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24 Midface Trauma Reconstruction
319
4. Alveolar
The zygomatic bone is considered to have a central malar body and three distinct
processes:
1. Temporal—Zygomatic arch is created by the articulation of this process to the
temporal bone, which is responsible for the maintenance of the anterior projection
of the malar eminence. The arch is also an attachment for the masseter muscle
and the deep temporal fascia. The frontal branch of the facial nerve follows a
course that is intimately associated with the anterior zygomatic arch. The temporomandibular joint and coronoid process are situated deep in the arch.
2. Orbital—Articulates with the orbital plate of the maxilla, forming the oor of
the orbit. It is no surprise that nearly 40% of patient with zygoma fractures
involving the orbital process have concomitant intraocular injury.
3. Maxillary—Inferior-medial articulation with the maxilla and forms part of the
anterolateral wall of the maxillary antrum.
The malar body is the strongest portion of the zygoma. It also forms an important
component of the lateral buttress. Traumatic disruption to the zygomatic complex
and lateral buttress often creates an inferior-medial rotation of the zygomatic bone.
This rotation is theorized to be the result of displacement by the masseter muscle [2].
It is imperative to understand the relationship between the maxilla, mandible,
and skull base, with the knowledge of the facial buttresses (Fig.24.2). There are
four vertical buttresses, which act as supporting pillars for facial form and function.
These buttresses represent the paths of a load of distribution for the powerful vertical forces of mastication. There are three paired buttresses:
1. Nasomaxillary (medial)—extending from the dentoalveolar arch near the canine
region, along the pyriform aperture, and ends at the medial orbital rim and frontomaxillary suture.
2. Zygomaticomaxillary (lateral)—begins from the region of the maxillary rst
molar, running superiorly through the body of the zygoma, and ends at the lateral
wall of the orbit and the frontozygomatic suture.
3. Pterygomaxillary (posterior)—begins at the maxillary tuberosity and extends
through the pyramidal process of the palatine bone, medial plate of the pterygoid
bone, and terminates at the basis of the sphenoid.
4. Additionally, there is a single midline vertical buttress termed the nasoseptum,
which includes the crista galli, vomer, cartilaginous septum, and perpendicular
plate of the ethmoid bone.
The alveolus, hard palate, infraorbital bar, and supraorbital bar make up the three
horizontal buttresses. Of note, the alveolus is dependent upon the patient’s dentition. Edentulousness predisposes the patient to a higher risk of traumatic disruption
due to alveolar atrophy. Upon traumatic events, disruption of the vertical and horizontal buttresses leads to a release of the maxilla from its bony attachments. This
320
Fig. 24.2 Vertical and
Horizontal Buttress of the
midface
D. A. Rengifo et al.
disruption results in a pull of the maxilla in a posterior-inferior direction due to the
forces of the medial and lateral pterygoid muscles, resulting in the commonly seen
anterior open bite deformity.
Several components of the neurovascular supply to the midface are important to
recognize and identify when planning for a safe surgical approach or to understand
a patient’s symptoms. The greater palatine artery and nerve emerge from the junction of the hard and soft palate and supply the mucosal and bone of the hard palate.
Fractures of the orbital oor or anterior aspect of the maxilla may result in paresthesia to the anterior teeth due to injury of the anterior superior alveolar artery. Fractures
of the posterior maxilla may result in molar paresthesia because of injury to the
posterior superior alveolar artery and nerve. Trauma to the orbital oor may result
in infraorbital nerve injury, which can present as numbness and pain in the entire
ipsilateral cheek, ala of the nose, and upper lip.
24 Midface Trauma Reconstruction
321
Classification
Le Fort’s proposed classication system was published in 1901. His ndings subsequently set the qualications for different types of midface fractures, depending on
severity [3].
Three patterns emerged from Le Fort’s studies, termed Le Fort I, Le Fort II, and
Le Fort III fractures (Fig.24.3).
• Le Fort I
– Clinical correlate of a oating maxilla
Horizontal fracture in the anterior maxilla that occurs above the palate and
alveolus and includes the nasal septum.
