Trauma

div epub:type=”chapter” role=”doc-chapter”>

© Springer Nature Switzerland AG 2021

R. Reti, D. Findlay (eds.)Oral Board Review for Oral and Maxillofacial Surgerydoi.org/10.1007/978-3-030-48880-2_7

7. Maxillofacial Trauma

Carlos A. Ramirez1  , Tirbod Fattahi2, Jason E. Portnoff3, Rishad Shaikh4, Jason Margolis5, James A. Kraus6, David Chang7, Lina Alsad8, Andre H. Montazem9, Robert Reti10 and Damian Findlay11
(1)

Ascension-St. John Hospital, Oral/Maxillofacial Surgery, Detroit, MI, USA
(2)

University of Florida College of Medicine, Jacksonville, OMFS, Jacksonville, FL, USA
(3)

Nova Southeastern University College of Dental Medicine, Department of Oral and Maxillofacial Surgery, Boca Raton, FL, USA
(4)

Midwest Oral Maxillofacial and Implant Surgery, St. Louis, MO, USA
(5)

Carilion Roanoke Memorial Hospital, Plastic & Reconstructive Surgery, Dental Department, Roanoke, VA, USA
(6)

Tufts Medical Center, North Boston Oral & Facial Surgery, Amesbury, MA, USA
(7)

Tufts University School of Dental Medicine Oral and Maxillofacial Surgery, Tufts Medical Center, Oral and Maxillofacial Surgery, Boston, MA, USA
(8)

Broward Health Medical Center, OMFS, Miami, FL, USA
(9)

Elmhurst Hospital Center, Oral/Maxillofacial Surgery, Elmhurst, NY, USA
(10)

Southwest Oral Surgery, St. Louis, MO, USA
(11)

Oral Facial Surgery Institute, St. Louis, MO, USA
 
 
Carlos A. Ramirez
Keywords

Glasgow Coma ScalePrinciples of FixationHouse-Brackmann ScaleNasopulmonary reflexMarcus Gunn PupilHorner’s SyndromeBone HealingCondyle FractureEdentulous Mandible FractureLeFort FractureZygomaticomaxillary Complex FractureNaso-Orbital-Ethmoid FracturesTelecanthusCanthopexyFrontal Sinus FractureCranializationEnophthalmosRetrobulbar HemorrhageLateral RetinaculumSympathetic OphthalmiaJones TestNasofrontal DuctCSF Leak

Basic Trauma Principles

Hypovolemia (Table 7.1)

  • Can be caused by bleeding or massive urinary or gastrointestinal fluid losses.

  • One or two large bore (≥16 gauge) peripheral IVs should be inserted.

  • Focused abdominal sonography for trauma (FAST) in a hypotensive patient to rule out intra-abdominal hemorrhage or cardiac tamponade.

Table 7.1

Classes of Hemorrhagic Shock. Based on a 70 kg Person

Classes of Hemorrhagic Shock

 

1

2

3

4

Blood loss (ml)

<750

750–1500

1500–2000

>2000

Pulse rate (BPM)

<100

100–120

120–140

>140

Blood pressure

Normal

Normal

Decreased

Decreased

Respiratory rate (per minute)

12–20

20–30

30–40

>40

Urine output ml/hr

>30

20–30

5–15

Scarce

Mental status

Slightly anxious

Mildly anxious

Confused

Lethargic

Glasgow Coma Scale (Table 7.2)

  • Objective measure of patient’s neurological status and used serially to track clinical progress.

  • Can be applied to patients 5 years of age and above.

  • Use best response (left vs. right differential).

  • Score 8 or less, early airway protection encouraged due to concern of respiratory arrest or hypoxia leading to secondary brain injury.

  • Score minimum is 3.

  • Requires serial exams and a CT scan of the head.

Table 7.2

Glasgow Coma Scale. Mnemonic to remember points allotted for each GCS component “4 Eyes, Jackson 5 (voice) and V6 (motor)”

Eye opening response

Verbal response

Motor response

Points

No response

No response

No response

1

To pain only

Incomprehensible

Extension in response (decerebrate posturing)

2

To verbal stimuli, command, speech

Inappropriate words

Flexion in response to pain (decorticate posturing)

3

Spontaneous–opening with blinking

Confused conversation, but able to answer

Withdraws in response to pain

4

 

Oriented

Purposeful movement to pain

5

   

Obeys commands for movement

6

Head Injury Classification

  • Severe Head Injury/Coma – GCS score of 8 or less.

