Maxillofacial Traumatology: Fractures Of The Middle Third Of The Facial Skeleton II PDF

MAXILLOFACIAL TRAUMATOLOGY: FRACTURES OF THE MIDDLE THIRD OF THE FACIAL SKELETON Dr. Saeed Hameed Tutmayi B.D.S. , M.Sc. (OMFS) F.K.H.C.M.S.(MaxFac) Lec-1- Traditionally the facial skeleton has been divided into an upper, middle and lower third. The lower third i...

MAXILLOFACIAL TRAUMATOLOGY: FRACTURES OF THE MIDDLE THIRD OF THE FACIAL SKELETON Dr. Saeed Hameed Tutmayi B.D.S. , M.Sc. (OMFS) F.K.H.C.M.S.(MaxFac) Lec-1- Traditionally the facial skeleton has been divided into an upper, middle and lower third. The lower third is the mandible. Middle third of the facial skeleton is defined as an area bounded superiorly by a line drawn across the skull from the zygomaticofrontal suture of one side, across the frontonasal and frontomaxillary sutures to the zygomaticofrontal suture on the opposite side, and inferiorly by the occlusal plane of the upper teeth, or, if the patient is edentulous, by the upper alveolar ridge.  INTRODUCTION Types of the fractures Displacement of the fractured segments Methods of treatment of fractures TYPES OF MIDFACE FRACTURES Open (compound) fractures Closed (simple) fractures Simple fracture is not exposed to outside. Compound fractures are exposed to outside chance of infection would be increased and prophylactic antibiotic would be required. Note: exposure of the fracture to outside can happen through the skin, periodontium, paranasal sinuses, and the nose. Accordingly, all of fractures in the tooth bearing areas of the mandible, maxilla, nasoethmoidal complex, orbital floor, and the zygoma are considered compound fractures. Other fractures of maxillofacial skeleton are considered simple fractures if they are not exposed to outside through a wound in the overlying skin.  Displacement of the Fracture Segments Immediate displacement : caused by the impact Later displacement: caused by the muscle pull The base of the skull (where the frontal bone articulates with the sphenoid) extends backwards and angled downwards at approximately 45° to the occlusal plane of the upper teeth. Impacts with large force can cause displacement of mid third of facial skeleton posteriorly and downwards, along the slope of the sphenoid. Backward displacement along the inclined skull base, this allows for the posterior teeth of the maxillae contact the posterior mandibular teeth prematurely and produce an anterior open bite. Occasionally this displacement is sufficient to cause lengthening of the face. The pterygoids attaches the posterior maxilla to the mandible. When these muscles are in function, they can displace the maxilla back and down. Downward and backward displacement of the fractured maxilla caused by posterior muscle pull.  Treatment of Fracture Reduction: 1. Open reduction 2. Closed reduction Fixation: 1. Direct fixation 2. Indirect fixation Reduction: Correction of the fracture by bringing the displaced segments back to their anatomical position Fixation: Holding the reduced segments fixed till they heal up Indirect fixation of the fracture by intermaxillary fixation (IMF)  Treatment Methods Open reduction with direct fixation Closed reduction with indirect fixation The Facial Skeleton The bones constituting the middle third of the facial skeleton which may be fractured following trauma to this region are as follows: 1. The two maxillae; 2. The two palatine bones; 3. The two zygomatic bones (malar bones in old terminology) and their temporal processes; 4. The two zygomatic processes of the temporal bones; 5. The two nasal bones; 6. The two lacrimal bones; 7. The vomer; 8. The ethmoid bone and its attached conchae (turbinate bones in old terminology); 9. The body and lesser and greater wings of the sphenoid bone are not normally fractured, but the pterygoid processes of the sphenoid bone are almost invariably involved in extensive fractures of the middle third of the facial skeleton.  SURGICAL ANATOMY The skeleton of midface Articulation with the base of the skull Involvement of the dura and cranial nerves Involvement of the blood vessels Involvement of the paranasal sinuses  The Skeleton of Midface The bones of the midface can be thought of as a series of vertical and horizontal bony struts or ‘buttresses’ surrounding the sinuses, eyes and uppermost part of the respiratory tract. Joining these buttresses together is wafer-thin bone. The forces of mastication are thus distributed round the nasal airway, globes and paranasal sinuses as they pass upwards to the relatively rigid skull base  THE SKELETON OF MIDFACE Representation of facial buttresses. Four horizontal buttresses