Results in separation of the palate from the maxilla.
The fracture line passes along the nasal oor, pyriform aperture, canine
fossa, and lateral maxillary wall. Occasionally involves the inferior aspect
of pterygoid plates.
• Le Fort II
– Characterized by a separation of the maxilla, nasal bones, and the nasal sep-
tum from the skull and lateral midface.
Fig. 24.3 Le Fort fracture
patterns
322
D. A. Rengifo et al.
Fracture line follows the frontomaxillary suture, extending through the
infraorbital margin to the zygomatic-alveolar crest.
Fracture line also courses around the maxillary tuberosity into the pterygoid process of the sphenoid bone and travels to the perpendicular plate of
the palatine bone.
• Le Fort III
– Results in craniofacial disjunction.
Characterized by complete separation of the midface from the cranium.
Fracture line follows the medial wall, oor, and the lateral wall of the orbit
between the nasofrontal suture and the zygomatic-frontal suture.
Fracture incorporates the zygomatic arches laterally and the ethmoid, lamina perpendicularis of the palatine bone, and pterygopalatine fossa
medially.
This system is still widely used today, though only a minority of current maxillofacial fractures t exactly with the initially described patterns. Le Fort acknowledged that his three fracture patterns often occurred in combination and often
associated with several unclassied fractures. Thus, common nomenclature includes
pure Le Fort fractures, as well as non-Le Fort fractures, such as palatal parasagittal,
medial maxillary, and anterior maxillary fractures. The prevalence of non-Le Fort
fractures may be due to the high forces that are more often involved in injuries in the
modern world, as motor vehicles and industrial machinery have become commonplace. Le Fort’s classication provides a solid foundation from which to organize a
treatment plan; however, the surgeon must keep in mind that these classications do
not provide a full description of the degree of fracture displacement and
comminution.
There are no standard classication systems for zygomatic complex fractures
because of the impractical and inadequate quality of previously proposed classications. The classication proposed by Jackson, however, is the more clinically relevant system that the authors of this chapter prefer. This classication encompasses
four types of zygomatic fractures: (1) Nondisplaced that requires no surgical treatment, (2) Localized segmental fractures, requiring exposure and direct xation, (3)
Low velocity displaced tripod fractures, requiring simple elevation or direct exposure and rigid xation, (4) High velocity comminuted tripod fractures, requiring
wide surgical exposure and rigid xation at multiple points [4].
Indications andContraindications
Surgical intervention and reconstruction may be necessary if there is a loss of function or obvious deformity. The absolute indication for surgical intervention of the
midface is persistent diplopia and other vision changes that can be conrmed to be
24 Midface Trauma Reconstruction
323
secondary to bony trauma. Secondary indications include malocclusion, trismus,
airway concerns, and cosmetic deformities. Patients with signicant medical comorbidities and high surgical risk can also be offered observation and no treatment,
in the case were major visual changes are not exhibited.
Clinical Assessment
Prior to initiating any operative planning, it is imperative for the surgeon and their
team to ensure surgical safety. This includes assessment of acute airway issues or
other injuries sustained at the same time as facial injuries. It is not unusual for
patients to suffer from traumatic brain injuries secondary to the same mechanism of
injury that caused facial fractures. Secondary medical issues, especially those
requiring long-term anticoagulation or those with a high propensity to cause poor
healing, including tobacco abuse and diabetes, should be evaluated and treated
appropriately.
Diagnosis and clinical assessment of midfacial trauma is mandatory to assure
success in management despite the availability of radiographic studies. Assessment
of neurologic function and cervical spine precede the evaluation of the fractures for
operative intervention.
The examination should include the mechanism of injury, facial analysis to evaluate infraorbital ecchymosis or edema as well as changes in facial height and width,
assessment of cerebrospinal uid rhinorrhea, and evaluation of occlusal status.
Occlusion tends to be dictated by fracture orientation. In the setting of transversestyle fractures of the midface, the clinical exam may reveal a retro-displaced maxilla, premature contact of the molars, and subsequent open bite deformities. Vertical
fractures through the hard palate classically show crossbite on clinical exam. As
part of the examination, palatal mobility should be assessed. This is performed by
grasping the maxilla between the thumb and index nger and rocking the maxilla in
a side-to-side and anterior-posterior direction.