  • Moderate Head Injury – GCS score of 9–12.

  • Mild Head Injury – GCS score of 13–15.

  • Denotation of T after the score is applied to an intubated patient.

Zones of the Neck for Penetrating Trauma (Fig. 7.1)

  • Zone 1 – thoracic inlet to cricoid cartilage.

  • Zone 2 – cricoid cartilage to angle of the mandible.

  • Zone 3 – angle of the mandible to the base of the skull.

  • Zones 1 and 3 are usually worked up using conventional or, more commonly now, CT angiography due to difficulty in access.

  • Due to the multiple organ systems represented in the neck, multiple systems can be impacted by a single penetrating insult. Insults may result in cervical spine, carotid, esophageal, and/or laryngeal injuries.

  • Patients who are unstable or present with hard signs such as bruits, thrills, large/pulsatile hematomas require immediate exploration.

../images/428304_1_En_7_Chapter/428304_1_En_7_Fig1_HTML.png
Fig. 7.1

Zones of the neck. (Reprinted with Permission from Georgopoulos C. Chap. 86 – Neck Trauma. Sixth Edition. Emergency Medicine Secrets. Elsevier Inc.; 2016)

Principles of Fixation

Rigid Fixation:
  • Fixation that prevents interfragmentary movement when a load is applied.

Semi-Rigid Fixation:
  • A form of fixation that is not of sufficient strength to prevent interfragmentary movement during loading but is adequate to allow union of bone.

Load Bearing:
  • Hardware of sufficient strength that is able to bear the entire load.

  • Plates and screws to immobilize the fractured segments.

  • Use of thicker, rigid plates with bicortical screws to immobilize the fracture segments or lag screws.

  • Requires at least three screws on each segment when plates are used.

Load Sharing:
  • Form of hardware that is unable to bear all functional load across fracture.

  • Open reduction, internal fixation without relying solely on the plates and screws to immobilize the fracture segments.

  • Uses miniplates and monocortical screws along the lines of osteosynthesis as described by Champy.

Ideal Line of Osteosynthesis of the Mandible:
  • Described by Maxime Champy in 1976 [1].

  • A line around the mandible where plating the tension and compression forces are balanced, thus offering the best biomechanical advantage for positioning of plates and screws.

Plates and Screws for Internal Fixation

  • Non-locking plates/screws:

    • Plates must be adapted intimately to the bone.

    • Compression of the plate onto the bone may cause bone resorption under the plate.

  • Locking plates/screws:

    • Screws lock into the plate while it is being tightened.

    • Does not require a perfect adaptation of the plate to the bone.

    • The plate bears the load of mechanical forces.

  • Plate and screw dimensions:

    • Most plates are composed of titanium.

    • Plating systems are named by the outer diameter of the screws.

  • Thread shape:

    • Self-drilling – insertion without pre-drilling or tapping.

    • Self-tapping – requires pre-drilling of a pilot hole, the insertion of the screw will create its own thread in the bone.

Bone Healing

  • Bone healing is altered by types of fixation and mobility of the fracture site in relation to function.

  • Primary bone healing:

    • No fracture callus forms.

    • Heals by a process of:

      1. (a)

        Haversian remodeling directly across the fracture site if no gap exists (contact healing)

         
      2. (b)

        Deposition of lamellar bone if small gaps exist (gap healing).

         
    • Requires absolute rigid fixation with minimal gaps.

  • Secondary bone healing:

    • Bony callus forms across fracture site to aid in stability and immobilization.

    • Occurs when there is mobility around the fracture site.

    • Secondary bone healing involves the formation of a subperiosteal hematoma, granulation tissue, and then a thin layer of bone forms by membranous ossification. Hyaline cartilage is deposited, replaced by woven bone and remodels into mature lamellar bone.

Approach to the Facial Trauma Patient

History of Present Illness

  • Mechanism of injury and loss of consciousness are important points to note. It is difficult to assess a history from an unstable trauma patient and, therefore, witnesses should be questioned.

  • Confirm ATLS/PALS has been performed. Threshold for intubation should be low. Ensure appropriate consultations have been made, e.g., neurosurgery, ophthalmology, orthopedic surgery, and pediatric surgery, etc., if necessary.

