Download Zygomatic fractures

ZYGOMATIC FRACTURES
HYSTORY
 1751 duVerney reported 2 cases. took advantage of the mechanical forces of the
masseter and temporalis muscles on the zygoma in a unique approach to closed
reduction technique
 1906 Lothrop devised the transantral approach.
 1909 Keen categorized zygomatic fractures as those of the arch, the body, or the
sutural disjunction. He was the first to describe an intraoral approach to the
zygomatic arch in which an incision is made in the gingivobuccal sulcus.
 1927 Gillies described an original approach to reduce a depressed malar bone. He
was the first to reach the malar bone through an incision made behind the hairline
and over the temporal muscle. Gillies further described the use of a small, thin
elevator that is slid under the depressed bone, thus enabling the surgeon to use the
leverage of the elevator to reduce the fracture. The Gillies method remains in use
today to elevate the arch. the nasal approach
 1942 Adams first used suspension wires for reduction and fixation
 1950 Fryer reported using Kirschner wires for stabilization
 1972 Michelet and Festal first reported rigid fixation for fractures of the midface
ANATOMY
 Sicher and DeBrul were the first to depict facial anatomy in terms of structural
pillars or buttresses.
 This concept allows consideration of an approach for reduction of midface
fractures and ultimately the production of a stable reconstruction.
 Manson have elucidated this concept further by emphasizing the idea that the mid
face is made of sinuses that are supported fully and fortified by vertical and
horizontal buttresses of bone.
 maxilla and the associated bones of the mid face are oriented to resist the vertical
forces of mastication. This is accomplished through 3 paired vertical buttresses
(from anteromedial to posterolateral): the nasomaxillary buttress, the
zygomaticomaxillary buttress, and the pterygomaxillary buttress. An additional
unpaired midline support is the frontoethmoid-vomerine buttress
 These buttresses help give the zygoma an intrinsic strength such that blows to the
cheek usually result in fractures of the zygomatic complex at the suture lines,
rarely of the zygomatic bone.
 The superior and inferior orbital rims and alveolar ridge constitute a group of
weaker horizontal buttresses.
 While these structures provide some protection against horizontal forces, they can
withstand much less force than the vertical buttresses. Therefore, vertical impact
tends to be better absorbed within the facial skeleton, which resists fracture, while
horizontal impact tends to overcome the weaker horizontal buttresses and shear
through the vertical pillars.
Principle vertical buttresses
1. Frontoethmoid-vomerine buttress
2. Medial or nasomaxillary buttress
 extends from the cuspid and anterior portion of the maxillary alveolus
along the piriform aperture, the medial side of the orbit, through the
anterior lacrimal crest, and the nasal process of the maxilla to the superior
orbital rim and nasoethmoidal region
3. Lateral or zygomaticomaxillary buttress.
 extends from the maxillary alveolus across the anterior molar to the
zygomatic process of the frontal bone and laterally to the zygomatic arch.
4. Posterior or pterygomaxillary
 attaches the maxilla posteriorly to the pterygoid plates of the sphenoid
bone.
 Restoration of the zygomaticomaxillary buttress prevents the inferior deviation of
the orbit and provided good zygomatic contour.
 Restoration of the nasomaxillary buttress prevents the superior and posterior
deviation of the alar base of the nose
 Restoration of the pterygomaxillary buttress prevented the superior and posterior
deviation of the upper lip.
Horizontal buttress
Principle buttresses
1. Supraorbital bar
2. Infraorbital rim
3. Maxillary alveolar ridge and palate
4. Mandible
 2 types of horizontal buttress – coronal and sagittal.
 The central part of the face lacks a sagittal buttress and thus projection is often loss
with trauma here
 The zygomaticomaxillary complex has 4 sutures
1. zygomatico-frontal suture
2. zygomatico-temporal suture
3. zygomatico-maxillary suture
4. zygomatico-sphenoidal suture
 even though a ZMC fracture is commonly referred to as a trimalar or tripod
fracture, a “complete ZMC fracture” technically should be really called a tetrapod
fracture. The reason being that ZM and ZS sutures are often considered together as
one unit
RADIOGRAPHIC FINDINGS
 Plain xray
Waters view, PA, Caldwell view, submentovertex view
 CT scan including coronal views or reformats
CLASSIFICATION
 ZMC fractures are second to nasal fractures in frequency.
