OS2 - Fractures of the Mandible Management Flashcards
(117 cards)
1
Q
What is A?
A
the condylar head (which leads to the condylar neck)
2
Q
What is B?
A
coronoid process (which is then attached to the ascending ramus along the oblique ridge)
3
Q
What is C?
A
coronoid notch
4
Q
What is D?
A
5
Q
What is E?
A
angle of the mandible
6
Q
What is F?
A
mental foramen
7
Q
What is G?
A
mandibular symphysis (at midline)
8
Q
What is the area between G and F?
A
the parasympysis (the area between the mental foramen and the mandibular symphysis)
9
Q
What is this area? (orange line)
A
body of the mandible
10
Q
What is this area? (blue line)
A
symphysis of the mandible
11
Q
What is this area? (yellow line)
A
parasymphisis of the mandible
12
Q
What does the condylar process contain?
A
head and neck of condyle
13
Q
What is the muscle attachment for the lateral pterygoid?
A
pterygoid fovea
14
Q
What attached on the oblique line?
A
the mylohyoid muscle
15
Q
What attached to the mental tubercles?
A
the mentalis muscle
16
Q
Summary of mandible anatomy
A
17
Q
How is ‘a fracture’ defined?
A
a break or a breach in the continuity of normal anatomical structure of a bone (usually but not always) by the application of excessive force resulting in 2 or more fragments of the involved bone?
18
Q
Why does the mandible often break into more than 2 fragments?
A
due to its horseshoe shape and transmission of forces
19
Q
What are points of weakness in the mandible which preferentially fracture?
A
the condylar necks, act as a crumble zone to prevent the mandible displacing backwards into the base of the skull
20
Q
How common are mandibular fractures?
A
- account for 36-70% of all facial fracture
- the second most common facial fracture after nasal fractures
- 10th most common fracture all bones in body
21
Q
What are the common causes of mandibular fractures?
A
- assault
- sport injury
- road traffic accidents
- pathological (due to weakening because of cysts/tumours etc)
22
Q
What are the types of fractures?
A
- simple
- compound
- comminuted
- greenstick
- pathological
23
Q
What is a simple fracture?
A
- tends to suggest an undisplaced fracture where the overlying periosteum is intact
- would look like a small crack on an xray but the fragments haven’t moved apart
24
Q
What is a compound fracture?
A
- perforated through the overlying periosteum, and often through the skin
- any fracture that involves a tooth socket is a compound fracture as the fracture line runs through PDL which exposes the fracture to the oral microbiota
- higher potential for would infection vs simple fractures
25
What is a comminuted fracture?
- fracture pattern has multiple fracture lines, tends to be more high impact fractures e.g. high speed RTAs, bullet wounds
- bone broken into small fragments
26
What is a greenstick fracture?
- uncommon in the mandible, associated with children
- flexing of the bone such that one of the outer cortexes will fracture but the inner will flex so there is no displacement
27
What kind of fracture site is A?
dental-alveolar fracture
28
What kind of fracture site is B?
condylar
29
What kind of fracture site is C?
Corona i’d
30
What kind of fracture site is D?
Ramus
31
What kind of fracture site is E?
Angle
32
What kind of fracture site is F?
Body
33
What kind of fracture site is G?
Parasymphysis
34
What kind of fracture site is H?
symphysis
35
What is the most common mandibular fracture site?
condylar or angle, followed by parasymphysis
36
Why is the angle of the mandible a common site of fracture?
because there is often an eruption, partially erupted, or completely unerupted mandibular third molar present which makes this area a point of weakness
37
Why is the parasymphysis a common site of fracture in the mandible?
due to long rooted mandibular canines making this area a point of weakness
38
Why can coronoid fractures be difficult to manage?
the temporalis muscle attachment may pull the fragment and displace it into the infraorbital space
39
What effect can the muscles attached to the mandible have in terms of mandibular fractures?
dependent on the pattern of fracture the muscles can pull the fracture together or pull it apart causing displacement of the fracture
40
What are the 4 pairs of muscles of mastication?
- masseter
- temporalis
- lateral pterygoid
- medial pterygoid
41
Other than the muscles of mastication, what muscles attach to the mandible?
- mylohyoid
- genioglossus
- geniohyoid
- anterior belly of digastric
- mentalis
- buccinator (to an extent)
42
Where does the lateral pterygoid muscle attach to the mandible?
pterygoid fovea on the medial aspect of the condylar neck
43
What effect can the lateral pterygoid have on a mandibular fracture?
tends to pull the condylar neck downwards and inwards (anteriorly and medially), so has a greater potential for causing displacement and dislocation of the condylar head
44
What effect can the temporalis, masseter and medial pterygoid have on a mandibular fracture?
tend to displace the proximal segment superiorly and medially
45
What effect can the digastric, geniohyoid, genioglossus and mylohyoid have on a mandibular fracture?
tend to displace the anterior segment inferiorly and posteriorly, can cause the bucket handle fracture
46
What are favourable/unfavourable patterns of fracture?
favourable - muscles are pulling the fragments together
unfavourable - muscles are pulling the fragments apart
47
What factors determine the amount of displacement of a mandibular fracture?
the pattern of fracture, degree of communication, teeth in the fracture line and muscle pull
48
What can be seen here?
bilateral displaced unfavourable fractures, one at RHS angle of mandible, one at LHS parasymphysis
49
What kind of fracture is this?