  • Ensure C-spine has been evaluated and appropriate precautions taken. It’s desirable to have the head and spine cleared prior to surgical intervention if possible.

Physical Exam

  • After confirming the patient is stable and the airway secure, begin the head and neck trauma exam. This should be systematic and concise.

  • Evaluate general demeanor and responsiveness. Patient cooperation may be extremely difficult with pediatric or inebriated patients.

  • Evaluate neurological status to determine the level of consciousness (Glasgow scale).

  • Evaluate for facial asymmetry, lacerations (rule out Stenson duct or facial nerve injury), edema and ecchymosis.

  • Examine the cranial nerves II–XII and note any paresthesia (V1, V2, V3), or facial nerve deficits.

  • If the orbit is involved, evaluate extra ocular movements, pupillary reaction, direct and consensual visual reflexes, monocular (indicative of retinal detachment) or binocular diplopia (can be secondary to edema or entrapment and restriction of gaze). Tonometry should be used for evaluating intraocular pressure. A fundoscopic exam is indicated for for evaluating the retina and optic nerve, and hyphema. A slit lamp exam is useful in evaluating the eyelids, lacrimal system, cornea and to rule out the presence of foreign bodies. Exam should assess for the presence of proptosis, dystopia (disturbance in globe position in the vertical and horizontal planes) or enophthalmos. Look for periorbital ecchymosis (Racoon eyes). Evaluate for telecanthus. Consider ophthalmology exam/clearance.

  • Evaluate the ears for the presence of ecchymosis behind the ears (Battle’s sign) or otorrhea, which may be indicative of a base of skull fracture (if positive neurosurgical consultation is required). Rinne and Weber exam to screen for hearing. Otoscopic exam to evaluate tympanic membrane and EAC (if injury apparent ENT should be consulted).

  • Evaluate for exit wounds if a projectile was involved.

  • Evaluate the midface for loss of projection, edema, ecchymosis, and step deformities.

  • Evaluate the nose for asymmetries, blood, rhinorrhea, and septal hematoma.

  • Evaluate jaws for range deviations on opening (this may indicate a condylar or subcondylar fracture), arch step deformities, lingual ecchymosis (highly indicative of a mandible fracture), hematomas, and intraoral lacerations.

  • Evaluate the state of the dentition (dental fractures, missing teeth, changes in occlusion). For a pediatric patient correlate dental development with chronological age.

  • Evaluate for a chin laceration, preauricular edema, or ecchymosis as these can be suggestive of a condylar fracture.

  • The floor of mouth swelling or the possibility of airway compromise should be noted.

Imaging

  • High-resolution maxillofacial computed tomography (CT) is the gold standard for evaluating facial trauma. Consider obtaining 3D reconstruction for surgical treatment planning and using it as an aid to discuss treatment with the family of the patient.

  • If trauma is isolated to the mandible or dentition an orthopantomogram can be used.

  • Plain film X-rays have limited value in the maxillofacial trauma patient.

  • If teeth are missing or unaccounted for secondary to the trauma then an abdominal X-ray (KUB) and chest X-ray must be performed.

Mandibular Trauma

Nomenclature

  • Fracture types:

    • Simple/closed – not opened to the external environment.

    • Compound/opened – fracture extends into an external environment.

    • Comminuted – splintered or crushed.

    • Greenstick – only one cortex fractured.

    • Pathologic – pre-existing disease of bone leads to fracture.

  • Muscle Action Classification:

    • Vertically favorable vs. non-favorable, based on resistance to medial pull.

    • Horizontally favorable vs. non-favorable, based on resistance to upward movement.

Physical Exam

  • Tenderness over the region of suspected fractures.

  • Malocclusion:

    • Anterior open bite – bilateral condylar or angle fractures.

    • Unilateral open bite – ipsilateral angle, condylar and parasymphyseal fractures.

    • Posterior crossbite – symphyseal and condylar fractures with splaying of the posterior segments.

    • Prognathic bite – TMJ effusions.

    • Retrognathic bite – condylar or angle fractures.

  • Loss of form – bony contour change, soft tissue depressions, deformities.

  • Loss of function – can be from guarding, pain, or trismus.

    • Deviation on opening toward the side of the condylar fracture.

