Chap 17.pmd - University of Michigan Kellogg Eye Center

Transcription

220 Surgical Atlas of Orbital Diseases
17
Orbital Fractures
CHAPTER
Alon Kahana, Mark J Lucarelli, Cat N Burkat, Richard K Dortzbach
INTRODUCTION
The surgeon encounters orbital fractures in the acute,
subacute and chronic settings. In each situation, the
treatment goals are similar-restoration of orbital
integrity and volume. However, the nuances of
treatment can vary widely according to the specific
setting and injury. In this chapter, we will attempt
to provide an overview of how we approach orbital
fractures in a variety of settings, and provide enough
reference materials to satisfy the need for additional
study.
as part of La Forte II or III fractures. Fractures
involving the buttresses typically present with larger
displacements. Alternatively, when the buttresses are
intact, trapdoor-type fractures are more common.4
The anatomic landmarks of most fractures
correlate with the bony anatomy (Figure 17.2). Floor
ANATOMY
The adult human orbit has a volume of approximately
30 ml, of which the globe accounts for approximately
7 ml, or about 25%.1 It traditionally is said to be
formed of 7 bones: maxillary, zygomatic, frontal,
lacrimal, ethmoid (lamina papyracea), palatine, and
the sphenoid, although the greater and lesser wings
of the sphenoid develop independently during
embryogenesis [the alisphenoid (greater wing) and
orbitosphenoid (lesser wing) bones].2 The optic canal
is part of the lesser wing of the sphenoid.
Orbital bony strength is dependent on a series
of dense bony buttresses that provide structural
integrity and create a protective frame around the
eye. Anteriorly are the frontomaxillary and
frontozygomatic buttresses. Posteriorly is the
pterygomaxillary buttress (Figure 17.1).3-9 Orbital
fractures can be classified as blow-out fractures (no
rim involvement), and fractures that involve the rim
Figure 17.1: Orbitomaxillary buttresses. Nasomaxillary (medial),
zygomaticomaxillary (lateral). Based on Gruss et al., 1986.
Diagrammatic representation of the maxillary buttresses showing the
two anterior buttresses (medial or nasomaxillary and lateral or
zygomaticomaxillary) and the posterior buttress (pterygomaxillary).
The relationship of these buttresses to the cranial base above, the
mandible below and the correct occlusion is seen
Orbital Fractures 221
fractures often extend up to the infraorbital groove
and/or canal, since the thin bone of the floor abuts
the stronger bone of the canal. Posteriorly, floor
fractures nearly always leave the most posterior
portion intact since it is part of the large and strong
palatine bone. Medially, floor fractures often leave
intact the inferomedial strut, a part of the
frontomaxillary buttress.10, 11 Medial wall fractures
often end at the frontoethmoidal suture line: the
lamina papyracea is very thin, whereas the frontal
bone is thick and supported by the cribriform plate.
Lateral wall fractures often occur as part of a
complex fracture involving the zygomatic arch and
the maxillary bone.
Orbital nerves and vascular bundles can often
be involved in orbital fractures, and serve as
important landmarks (Figure 17.2). Since the
infraorbital nerve often abuts the floor fracture edge,
it is commonly contused by the trauma but rarely
severed. Hence, hypoesthesia in the V2 distribution
of the trigeminal nerve is very common following
orbital trauma, but such numbness typically resolves,
at least partially, several weeks to months after injury
unless surgical repair causes further damage. Just
posterior to where the infraorbital groove and canal
meet, a perforating branch of the infraorbital artery
is often encountered, which can cause significant
bleeding if not isolated and cauterized in the course
of surgical repair.12
The zygomatic bone contains foramina for both
the zygomaticofacial and the zygomaticotemporal
nerves, branches of the V1 division of the trigeminal
nerve. Overall, the area innervated by these nerves
is small, and patients often tolerate hypoesthesia
associated with injury to these nerves, which may
occur from surgery as well as from the initial injury.
Injury to the infratrochlear, posterior ethmoidal
and/or anterior ethmoidal neurovascular bundles are
uncommon, but can be associated with significant
bleeding. Superomedial orbital injury may also be
associated with damage to the trochlea, causing
torsional diplopia.
Orbital fractures can often cause ocular dysmotility. There are several general etiologies in the
acute setting: direct muscle damage and/or edema,
nerve damage, or muscle entrapment. The restriction
caused by muscle entrapment often involves the
orbital fibrous connective tissue complex, of which
the extraocular muscle pulleys and septa are a part.13,14
Hence, herniation and entrapment of orbital
connective tissue that is associated with an
extraocular muscle can often cause a clinical picture
of entrapment even though the muscle itself is not
incarcerated in the fracture. Such findings can often
Figure 17.2: An anterior-posterior view into the right bony orbit
be subtle. So a high index of suspicion is important
(Figures 17.3A and B, and 17.4A to D).
Finally, the optic nerve enters the optic canal near
the apex of the orbit. Blunt trauma can result in optic
nerve injury through several mechanisms: collapse
of the optic canal with crush injury to the nerve, injury
of perforating vessels to the optic nerve, hemorrhage
with compressive optic neuropathy, severing through
avulsion of the nerve, and direct injury to the globe
with transmission of the impact posteriorly (Figures
17.5 and 17.6).
EXAMINATION
A patient with orbital trauma requires a complete
history and ophthalmic examination, including a
dilated fundus examination. Any loss of consciousness should be documented, and the possibility
of an intraocular or intraorbital foreign body must
be addressed. The possibility of an open globe should
be considered in every patient with orbital trauma,
and an open globe must be ruled out prior to any
orbital evaluation and management. Loss of vision,
dysmotility, hyphema, and 360° subconjunctival
hemorrhage are often associated with a ruptured
globe.
When the examination occurs in an intensive care
setting, as is often the case, exact history and a full
examination cannot be obtained. In such a setting,
early evaluation of the pupils, prior to sedation/
analgesia-related miosis, is critical to identifying optic
nerve trauma and a relative afferent pupillary defect
(RAPD). Intraocular pressure should be measured
with a handheld device, such as a Tonopen
(Medtronic Ophthalmics, Minneapolis, MN, USA),
and high intraocular pressure treated aggressively.
In an alert patient with loss of vision and elevated
intraocular pressure, the possibility of a retrobulbar
hemorrhage must be assessed, and when appropriate,
a lateral canthotomy with cantholysis performed
acutely. Particular attention must be given to
patients who are on blood-thinning medications,
such as warfarin, which can make an orbital
hemorrhage both more likely and more severe.