Knight and North identified six groups
1
Undisplaced
2
Arch Fractures
3
4
5
6
Unrotated body fractures
Medially rotated body fractures
Laterally rotated body fractures
Complex (presence of additional
fracture lines across the main
fragment )
Stable 100%
Stable 100%
Associated with Trismus, Gillies lift
Stable 60%
Unstable100%
Stable 100%
Stable 30%
Mason with a more recent classification (CT based)
 Classified on the basis of segmentation and displacement as evident on CT
 Low-energy, middle- energy, and high-energy
MANAGEMENT
Undisplaced zygomatic fracture
 no therapy
 6 weeks to heal
 review early in course to ensure no further displacement, orbital floor
Displaced fractures
Arch
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Malar
usually stable after Gilles approach and reduction
splinted by temporalis muscle and fascia and masseter muscle
if extensive comminution need to consider coronal approach and ORIF
Other options include
1. bolster sutures
2. balloon catheter
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closed reduction if malar is one segment
stability is assessed post op by palpation and repeat Xrays if needed
note the post surfacr of the zygoma constitutes most of the lateral orbital wall
and part of the floor. Therefore by definition fracture is also an orbital floor
fracture
Manson and colleagues summarized the indications for treatment as follows
Low-energy
 18%
 no reduction
Middle-energy
 77%
 complete fractures at all buttresses with mild to moderate
displacement
 wide range of comminution
 treated with ORIF anterior buttress articulations
High-energy
 5%
 comminution in the greater wing of the sphenoid
 lateral displacement and posterior segmentation of the arch
 coronal exposure and ORIF
EXPOSURES
 Upper gingivo-buccal incision
 Lateral-brow or upper blepharoplasty incisions
 Lower eyelid/Extended subciliary/Transconjunctival incision
 Coronal incision especially for complex fractures involving NOE fracture;
medial, lateral,superior fractures of obit; LeFort and frontal bone fractures.
BIOMECHANICS
 Primary bone healing allows quicker and stronger healing of a fracture than callous
healing.
 Rigidly fixated bone grafts maintain their position and volume better than
mobile grafts. Furthermore, rigid fixation helps the bone heal by primary
processes rather than by fibroelastic processes.
 Wires confer stability on 1 plane only whereas plates and screw offer 3 planar
stability
 Biomechanical studies show three-point fixation with miniplates or wires offered
the greatest stability.
 Two-point fixation with miniplates also offered acceptable fixation.
 Plates offer greater stability than the wires with less points of fixation, mainly with
two-point and one-point fixations.
 Mechanical studies that approximate the actual sustained forces observed
physiologically show that at least two miniplates (with 1 miniplate stronger than 3
points of wire fixation and slightly weaker than 3 plates) are required
 Long-term experimental studies demonstrate that miniplates maintain the
osseous volume of bone grafts and prevent nonunion at bone graft contact
points better than wires.
Summary
 Rigid fixation with plates and screws is the best form of bony fixation; it restores
3-dimensional stability and allows for the least amount of motion between ends of
fragments, the main cause of bone resorption and instability.
COMPLICATIONS
Infection
 Sinusitis(4-8%) has been found to be the most common type of infection seen in
postoperative patients but preseptal cellulitis and dacryocystitis also can occur.
 reduce with careful recon., biocompatibility of graft and avoidance of antral
packing
Diplopia
 10% initially
 5% permanent (ie half the above)
 most common with posteriorly located floor fractures
 causes are tethering of orbital contents (fat, muscle etc), injury to nerves, scar
tissue tethering
Enophthalmos (3-4%)
 indicated when the inferior orbital rim is deficient by more than 1 cm
 The most common causes of enophthalmos include the failure to properly
reduce displaced zygoma fractures and malunited zygoma fractures; blow-out
fractures of the orbit, fat atrophy, soft-tissue contracture, and fibrosis.
 split calvarium, iliac crest, split rib
 incidence of late enophthalmos is 3%
 great care must be taken to reconstitute preinjury orbital volume because late
enophthalmos is very difficult to treat
Traumatic optic neuropathy (1.3-2.1%)
 mildest symptom is diminished color perception
 better prognosis if not associated with orbital injury or penetrating eye injury
Persistent infraorbital nerve anesthesia (20-50%)
 dysesthesia of the skin of the nose, cheek, lower eyelid, upper lip, gingiva, and
teeth of the affected side.
 long-term dysfunction of 20-50%,
 Some have noted significant improvement in sensory function after open
reduction and internal fixation with plates versus a closed reduction technique.