    • Inability to open due to impingement of coronoid or ramus on the zygomatic arch.

    • Premature contacts from alveolar, angle, ramus, or symphysis fractures.

  • Edema.

  • Abrasions/lacerations – the potential for compound fractures.

  • Ecchymosis – especially floor of the mouth, symphyseal, or body fracture.

  • Crepitus with manipulation.

  • Altered sensation/paresthesia.

  • Loss of teeth – require chest X-ray to rule out aspiration if not accounted.

Radiographic Evaluation

Panoramic Radiograph :
  • Most informative radiographic tool.

  • Shows entire mandible and direction of fracture (horizontal favorable, unfavorable).

  • Disadvantages:

    • Patient must sit up-right/cooperative/non-sedated or intubated.

    • Difficult to determine buccal/lingual bone and medial condylar displacement.

    • Some details are lost/blurred in the symphysis, TMJ and dentoalveolar regions.

Mandible Series:
  • Towne’s view, anteroposterior and both oblique views.

Computed Tomography (CT):
  • Excellent for showing intracapsular condyle fractures.

  • Can get axial, sagittal, and coronal views; 3-D reconstructions.

  • Disadvantage:

    • Expensive.

    • A larger dose of radiation exposure compared to plain film.

    • Difficult to evaluate the direction of fracture from individual slices (reformatting to 3-D overcomes this).

Treatment of Mandible Fractures

Closed Reduction (Table 7.3):
  • Contraindications:

    • Medical conditions that should avoid intermaxillary fixation.

    • Alcoholics.

    • Seizure disorders.

    • Mental retardation.

    • Nutritional concerns.

    • Respiratory diseases (COPD).

    • Unfavorable fractures.

Table 7.3

Advantages and disadvantages of closed reduction

Advantages

Disadvantages

Low cost

No absolute stability (secondary bone healing)

Short procedure time

Oral hygiene difficulty

Can be done in a clinical setting with local anesthesia or sedation

Possible TMJ sequelae

Easy procedure

Muscular atrophy/stiffness

No foreign body in patients

Myofibrosis

 

Possible effect on TMJ cartilage

 

Decreased range of motion

 

High degree of compliance required

 

Weakness of muscles due to disuse

 

Osteoporotic changes due to disuse

Techniques for Closed Reduction:
  • Erich arch bars.

  • Ivy loops.

  • Essig Wire.

  • Intermaxillary fixation screws.

  • Splints.

  • Bridal wires.

Length of Intermaxillary Fixation:
  • Based on multiple factors:

    • Type and pattern of fracture.

    • Age of patient.

    • Involvement of intracapsular fractures.

  • Average adult – 3-4 weeks.

  • Children 15 years or younger – 2-3 weeks.

  • Elderly patients – 6-8 weeks.

  • Condylar fractures – 2-4 weeks.

Open Reduction

  • Implies accessing the fracture through skin or mucosa to aid in visualization and reduction of the fracture.

  • Indications:

    • Unfavorable/unstable mandibular fractures.

    • Patients with multiple facial fractures that require a stable mandible for basing reconstruction.

    • Fractures of an edentulous mandible fracture with severe displacement.

    • Edentulous maxillary arch with opposing mandible fracture.

    • Delayed treatment with interposition of soft tissue that prevents closed reduction techniques to re-approximate the fragments.

    • Medically compromised patients.

    • Gastrointestinal diseases.

    • Seizure disorders.

    • Compromised pulmonary health.

    • Mental retardation.

    • Nutritional disturbances.

    • Substance abuse patients.

Contraindications for Open Reduction
  • If a simpler method of repair is available, maybe better to proceed with those options.

  • Severely comminuted fractures.

  • Patients with healing problems (radiation, chronic steroid use, transplant patients).

  • Mandible fractures that are grossly infected.

Edentulous Mandible Fractures

  • Biomechanics differ for edentulous fractures compared dentate mandible fractures:

    • Decreased bone height leads to a decreased buttressing effect (alters plate selection).

    • Significant bony resorption in the body region.

    • Significant effect of muscular pull, especially the digastric muscles.

    • Incidence of fractures highest in the body.

    • Atrophy creates saddle defects in the body.

  • Biological differences:

    • Decreased inferior alveolar artery (centrifugal) blood flow.

    • Dependent on periosteal (centripetal) blood flow.