Canthotomy incision is a simple and fairly benign
technique for rapidly reducing vision-threatening
orbital pressure, and the addition of a cantholysis can
further improve the decompression.15 It is not rare
for patients with an orbital compartment syndrome
to report improvement in vision within minutes of a
canthotomy and cantholysis. Evacuation of an orbital
hematoma in the acute setting has been described,
including a minimally invasive technique.16
While extraocular motility cannot be evaluated
in the sedated patient, radiologic suggestion of
entrapment should be further investigated with
forced duction testing at the bedside, which the
sedation facilitates (Figures 17.7A to E). It should be
A
A
B
Figures 17.3A and B: Mild muscle entrapment. Patient is a 45 years
old man who suffered a left blow-out fracture and experienced
diplopia in upgaze. He presented several weeks after his initial trauma
with a CT scan taken shortly after the injury. Examination found mild
restriction of the left eye in upgaze. The CT scan showed left inferior
rectus rounding, consistent with muscle entrapment. He was only
minimally symptomatic in upgaze with no diplopia in primary or
downgaze, and did not require surgical repair
B
C
D
Figures 17.4A to D: Severe entrapment with muscle pinching. Patient is a 19-year-old college student involved in a nightclub alteration, who
attributed his pain to swelling and bruising. One week later, when the swelling subsided, he continued to have pain and nausea with eye
movement, with significant diplopia. Examination revealed right inferior rectus restriction (A and B). CT showed pinching of an entrapped
muscle in a small minimally-displaced floor fracture (C). Urgent exploratory surgery found a dusky IR. After muscle release and fracture repair,
he was instructed to patch his uninjured left eye and use his right eye to read and do homework. Over the next few weeks, motility recovered
to better than 80% of normal, with only minimal diplopia in extreme down and up-gaze (D)
Figures 17.5: Optic canal injury. Patient was a 12 years old involved
in an unhelmeted accident while riding an all terrain vehicle (ATV).
She developed a left relative afferent pupillary defect. Maxiface CT
scan revealed evidence of fractures (arrowhead) through the
sphenoid sinus extending into the left optic canal, with a small air
bubble located at the intracranial opening of the optic canal (arrow).
Figures 17.6: Axial section of CT scan showing small air bubble
(arrow) at the intracranial opening of optic canal. These subtle fracture
findings are a common occurrence in pediatric patients in whom the
bones are malleable
A
B
C
D
E
Figures 17.7A to E: Forced ductions – before (A) and after (B) repair. (A) Forced ductions before repair demonstrating vertical restriction,
(A to C) Forced ductions after floor fracture repair with release of entrapped inferior rectus muscle, demonstrating normal ductions (D and E)
remembered that ductions may also be limited by
orbital edema, so the ductions should be compared
with one another. Often, the pupils cannot be dilated
because of the tenuous neurological state of these
patients in the immediate postinjury period. In these
cases a direct ophthalmoscope may be used to view
the vitreous and disc. A vitreous hemorrhage should
be noted and further investigated for a possible
rhegmatogenous retinal detachment using B-scan
ultrasound. Likewise, the presence of a corneal
abrasion or a hyphema should be assessed and treated.
The evaluation of facial fractures is often
performed by a multi-disciplinary team, and it is
important to communicate effectively with other
members of that team. The orbital evaluation should
include palpation of the rim for any step-offs, and of
the periorbital region for crepitus (Figures 17.8A
and B). If the patient is alert, sensation in the
trigeminal distribution can be assessed. Hypoesthesia
in the distribution of the V2 branch of the trigeminal
suggests an orbital floor fracture, but can also be
associated with nerve contusion and orbital edema.
Hertel exophthalmometry is a useful indicator of the
risk of enophthalmos, and in our experience,
the presence of 1.5 mm or more of enophthalmos
in the acute posttrauma period suggests that
further enophthalmos may develop once swelling is
reduced.
Additional structural and functional consequences of orbital fractures should be carefully
assessed. Attention should be given to integrity and
symmetry of the medial and lateral commissures.
Zygomatic fractures can often cause lateral canthal
dystopia (Figures 17.9A to D), whereas nasoethmoid
A
B
Figures 17.8A and B: Lateral canthal dystopia post-ZMC fracture
repair. Note the right lateral canthal dystopia. Patient had suffered a
motor vehicle accident with right orbital fractures. His zygoma was
reduced to achieve alignment in 2 dimensions (rather than 3
dimensions), with resultant enlargement of the orbital cavity. He
presented to our clinic with enophthalmos and diplopia. Subsequent
surgical repair resolved his enophthalmos and diplopia
A
B
C
D
Figures 17.9A to D: Traumatic telecanthus (A). Patient suffered significant facial trauma following a fall, with severe comminuted nasoethmoid
fractures along with maxillary and zygomatic fractures (B and C). Initial repair did not fully restore the anatomy of the medial canthus and she
was referred for a consultation. Intraoperatively, scar tissue was debulked and miniplate fixation was used to anchor the medial canthal
tendon. Postoperatively, she has medial scleral show, and only 1mm of telecanthus (D)
fractures can often cause telecanthus (Figures 17.10A
and B). Nasoethmoid fractures are also associated
with damage to the nasolacrimal duct, leading to an
increased risk of posttraumatic epiphora.
Often, surgical repair of orbital fractures can be
delayed until a better examination can be performed
and an informed consent can be obtained. In this
setting, useful adjuncts in the evaluation of diplopia
and ocular dysmotility are ocular alignment measurements of heterotropia, and the binocular visual field
(also known as diplopia field) which uses the
Goldmann perimeter to delineate the area of fusion.
IMAGING
Computed tomography (CT) scan without contrast
continues to be the workhorse of orbital fracture
imaging. A study including axial, coronal and sagittal
cuts through the orbit is prefered.9, 17 Displacement
should be noted using the bone-window, whereas
the presence of soft-tissue herniation, including fat
and muscle herniation, should be assessed using the
soft-tissue window. A careful and systematic review
of the orbital bones is necessary in order to avoid
missing a small fracture that may be clinically
relevant. Once a fracture has been identified, the
imaging study is carefully reviewed for other facial
fractures, especially nasal, frontal, zygomatic arch,
and mandibular fractures, as well as any fractures of
the orbital buttresses. The orbital rim, inferomedial
strut, and the bony platforms at the edges of fracture
are assessed. The repair of pan-facial fractures in most
centers is coordinated with the rest of the trauma
team in order to achieve the best possible outcome
for the patient. Of great import is the overall size of
the orbital fractures, as well as the extent of
displacement. We typically recommend surgical
repair for orbital wall fractures that total more than
50% of the size of the orbital floor, since such
fractures, when not repaired, can lead to significant
enophthalmos.18 (Figures 17.11A to C).
Next, the soft-tissue windows should be carefully
examined for herniation of fat and/or extraocular
muscle. However, it is important to emphasize that
muscle entrapment is a clinical diagnosis, not a
radiological diagnosis. The presence of retrobulbar
hemorrhage should be noted, and its size
approximated. The appearance of the extraocular
muscles should be carefully noted for a rounding
effect (which may signify entrapment) or for
enlargement that can be associated with a hematoma
(Figure 17.3). If muscle entrapment is noted clinically
but not supported radiologically, we recommend that
surgical exploration be carefully considered.
A
B
A
B
Figures 17.10A and B: Naso-ethmoid comminuted fracture repair
with miniplates, and fixation of the medial canthal ligament to the
miniplates. A nasal splint with silastic bolsters can facilitate
reconstruction of the medial canthal architecture
C
Figures 17.11A to C: Enophthalmos. Three examples of clinicallyapparent enophthalmos resulting from orbital trauma
IMPLANT MATERIALS
The choice of material for orbital fracture repair is
broad, and includes both autogenous tissues and
alloplastic materials. Each has advantages and
disadvantages.19
Alloplastic implants are easily available, requiring
no harvesting procedure with its associated
morbidity. Several, such as titanium plates and
porous polyethylene, have proven over time to be
strong and effective. 20-24 The disadvantage of
alloplasts is that they do not completely integrate
with the living orbital tissues, which can lead to early
and late complications, including infection, exposure
and/or extrusion. The bacterial load required to
infect an alloplastic implant can be lower by a factor
of 10,000 than for an autogenous graft.25 Implant
exposure can particularly pose a risk for infection. In
addition, because the integration of even the best
alloplastic implants is incomplete, migration and
exposure can occur, both in the early postoperative
period and as a late complication. Finally, when a
complication occurs with an alloplastic implant,
management will often require removal of the
implant, which can be challenging.
