INTERNAL RIGID FIXATIONThe term internal rigid fixation has many definitions. One definition is “any form of bone fixation in which otherwise deforming biomechanical forces are either countered or used to advantage to stabilize the fracture fragments and to permit loading of the bone so far as to permit active motion”Examples of rigid fixation in the mandible are the use of two lag screws or bone plates across a fracture, the use of a reconstruction bone plate with at least three screws on each side of the fracture, and the use of a large compression plate across a fracture
ADVANTAGES Prevention of interfragmentary mobility leading to a peculiar type of bone healing where no callus forms. The bones instead go on to heal by a process of haversian remodeling. A remodeling phase then converts the entire area to morphologically normal bone. This type of bone healing is termed primary or direct bone union, and it requires absolute immobilization between the osseous fragments, and minimal distance (gap) between them.
Fractures of the angle under most functional situationstend to “open” at the superior border.Champy miniplate technique functions extremely well for this fracture and consists of a 2.0 mm miniplate applied with monocortical screws along the superior border. Because metallic plates have high tensile strength, even thin plates work adequately at the angle to prevent the tendency for a gap to form at the superior border under function. The advantages to using the Champy method include a decreased risk of infection, shorter operating time, and more rapid return to form and function when compared with other more rigid techniques.
Isolated fractures of the mandibular body behave similarly under function,with a tendency for a gap to form at the superior surface, but the more anterior the fracture, the more tendency for torquing of the fragments to occur, causing mediolateral misalignment of the inferior border. A plate or lag screws on the body of the mandible is necessary to prevent the mediolateral displacement that accompanies the torquing motion under function. For isolated body fractures, this can be a relatively small plate, such as a 2.0 mm miniplate or even a single lag screw combined with a solid arch bar.
The anterior mandible undergoes shearing and torsional (twisting) forces during functional activities. Application of fixation devices must therefore take these factors into consideration. This is why most surgeons advocate two points of fixation in the symphysis: either two bone plates, two lag screws, or possibly one plate or lag screw combined with an arch bar
MID-FACIAL FRACTURES Anatomy The maxilla, palate, nasal bones, and zygomas comprise most of the midfacial skeleton. The ethmoids, greater wing of the sphenoid, and frontal bone comprise elements of the bony orbit and connect the anterior facial skeleton to the cranial base. Forces directed onto the midfacial skeleton are absorbed and transmitted through vertical and horizontal buttresses. These buttresses constitute areas of dense, thick bone that support the maxilla and are more resistant to deformation when forces are applied. They are not only important in protecting the vital structures of the midface but they are also essential landmarks used during reconstruction. The buttresses provide higher quality bone for internal fixation and guide reconstruction of facial height, width, and projection.
MIDFACIAL BUTTRESSES The midface is more resistant to vertical forces than horizontal and shear forces. This resistance is because of the strength of the vertical buttresses: Nasomaxillary (medial) Zygomaticomaxillary (lateral) Pterygomaxillary (posterior)
Antero-posterior buttresses: frontal (1), zygomatic (2), and maxillary (3).
Although the horizontal buttresses have less impact on force dissipation, they are important for the restoration of facial width. The horizontal buttresses include: Superior orbital rims (superior) Inferior orbital rims/zygomatic arch (central) Maxillary alveolus (inferior)
MAXILLARY FRACTURES
Le Fort I Level Maxillary fractures at the Le Fort I level traverse the lateral antral wall, the lateral nasal wall, and the lower third of the septum, and they separate at the pterygoid plates. Thus, the entire mobilized segment consists of the maxillary alveolar bone, the palatine bone, the lower third of the nasal septum, and the lower third of the pterygoid plates. The superior two-thirds of these bones remain associated with the face.Le Fort II Level Unlike the horizontal separation noted in the Le Fort I fracture, the Le Fort II fracture is pyramidal in shape. The fracture extends from below the nasofrontal suture through the nasal bones along the maxilla to the zygomatico-maxillary suture and includes the medial inferior third of the orbit. The fracture then continues along the zygomatico-maxillary suture to and through the pterygoid plates. The septum is also separated superiorly. The segments may be intact below this line of fracture, but they are most often comminuted
Le Fort III Level Fractures at the Le Fort III level involve the nasal bones, the zygomas, the maxillae, the palatine bones, and the pterygoid plates. These fractures essentially separate the face along the base of the skull. The fracture line extends from the nasofrontal suture along the medial wall of the orbit through the superior orbital fissure. It then extends along the inferior orbital fissure and the lateral orbital wall to the zygomatico-frontal suture. The zygomatico-temporal suture is also separated. The fracture then extends along the sphenoid bone, separating the pterygoid plates. The septum becomes separated at the cribriform plate of the ethmoid. Le Fort III fractures are most often comminuted.