    • Medical conditions that delay healing.

    • Decreased ability to heal with age.

  • Closed Reduction.

    • Use of circummandibular wires fixated to the piriform rims and circumzygomatic wires with patient’s denture or Gunning style splints.

    • Requires IMF – usually longer periods due to age.

  • Open Reduction Techniques:

    • Treat mandible >20 mm as dentate mandible.

    • Requires load bearing type plates.

    • Due to poor healing quality of bone and reduced osteoprogenitor cells, bone grafts are commonly incorporated to transplant osteocompetent cells and augment mandible.

    • Reduction may be aided by the adaptation of miniplates at the inferior border.

Condylar Process Fractures

  • Usually unilateral, and from indirect trauma from the opposite side of insult.

  • Will have ipsilateral premature closure and midline pull on side of the fracture.

Classifications:

  • Wassmund Scheme [2]:

    • I – minimal displacement of the head (10–45°).

    • II – fracture with tearing of medial joint capsule (45–90°), bone still contacting.

    • III – bone fragments not contacting, condylar head outside of capsule medially and anteriorly displaced.

    • IV – head is anterior to the articular eminence.

    • V – vertical or oblique fractures through the condylar head.

  • Condylar fractures (AO classification – see Fig. 7.2):

  • Goals of condylar fracture repair:

    • Pain-free mouth opening with an opening of 40 mm or greater.

    • Good mandibular motion of jaw on all excursions.

    • Restoration of pre-injury occlusion.

    • Stable TMJs.

    • Good facial and jaw symmetry.

../images/428304_1_En_7_Chapter/428304_1_En_7_Fig2_HTML.png
Fig. 7.2

AO Classification of Condyle Fractures. The condylar neck region can be divided into high and low halves by equally dividing the distance between the sigmoid notch line and the lateral pole line. (Copyrighted by AO Foundation, Switzerland)

Treatment Options for Condylar Fractures
  • Non-surgical – diet, observation, and physical therapy.

  • Closed Reduction:

    • Treated with a short course of IMF with post-operative physical therapy.

  • Open Reduction [3]:

    • Zide’s Absolute Indications:

      1. (1)

        Middle cranial fossa involvement with disability.

         
      2. (2)

        Inability to achieve occlusion with closed reduction.

         
      3. (3)

        Invasion of joint space by a foreign body.

         
      4. (4)

        Lateral capsule violation and displacement.

         
    • Zide’s Relative Indications:

      1. (1)

        Bilateral condylar fractures where the vertical facial height needs to be restored.

         
      2. (2)

        Associated injuries that dictate early or immediate function.

         
      3. (3)

        Medical conditions that indicate open procedures.

         
      4. (4)

        Delayed treatment with misalignment of segments.

         
  • Closed reduction techniques rarely produce pain, limit function, or produce growth disturbances.

  • Open reductions techniques show an early return to normal function, but are technique sensitive, time extensive, and can lead to facial nerve dysfunction depending upon surgical approach.

Teeth in the Line of Fracture

Generally accepted tooth to be removed if:

  • Gross mobility.

  • Periapical pathology.

  • Preventing reduction.

  • Roots with a fracture.

  • Exposed root.

  • Delay in repair from time of fracture.

  • Recurrent infection at the fracture site despite antibiotic therapy.

Complications

Malunion – Fracture that has healed in non-anatomic alignment. More common when complex fractured with multiple segments. May also be due to occlusion that is forced into position, loose IMF, inadequate reduction, or poor adaptation of a fixation plate. If there are minor dental discrepancies, orthodontic or occlusal adjustments can be used as treatment. Early recognition may allow for breaking down hardware and proper alignment. Late identification can mean osteotomies at the fracture sites or orthognathic concepts with surgical stents to reestablish occlusal and facial qualities.

Non-union – Arrested healing after the appropriate time has passed (mobility after 4 weeks without treatment and 8 weeks with surgical management). Can be multifactorial but includes mobility at the fracture site, poor reduction, infection, substance abuse, delay in treatment, or tooth in line of fracture. Diagnosis is characterized by persistent pain, mottled bone at the fracture site, mobility of mandible, and sign of hardware loosening/failure. Treatment occurs after infections are controlled and oral/cutaneous communications have closed. Establish occlusion and a rigid fixation plate is placed. Screw placement is recommended to be 1 cm from borders of segments as some bone is thought to be non-vital. The bone edges are smoothed, and commonly a cancellous bone graft is used to reconstruct the continuity defect if needed.