Alloplastic materials include porous polyethylene
(e.g. Medpor, Porex Surgical, Newnan, GA, USA),
hydroxyapatite (e.g. Biocoral, Wilmington, DE,
USA), titanium mesh (such as from KLS Martin,
Tuttlinger, Germany; Stryker Craniomaxillofacial,
Portage, MI, USA; Synthes Inc., West Chester, PA,
USA), and nylon (such as Supramid, S. Jackson,
Alexandria, VA).
Titanium is a strong, inert metal. It does not
integrate but can be easily fixated to the surrounding
bones and can provide excellent support for orbital
structures. 23 If bone resorption occurs, it may
infrequently require removal. Overall, titanium mesh
can be an excellent choice for orbital fracture repair
and has a significant track record of safety. 24
However, in our experience, reoperations following
implantation of titanium mesh are more difficult as
fibrous scar tissue insinuates itself into the holes of
the mesh (Figures 17.12A and B). Hence, titanium
mesh is not our first choice in the repair of orbital
floor fractures. In cases of severe obliteration of more
than one of the orbital walls, titanium mesh may be
an excellent choice, owing to its ability to be shaped
A
B
Figures 17.12A and B: Titanium mesh with scarring. Patient is a
young woman who was injured in a motor vehicle accident. She
suffered severe ocular injuries that eventually resulted in an
enucleation. In addition, she underwent floor fracture repair with
titanium mesh. Her implant motility was severely limited and she
developed significant enophthalmos with superior sulcus deformity.
She was referred for an orbital consultation and underwent orbital
volume augmentation. Intraoperatively, her inferior rectus and
surrounding orbital tissues were found to be tightly adherent to the
titanium mesh, with extensive scarring through the holes in the mesh.
These were dissected off to free the orbital tissues from incarceration
in the titanium mesh
and maintain the desired shape. The use of titanium
mini-plates in the stabilization of orbital rim and
buttress fractures is a mainstay of fracture fixation
techniques.
Nylon sheets come in a variety of sizes and are
easy to use.26 Fixation can be achieved with a fibrin
sealant (e.g. Tisseel, Baxter, Deerfield, IL, USA) or a
biological glue (BioGlue, CryoLife, Kennesaw, GA,
USA). However, late complications with nylon sheets
are not uncommon, and in particular, the capsule that
forms around the nylon sheet can spontaneously
hemorrhage.27
Our preferred alloplastic implant material is
porous polyethylene, which is strong, biocompatible
and can integrate well.20, 28-30 Medpor Barrier implants
(Porex Surgical, Newnan, GA, USA), are porous
polyethylene plates that are coated with a thin, nonporous, high density polyethylene barrier that is
heat-bonded to the porous material on one side. This
barrier is positioned toward the orbital tissues to
reduce scarring and attachment of orbital tissues to
the plate.31 The barrier also has the added benefit of
strengthening the sheet. Porous polyethylene
implants can also be easily secured to the rim with
screws if necessary, either using a channel implant
or directly through the porous polyethylene. They
are malleable and can be cut into various sizes and
shapes with a large Metzenbaum scissors. A newer
version of the porous polyethylene implant is the
TITAN implant (Porex surgical), which can hold
curved shapes particularly well. This implant is well
suited for repair of large floor fractures and
reconstructions that involve both the floor and the
medial wall (such as loss of the inferomedial strut)
(Figures 17.13A to D). The titanium mesh embedded
in the porous polyethylene contains holes through
which screws can be placed for improved fixation if
necessary.
Autogenous bone grafts have a proven track
record of reliability, but require a harvesting
procedure unless a cadaveric bone graft is used. Given
recent concerns with infectious agents and prion
diseases, cadaveric bone grafts may be seen as less
desirable to many patients. Fresh bone contains living
osteocytes and integrates well with the surrounding
bones. When cranial bone is used, early integration
is achieved and minimal resorption is observed.32-34
This is most likely the result of the neural crest origin
of calvarial bone, which is shared with orbital bones.
The neural crest-derived craniofacial bones form
through intramembranous ossification, whereas the
mesodermal bones of the ribs and pelvis form
through endochondral ossification.35, 36 Calvarial bone
can be harvested without the need for surgical
preparation of a different body site (Figures 17.14A
to D). In addition, calvarial access can be hidden
behind the hairline, and when a bicoronal approach
is used for orbital fracture repair, the same exposure
can be used for harvesting the graft. A major
disadvantage of calvarial bone grafts is that despite
the overall safety of the harvesting procedure, the
A
C
B
D
Figures 17.13A to D : Medpor TITAN in complex fractures and orbital reconstructions. A: Posterior large medial wall fracture and Medpor TITAN
implant prior to placement. The implant was cut to size, incorporating a notch for the inferior oblique. It was then bent and placed into position.
A=anterior. P=posterior. S=superior. B: Even a large Medpor TITAN implant can be bent and will hold its shape. This patient underwent orbital
reconstruction following excision of sino-orbital squamous cell carcinoma that involved the inferomedial orbital bones. Fixation was achieved
with glutaraldehyde-crosslinked albumin adhesive (BioGlue, Cryolife Inc)
A
B
C
D
Figure 17.14A to D: Calvarial bone grafts. After exposure of the skull, a partial thickness calvarial graft is harvested.
Next, it is used to repair an orbital floor fracture
inner table can be penetrated, and bleeding and brain
damage can occur.37-39 Particular care must be taken
to avoid harvesting within 2 cm of midline in order
to prevent injury to the sagittal sinus.40 Patients will
often feel a depression at the donor site, which must
be explained preoperatively. At our institution, we
rarely use calvarial bone grafts, and when we do, it
is in the context of extensive craniofacial reconstruction performed by a team that includes
craniofacial and neurological surgeons.
Iliac crest and rib bone grafts are commonly by
plastic surgeons. They offer a large supply of easily
accessible cortical bone. Ribs are malleable, which
can be both an advantage and a disadvantage. Iliac
bone is hard and can be difficult to contour but can
be used successfully.41 Donor site morbidity, in the
form of bleeding, pain, and gait disturbance, can be
significant. Both types of bone are of mesodermal
origins, and ossify through an endochondral process.
Their harvest into the neural crest-derived facial
skeleton can result in delayed integration and
significant resorption. We rarely use rib or iliac crest
bone grafts, which are more commonly considered
in facial reconstruction following craniofacial tumor
resection, and is beyond the scope of this chapter.
The interested reader is encouraged to refer to the
excellent reviews and textbooks that focus on this
subject (e.g. Holck and Ng, 200642).