The assessment of zygoma fractures involves the evaluation of malar projection,
lateral canthus position, telecanthus and pseudo-telecanthus, tenderness along the
frontozygomatic suture, trismus, lateral subconjunctival hemorrhage, paresthesia of
midface and lip. Additionally, the elicitation of severe pain or decreased mobility
when asking the patient to move their jaw in the direction away from the suspected
side of trauma may key the surgeon to suspect severe displacement caused by a
zygomaticomaxillary fracture due to impingement of the ipsilateral coronoid
process.
Le Fort fractures of the midface can signicantly affect the natural position of the
patient’s dentition, and therefore, foregoing repair of these fractures will interfere
with mastication. Often, zygomatic fractures are reduced for cosmetic reasons;
324
however, these fractures may cause trismus and difculty chewing due to impingement on the temporalis muscle. Additionally, zygomatic fractures may cause globe
dysfunction and malposition, given the contribution of the zygoma to the bony orbit.
While this chapter does not include orbital reconstruction, ophthalmological
examination is an absolute necessity prior to any operative intervention of the midface. The assessment of both the surgeon and ophthalmology will encompass the
appropriate preoperative evaluation. Visual assessment should include measurement of orbital pressures as well as ruling out ocular and retinal injury by ophthalmology. Extraocular eye movements need to be assessed to dene any concerns for
entrapment and/or nerve injury.
D. A. Rengifo et al.
Preoperative Planning
The appropriate rst step to achieve proper reconstruction consists of an in-depth
evaluation of radiographical studies. 1.5–3mm ne-cut CT scans are the standard
for imaging evaluation of the midface. Imaging should extend from the cranial apex
to the inferior edge of the mandible. This is important both for thorough assessment
of the patient as well as setting up intraoperative navigation at the time of surgery.
Assessment in all three radiographic planes should be performed. Added guidance
can be gleaned from three-dimensional renderings of the CT scans which are
becoming more widely available. These reconstructed CT images are excellent at
examining the zygomatic complex, especially when there are comminuted fractures, which can disorientate when assessed in a single plane. The 3D renderings
fall short when examining the orbit. Because of the thinness of the bone, there are
often gaps in the image that can be mistaken for bone loss or fracture that are
artifacts.
The order of reduction should also be planned during the imaging review. In the
setting of multiple fractures, less distorted fractures should be addressed rst to
facilitate the reduction of the more severe fractures. Bilateral fractures should be
addressed similarly, as the reduction of the less distorted side will facilitate the
reconstruction of the more involved contralateral trauma.
Instrument/Equipment Setup
To have success in midface reconstruction while decreasing the patient’s risk under
general anesthesia, the surgical team must make sure the appropriate instrumentation is available prior to surgery.
The room setup should ideally include the bed rotated 180° from anesthesia and
the patient’s imaging readily available. We have found surgical adjuncts such as the
use of intraoperative endoscopy and navigation useful in many cases. The use of
24 Midface Trauma Reconstruction
325
such instrumentation can require a unique setup as well as signicant space within
the operating room, which needs to be accounted for. Further, the use of intraoperative imaging, including CT scanners, has been invaluable, especially in complex
cases. In many institutions, this modality is in high demand, and therefore, brought
into the operating room when needed during a case. The placement of the OR table
to expedite this process should be considered. Additionally, if preoperative planning
of screws and plates has been performed, these diagrams should be in the room and
available for the surgeon to evaluate during the entire procedure.
Nursing and scrub technicians should have the following available:
• Dilute betadine face prep.
• Local anesthetic.
• Items to protect the eye: lacrilube, corneal shield, erythromycin ophthalmic
ointment.
• Peridex oral solution to adequately clean the oral cavity.
• Maxillo-mandibular xation instruments of surgeon’s choice.
• Trauma midface set that includes the following:
– Oral retractor tray.
– Rowe forceps.
– McKesson bite block.