in red (from top to bottom: frontal, zygomatic, maxillary, mandibular). Four vertical buttresses in green (from lateral to medial: posterior mandibular, pterygomaxillary, zygomaticomaxillary, nasomaxillary) Articulation With the Skull Base The base of the skull (where the frontal bone articulates with the sphenoid) extends backwards and angled downwards at approximately 45° to the occlusal plane of the upper teeth. In the midline the cribriform plate of the ethmoid makes contact with the meninges of the brain and transmits the olfactory nerves  Involvement of the Dura and Cranial View of the anterior cranial Nerves base showing the cribriform plate of the ethmoid with the olfactory nerve foramina and midline crista galli. This fragile bone is fractured in high midface Le Fort type and severe naso-orbito-ethmoid injuries. Damage to the underlying dura may result in cerebrospinal fluid rhinorrhea. Patient with a high level midface fracture involving the cribriform plate with breach of the dura mater and cerebrospinal fluid (CSF) rhinorrhoea. The mixture of CSF (which does not coagulate) and blood (which does) results in a so-called ‘tramline’ pattern of discharge from the nose, as seen on the patient’s left side. Note also the classical signs of a high level fracture including bilateral circumorbital ecchymosis (‘panda eyes’) and early gross facial swelling. Involvement of Nerves Olfactory nerves Optic nerves Oculomotor nerve 3O2T1A Trochlear nerve Trigeminal nerve Abducent nerve  Oculomotor Nerve Injury Involvement of the oculomotor produces outward and downward shifting of the eye globe and diplopia, It also produces a fixed dilated pupil, not responding to light, and ptosis of upper eyelid (LR6SO4)3 LR6 = Lateral rectus muscle is supplied by the sixth cranial nerve (abducent nerve) SO4 = Superior oblique muscle is supplied by the fourth cranial nerve (trochlear nerve) All other ocular muscles are supplied by the third cranial nerve (oculomotor nerve) (LR6SO4)3  Trochlear nerve Injury Injury to the trochlear nerve cause weakness of downward eye movement with consequent vertical diplopia (double vision). The affected eye drifts upward relative to the normal eye, due to the unopposed actions of the remaining extraocular muscles. The infraorbital nerve is a branch of the maxillary nerve, itself a branch of the trigeminal nerve (CN V). It travels through the orbit and enters the infraorbital canal to exit onto the face through the infraorbital foramen. The branches of the infraorbital nerve innervate the lower eyelid, the lateral inferior portion of the nose and its vestibule, the upper lip, the mucosa along the upper lip, and the vermilion. When this nerve get crushed by direct trauma or compressed by the surrounding broken bones, numbness in the area supplied by this nerve. Isolated abducent nerve injury can happen with fracture of the zygomatic bone. Eye with abducent nerve injury The eye is pulled in toward the nose because the medial rectus muscle works without opposition...  Superior Orbital Fissure Syndrome a b Superior orbital fissure syndrome due to fracture involving the left posterior orbit. (a) Paralysis and ptosis of upper eyelid. (b) Ophthalmoplegia with lack of movement of left eye in all positions of gaze (attempted downward gaze shown here). The patient also had anesthesia of the left cornea and supra-orbital region. All these signs and symptoms usually resolve spontaneously with time. Retrobulbar Hemorrhage  Classification of Fractures on an Anatomical Basis Fractures involving the occlusion Fractures not involving the occlusion  Fractures involving Le Fort I (low-level or Guerin) the occlusion Le Fort II (pyramidal) Le Fort III (high-level or cranio-facial disjunction)  Le Fort I Fracture (Gue’rin Fracture) a Frontal view. b Lateral view. c Paramedian section Course of the fracture line in Le Fort I fracture. Le Fort I: the fracture starts from nasal septum to the lateral pyriform rims, travels horizontally above the teeth apices, crosses below the zygomaticomaxillary junction, and traverses the pterygomaxillary junction to fracture the lower third of the pterygoid plates Hematoma in the maxillary vestibule. The contusion and edema which can extend to the upper lip. Ecchymosis at the junction of hard and soft palate ‘Guérin sign’ Bimanual palpation for Le Fort I fracture: one hand grasps the maxilla and elicits the mobility, while the fingers of the other hand kept lateral to the pyriform fossa feel the abnormal mobility Clinical Presentation of Le Fort I Fractures Bruising of upper lip and lower half of midface Hematoma intra-orally over root of zygoma Ecchymosis