GENERAL OPERATIVE
CONSIDERATIONS
In evaluating orbital fractures, several issues should
be addressed. These include any indications for
fracture repair (such as fracture size and diplopia
with entrapment), the timing of fracture repair,
managing patient expectations, working with multiple
surgical services, risk of infection and antibiotic
coverage, orbital edema and the use of steroids,
concomitant management of soft tissue injuries, the
use of blood thinning products, and elective versus
urgent repair. Patients should be advised to avoid
blowing their nose,43 and prescribed nasal saline spray
2-4 times daily. Patients are instructed to keep their
head elevated, and to use ice-cold compresses for 23 days. Any blood thinning medications, especially
aspirin, clopidogrel (Plavix, Bristol-Myers Squibb) or
warfarin, should be discontinued in co-ordination
with the prescribing internist. Other blood thinning
products include non-steroidal anti-inflammatory
drugs, vitamin E, garlic, ginseng, and ginkgo
biloba.44,45 With patients on warfarin, the prothrombin
time should be checked in the early preoperative
period. Since an orbital hemorrhage can have
catastrophic effects on vision, care must be taken in
operating on anticoagulated patients.
Antibiotics
Orbital cellulitis is a serious but uncommon
complication of orbital fractures.46 Practice patterns
vary widely regarding the use of antibiotics in the
context of orbital fractures. Multiple published studies
have shown that postoperative antibiotics do not alter
the rate of infection associated with orbital fractures,
although good studies have not been performed.22,47,48
A randomized trial with 181 patients who underwent
open reduction and fixation of mandibular fractures
also showed no advantage to postoperative
antibiotics.49 Risk factors for orbital infection in the
context of orbital fractures include open fractures,
sinusitis, and contaminated wounds. 46 In these
situations, we always give preoperative antibiotics,
since preoperative administration of antibiotics
has been shown to provide improved prophylaxis.50
In addition, in cases of frank wound contamination,
we carefully treat the wounds with 5% Betadine
solution and irrigate the wound intraoperatively
with bacitracin solution. Our antibiotics of choice are
Cefazolin, Ampicillin-Sulbactam (Unasyn, Pfizer,
NY, USA) or Clindamycin, with the latter two
providing improved coverage of anaerobic microorganisms.
The risk of antibiotic overuse cannot be overemphasized. The human body is continuously
colonized by bacteria that exist in steady-state
equilibrium in the context of the normal flora.
Treatment with antibiotics alters the equilibrium,
which can potentially lead to the proliferation of
antimicrobial-resistant pathogenic organisms. Hence,
overuse of antibiotics can cause an infection with
resistant bacteria. We usually limit antibiotic usage
to the preoperative setting, with administration prior
to surgical incision in order to achieve significant
tissue concentration at the surgical site intraoperatively. Postoperative antibiotics are given only
if there are active signs of infection or if systemic
steroids are prescribed in the context of a higher risk
of infection (as discussed below).
Steroids
Glucocorticoids can be extremely useful in the
perioperative management of orbital fractures.51-53
However, their use can lead to complications,
especially an increased risk of infection. Hence, any
steroid administration is done using a very rapid
taper regimen.
The most useful contexts of steroid usage are in
the preoperative assessment of extraocular muscle
function and in the prophylaxis of postoperative
emesis (which can cause implant movement and
bacterial spread). In the preoperative setting, it is
sometimes difficult to distinguish between extraocular muscle contusion or edema and frank muscle
entrapment. This distinction is important to make
since it can strongly influence the decision to
recommend surgical exploration repair. Therefore,
when there is significant dysmotility associated with
moderate to severe orbital edema, a small orbital
fracture and no obvious entrapment radiologically,
we document the dysmotility with a binocular visual
field (also known as a diplopia field, performed with
both eyes open on a Goldmann Perimeter), and
prescribe a rapid taper of Prednisone or
Methylprednisolone over the course of 5-7 days. A
typical Prednisone taper for an adult would be 40,
30, 20, 10, and 5 mg over the course of 5 days. We
re-evaluate motility toward the end of the treatment
course (in 5-7 days) and reassess the need for surgical
intervention. In numerous cases, these exams will
reveal significantly improved motility and near
resolution of diplopia, avoiding the need for surgical
exploration of a fracture that was otherwise too small
to warrant surgical repair.
Another context for prescribing a steroid taper
is in children, who tend to swell more and scar faster.
We try to operate on children earlier (within 1 week
and in cases of severe restriction, even sooner). A-5
day steroid taper can help control posttraumatic
edema and facilitate early and safe surgery.
Intraoperative IV steroids can be very useful in
two respects: control of nausea, and expedited
resolution of postoperative edema and discomfort.
In an adult, 8-10 mg of Dexamethasone are often
given by the anesthesiologist toward the end of
surgery. Intraoperative steroid irrigation of the orbit
is performed rarely, and usually in the context of
late repair of a scarred musculoseptal system.
Infrequently, a postoperative steroid taper is
prescribed if severe edema is anticipated (e.g. late
repair of severely scarred orbit), or if edema would
interfere with the postoperative evaluation and
patient management (e.g. with extraocular motility
evaluation). However, there are no good studies to
direct perioperative steroid use, and the potential
side effects must be fully considered.
Pediatric patients
Special attention must be given to nondisplaced
fractures and floor fractures in pediatric patients
since muscle entrapment with frank muscle pinching
may occur.54 Steroids will not only fail to resolve the
dysmotility, but will also delay needed surgical
intervention, which can lead to irreversible muscle
injury. Such fractures have been termed "greenstick"
fractures, and are the result of the fact that the facial
bones of children have a higher cancellous
composition and thinner cortices, resulting in
increased bone flexibility.55-58
At times, orbital floor fractures result in minimal
soft tissue injury, no orbital edema and no
enophthalmos but severe dysmotility with entrapment, pain, and nausea. CT scanning may only
demonstrate minimal tissue herniation and fracture
displacement. This presentation has been termed
"white eye syndrome."54, 59 Clinical signs of muscle
pinching and entrapment include restriction in
upgaze, severe pain worsened by upgaze, and
oculocardiac reflex induced by upgaze, which can
include nausea, vomiting, bradycardia and/or
syncope.58, 60, 61 Timely management of fractures with
muscle pinching is essential in order to reduce the
risk of irreversible muscle damage and strabismus,
both in the pediatric and adult population. In patients
with White Eye Syndrome, surgical exploration and
repair must be carried out urgently. The examination
of a child who is in pain and distressed following
orbital trauma can be quite challenging, and the
surgeon must maintain a high level of suspicion,
especially when the eye and orbit appear normal but
there may be a motility disturbance.
Timing of surgery
The ideal timing of surgical exploration and repair
depends on the clinical findings, the overall medical
condition of the patient, the radiographic evidence
and any concomitant injuries. Delayed repair has the
advantages of reduced swelling, a more thorough
preoperative evaluation, and an increased opportunity to establish a meaningful patient-doctor
relationship prior to any surgery. Early repair has
the advantage of reduced fibrosis and scarring. In
general, we prefer to repair orbital fractures within
2 weeks of injury once the majority of post-traumatic
edema has resolved.18, 60
There are several exceptions to this “2 week”
guideline whereby early or late intervention would
be preferred. First, if the patient's overall medical
condition is unstable, then medical stabilization must
take precedence. Second, if entrapment with muscle
pinching is encountered (often in children as part of
a White Eye Syndrome), urgent repair is advisable
in order to reduce the risk of irreversible muscle
damage. Third, when the optic nerve may be
compromised, the status of the optic nerve should
be properly investigated prior to any orbital surgery.
