Maxillofacial Flashcards
Lone protrudor mandible
Lateral pterygoid
Inward displacement mandible
Lateral and medial pterygoid
Vertical buttress
Nasomax
Pterygomax
Zygomatfront
Zygomatmax
Maximum bite forces(3)
200-300n incisors
300-600n premolar
500-700n molars
Forces acting on the mandible
Tension
Compression
Torsion (symphysis)
Observation and ff up for a greenstick considered a
Treatment
4 surgical steps in fx management
Adequate exposure
Fragment reduction : goal establish preinjury bone anatomy prior to reduction
Adequate internal fixation
Meticulous wound closure - muscle and periosteal resuspension
Bone healing
Primary - no motion across fx. Only titanium
Secondary- callous formation
No BH
Secondary bh cascade?
Hematoma - fibroblasts occur
Granulation/connective tissue formation - increased stiffness
Compact bone - mineralization from fragment ends toward center of fracture gap.
Do reduction <2 weeks to prevent cascade
Delayed union?
Clinically prolonged healing period but cascade is similar
<3 mos healing
Non union bh?
> 3mos healing
Fragment ends too wide
Le fort 1 (guerin)
Horizontal sep maxilla. From base of maxillary sinus to lower border nasal septum and pterygoid
5 articulations of zm:
Frontal process/zf butres Zm buttress/zm but Inf orbital rim Zyg arch Zygosphenoid /zs but
If 2 point fixation zmc?
Zf and zm (if 2 point)
Zm- strongest mastication butress
Zf- strongest butress
Ideally 5 point fixation
If 1 point either zf or zm
Accuracy of reduction in desc
Zs Zygomatic arch Zm but Infraorbital room Zf shture line
Stable fix
Zm Zf zs Zygo arch Infraorbital rim
Blow out fx types?
Pure only orbital floor
Impure may orbital rim
Where teardrop sign seen
Waters view xray
Kazanjian and Converse Forces per square inch to fracture? Frontal? Nasal? Premaxilla? Mentum to the mandible? Condyle? Zygoma?
120-180G 39-80G 150G 70-110G 35-80G 50-80G
Timing of reduction after nasal bone injury?
Asap 1-2 h after injury
After 2-3 days for swelling to subside
<10 days before fibrous development (10-14d)
Nasal bone reduction possible until how many days?
21 days
Intranasal packs are in place for how long?
3-5days
Nasal splints are in place for how long?
7-10days
Mandibular body is until what area?
Between 2nd and 3rd molar
Classification of dentures?
Class I - dentulous, dentition on both sides of the fx
Class II - some dentition present
Class III - completely edentulous
Comprises mandibular xray series?
APO
For condylar fx, what x ray view can be used?
High townes view
Imaging of choice for mandibular fx?
Panorex
How many screws for screw IMF?
4-6
Absolute indications for open reduction of condylar fx? (4)
- Condylar displacement into middle fossa
- Inability to obtain reduction
- Lateral extracapsular displacement of the condyle
- Invasion by a foreign body
What are the indirect signs of fracture on ct?
Air fluid level
Complete opacification of the sinus with blood
Gas outside the sinus
Divisions of occipital bone?
Basioccipital
Condylar
Squamosal
Strane and robertson classification of nasal fractures by depth of injury?
Plane 1: anterior nasal spine, anterior septum, lower ends of the nasal bones
Plane 2: greater nasal bone fracture but does not involve the orbital rims
Plane 3: NOE complex disruption