Osteomyelitis – Complaint of continued pain, paresthesia, feeling of the mobility of plate. Diagnosis can be made with labeled white blood cell scans (indium-111), bone scans (technetium 99), MRI, or biopsy of bone. Treatment can involve removal of hardware with closed reduction, resection/debridement/cortication of bone, placement of rigid fixation, IV antibiotics, and consideration of hyperbaric oxygen therapy.

LeFort Fractures

  • Transfacial fracture of the midface, involving the maxillary bone and surrounding structures in either a horizontal, pyramidal, or transverse direction. It involves the pterygomaxillary suture and the nasal septum.

  • Classified according to the experiments by anatomist Rene LeFort.

Classifications (Fig. 7.3)

LeFort I (Horizontal Fracture)  – extends above the apices of the maxillary dentition across the nasal septum and maxillary sinuses. Posteriorly it extends through the pyramidal process of the palatine bone and the pterygoid processes of the sphenoid bone. It also may involve the fracture of the palate.

../images/428304_1_En_7_Chapter/428304_1_En_7_Fig3_HTML.png
Fig. 7.3

LeFort fracture patterns and recommended plating schemes. (Copyrighted by AO Foundation, Switzerland)

LeFort II (Pyramidal Fracture) – extends from the nasofrontal region down through the medial orbital wall, crossing the inferior orbital rim and zygomatic buttresses. Posteriorly similar to a LeFort I fracture.

LeFort III (Complete Craniofacial Disjunction) – fracture lines extend through the nasofrontal junctions, zygomaticofrontal articulations, zygomaticomaxillary suture, temporozygomatic suture, pterygomaxillary junction, medial and lateral orbital walls, and superior articulation of the nasal septum.

Rarely is there a pure category of fracture; usually there’s a mixed combination.

Physical Exam

  • Generally, look for increased facial height (equine facies), loss of anterior projection (dishpan facies). Look for edema, lacerations, contusions, hematoma formation, and ecchymosis.

  • Ocular – pupils, extraocular muscle function, visual acuity, ocular pressure, subconjunctival hemorrhage, infraorbital nerve sensation, and intercanthal distance.

  • Battle Sign – ecchymosis in the mastoid region, suggestive of a base of skull fracture. Can be seen in midfacial fractures due to high-energy injuries.

  • Palpate – look for tenderness, crepitus, bony step deformities, mobility of segments at zygomaticofrontal and nasofrontal sutures, or maxillary mobility.

  • Nasal – rhinorrhea, septal hematoma, epistaxis, mobility of nasofrontal suture.

  • Intraoral exam – evaluate dentition, relative class III malocclusion, vestibular ecchymosis, tooth loss/fracture, and occlusion and anterior open bite.

Radiographic Evaluation

Maxillofacial CT with axial, coronal, and sagittal cuts. There are four key areas to evaluate.

  • Pterygoid plates, strong indication of LeFort fracture.

  • Lateral margin of nasal fossa, suggestive of LeFort I fracture.

  • Inferior orbital rim, suggestive of LeFort II.

  • Zygomatic arch, suggestive of LeFort III.

Principles of LeFort Fracture Management

  • Nondisplaced fractures without clinical compromise can be managed by a soft diet with observation or 4–6 weeks of IMF.

  • Edentulous patients may be treated with open treatment or observation.

  • Treat as soon as possible. The longer open or compound fractures are untreated, the greater incidence of infection and malunion.

  • Fixate fractures to allow immobilization and optimal healing.

  • Use buttresses for fixation.

  • Restore preoperative occlusion.

  • Ensure to treat nasal complex and orbital fractures as indicated.

Approaches to LeFort I

  • Access is via the transoral approach.

  • Place into IMF (consider using disimpaction techniques if necessary to aid in the alignment of fractures and restoration of occlusion).

  • Reduce fractures and plate stabilization at piriform rims and zygomaticomaxillary buttresses.

  • Check occlusion.

Approaches to LeFort II

  • Access is via transoral and/or periorbital/coronal approach.

  • Place into IMF.

  • Reduce fractures and plate stabilization at the piriform rim, zygomaticomaxillary buttresses, orbital rim, and management of NOE component if necessary.