Otherwise, surgery may further compromise the
already-traumatized nerve, or the patient may
perceive the surgery as the cause of any optic nerve
damage. The status of the globe and the possibility
of a retinal detachment must also be fully
addressed prior to any orbital fracture surgery.
Finally, if other surgical interventions are planned,
coordinating care can be an overall advantage to the
patient by minimizing multiple inductions of
anesthesia.
Another softer exception to the 2-week rule is
the pediatric population. Children swell more, but
their edema resolves faster. They heal and scar faster,
and are more prone to greenstick fractures and
muscle pinching. Hence, expedited repair is often
recommended for children.
Decision: repair or not repair?
Surgical repair of orbital fractures is a very safe
procedure when done appropriately. Nevertheless,
surgery can cause complication.62, 63 The decision of
whether to repair an orbital fracture is complex, and
must rely on the individual circumstances as well as
on the experience of the surgeon. However, several
guidelines have been published that can be of great
help in making a recommendation regarding surgical
repair. These guidelines address the risk of posttraumatic enophthalmos, 64 ocular dysmotility,
diplopia, and facial deformity.
Fracture size correlates well with the risk of posttraumatic enophthalmos.18, 65 Hence, radiographic
assessment of fracture size can be a critical part of
the decision tree. There are several methods that have
been advocated in the evaluation of post-traumatic
enlargement of orbital volume. When the zygoma is
not involved, it is simplest to assess whether the sum
of orbital floor and medial wall fractures constitutes
half of the floor or more. This algorithm is simple to
execute but does not take into account any lateral
wall/ZMC fractures. 65 Another method requires
measurement of the added volume caused by the
fracture. This is determined by comparing the
fractured orbit with the non-traumatized orbit.66-68
For example, using one algorithm, measurements that
reveal greater than 13% orbital volume enhancement
would lead to a recommendation for surgical repair.67
The weakness of this algorithm is that many patients
sustain injury to both orbits, which precludes useful
comparison.
Zygoma fractures can seriously complicate any
volumetric assessment, since floor fractures are often
present but get reduced once the ZMC fracture is
reduced. 65 Nevertheless, the rotation and/or
displacement of a fractured zygoma can lead to
severe orbital volume changes, and incomplete
reduction of ZMC fractures can be a common cause
for postoperative enophthalmos. ZMC reduction
requires special care since without three point
fixation, reduction may be incomplete although the
fracture may appear well aligned along the orbital
rim. Rotation and orbital volume expansion can still
occur and can often be hard to detect. Hence, threepoint reduction of ZMC fractures with proper
fixation should be the goal of these surgical
repairs.65,69,70
Ocular dysmotility and diplopia are debilitating
consequences of orbital trauma. Ocular dysmotility
can occur for several reasons, and it is the task of the
surgeon to distinguish between the etiologies in
order to make the appropriate recommendation.
Posttraumatic extraocular muscle dysfunction can
occur as a result of muscle contusion, hematoma,
fibrosis or avulsion, muscle entrapment with or
without pinching, cranial nerve injury and muscle
paresis, generalized orbital swelling, or contracture
of the antagonist muscle. Muscle fibrosis or
contractures are later complications that must be
prevented by proper management. However, at
times it can be very challenging to distinguish
between ocular dysmotility with or without
entrapment. Limitation in up-gaze with associated
pain and nausea can be telltale signs of muscle
entrapment. In addition, CT scans can be particularly
helpful in this task. Rounding of an extraocular muscle
is often associated with entrapment. The radiologist
and surgeon must be particularly cognizant of orbital
tissue herniation without frank muscle herniation:
the herniated tissues may cause entrapment by virtue
of their numerous fibrous attachments to a muscle.
Such a fracture should be repaired.
Some surgeons advocate exploration and repair
of orbital floor fractures for non-resolving infraorbital hypoesthesia. However, a meta-analysis of
the literature found little evidence to support
such a recommendation since the reported
surgical outcomes were poor. However, if infraorbital pain is worsening, exploration is probably
warranted.71-73
The decision to operate is complex and must be
individualized. Our preference is to operate within
2 weeks of injury except in children, in which case
surgical repair would preferably take place within a
week. In cases with pinched muscles, urgent repair
within 1-3 days of injury would be advocated. When
orbital edema makes the evaluation difficult, a steroid
taper can be very helpful. When the examination is
inconclusive, a re-examination is warranted and can
be critical to making the proper diagnosis and
surgical plan.
Irrespective of the type and location of the
fractures, the goals of surgery are fundamentally
similar: repositioning of herniated orbital tissues,
reconstructing the orbital bony support, and restoring
normal orbital volume and structure.
FLOOR FRACTURES
Orbital floor fractures are common, and result from
blunt orbital trauma in which force is delivered to
the thin bones of the orbital floor, typically along
the infraorbital canal. Often, an orbital floor fracture
will not involve the orbital rim, which is much thicker
and stronger. In such an instance, the term "blowout fracture" is often applied. The term was first used
by Smith and Regan in 1956 to describe orbital
fractures caused by striking the orbital rim with a
hurling ball.74-76
The orbital floor is the shortest of the walls. It
consists of the roof of the maxillary sinus with a small
contribution posteriorly from the palatine bone, and
contains the infraorbital groove and canal. The edge
of the canal forms a weak spot in the floor structure.
Hence, most floor fractures extend up to the canal,
but the canal is often left mostly intact.
Concomitant displaced zygomatic fractures
should be repaired first, since reduction and fixation
of the ZMC fracture will often reduce the floor
fracture as well.65 Floor fractures are often associated
with medial wall fractures. When making the
decision to proceed with or forgo surgery, the total
wall area involved by the fracture, including the floor
and medial wall, must be taken into account and
addressed.
The evaluation of a suspected floor fracture often
requires CT scanning with coronal sections, which
facilitates the assessment of bone displacement and
extraocular muscle findings. It must be emphasized
again that muscle entrapment is a clinical diagnosis,
which should be supported by the radiologic
evidence but need not be.
Extraocular muscle entrapment in the context of
orbital floor fractures is not uncommon.(Figure 17.4)
However, the finding of muscle entrapment can be
subtle, and a high level of suspicion must be
maintained (Figure 17.3). Tissue herniation is very
common in the context of orbital floor blow-out
fractures. All orbital tissues must be retrieved and
repositioned into the orbit at the time of repair;
otherwise, tissue incarceration can lead to necrosis
and permanent muscle dysfunction.
Our favored approach to the inferior orbit is
through a transconjunctival approach.77-80 We usually
avoid the lateral canthotomy and inferior cantholysis,
but at times, when better exposure is required for a
larger fracture, a tighter orbit, or more extensive
herniation, the canthotomy and cantholysis can
greatly aid in obtaining adequate exposure. Care must
be taken to perform the exposure correctly to avoid
postoperative complications.81 The inferior fornix and
lateral canthus are infiltrated with 2-3 ml of local
anesthetic containing 1% Lidocaine, 0.25%
Bupivicaine, and 1:100,000 dilution of epinephrine.