CLINICAL PRESENTATION Soft tissue lacerations, edema, nasal bleeding, pain, ecchymosis, and bony steps along the fractures lines may be appreciable on visual inspection and palpation. In addition, a change in occlusion is often found. For LeFort I fractures: maxillary mobility may be present. However, the absence of mobility does not preclude a fracture. If the maxilla has been impacted, there may be no mobility and the anterior facial height may be decreased. There is typically an anterior open bite. Ecchymosis in the region of the greater palantine foramen, or Guerin sign, and ecchymosis in the buccal vestibule also indicate a LeFort I fracture. Cracked-pot sound on percussion of upper teeth.
LeFort II fractures typically present with periorbital and subconjunctival ecchymosis in addition to the findings outlined earlier. * A bony step at the infraorbital rim may also be detectable. * Disruption of the infraorbital nerve leads to anesthesia of the upper teeth, gingiva, upper lip, and lateral aspects of the nose. * Diplopia with restricted superior gaze. * If the nasal bones and maxilla are mobile, a LeFort II fracture should be suspected. * A dish-faced appearance may be present as a result of decreased nasal projection. * CSF rhinorrhea may be present, suggesting a basilar skull fracture.
LeFort III fractures involve mobility of the maxilla, nasal bones, and zygomas as a single unit. A palpable bony step may be present at the zygomaticotemporal or zygomaticofrontal suture. As with LeFort II fractures, bilateral periorbital edema (raccoon eyes) and CSF rhinorrhea may be present. Lengthening of the facial height, orbital hooding, and enophthalmos are also typically present. Tenderness and deformity of the zygomatic arches. Tilting of the occlusal plane with gagging on one side. Ecchymosis over the mastoid region (Battle sign) may be present, in addition to CSF otorrhea and hemotympanum.
MODALITIES OF TREATMENT 1. Closed reduction and IMF 2. Open reduction and direct fixation: Plating or wiring 3. Suspension wiring: Circumzygomatic, Fronto-zygomatic, Infraorbital rim wire, Piriform fossa wire, Circumpalatal 4. External fixation: Head frame, Halo-frame, Plaster of Paris head cap 5. K-wire or Steinman pin
In cases involving fractures with minimal displacement and no change in occlusion, no treatment other than a nonchew diet for approximately 4 weeks may be indicated. However, these cases are rare. Closed reduction techniques involving (IMF) for a period of 4 to 6 weeks can be used. In cases in which there is displacement of the maxilla with an occlusal discrepancy, Rowe disimpaction forceps can be used to mobilize and reduce the maxilla.
A, Rowe disimpaction forceps.
B, Application of the forceps.The most common treatment of maxillary and LeFort fractures remains open reduction with internal fixation. The general treatment approach involves: Exposure of the fractures Mobilization and reduction of fracture segments Establishment of occlusal relationships (IMF) Rigid or semirigid fixation Bone grafting when necessary Resuspension/repair of soft tissue injuries
The most common approach for exposure of a LeFort I level fracture is the buccal vestibular incision
Next, the fractures are fixated with either bone plates or interosseous wiring. The fixation pattern and method are dependent on the specific fracture location and bone available. The most common method is to use 4-point fixation at the zygomaticomaxillary and nasomaxillary buttresses with 1.5-mm to 2.0-mm miniplates. If bony gaps exist, autogenous grafting can be used.
Suspension wiring is sometimes used in addition to direct wiring or bone plating. The purpose of suspension wiring is to provide stabilization of fractured bones by suspending them to a more stable bone superiorly. The use of direct and suspension wire fixation does have significant limitations in many cases. The limited rigidity of wires may make it difficult to reconstruct and maintain the appropriate anatomic contours. Rigid fixation using plating systems for the most part has eliminated the need for suspension wires.