– Army/Navy retractors.
– Minnesota retractors.
– Periosteal Elevator—(#9 Elevator).
– Right angle retractor.
– Drill and Irrigation—run at 20,000 rpms.
– Carroll-Girard screw (gure of Carroll Girard).
– Midface plates with associated screws.
– Infraorbital instruments, which include Desmarres retractor, Jaeger lid plate
retractor, as well as orbital oor plates.
Surgical Approaches totheMidface
As with any facial trauma, care should be given to establishing and maintaining the
airway. Most midface injuries do not result in malocclusion or require the need for
mandibular-maxillary xation (MMF); therefore, traditional oropharyngeal intubation is adequate. In cases where MMF may be necessary, transnasal intubation may
be required. In these cases, assessment of any skull base injury is crucial. When
airway instability is a major concern, the anesthesia and surgical teams must determine the best course of action. This may include beroptic transnasal intubation,
transcutaneous submental intubation, or tracheostomy.
326
Fig. 24.4 (a) maxillary
vestibular approach. It can
be extended (b) for greater
lateral exposure. It is
important to maintain at
least a centimeter cuff of
mucosa from the gingiva to
assist with closure
b
a
D. A. Rengifo et al.
All patients with midface fractures should receive prophylactic antibiotics since
most of these fractures are considered to be open, and mucosal disruption is either
caused by the injury or the surgical approaches. Often, intravenous steroids can aid
in perioperative edema that is commonly encountered.
Prior to discussing the operative techniques addressing bony reconstruction, the
surgeon must determine the appropriate incisions and approaches to the midface.
When available, existing lacerations often provide the most direct approach to the
bony skeleton.
The maxillary vestibular approach is the most common approach to the midface
(Fig. 24.4). Local anesthetic/vasoconstrictor is injected submucosally, just above
the mucogingival junction, to mitigate bleeding. After adequate time for vasoconstriction, the incision is made along the gingival mucosa, maintaining no more than
a centimeter cuff of the mucosa. This provides enough tissue to close the incision at
the completion of the case but does not limit exposure of inferior maxillary fractures
or the ability to place reconstructive plates. The incision is carried down to the subperiosteal plane. From there, the soft tissue of the cheek is elevated in a subperiosteal plane. As dissection is carried superiorly, identication and protection of the
infra-orbital nerve becomes important. Given that the nerve exists along the vertical
mid-pupillary line, we routinely elevate the malar tissue by creating two pockets.
One, aimed directly towards the most medial aspect of the infra-orbital rim which
exposes the medial buttress. The other is along the most lateral aspect of the rim,
which exposes the lateral buttress. Care is taken during elevation not to slip more
than 1–2mm superior to the rim edge to avoid injury of the globe. Once the elevator
is slightly over the rim, the inferior aspect of the elevator is rotated superiorly, while
the superior edge of the elevator remains xed and acts as a fulcrum on the rim.
When medial and lateral pockets are completely dissected in this fashion, most of
the soft tissue between the pockets is also elevated, and the infraorbital nerve and
foramen will come into view with minimal risk of injury. A right-angle clamp is
24 Midface Trauma Reconstruction
Fig. 24.5 Lateral
blepharoplasty incision.
Placed within a natural
skin rhytid, this incision
can be used to expose the
zygomatic-frontal
suture line
327
then used to dissect the soft tissue sitting just superior to the infraorbital nerve. This
will expose the mid portion of the infraorbital rim and, quite often, any infraorbital
rim fractures. In our hands, this has allowed for assessment and, at times, plating of
this fracture line without the need of a periorbital incision.
The transconjunctival approach is still useful when reduction and xation of the
orbital oor or infraorbital rim are required. This is our preference of surgical
approaches to the region. The details of the approach, as well as other transcutaneous approaches to the orbit, are discussed in detail in the orbital trauma chapter.
