access to the occlusion will determine whether oral, nasal, or submental intubation is most appropriate. An oral tube can be used if the patient is edentulous or has many missing teeth without a reproducible occlusion. Nasal intubation is generally safe even with significant midface trauma, but is best performed under direct visualization with fiberoptic guidance to prevent inadvertent intracranial injury. When nasal intubation is not possible and the occlusion must be established, submental intubation is a useful alternative. Oral intubation is followed by passing the oral end of the endotracheal tube through an incision in the floor of mouth and submental neck. Postoperatively, the tube is passed back into the mouth and the patient can be extubated. If prolonged assisted ventilation is anticipated, an elective tracheostomy should be considered preoperatively.




Figure 22-4. Lateral canthotomy. A: Canthal tendon anatomy. B: Lateral canthotomy. After clamping the tissue for hemostasis, a horizontal cut is made with scissors through skin, orbicularis oculi, and conjunctiva of the lateral palpebral fissure. This is usually not sufficient to reduce intraocular pressure (IOP). C: Inferior cantholysis. Next, the lower lid is retracted to expose the inferior limb of the canthal tendon which is oriented horizontally. After dissecting it free, the tendon is cut with scissors oriented vertically. Though not usually required, if IOP is still elevated, the superior limb can be dissected free and transected as well.


Related to choice of airway, fractures of the tooth-bearing maxilla and/or mandible require the patient to be on a nonchew diet for 6 weeks. After a 1-week inflammatory phase, a soft callus forms over 2 to 3 weeks. At this point the fracture is stable enough to prevent shortening but it is still susceptible to angular forces. A hard callus then replaces the soft callus and can take up to 3 to 4 months. For this reason, it is generally recommended to limit chewing forces for 6 weeks (in adults) and to avoid additional trauma for 3 months.16 If there are minimal concomitant injuries, most patients are able to maintain nutritional requirements with enteral intake, often with oral supplements. If there are other significant injuries, especially those resulting in altered mental status or prolonged ICU stay, a nasogastric tube or gastrostomy tube may be needed.


MAXILLARY FRACTURES


5 The famous study by Rene Le fort in 1901 is the basis for the current classification system of maxillary fractures (Fig. 22-7).17 Physical examination reveals periorbital ecchymosis and edema, epistaxis, a retruded midface, palatal ecchymosis, malocclusion, numbness in the V2 distribution, mobility of the maxilla at the piriforms, nasofrontal or zygomaticotemporal sutures. Epiphora results if the nasolacrimal duct is obstructed.


Computed tomography (CT) is the imaging modality of choice for midface injuries, especially if the orbit is involved or if an operation is planned. Treatment includes reduction, and usually disimpaction of the maxilla, using the occlusion as a guide when possible, followed by immobilization (either maxillomandibular fixation or rigid fixation to an adjacent stable facial structure) (Fig. 22-8).




Figure 22-5. A,B: The left facial nerve was explored given the location of the laceration (i.e., proximal to the lateral canthus) and a severed branch to the upper lip was anastomosed under microscopic visualization by Dr. Hadlock.


ZYGOMATICOMAXILLARY COMPLEX FRACTURES


The zygoma articulates with the frontal, sphenoid, temporal and maxillary bones, forming a “complex” (Fig. 22-9). It also forms the infraorbital rim and orbital floor. Physical examination shows periorbital ecchymosis and edema, flattening of the cheek, downslanting of the lateral canthus, enophthalmos, or stepoff at the infraorbital rim. Paresthesia of the infraorbital distribution suggests nerve entrapment in the line of fracture. Less common is limitation of mouth opening which occurs if the zygomatic arch is depressed and impinges on the coronoid process of the mandible. Because of the close association with the orbit, a preoperative ophthalmology examination is prudent.18


CT scan is the gold standard in order to best appreciate the degree of rotation and/or depression, as well as to evaluate the orbital floor component. Historically, the Water view radiograph was used, and it is with this image that the well-known and still used Knight and North Classification system was developed.19 This classification system which describes zygomaticomaxillary complex (ZMC) fractures by rotation, depression, and comminution, predicts fracture stability after reduction. With the use of CT scans and rigid fixation, this classification system may not be as relevant. Another classification system developed by Manson in 1990 divides ZMC fractures into low-energy, mid-energy, and high-energy fractures.20




Figure 22-6. A,B: The left parotid duct was cannulated and clear salivary flow identified. A stent was left in place for 21 days.




Figure 22-7. A: Le Fort I fractures are horizontal fractures that span across the piriform rims along the floor of the nose, through the maxillary sinus around to the pterygoid plates posteriorly. Le Fort II fractures are pyramidal in shape and include the nasal bones, infraorbital rims, in addition to the zygomaticomaxillary buttress and pterygoid plates. Le Fort III is a separation of the entire face from the skull base and includes the nasofrontal suture and medial orbit, zygomaticotemporal suture at the lateral orbit around to the pterygoid plates. B,C: Maxillofacial CT of the same patient as above, showing Le Fort I, II, III level fractures and significantly displaced bilateral mandibular body fractures. A CTA and subsequent angiogram showed transection of the bilateral internal maxillary arteries without a target for embolization.


6 Surgical treatment is usually delayed until swelling resolves to better evaluate any cosmetic deformity and to allow easier surgical access if needed. Nondisplaced, stable fractures can be observed. Indications for open treatment include cosmetic deformity, enophthalmos, or diplopia when the orbital floor component is significant, paresthesia of the V2 distribution and limitation of mouth opening from coronoid impingement. If there is enophthalmos, or high likelihood of future enophthalmos secondary to herniation of orbital contents into the maxillary sinus, dystopia, or diplopia that does not resolve once the swelling goes down, the orbital floor will also require reconstruction (see also orbital fractures) (Figs. 22-8 and 22-10).2124


NASO-ORBITAL–ETHMOID FRACTURES


Naso-orbital–ethmoid (NOE), a term coined in 1973, describes a facial subunit that is widely considered to be the most complex of all facial fractures that is uncommonly injured, comprising only 2% to 15% of all facial fractures, and rarely occurs in isolation (usually accompanied by midface or frontal sinus fractures).25 The complex consists of the medial orbital walls, nasal bones, frontal process of the maxilla, nasal process of the frontal bone, and the ethmoid sinuses. Bleeding may be secondary to injury of the anterior or posterior ethmoidal arteries along the medial orbital wall. The clinical examination is most notable for periorbital ecchymosis and edema, subconjunctival hemorrhage, a depressed nasal radix with a wide or flattened dorsum and upturned tip, and telecanthus with increased intercanthal distance to over 35 mm. CSF rhinorrhea may be present if the cribiform plate is involved, as can enophthalmos, depending on the degree of medial orbital volume increase. Epiphora may also be present if there is damage to the lacrimal drainage system. A complete ophthalmologic examination is required to rule out ocular injury.18




Figure 22-8. Same patient after open reduction and internal fixation of the bilateral Le Fort I, II, and III fractures, after repairing the mandible and using the occlusion as a guide to work from bottom-up. A: Intraoperative photos of Le Fort I ORIF. B: Postop CT scan.

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May 5, 2017 | Posted by in GENERAL SURGERY | Comments Off on Maxillofacial Injuries
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