  • The orbital floor should be treated last after ensuring that the zygoma and the maxilla are in the proper position to prevent increased orbital volume.

  • Check occlusion.

  • Nasal repairs as needed.

Approaches to LeFort III

  • Access is usually via a combination of the transoral, lower lid, coronal approaches.

  • Good mobilization.

  • Place into IMF.

  • Reduce fractures ensuring restoration of adequate facial height and width.

  • Fixate starting at the frontozygomatic suture, nasal region, zygomaticomaxillary buttresses, piriform rims, and zygomatic arch as needed.

  • Check occlusion.

  • Reduce/reconstruct orbit.

  • Nasal reduction as needed.

Description of the Maxillary Vestibular Approach

  • Length of the incision depends on the area of interest or extent of injury. Can be unilateral or bilateral.

  • Incision is placed ~3–5 mm superior to the mucogingival junction making sure to leave adequate unattached gingiva for closure. (Usually extends posteriorly to first molar.)

  • Incise through mucosa, submucosa, and periosteum down to the bone using electrocautery Bovie or #15 blade.

  • Subperiosteal dissection superiorly and anteriorly to piriform buttress and posterior to zygomaticomaxillary buttress.

  • May encounter infraorbital canal and neurovascular bundle if dissection extends enough superiorly.

  • If necessary, may need to dissect nasal mucosa from the lateral wall, floor, or septum using a Freer elevator.

Complications

  • Malocclusion Noted After IMF Is Released – Occlusion may spring open after the IMF is released. Remove fixation and then place patient back in IMF and make sure occlusion is stable and condyles are in the fossa before fixating fractures again; remove from IMF and recheck occlusion.

  • Malocclusion Noted 1 Week Postoperatively – Most likely loss of fixation. Obtain new imaging to confirm and if fixation failed then return to OR to correct. If malocclusion is minor and fixation appears intact on imaging, then allow full healing of fractures and refer for orthodontic correction of the minor malocclusion.

  • Bleeding During Mobilization of the Maxilla – If from the pterygoid muscles at posterior maxilla, then treat with surgicel or fibrin sealants. If from the pterygoid plexus, then treat with local anesthesia and packing. If from the terminal branches of the maxillary artery (descending palatine, PSA, or sphenopalatine arteries) treat with vessel clips and/or anterior and posterior nasal packs. If local hemostatic measures are used and bleeding is still not controlled, then consider embolization with interventional radiology. Late bleeding may occur due to pseudoaneurysm formation.

  • Malunion – May require osteotomies or onlay grafting to address the resulting anatomical anomaly.

  • Nonunion – Continual mobility noted after 8 weeks after the fixation has been placed. May require removal of faulty fixation, bone grafting, and placement of rigid internal fixation.

Zygomaticomaxillary Complex (ZMC) Fractures

  • The zygoma has four articulations (frontozygomatic, zygomaticomaxillary, zygomaticosphenoid, and zygomaticotemporal). These sutures represent common areas of fracture points.

  • It should be noted that the weakest portion of the zygomatic arch is not the zygomaticotemporal suture, but a point approximately 1.5 cm posterior to this suture.

Classification of ZMC Fractures

  • The most commonly quoted is Knight and North, based on the direction of displacement on a Water’s view radiograph.

    • Group 1 – nondisplaced.

    • Group 2 – arch fractures.

    • Group 3 – unrotated.

    • Group 4 – medially rotated.

    • Group 5 – lateral rotation outward.

    • Group 6 – complex fractures.

  • Zingg Classification based on review of CT scans.

    • Type A fractures are incomplete zygomaticomaxillary complex and broken into three subcategories:

      • A1 – Isolated arch fracture.

      • A2 – Isolated lateral wall.

      • A3 – Isolated inferior orbital rim.

    • Type B – monofragment with all four buttresses.

    • Type C – comminution of zygomatic bone.

Physical Exam

  • ZMC fractures are also orbital fractures. An ocular exam is imperative including visual acuity, assessment of extraocular muscles in the six cardinal fields of gaze, integrity of rim, ecchymosis, hyphema, shape of pupil (traumatic mydriasis or iridodialysis), reactivity of pupil, size of pupil, subconjunctival ecchymosis, periorbital edema/ecchymosis, and chemosis and position of the globe. Deepening of the supratarsal crease is one of the earliest signs of enophthalmos.