The patient's face and any wounds are carefully
prepped with 5% Betadine solution, and sterile
drapes are placed. We routinely place a lubricated
plastic corneal protective shield on the globe.
First, forced ductions are performed to assess
for muscle entrapment (Figure 17.7). Next, the
assistant retracts the lower eyelid down with a
Desmarres retractor. The surgeon uses a malleable
retractor to sweep the orbital fat posteriorly and
drape the conjunctiva and lower lid retractors over
the inferior orbital rim (Figure 17.15A). The surgeon
then uses a monopolar electrocautery device with a
microdissection needle (such as the Colorado needle,
Colorado biomedical, Evergreen, CO, USA) to cut
through conjunctiva, lid retractors and orbital rim
periosteum to reveal the bony rim. The incision is
made inferiorly in the fornix (at least half way
between the inferior edge of the tarsus and the
deepest part of the fornix) to help minimize cicatricial
changes (retraction or entropion) of the eyelid
margin (Figure 17.15B). We then use a Freer elevator
to lift the periorbita off of the orbital floor. Our
dissection is guided by the CT findings: the initial
sub-periosteal dissection is performed away from the
fracture and then brought to the fracture site. The
fracture edges are carefully defined and visualized.
A malleable retractor is used to gently retract the
globe superiorly while the herniated orbital contents
are lifted back into the orbit using a Freer elevator.
Often, the herniated tissues need to be bluntly
separated from any early scars that form at the edge
of the fracture and in the maxillary sinus; this must
be done slowly and carefully, taking care to avoid
injury to the infraorbital neurovascular bundle and
the perforating artery. The maxillary sinus is typically
well visualized through the fracture (Figure 17.15C).
When the sinus is full of blood, we typically evacuate
the blood using suction, which also improves
visibility.
Once the herniated tissue is released, a Teflon
sizer (DuPont, Wilmington, DE, USA) is used to assess
the size of the needed implant (Figures 17.15D and
E). In the absence of a sizer, aluminum foil from a
suture packing, sterilized X-ray film, or any other
similar strong and sterile material can be used.
Adequate overlap with the fracture edges must be
confirmed. Particular attention must be given to
avoidance of orbital tissue incarceration between the
implant and the fracture's bony ledges.
The implant is soaked in an antibiotic solution
(e.g. bacitracin solution), and cut to size with the
appropriate scissors (Figure 17.15F). It is then molded
into the proper curvature. It is slipped carefully into
the orbit to cover the fracture (Figures 17.15G to I).
If a porous polyethylene implant with high density
"barrier" surface is used, the barrier side is oriented
toward the orbital soft tissue and the porous surface
turned toward the maxillary sinus. Care must be
taken to avoid an implant that is too long which might
cause damage to the orbital apex. The support of the
implant by the bony ledges is confirmed, and any
tissue incarceration is reduced. The end point should
be a stable implant that can slide 1 mm with gentle
force but is otherwise immobile. When implant
stability is in question, the implant should be rigidly
fixated to the bony rim with a titanium microscrew.
Figure 17.15A: The lower lid is retracted and the rim palpated. A
malleable retractor is used to protect the globe, expose the rim, and
keep the fat pads pushed posteriorly
Figure 17.15B: The monopolar unit with a micro-dissection needle is
used to incise conjunctiva, eyelid retractors and orbital rim periosteum
deep in the inferior fornix
Figure 17.15C: After elevation of the periorbita with a freer elevator,
the orbital floor fracture is exposed. A combination of the freer elevator
and thin retractors is used to retrieve any prolapsing orbital contents
from the maxillary sinus
Figure 17.15D: The position, dimensions and posterior-most aspect
of the floor fracture are measured with the help of a probe
Figure 17.15F: Once the correct sizer is identified, the Medpor
implant is cut to size
Figure 17.15E: A Teflon sizer is used to assess
coverage of the fracture
G
H
I
Figures 17.15G to I: The implant is placed on top of the fracture. Care must be taken not to incarcerate any
orbital tissues between the implant and the orbital floor
MEDIAL WALL FRACTURES
Figure 17.15J: Once the implant is stable, the eyelid retractors are
reapproximated using buried interrupted sutures
A screw can be placed right through the Medpor
Barrier implant or through the TITAN MTB implant.
Some surgeons favor surgical glue for fixating the
implant temporarily. The Desmarres retractor is then
removed, and the eyelid retractors sutured with
buried, interrupted 7-0 polyglactin (Vicryl) suture
using 3-point fixation (Figure 17.15H). The
conjunctiva is left unsutured.
When no bony ledge is present to support the
fracture, cantilevering of the TITAN implant or a
Medpor Channel plate over the rim can provide rigid
fixation. Some surgeons favor titanium mesh in this
situation.
Other methods of fixation include the use of fibrin
sealant (such as Tisseel, Baxter, Deerfield, IL, USA)
and biological glue. BioGlue (CryoLife, Kennesaw,
GA, USA) is a two-component glue, containing
engineered bovine albumin in one tube and a
glutaraldehyde solution in the other. When the two
substances mix, the glutaraldehyde cross-links
albumin molecules to each other and to the
surrounding proteins. Glutaraldehyde cross-linking
resembles a peptide bond, and hence can easily form
covalent bonds among proteins in contact with the
chemical. When a porous implant is used, the albumin
infiltrates through the pores as it gets cross-linked,
resulting in strong biocompatible chemical bonding
of the implant to the surrounding tissues. The use of
biological glues and sealants is particularly useful
when implant stability is in question, yet the surgical
exposure is inadequate for complete rigid fixation
(often because the globe should only be retracted
gently and carefully).
Medial wall blowout fractures are common but
historically were under-diagnosed because they can
be asymptomatic in the acute post-traumatic
phase.4, 65 The nearly ubiquitous use of CT scanning
in the United States in the evaluation of facial fractures
has made the diagnosis of medial fractures much
easier. 82 However, when CT is unavailable, the
evaluating physician must maintain a high level of
suspicion. Epistaxis can be associated with medial
wall fractures because of tears in the sinus mucosa.
The epistaxis is typically self-limited. Visionthreatening orbital hemorrhage can occur if the
anterior or posterior ethmoidal vessels are injured.
It is important to remind patients to avoid blowing
their nose, since this can lead to orbital emphysema
and a compartment syndrome (Figures 17.16A and
B).43, 83
The thin lamina papyracea constitutes most of
the medial wall of the orbit, behind the posterior
lacrimal crest. The medial orbital wall is completed
posteriorly by the lesser wing of the sphenoid, and
anteriorly by the lacrimal bone. Both the sphenoid
and the lacrimal bones are thicker. Hence, medial
wall fractures occur because of the weakness of the
thin lamina papyracea, and are typically localized at
the boundary between the lamina papyracea and one
of the thicker bones. Medial wall fractures commonly
occur in the context of orbital floor blowout fractures,
but can also occur in isolation.4, 26 They can also be
associated with nasal fractures, which can lead to
A
B
Figures 17.16A and B: Orbital/periorbital emphysema. Monocular
patient was assaulted with a blow to the left orbit. He presented to
the emergency department after blowing his nose, leading to severe
pain and reduced vision. In the ER, his intraocular pressure was
measured at 60 mm Hg. Emergent lateral canthotomy and inferior
cantholysis were performed, resulting in decompression of the orbit,
restoration of vision and rapid decline in intraocular pressure to the
teens. A CT scan following the cantholysis revealed air in the orbit.
