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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 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 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 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