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In temporal bone fractures:
__% are open
__% CNVII involved
__% CSF fistulas
- 60% open
- 20% transverse
- 80% longitudinal
- 7% CNVII involved
- 17% CSF leak
The body of the mandible is defined as the portion of the bone between the canines
and the anterior attachment of this muscle.
How will the location of the inferior alveolar nerve differ in an edentulous
mandible as compared to one with teeth.
- The nerve will be closer to the oral surface.
- The tooth-bearing portions of the mandible atrophy from the top-down
When numbering teeth, where would you begin and end counting?
Tooth #1 is the right maxillary 3rd molar, progresses to the left maxilla, then to the left mandible. Tooth #32 is the right mandibular 3rd molar.
These are the three posterior muscles that raise the mandible.
Temporalis, Medial Pterygoid, Masseter. The masseter muscle attaches broadly to the inferolateral surface of the ramus, whereas the pterygoids attach to the medial surface. The temporalis attaches to the coronoid process.
The reported specificity of high-resolution (1-mm) helical CT in identifying mandible fractures (answer within 5%).
100%. The same study found the sensitivity for panorex was 86%.
This fracture should be suspected in a patient with left sided open bite deformity who’s mandible deviates to the right when open.
Right sided subcondylar fracture. A subcondylar fracture commonly presents with contralateral open bite deformity and deviation to the ipsilateral side when opened.
This fracture should be suspected in a patient with anterior open bite deformity and
premature posterior contact.
Bilateral subcondylar fractures
This type of plain film view assesses the integrity of the subcondylar region and coronoid process
Low Towne’s view
This is the name of the deformity in a
patient with a maxillary buccal cusp that is lingual to the equivalent mandibular buccal cusp.
- Crossbite. The maxillary arch is wider than the mandibular arch. If a maxillary cusp lies lingual to it’s mandibular equivalent, the
- patient has a crossbite.
This is where you find the mesiobuccal cusp of the maxillary first molar in a bite classified Angle Class II.
Anterior to the mesiobuccal groove of the mandibular first molar.
Fractures at this part of the mandible most commonly develop complications
- The angle. Fractures here extend from the
- tooth-bearing region to the much thinner bone of the ramus. The vector of masseter forces often complicate healing.
This is the most commonly fractured region of the mandible
- Subcondylar region. The condylar head of the mandible is connected to the vertical ramus by the relatively thin and weak condylar neck. Condylar (36 percent), body
- (21 percent), angle (20 percent), symphysis (14 percent), alveolar ridge (3 percent), ramus (3 percent), and coronoid fractures (2
Do to the greater potential for torque and rotational movement in this region, two
miniplates are always required
to obtain a stable fixation.
True or False. The rate of complications
related to a mandible fracture increases if the repair is delayed more than 72
False. Definitive repair of a mandibular fracture is not a surgical emergency, and treatment is often delayed in the multiply injured patient. A recent study comparing patients undergoing repair within 3 days of injury to those repaired after 3 days found no increase in complication rates. This presumes prophylactic antibiotics are started.
Open fixation of mandibular fractures in
pediatric patients are avoided, and monocortical screws used preferentially, due to a fear of injuring this structure.
Two of the three indications to remove a tooth after a mandibular fracture.
- Tooth within the fracture line interferes with occlusion.
- Evidence of infection of a tooth within the fracture line.
- Fractured tooth, nonviable tooth, exposed pulp.
This is the most common complication after repair of a mandible fracture.
Wound infection. Rate of wound infection is higher in fractures treated by ORIF. Other complications that occur less often include malocclusion, nonunion, malunion, tooth loss, trismus, ankylosis, deviation, unsightly scars, and paresthesias.
Wolff’s Law states that bone remodeling occurs in response to this.
Mechanical forces acting on the bone. This, unfortunately, means that bone will not remodel to optimize dental function or asthetics.
When tension plates and compression plates are utilized together, this is the one that should be placed first.
It is critical that the tension zone be controlled first, the compression plate on the inferior mandible will distract the alveolar portion of the fracture of placed first.
This technique of mandibular fracture repair
utilizes only a small monocortical plate at the tension zone, often without addressing the compression zone.
The Champy Technique
When an oblique fracture generates bone segments that overlap rather than abut each
other, this method of fixation is recommended.
Lag screws are placed such that the first cortex functions as a washer and the two cortices are drawn together as the screw is tightened.
An 89 year old female presents with a simple fracture of the mandibular body. She is edentulous with a notably atrophic mandable. Describe the type of fixation recommended for this repair.
A common misconception is that, because the mandible is small, only a small plate is required for repair. An atrophic mandible is a contraindication to a load-sharing repair. A load-bearing repair with long, strong plates and multiple fixation points with bicortical screws is required.
The 4 classic indications for open reduction of subcondylar fractures. [Not including the following relative indications: 1. B/L fx in edentulous mandible, 2. When splinting is not recommended, 3. B/L fx with comminuted midface fractures, 4. B/L fx with gnathologic problems]
- Condylar displacement into the middle fossa,
- Inability to obtain closed reduction
- Lateral extracapsular displacement of the condyle
- Invasion by a foreign body
What is the maximum dose of lidocaine you can inject? What is the maxium dose of lidocaine with epinephrine?
5 mg/kg lido, 7 mg/kg lido/epi
What volume 1% lido with 1:100,000 epi can you give a 15 kg child?
If a facial nerve laceration is identified, when should it be repaired?
What determines whether the nerve can be repaired primarily or if a graft is needed?
If there is less than 1 cm separating the proximal and distal segment, it can be repaired primarily
How long after injury will the distal end of the nerve continue to stimulate?
Usually 3 days until wallerian degeneration occcurs, but as long as 7 days
In a stable patient with a penetrating neck wound, when would you order angiography?
- Zone 1 (mortality rate 12%):
- – Angiography regardless of symptoms
- Zone 2
- – Consider angiography if asymptomatic
- – Symptomatic, neck exploration in OR
- – Can be managed expectantly in trauma center with 24hr radiology and endoscopy)
- Zone 3
- – angiography regardless of symptoms
What are the various ways to evaluate the esophagus after penetrating injury?
- – Good sensitivity. Risk of mediastinitis if it extravasates.
- – Low morbidity. Comparatively insensitive for pharyngoesophageal injury
- Flexible esophagoscopy
- – Poor sensitivity, low morbidity. No general anesthesia.
- Rigid esophagoscopy
- – High sensitivity. Requires general anesthesia.
Describe the classifications of NOE fractures.
- Type I: A large central fragment containing the medial canthal ligament is freed from the surrounding bone.
- Type II: Significant comminution, but the fragment containing the medial canthal ligament is still repairable.
- Type III: The tendon is either detached or attached to an unusable fragment.
Which muscle is responsible for making mandible fractures vertically unfavorable?
Which muscles elevate the mandible?
masseter, temporalis, medial pterygoid