Suspension wiring techniques: 1, Frontal bone suspension. 2, Piriform rim wiring. 3, Inferior orbital rim suspension. 4, Circumzygomatic suspension
The severely comminuted midface injury may create a challenge for open reduction. In patients who cannot undergo autogenous grafting or for those who do not tolerate IMF because of medical or psychological reasons, external fixation with a halo head frame can be used.
ZYGOMATICO-ORBITAL FRACTURES
Zygomaticomaxillary complex fracture types: (A) type A1, isolated zygomatic arch fracture; (B) type A2, isolated lateral orbital wall fracture; (C) type A3, isolated infraorbital rim fracture; (D) type B, tetrapod fracture; (E) type C, multifragment zygoma lateral orbit complex fracture.CLINICAL PRESENTATION * Patients with nondisplaced ZMC fractures may exhibit only soft tissue signs such as ecchymosis and edema overlying the fracture sites and conjunctival hemorrhage. * Displaced fractures will generally cause ipsilateral facial flattening .The zygomatic arch may be intact, fractured and depressed, or bowed out. * Displaced ZMC and isolated zygomatic arch factures may also cause trismus as a result of spasm of the masseter muscle or mechanical impingement of the coronoid process against the displaced fragments. * Others: Enophthalmos, Diplopia or squint, Limitation of ocular movements, Anesthesia or paraesthesia of the cheek, Buccal ecchymosis, Gagging of the posterior teeth on the injured side, Step deformity at fronto-zygomatic and zygomatico-maxillary sutures, and epistaxis.
Evaluation of the extraocular muscles is performed by finger tracking. A forced duction test will generally differentiate between mechanical entrapment and restriction secondary to edema or contusion. If restricted range of motion is detected, topical anesthesia is applied to the sclera and the forced duction test is performed by grasping the insertion of the rectus muscles at two simultaneous points with two pairs of Adson forceps.
Typical appearance of a patient with a displaced fracture of the right zygomaticomaxillary complex. There is flattening in the area of the right malar eminence. Superior view of the same patient showing an obvious decreased projection of the fractured zygoma on the right.
Enophthalmos in a patient with a displaced zygomatico-maxillary complex fracture complicated by a fracture and inferior dislocation of the orbital floor
RADIOGRAPHIC EXAMINATIONComputed TomographyCT is the gold standard for radiographic evaluation of zygomatic fractures. Axial and coronal images are obtained to define fracture patterns, degree of displacement, and comminution and to evaluate the orbital soft tissues. Plain Radiographs Waters’ View Caldwell’s View Submentovertex View
SURGICAL APPROACHES
Coronal approach A coronal flap is a useful approach when extensive exposure of the zygomatic arch, zygoma, and orbit is indicated. Supraorbital eyebrow approach A 2-cm incision placed over the lateral portion of the eyebrow allows rapid access to the lateral orbital rim and the zygomaticofacial suture. Maxillary vestibular approach Rapid and esthetic access to the anterior portions of the midface and zygomaticomaxillary buttress can be obtained through this approach. Lower eyelid approaches 3 surgical options are available: The subciliary, lower eyelid crease, and transconjunctival approaches are the most commonly used methods.Gillies' temporal approach for the elevation of a depressed fracture's zygomatic complex
Displaced fractures are best managed by open reduction and fixation at two to three points. In the absence of comminution or instability at the zygomatic arch, reduction under direct visualization plus fixation at the frontozygomatic suture, zygomaticomaxillary buttress, and inferior orbital rim remains the best treatment option.Intraoral exposure and fixation of zygomaticomaxillary buttress fracture.
BLOW-OUT FRACTURES Orbital fractures are generally the result of blunt force trauma to the eye, causing a fracture of the thin bony wall or floor of the orbit. Increased pressure from sneezing, nose blowing, or coughing may precipitate air passage through a previously injured inferior or medial orbital wall. The inferior rectus muscle may become entrapped, resulting in diplopia on upward gaze. Injury to the inferior orbital nerve may result in decreased sensation of the cheek and upper lip.