or laceration in palate (Guerin sign: Ecchymosis palate –greater palatine foramen bilaterally) Mobility of whole of dentoalveolar segment of upper jaw Palpable crepitation in upper buccal sulcus ‘Cracked pot’ percussion note from upper teeth  Le Fort II Fracture a Frontal view. b Lateral view. c Paramedian section Course of the fracture line in Le Fort II fracture. Starts from nasal bridge at or below the nasofrontal suture through the frontal processes of the maxilla, iInferolaterally through the lacrimal bones and inferior orbital floor and rim through or near the inferior orbital foramen, and inferiorly through the anterior wall of the maxillary sinus. It then travels under the zygoma, across the pterygomaxillary fissure, and through the pterygoid This fracture is typically higher than the Le Fort type I fracture posteriorly. As with the Le Fort type I pattern, the nasal septum may also be involved. The fracture can be unilateral or bilateral. Elongation of the midface with bilateral circumorbital ecchymosis Subconjunctival hemorrhage Retrusion of the midface. Bimanual palpation in a case of Le Fort II fracture, one hand grasps the maxilla and elicits the mobility, while the fingers of the other hand kept over the infraorbital area feel the abnormal mobility  Clinical Features in Le Fort II fractures Gross oedema of soft tissues over the middle third of the facial skeleton Bilateral circum-orbital ecchymosis (Black eye) Bilateral sub-conjunctival haemorrhage (medial half) Nasal deformity  Step deformity at infraorbital margins Mobility of midface detectable at nasal bridge and infraorbital margins Anaesthesia or paraesthesia of cheek Bleeding from nose or nasal obstruction from clotted blood ‘Dish-face’ deformity of the face with occasional noticeable lengthening  Gagging on the posterior teeth Difficulty in opening mouth, and sometimes inability to move the lower jaw Mobility of the upper jaw ‘Cracked-pot’ sound on tapping teeth No tenderness over, or disorganization and mobility of zygomatic bones and arch  Le Fort III Fracture a Frontal view. b Lateral view. c Paramedian section Course of the fracture line in Le-Fort III fracture. Le Fort III fractures (transverse), also termed craniofacial dysjunctions, may follow impact to the nasal bridge or upper maxilla. These fractures start at the nasofrontal and frontomaxillary sutures and extend posteriorly along the medial wall of the orbit through the nasolacrimal groove and ethmoid bones. The thicker sphenoid bone posteriorly usually prevents continuation of the fracture into the optic canal. Instead, the fracture continues along the floor of the orbit along the inferior orbital fissure and continues superolaterally through the lateral orbital wall, through the zygomaticofrontal junction and the zygomatic arch. Intranasally, a branch of the fracture extends through the base of the perpendicular plate of the ethmoid, through the vomer, and through the interface of the pterygoid plates to the base of the sphenoid. Elongation of the face Patient with a high level midface fracture involving the cribriform plate with breach of the dura mater and cerebrospinal fluid (CSF) rhinorrhoea. The mixture of CSF (which does not coagulate) and blood (which does) results in a so-called ‘tramline’ pattern of discharge from the nose, as seen on the patient’s left side. Note also the classical signs of a high level fracture including bilateral circumorbital ecchymosis (‘panda eyes’) and early gross facial swelling.  Diagnosis of CSF Fluid coming from the nose 1. If bloody fluid, one may look for the halo sign (or ring sign). Dab some of the blood on a could be: tissue. If there is CSF mixed with the blood, it will a) Bloody fluid: could be pure move by capillary action further away from the center than the blood will. blood or a mixture of blood and CSF 2. If clear fluid, CSF should have glucose in it, b) Clear fluid: could be nasal whereas this is unlikely in normal nasal secretions, and so measuring the glucose (initially secretion or pure CSF on dipsticks, and then formally) is helpful. If in doubt one may measure the level of beta-2-transferrin in the fluid. This protein is only found in CSF, and if found in fluid coming from the nose or ears, the diagnosis of CSF leak is confirmed. Beta-2-transferrin protein Bimanual palpation: abnormal mobility at the nasofrontal junction 5. Mobility of midface detectable at nasal bridge and zygomaticofrontal suture area 6. Possible diplopia 7. Pupils tend to be level unless there is gross unilateral enophthalmos 8. Nasal bones move with midface as a whole but often otherwise intact 9. Cerebrospinal