His lateral canthus was repaired 4 days later
telecanthus and possible damage to the nasolacrimal
drainage apparatus.84, 85
Described approaches to the medial wall fracture
include a Lynch incision in the medial canthus, a
bicoronal incision, a medial upper lid crease incision,
or a transconjunctival incision. However, our
preferred approach is the transcaruncular incision.8688
When the medial wall fracture is large, or associated
with a floor fracture, multiple incisions may be
necessary, such as a secondary lower lid fornix
incision.26, 89
The transcaruncular approach requires meticulous
hemostasis in order to properly expose and visualize
the fracture,. Pinpoint cautery with a micro-dissection
needle (e.g. Colorado needle, Colorado Biomedical,
Evergreen, CO, USA) is very helpful, as is the use of
thrombin solution, absorbable gelatin sponge
(Gelfoam, Pfizer), FloSeal (a combination of gelatin
foam and thrombin, Baxter) or 3% hydrogen peroxide
solution. Care must be taken with hydrogen
peroxide, since it can inhibit tissue healing, and its
use has been associated with air embolization.90-92
Good lighting is also important, and a head-mounted
light source is nearly always used in our cases.
Prior to initiating surgical repair, forced ductions
are performed to assess for muscle entrapment
Figure 17.17A: Transcaruncular exposure of the left medial wall
following disinsertion of the inferior oblique muscle
(Figure 17.7). The transcaruncular approach begins
with infiltration of the medial fornix with local
anesthetic containing 1:100,000 dilution of epinephrine. An incision is made through the caruncle
anterior to the plica semilunaris using Westcott
scissors.86, 87 The incision is extended superiorly and
inferiorly along the conjunctival fornices in order to
create sufficient exposure and prevent uncontrolled
tearing of the conjunctiva intraoperatively. A
sufficient distance away from the canaliculi is
maintained. Curved Stevens tenotomy scissors are
then used to bluntly dissect along Horner's muscle,
which inserts on the posterior lacrimal crest. Care
must be taken not to iatrogenically fracture the lamina
papyracea just posterior to the crest, since this will
make subsequent elevation of the periorbita more
challenging. Once the posterior crest is exposed, the
periorbita is incised with a monopolar unit and a
microdissection needle. Achieving excellent
hemostasis is critical at this point. Next, a Freer
elevator is used to lift the periorbita anteriorly in
order to fully expose the posterior lacrimal crest. The
periorbita is then lifted posteriorly to create a subperiosteal dissection plane along the lamina
papyracea (Figures 17.17A and B). The anterior
ethmoidal neurovascular bundle is typically found
approximately 24 mm posterior to the posterior
lacrimal crest, along the fronto-ethmoidal suture line.
This neurovascular bundle is carefully and thoroughly
cauterized with a bipolar cautery unit, and then
divided with the monopolar unit. The subperiosteal
dissection is then completed to fully expose the
fracture.
Figure 17.17B: Inferior oblique isolation. The IO muscle may be tagged
with 6-0 polyglactin sutures and the origin disinserted to provide good
exposure
If the fracture is very posterior, the posterior
ethmoidal bundle may be encountered. In such cases,
the posterior ethmoidal bundle should be carefully
cauterized with the bipolar cautery to avoid intraor postoperative hemorrhaging. The posterior
bundle is typically found approximately 12 mm from
the anterior bundle, and on average only 6 mm from
the optic canal.
After adequate hemostasis and exposure are
achieved, herniated orbital tissues are retrieved and
repositioned into the orbit. The fracture size is
measured, and implant properly sized. We have
found Teflon implant sizers to be very useful at this
step. The implant is then placed over the fracture,
ensuring that no orbital tissues are left incarcerated.
When using a Medpor Barrier plate, the barrier side
should be turned toward the orbit to reduce the risk
of tissue scarring to the implant.
If the fracture extends inferiorly to involve the
orbital floor, an inferior fornix transconjunctival
incision can be made to increase exposure. At times,
the inferior oblique muscle must be disinserted from
its origin. At the end of the case, the oblique is then
reapproximated to its origin with 6-0 polyglactin
suture. The floor and medial wall fractures can be
repaired with a single implant. For this, the Medpor
TITAN Barrier implant is ideal, since it can be molded
into the required semi-cylindrical shape and will
maintain this shape. Such a large implant is better
placed through the inferior fornix incision, and then
the positioning adjusted through the caruncular
incision. Some surgeons advocate multiple implants
that can overlap, using very thin implants.26
Closing the transcaruncular incision involves
placing one to three buried interrupted 6-0 fastabsorbing plain gut sutures to close the caruncular
conjunctiva.
Medial wall fractures are particularly challenging
to repair when they are part of a comminuted nasoethmoid fracture.93 In these circumstances, posttraumatic telecanthus is common, and can be quite
disfiguring (Figure 17.9). Repair of the fractured
posterior lacrimal crest and stabilization of the medial
canthal tendon should be attempted during primary
repair. Good exposure is critical, and when the nasoethmoid fractures are part of panfacial trauma,
a bicoronal approach has many merits.94 Transnasal
wiring has been described for the repair of post-
traumatic telecanthus,93, 95 and may be necessary in
combination with miniplate fixation when repairing
severely comminuted naso-ethmoid fractures.
However, whenever possible, we favor miniplate
fixation of the comminuted bones and the medial
canthal tendon (Figures 17.10A and B).96
LATERAL WALL AND
ZYGOMATICO MAXILLARY
FRACTURES
Fractures of the lateral wall of the orbit are common,
and typically result from direct blunt trauma to the
zygoma and lateral orbital rim. The zygoma
articulates with the sphenoid, maxillary, frontal and
temporal bones. Therefore, fractures of the zygoma
can often disrupt the architecture of the entire region,
and hence are often referred to as zygomaticomalar
complex fractures (ZMC fractures). Importantly, the
orbital floor is always fractured in the context of a
displaced zygomatic fracture, but will typically reduce
once the zygoma fracture is reduced.65
Numerous surgical approaches to the ZMC
fracture have been described for open reduction,
including transconjunctival,78, 97-99 intraoral,100 temporal
(Gillies), brow incision and bicoronal flap. In
addition, some surgeons advocate closed reduction
or observation for non-comminuted and uncomplicated zygoma fractures.101, 102 The approach to the
ZMC fracture is greatly aided by careful evaluation
of the CT scan, and different classification systems
have been proposed in an effort to provide guidance
to proper preoperative planning. Whichever
approach is chosen, a reduction of the zygoma should
attempt to replace the zygoma back into its normal
anatomic location. Because the zygoma can rotate
around an axis formed by the inferolateral orbital
rim, reduction of just the fronto-zygomatic and
zygomatico-maxillary sutures is not sufficient: a third
point of alignment should be confirmed in order to
ensure proper reduction and avoid late enophthalmos.65 Exploration of the lateral floor of the orbit
can greatly assist in the fracture reduction, as well
as help avoid orbital tissue incarceration between
the zygoma and the sphenoid bones.