The upper blepharoplasty incision (Fig.24.5) is invaluable when assessing and
treating zygomatico-frontal (ZF) fractures. It can also be used to evaluate the
zygomatico- sphenoid (ZS) suture line within the orbit. The incision allows the surgeon to determine If the zygomatic complex has been elevated and rotated back into
place appropriately. If the ZMC complex is under-elevated or under-rotated, an
excess in overall orbital volume will remain, leading to postoperative enophthalmos
and dystopia. These are two of the most common postoperative misalignments
encountered, especially early in a surgeon’s career. The upper blepharoplasty incision heals exceptionally well, so we have utilized this approach ever-increasingly.
Prior to beginning the approach, the cornea can be protected with temporary tarsorrhaphy or corneal shields. The incision is designed in the lateral half of the upper lid
in a curvilinear fashion and can be extended into the natural lateral lid rhytids, also
known as the crow’s foot. After this marking is completed, the planned incision can
be injected with local anesthetic with vasoconstrictor. After adequate time has been
given to local anesthesia with a vasoconstrictor, a 15-blade is used to incise the skin
and subcutaneous tissue in a medial to lateral direction. Once the orbicularis oculi
328
D. A. Rengifo et al.
muscle is exposed, a slit should be made in the lateral aspect to allow the introduction of scissors into the preseptal plane. The dissection continues medially underneath the muscle, and the orbicularis is then divided, which leaves the orbital septum
intact. The musculocutaneous ap is then sharply elevated in a medial-to-lateral
fashion towards the superolateral rim to expose the periosteum. The periosteum is
then sharply divided along the superolateral orbital rim. Periosteal elevators are
used to expose the lateral rim and orbit. This allows for assessment of the ZF suture
line and any fractures in the area. Dissection can then be carried into the orbit in the
subperiosteal plane. As the dissection proceeds deeper into the orbit, the ZS suture
line is exposed.
Indirect approaches to the zygomatic arch include the transoral (Keen) approach,
as well as the temporal (Gillies) approach. These are useful when treating a pure
zygomatic arch fracture without instability of the zygomatic complex. The Gillies
approach begins with a 2-cm temporal incision within the hairline, designed 2.5cm
superior to the arch and anterior to the helix. Sharp dissection continues in the subcutaneous tissue and supercial temporal fascia and terminates at the deep portion
of the deep temporal fascia. The deep temporal fascia is then incised, and a sharp
elevator is introduced deep to the temporalis fascia and moved in the windshield
wiper motion until it sits medial to the zygomatic arch. Dissection under the supercial layer of the deep temporalis fascial avoids injury to the frontal branch of the
facial nerve. An elevator of choice can then be introduced for the reduction of the
fracture. The surgeon should not use the squamous portion of the temporal bone as
a fulcrum.
The Keen approach begins by design of a 2-cm lateral maxillary vestibular incision and the mucosa is incised with electrocautery or a scalpel blade. The elevator
of choice is then introduced and advanced towards the medial aspect of the zygomatic arch fracture that needs reduction. We have found that in the majority of
cases, a Keen approach enables adequate reduction without leaving a scar on the
skin or risking injury to the temporal branch of the facial nerve. In rare cases, the
limited leverage obtained by the keen approach is not enough to reduce the fracture.
In such cases, the Gilles approach may be necessary. In both of these indirect
approaches, palpation will conrm the appropriate reduction. We have found the use
of intraoperative imaging benecial in conrming reduction.
The coronal approach is rarely used in the setting of midface reconstruction
unless there are severe fractures of the zygomatic arch or trauma is in conjunction
with panfacial fractures. In these cases, this approach is used to treat the zygomatic
arch or the ZF suture line via a direct approach. The incision should be designed to
sit several centimeters posterior to the hairline . Care should be given to the regression of the natural hairline with time, which may lead to exposure of a once-hidden
scar. The incision is extended inferiorly, either pre- or postauricular, to expose the
zygomatic arch. Hair preparation and design of incision (zigzag, bow, wave pattern)
should be performed per the surgeon’s preference. Local anesthetic with vasoconstrictor is then injected into the subgaleal plane, and after the appropriate time for
effect is allowed, the initial incision is made with a scalpel or electrocautery. We
routinely utilize bipolar cautery for hemostasis of the skin edge of the coronal ap.