  • Flattening of the malar eminence. Decreased projection is best assessed from a bird’s eye view.

  • Depression in the preauricular region denoting flattening of the zygomatic arch.

  • Antimongoloid slanting (due to disruption of the frontozygomatic suture and inferior displacement of Whitnall’s tubercle).

  • Neurological disturbances over the distribution of the infraorbital nerve.

  • Step deformities denoting discontinuity of the orbital rim, zygomaticomaxillary buttress, and frontozygomatic region.

  • Ecchymosis in the maxillary vestibule (Guerin’s sign).

  • Trismus if coronoid is impinged and possibly spasm of masseter.

  • Pupillary level – fracture of orbital floor allows for displacement of suspensory ligaments and Tenon’s capsule causing hypoglobus of the affected side.

Radiographic Evaluation

  • CT is the gold standard for evaluation of ZMC fractures. It allows for the visualization of all buttresses and to assess the degree of displacement and/or comminution. It also allows for assessing the orbital floor, muscle entrapment, and the integrity of the globe.

  • CT scans obviate the need for plain radiographs.

  • Plain radiographs that were used in the past for assessing ZMC fractures were the Caldwell and Submentovertex views (submentovertex views are still used intraoperatively to assess adequate reduction of the zygomatic arch).

Management of Zygomatic Fractures

Zygomatic Arch Fractures

  • Isolated zygomatic arch fractures can be approached via a Keen or Gillies approach.

  • Some surgeons wire/suture a finger splint or Fox shield over the arch to maintain reduction while healing.

  • Closed reduction has also been described using a towel clip to aid reduction.

  • ORIF of zygomatic arch fractures. Not performed for isolated arch fractures. Usually stabilized with miniplates as part of a high-impact ZMC fracture or a panfacial fracture.

ZMC Fractures

  • It is important to employ a systematic sequence when treating ZMC fractures. Multiple approaches are necessary to expose the frontozygomatic, zygomaticomaxillary, orbital rim, and orbital floor regions. Minimum two points of fixation are required.

  • Recommended sequencing of fixation:

    • Fixate the frontozygomatic region first to restore facial height of the complex.

    • Fixate the zygomaticomaxillary buttress region to restore facial projection and to ensure that the medially rotated body is back in its normal anatomical position.

    • Fixate the orbital rim to define orbital volume and facial volume.

    • The orbital floor should be managed last as it is critical that the aforementioned sites are placed back into alignment to prevent enophthalmos and facial widening.

  • Alignment of the sphenozygomatic suture is a good indicator of the three-dimensional position of the zygoma.

Complications

Malunion/Asymmetry – May result in facial widening and/or malar flattening. Can be managed by osteotomies (difficult due to lack of bony landmarks), onlay grafts, alloplastic implants, or a combination of the aforementioned. Consider navigational instrumentation when using custom implants.

Enophthalmos – Due to increase in orbital volume or atrophy of fat. Posttraumatic enophthalmos is difficult to manage. Requires placement of space-occupying material such as bone or prosthetic material behind the globe to displace it anterior. Consider custom implant.

Blindness – Rare but devastating either by direct trauma to globe or retrobulbar hematoma. In retrobulbar hematoma, the patient will have pain, proptosis, elevated intraocular pressure, and decrease in visual perception (first decrease in red-green color perception followed by decreased visual acuity).

Retrobulbar Hemorrhage – Managed by a lateral canthotomy or by reopening the surgical wound used for periorbital access to allow for decompression.

Vertical Dystopia – Reconstitution of orbital floor height with autogenous bone, alloplastic implant, or custom plate.

Orbital Fractures

Anatomy

  • Quadrilateral/pyramidal bony cavity with base facing anteriorly. The widest dimension is 1 cm posterior to the orbital rim.

  • Volume: 30 ml, 4 cm horizontal dimension, 3.5 cm vertical on average [4].

  • Medial walls parallel to each other ; lateral walls at 90 degrees to each other. Lateral wall to medial wall 45 degrees. (Fig. 7.4).

../images/428304_1_En_7_Chapter/428304_1_En_7_Fig4_HTML.png
Only gold members can continue reading. Log In or Register to continue

Jul 23, 2021 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Trauma
Premium Wordpress Themes by UFO Themes