When non-comminuted fracture displacement is
noted on examination and CT scans, we favor surgical
exploration and repair through a subconjunctival
inferior fornix and lateral canthotomy approach.99
First, forced ductions are performed to assess for
possible muscle entrapment. The lateral canthus and
inferior fornix are infiltrated with local anesthetic
containing 1:100,000 dilution of epinephrine, and a
lubricated plastic corneal protective shield is placed
on the eye. A lateral canthotomy and inferior
cantholysis (and sometimes superior cantholysis, too),
are performed to release the lateral canthal
attachments and provide good exposure of the lateral
rim. The lateral inferior fornix is then incised to reveal
the inferolateral rim. The periosteum is incised along
the entire exposed rim, and a freer elevator is used
to lift the periosteum and expose the rim from above
the fronto-zygomatic suture down to below the
maxillo-zygomatic suture and medially to the
infraorbital canal. When a depressed floor fracture
is present, the inferior fornix incision can be carried
out medially to provide full exposure of the floor.
Next, the zygoma must be properly reduced and
aligned along three points: the fronto-zygomatic
suture, the maxillo-zygomatic suture at the inferior
rim, and a third point that can be the zygomaticsphenoid suture at the lateral orbital floor, the
zygomatico-maxillary buttress, and/or the zygomatic
arch.65, 69, 70, 99 The first two points ensure anterior
alignment, whereas a third point ensures posterior
alignment. Failure to achieve posterior alignment can
predispose to enophthalmos by enlarging the
posterior orbital volume (Figure 17.8).
A useful tool in ZMC fracture alignment has been
the T-bar screw, also known as the Carroll-Girard
screw (Walter Lorenz Surgical, Jacksonville, FL,
USA).99, 103 This cork-screw-like instrument is screwed
onto the thick bone at the malar eminence and used
to manipulate the zygoma into proper position
(Figure 17.18A and B). This tool is particularly useful
in minimally-comminuted fractures, and allows for
exceptional control of the zygoma through a smallincision approach. However, when severe comminution exists without solid bone for placement of
the screw, multiple incisions would be required to
achieve complete reduction and rigid fixation.
Following reduction of the fracture, fixation is
accomplished using titanium miniplates. Forced
ductions are performed again to ensure that no
entrapment was caused by the fracture reduction.
The lateral floor is explored to assess the zygomatico-
A
B
Figures 17.18A and B: The Carroll-Girard (T-bar) screw is a powerful
tool for 3-dimensional control and manipulation of the zygomatic or
maxillary bones during orbital fracture repair. After drilling a small
guidance hole, the screw is positioned and attached to the T bar
(Photos courtesy of Benjamin Marcus, MD, University of Wisconsin)
sphenoid suture. Next, the periosteum is sutured and
the lower lid retractors are reapproximated using
buried interrupted 7-0 polyglactin suture. The lateral
canthal tendon is resuspended to the periosteum at
Whitnall's tubercle. If lower lid laxity is present,
horizontal tightening is performed to reduce the risk
of postoperative lower lid retraction. Placement of a
Frost suture can be done in the presence of
concomitant lower lid trauma and when the risk of
cicatricial ectropion is felt to be high.
LATE AND SECONDARY
FRACTURE REPAIR
As far back as 1957, Smith and Regan made the point
that "late cases are far more difficult to correct."74
Nevertheless, thirty years ago, many surgeons
advocated observation and delay of surgery for all
but the most severe orbital fractures.104, 105 However,
with the advent of CT scanning, an evolution in
implants and fixation devices, and greatly improved
surgical techniques, primary repair has become the
standard of care for symptomatic or large orbital
fractures. Still, there are occasions when late repair
of orbital fractures is still encountered. Some reasons
include lack of access to medical care following
trauma, misdiagnosis, multiple medical problems
preventing timely repair, or a suboptimal repair that
requires reoperation.
The goal of late fracture repair is the same as for
early repair, namely to restore orbital anatomy and
reduce or eliminate any symptoms. Late repair is
nearly always complicated by significant fibrosis and
abnormal anatomy that can distort the normal
anatomic landmarks. When dysmotility is a significant
symptom and its repair a main goal of the operation,
good motility measurements are critical, as is the
assistance of an expert in adult strabismus.
Dysmotility that results from entrapment can be
corrected when the muscle entrapment is reduced.
However, if the dysmotility is the result of
irreversible muscle or nerve damage, further orbital
surgery will not restore normal motility, and can
cause a significant increase in orbital fibrosis in
addition to the risk of an unnecessary orbital surgery.
Instead, strabismus surgery would be a better option.
Hence, careful diagnosis of the underlying cause of
dysmotility is crucial. In our practice, we will obtain
a CT scan to evaluate the bony anatomy, and
occasionally a dynamic MRI scan to evaluate the cause
of dysmotility. In addition, we request a consultation
from an expert in strabismus, and employ a teamoriented approach to caring for these patients.
A common reason for late surgical repair is severe
enophthalmos (Figure 17.11). In a paper by Koo et
al. (2006),64 clinically apparent enophthalmos was
found when enophthalmos was measured at 3-4 mm
or more. In such cases, patients must weigh their
symptoms against the risks of surgical complications.
It is important to emphasize that counseling and
managing expectations are very important for
achieving a result that is satisfactory to both the
surgeon and the patient.
Our approach to enophthalmos repair stresses
pre-operative counseling in order to clearly define
what the patient desires and what we believe can be
accomplished safely. Our surgical technique
emphasizes good exposure, optimized illumination,
and meticulous hemostasis. We employ the same
incisions that we utilize for early fracture repair,
namely the inferior fornix, lateral canthotomy/
cantholysis, and transcaruncular incisions. Often, the
main decision is whether to attempt reduction of a
healed fracture or to focus on the enophthalmos and
provide orbital volume augmentation through the
use of porous polyethylene implants. Given the
added risk of re-fracturing and reducing healed
fractures, we usually opt for orbital volume
enhancement and accept the mild deformities that
may be associated with poorly positioned but healed
ZMC fractures. For volume enhancement, we typically
utilize porous polyethylene wedge implants that are
shaped to reduce orbital volume or implants
with titanium that can be fixated at the orbital rim
(Figure 17.19).
Figure 17.19: Medpor wedge implant. Orbital volume enhancement
will often require placement of space-occupying implants. The Medpor
wedge implant, which comes in both right-sided and left-sided
configurations, is a useful tool. Alternatively, multiple flat implants can
be stacked to achieve the appropriate amount of volume augmentation
CONCLUSION
Orbital fractures are commonly encountered by the
ophathlmologist, otolaryngologist, and orbitofacial
plastic surgeon. Proper treatment requires a complete
ophthalmic evaluation, systematic review of the
radiographic evidence, and thoughtful surgical
planning with careful attention to anatomic principles.
The use of smaller and hidden incisions (particularly
conjunctival incisions) has made surgical treatment
of orbital fractures more esthetically satisfying while
reducing the risk of complications. The choice of
implant materials has never been greater, providing
the surgeon with options that can be tailored to the
needs of the patients. While surgical repair of orbital
fractures has advanced considerably over the past
50 years, there is no doubt that we will continue to
see innovations and further improvements in surgical
techniques, to the continued benefit of our patients.
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Chap 17.pmd - University of Michigan Kellogg Eye Center

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