A 22-year-old otherwise healthy woman was struck in the right eye with an open hand at evening. The next morning, she blew her nose and experienced an abrupt onset of right periorbital swelling. She later complained of numbness of the right cheek and diplopia on upward gaze. The examination result was unremarkable, except for a swollen right lower eyelid with palpable crepitus.
THEORIES Two mechanisms: hydraulic and buckling are generally believed to cause blowout fractures. The theory of the hydraulic mechanism suggests that the pressure increase of the orbital contents fractures thin and fragile parts of the orbital walls The buckling mechanism explains that the orbital walls bend in response to impacts, then fracture.
Blunt-force trauma from a baseball, causing an orbital floor blowout fracture, with bone fragments and orbital contents sagging into the maxillary sinus below.
Restricted eye movement
Subconjuctival approach and reconstructionIntraoperative photographs of orbital floor reconstruction for patient with orbital floor blow-out fracture. (A) Fixation of orbital rim fractures with 1.3-mm plate through transconjunctival approach with lateral canthotomy and inferior cantholysis. (B) Reconstruction of orbital floor with Medpor Titan porous polyethylene.
NASAL AND NASO-ETHMOID FRACTURES
Nasal fractures are classified according to extent of injury into 3 planes Plane I: .................... Plane II: .................... Plane III: ....................The nasal complex is the most frequently fractured bone in the face in the adult patient. Due to its location on the face, less force is required to fracture the nasal complex than any other facial bone. Because of the frequency of injury, as well as complex topography and different components (bone, cartilage, mucosa, skin) of the nasal complex, appropriate management of the acutely injured nose is imperative in order to prevent adverse sequelae.
Bilateral comminuted nasal bone fractures and septal deviation following motor vehicle collision.
Using appropriate nasal reduction forceps, the nasal bones and the septum must be reduced in the appropriate vector. The reduction must be maintained by intranasal packings and/or splints.
Walsham forceps, Boies elevator, Asch forceps
NOE injuries: PATTERNSIsolated NE injury: Usually this is due to severe impact confined to the nasal area. Maxilla’s frontal process(es) are fractured and depressed with nasal saddle deformity and elevation of nasal tip. Nasal bones may remain intact. Medial canthal ligament ismostly still attached to a large bony fragment which facilitates its repositioning.High –level NE injury (Craniofacial): In which, there is frontal bone fracture. This type may carry a risk of associated injury to the anterior cranial fossa. CSF –leakage is frequently present.Low –level NE injury: Characterized by crushing of NE complex. Concomitant Le Fort III or severe Le Fort II fractures are often present. This type is frequently associated with orbital floor fractures and severe ocular injuries.In severe impacts, especially those sustained by road traffic accidents, the last two patterns may be found concomitantly.
FINDINGS OF MY WORK (MASTER)* Incidence of NE fractures in midface trauma was estimated and found to be (11.8 %). * Road traffic accidents were the cause of injury in more than half of the cases. * Clinical signs associated with these injuries were examined and recorded as follows: Telecanthus in 15 cases (100 %), Saddle deformity in 13 cases (86.7 %), Lacerations in 11 cases (66.7 %), Mongoloid slant in 9 cases (60%), Enophthalmos in6 cases (40 %), CSF –leak in 5 cases (33.3 %), infraorbital paresthesia in 4 cases (26.7 %), diplopia 3 cases (20 %) septal deviation in 2 cases (13.3 %), and epiphora in 2 cases (13.3 %).
CONCLUSIONS (MSc thesis)* The majority of nasoethmoid (NE) injuries are combined with other facial fractures.* Nasoethmoid fractures should be considered in the diagnosis of all severe nasal, LeFort II, and LeFort III fractures. * Extended NE injuries can occur either as “ highlevel” or “low-level” patterns. In severe cases, the two forms may be present. * CSF–rhinorrhoea is a frequent finding in high –level NE injuries. * Enophthalmos should be suspected in every naso-ethmoid injury, especially when a concomitant zygomatic fracture exists.
PANFACIAL FRACTURES* Panfacial fractures are those involving the mandible, maxilla, and zygomatic complex at the same time and usually accompanying naso-orbito-ethmoid (NOE) and frontal bone fractures. * They are often associated with soft tissue injuries and loss of bony structures that can lead to severe posttraumatic deformities and disabilities like malocclusion, “dish” face deformity, and enophthalmos To be continued..