fluid rhinorrhoea may be clinically detectable 10. Cracked-pot’ sound on tapping teeth  Radiological Features of Midface Fractures not Involving Occlusion 1. Plain radiography: Occipitomental view PA view 2. OPG 3. CT scan 4. MRI 1. Intact lower orbital rims 2. Loss in continuity lateral wall of maxilla 3. Fracture lateral margin of pyriform 4. Radiopacity maxillary antrum Coronal CT scan section in Le Fort I fracture 3D CT scan showing Le Fort I fracture Plane X ray: Shows (1) the occipitomental (water’s view), (2) radiopaque maxillary sinuses, (3) deviation &/or fractured nasal septum 3D CT scan: showing the pyramidal Le Fort II fracture of the maxilla Coronal section CT scan as it shows involvement of the pterygoid plates in Le Fort fracture. In this case, the pterygoid plates are broken at their roots in Le Fort III fracture Treatment of the Le Fort Fracture Open reduction and direct fixation. Closed reduction and indirect fixation with : – Immobilization by internal suspension – Immobilization by external suspension  Open Reduction and Direct Fixation The surgical access for open reduction for treatment of Le Fort I fracture can be achieved through an intraoral incision in the mucobuccal fold from the upper right second molar to the upper left second molar Direct Fixation in Le Fort I Fracture Direct fixation can be achieved by: (1) Miniplate: Stabilization with L-shaped miniplates (1.5 or 2.0), Fixation with at least two screws on either side of the fracture line in order to avoid rotational instability. The plates are placed along buttresses (2) Trans- osseous wire fixation –buttress bone (lateral piriform rim and zygomaticomaxillary) (3) Bone graft across a comminuted Le fort I fracture In situations with bone loss in buttress areas, bone grafts, often in combination with miniplate fixation, should be used to bridge the defect. Surgical incisions to approach the fracture lines in Le Fort II fracture Direct Fixation in Le Fort II Fracture Miniplate at zygomaticomaxillary buttress, infraorbital rim and frontonasal junction The bicoronal flap for Le Fort III fracture Bicoronal flap reflected down to approach the fracture lines  Direct Fixation in Le Fort III Fracture Direct fixation by plating and screws  Closed Reduction and Indirect Fixation 1. Closed reduction 2. Indirect fixation by: – Immobilization by internal suspension + Intermaxillary fixation (IMF) – Immobilization by external suspension  Indirect Fixation Prevention of downward displacement of the fractured maxilla Prevention of backward displacement of the fractured maxilla Downward displacement of the Fractured Maxilla: 1. Early downward movement of the fractured maxilla is mainly caused by the impact 2. Late downward movement of the fractured maxilla is usually caused by gravity. It can be prevented by suspending the fractured segment to any stable point above the fracture line. Backward Displacement of the Fractured Maxilla: 1.Early backward movement of the fractured maxilla is mainly caused by the impact 2.Late backward movement of the fractured maxilla is usually caused by the effect of the posterior muscles pull. It can be prevented by IMF  Closed Reduction Loosely mobile : Finger manipulation Impacted: Rowe’s disimpaction forceps Use of the Rowe’s disimpaction forceps for reduction of Le Fort I fracture Two Carrol Girard screws can be used bilaterally (one in each side) to reduce the Le Fort III fracture back into its normal position Internal Suspension for Prevention of Downward Displacement 1. Suspension wire from frontal bone 2. Suspension wire from the pyriform aperture 3. Suspension wire from infraorbital rim 4. Suspension wire from zygomatic bone 4 1 2 3 In Le Fort I fracture, the fractured maxillary segment can be suspended from a stable point along the lateral rim of the pyriform aperture above the fracture line Circumzygomatic wiring Indirect Fixation in Le Fort II Fractures 1.Central frontal suspension (Kufner wire) 2.Circumzygomatic suspension 3 1 3.Lateral frontal suspension 2 By the use of theses wires the reduced maxilla is sandwiched between the mandible (sound bone bellow the maxilla) and the zygomatic bone or frontal bone (sound bone above the maxilla. This shall provide the required fixation Indirect Fixation in Le Fort III Fractures 1.Central frontal suspension (Kufner wire) 2. Lateral frontal suspension 3. Circummandibular wires to inforce the lower arch bar Lateral frontal suspension: the suspension wires are attached to lower arch bar, sandwiching maxillary segment between stable mandible and stable frontal bone Lateral frontal suspension IMF for Prevention of Backward Displacement