Bradycardia
 Triad of nausea, syncope and bradycardia = oculocardiac response
 mediated by the ophthalmic division of the trigeminal nerve (the afferent limb)
passing through the reticular formation to the vagus nerve’s visceral motor
nuclei.
 Suspect incarceration of intraorbital fat or muscle in the fracture line, even if
the fracture is undisplaced
Lacrimal gland injury
Soft-tissue descent with loss of malar prominence
 periosteal suspension of the lower eyelid and cheek to their anatomic position
on the orbital rim
Trismus (45%)
 particularly after a fracture involving the zygomatic arch.
 results from impingement upon the coronoid process of the mandible by a
depressed zygomatic arch. This may indicate a need for elevation of the
depressed arch, accurate reduction, and fixation.
 If new bone has formed in the space below the zygomatic arch and restricts the
movement of the mandible, an intraoral approach for coronoidectomy may be
required to permit mandibular movement.
Complications with plates and/or screws
 palpable plates and screws most common compliant (35%)
 pain, infection, or loosening of the fixation device
MAXILLARY FRACTURES
HISTORY
Initially extraskeletal fixation
Ipen internal K-wire 1933
1939 rubber band traction to immobilize difficult fractures of the midface
early 1970’s Ferraro and Berggren suggested rigid internal fixation
PRINCIPLES OF OPERATIVE MANAGEMENT
1. Early one-stage repair
2. Wide exposure of all fracture fragments
3. Disimpaction
4. Precise anatomic reduction
5. Immediate autogenous bone grafting
6. Simultaneous soft-tissue management
SURGICAL ANATOMY
 Le Fort studied patterns of fracture
1. LeFort I fracture is a low horizontal fracture with disruption of tooth-bearing
section of the maxilla. It extends horizontally through the inferior portion of the
maxilla separating the maxillary alveolus from the rest of the midface. Results in
a floating palate.
2. Fort II fractures produce separation and mobility of the midface, involves the
nasal bones, frontal process of the maxilla, the inferior orbital and lateral
maxillary sinus walls
3. LeFort III is a high horizontal fracture alongside the junction between the
cranial and facial skeleton. It results in craniofacial disjunction and separation
of the midface from the cranium at the level of the nasofrontal sutures lateral
through the orbits to the zygomatic arch and posteriorly to the pterygoid plates.
 Majority of complex facial injuries are not pure Le Fort fractures but combinations
of several types.
EPIDEMIOLOGY
 Personal altercations and MVA 2/3 of facial fractures
 Patterns II > I > III
 Sagittal fractures of the alveolar ridge and palate account for approx. 15% of
maxillary fractures
The incidence and nature of associated injuries:head(51%), chest(13%), abdomen
(5%), Ocular injuries(50%), Spinal injury(12-18%)
BIOMECHANICS
1. Women have consistently lower impact tolerance levels than men.
2. nasal bones have the lowest level of impact tolerance.
3. zygomatic arch is the second most fragile area.
4. maxilla is very sensitive to localized horizontal impacts.
5. mandible is much more vulnerable to lateral impacts than to frontal blows.
DIAGNOSIS
PHYSICAL EXAMINATION
Le Fort II and II
 bilateral circumorbital and subconjunctival haematoma
 gross bilateral oedema of the midface
 lengthening of the face
 malocclusion
 need to check for mobility of the midface and transverse stability of the
midface
 CSF leak
RADIOGRAPHIC INVESTIGATIONS
1. Full facial films initially
2. High resolution CT vital
MANAGEMENT
1. Stabilization of the patient
2. maintain function - pretraumatic functional occlusion and mastication,
3. restore form
INCISIONS
As described above
FIXATION
 With II and III open reduction and rigid fixation with plates and screws as well as
reconstruction of the orbital rim and floor
 Plates need prevent 6 motions - 3 translations and 3 rotations along the x, y and z
axes
 To prevent rotation in all three directions, three separate points that are not on the
same line must be fixed. The smaller the plate, the less mechanical advantage in
preventing rotation.
 Compression of the bone ends is not required for healing of fractures of the
midface, and small bone gaps (<5 mm) may be acceptable to preserve occlusion
and contour.
 at least two screws should be placed across either side of the fracture, and any
comminuted buttress fracture should be bone grafted to eliminate gaps.
 Manson believes the mandible is the pillar on which Le Fort fractures should be
stabilized on.
 Midfacial retrusion can be averted by placing the maxilla in proper occlusion
with the mandible using MMF and then stabilizing the midfacial buttresses
with plates.
 The use of arch bars, palatal splints, intraoral splints may be required
COMPLEX FRACTURES
1. ABC’s
2. Intubation +/- tracheostomy
3. Stabilize limb or life threatening injuries
4. Low GCS does not preclude fixation unless the prognosis is grave
5. Must keep ICP < than 25mmhg
6. Varies between centers with respect to timing
7. Usually midfacial buttresses destroyed with maxilla dislocating posteriorly and
superiorly. Use mandible to determine position
8. Must keep in mind 3D structure width, projection and height
ALGORITHM
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Mandibular fractures treated, reduced into proper relation to the cranial base and
stabilized
Maxilla into proper occlusion and held with IMF
Frontal bone and sinus are attended to
Fractures of zygoma reduced and stabilized first
Maxillary buttresses are reconstructed and stabilized by rigid fixation
Orbital fractures reduced +/- bone grafts
NOE complex reconstituted
Nasal fractures corrected including any nasofrontal separation
Facial lacerations and soft tissue injuries sutured and repaired
PALATAL FRACTURES
Classification (Hendrikson)
Type 1 - posterolateral
Type 2 - sagittal
Type 3 – parasagittal
Type 4 – paraalveolar
Type 5 – complex
Type 6 – transverse
Treatment
 In most cases, intraoral splints are used especially in the presence of comminution
 ORIF is used for selected cases
o Longitudinal incision along the palate followed by plating and IMF
EDENTULOUS MAXILLA
 Indications unclear
 More likely to manage conservatively with dentures and splints
PRIMARY BONE GRAFTING
 Important as allows early definitive correction for both the skeletal and soft tissue
injuries
 Introduced at the turn of the century
 Tessier 1967 and 1971
 Gradually increased in popularity
 Gruss believes gaps > 5mm require grafts esp. in lower maxilla and zygoma
 Usual donor sites cranium, thoracic cage, and iliac crest
 Membranous bone as believed superior volume retention
 There is the problem of graft resorption
 2 Large studies by Manson and Gruss revealed no significant increase in
complications in those who had bone grafts
 must keep in mind the donor site morbidity
PITFALLS
1. Inadequate reconstruction of the supraorbital ridge, which may produce flatness in
the area. Prevention: full-thickness rib graft or stacking of bone grafts in layers.
2. Comminution in the frontal and frontoorbital region. This makes it difficult to
stabilize the fragments while maintaining the appropriate convex contour of the
forehead. Prevention: use of long miniplates or microplates molded to the shape of
the skull and affixed with specifically designed 3-4 mm miniscrews.
3. Injury to the orbital roof with concomitant loss of the posterior wall of the frontal
sinus, resulting in direct communication between the anterior cranial fossa and
orbit. Prevention: reconstruction of the orbital roof to separate the cavities.
4. Excessive use of bone grafts in the orbital roof or supraorbital rim, causing
asymmetry, exophthalmos, and vertical dystopia. Prevention: careful
reconstruction to avoid overcorrection.
5. Orbital dystopia. Prevention: adequate exposure and reconstruction of the
zygomatic arch and lateral orbital rim and wall.
6. Bone destruction in the glabella and nasofrontal region. Prevention: reconstruction
with bone grafts and reattachment of the nasal bones to this rebuilt bony base.
COMPLICATIONS
1. Nerve conduction disorders
a. Infraorbital nerve hypoaesthesia persists in 17%
2. Ocular problems
3. Brain injury
4. CSF rhinorrhea
a. 35% incidence, most stop spontaneously
b. Dural repair should be considered only when the drainage is significant,
persists beyond 2 weeks, and is resistant to placement of a lumbar drain
5. Infection (<2%)
6. Prominence or exposure of plates and screws
a. 12% incidence of complications requiring plate removal
7. Malocclusion
8. Diabetes insipidus
9. Disturbance of smell and taste
a. 80% prevalence in LeFort III fractures
10. Nasal septal deviation