bucket handle fracture
50
What is a bucket handle fracture?
bilateral parasymphyseal fractures, in an edentulous mandible
51
What muscles are involved in a bucket handle fracture?
mylohyoid, genioglossus and digastric all pulling the anterior segment downwards and backwards
52
What is a guardsman’s fracture of the mandible?
often happens when someone falls chin first, the force causes a fracture in the midline of the mandible which then transmits the force bilaterally to the condylar necks causing condylar fracture
53
What is a guardsman’s fracture of the mandible?
often happens when someone falls chin first, the force causes a fracture in the midline of the mandible which then transmits the force bilaterally to the condylar necks causing condylar fracture
54
What muscles are involved in a guardsman’s fracture?
lateral pterygoid muscle attached to the pterygoid fovea on the medial portion of the condyle, therefore it will tend to contract and drag the condylar head inwards causing medial displacement of the coronoid process
55
What are the extra-oral clinical features of a mandibular fracture?
- pain
- swelling
- bruising
- trismus
- concurrent soft tissue injury - cut lip- dirt, tooth fragment
- otorrhoea of external auditory meatus tear may accompany condylar fractures
- anaesthesia/paraesthesia of lip
56
What are the intra oral clinical features of a mandibular fracture?
- haematology in the floor of the mouth (Coleman’s sign) and buccal mucosa
- malocclusion
- tongue - stable position, swelling
- step deformity
- gingival laceration
- mobility or loss of teeth, fractured teeth - inhaled, swallowed, in soft tissue
57
In a mandibular fracture, why is there often a haematoma in the floor of the mouth and buccal mucosa?
the periosteum overlying the bone has torn and there is a haemorrhage into the adjacent tissues
58
What does a step deformity indicate?
displacement of the fracture
59
How may an undisplaced or minimally displaced mandibular fracture present?
sometimes not an obvious step in the the occlusion or no obvious mobility, sometimes only a small gingival laceration or tear, or some bleeding around the teeth
important to assess whether there is any mobility as this indicates displacement
60
What radiographic views may be used in a dental practice to assess for mandibular trauma?
- DPT
- (if no DPT - lateral oblique - usually limited to dental hospitals)
- occlusal view
- periapical
61
What are the ideal radiographic views to assess for mandibular fracture?
- 2 radiographic views at 90 degrees to each other
- ideally a DPT and a PA mandible/facial bones
62
What specialist views may be used to assess condylar neck fracture?
reverse towne’s view
63
What is the best radiographic examination that can be done to assess mandibular fractures?
CBCT (secondary care)
64
How would this patient likely present clinically?
- pain
- paraesethsia/anaesthesia of the lip due to stretching of the IAN
- malocclusion / lateral open bite
65
What can a PA mandible/facial view help show?
can show displacement in the lateral/medial direction
66
Where are the fractures on this DPT?
- RHS body of mandible
- RHS condylar neck
67
Describe the fractures seen in this DPT
- bilateral minimally displaced angle of mandible
- involve the sockets of bilateral impacted 8s
68
How would this patient likely present clinically?
- pain
- likely facial swelling and bruising
- trismus
- may or may not have altered sensation of the lip
69
What would determine whether this patient needed management?
- if there is a malocclusion / only contact on the last molar with anterior open bite
- if any mobility of the fragments is possible
70
What radiographic view is this?
lateral oblique
71
Of all the bones of the face, why are fractures of the mandible most likely to develop infections?
many of the fracture lines will involve the socket of a tooth which is exposed to oral bacteria via the PDL
72
What kind of complications can occur when there is a delay to presentation/treatment of mandibular fracture?
- would dehiscence (break down)
- infection
- exposure of hardware which breakdown of the overlying mucosa
- non-union or fibrous union
73
What is done when a mandibular fracture has been referred to OMFS?
- radiographs
- management
- follow up
74
What happens to any teeth within the line of fracture?
almost always rendered non-vital and require RCT
75
What are the 2 types of technique for treatment of mandibular fracture?
- open techniques
- closed techniques
76
What are open techniques for management of mandibular fracture?
- the fracture margins are visualised intra-orally or extra-orally via an incision and aligned with plates
- this is generally the preferred options as the fracture is immobilised to allow a period of healing
77
What are closed techniques for management of mandibular fracture?
- the fracture margins are not directly visualised - no incision
- intermaxillary fixation (wiring the jaws together)
- there is often mobility at the fracture site that can have a detrimental effect on healing
78
What are the 2 principles of treatment in the management of mandibular fractures?
- reduction
- fixation
79
What is reduction/what does it do?
- aligns the bone ends anatomically
- recreates the normal anatomy
80
What is fixation/what does it do?
- prevents movement of the bone margins while healing occurs
- can be load bearing so that 100% of the functional load is supported by the fixation e.g. 2 large plates
- can be load sharing such that the load is distributed between the hardware and the bone margins e.g. one upper boarder plate and arch bars
81
How long does it take for bone to heal in an adult?
4-6 weeks
82
Is load bearing or load sharing more preferable?
load bearing
83
What are the methods of internal fixation?
- **mini-plates** (titanium, osseointegrate, most commonly used)
- reconstruction plates (edentulous mandible or very comminuted fractures, very thick and rigid)
- compression plates (push fracture ends together)
- lag screws (pierce through buccal and lingual cortex)
84
What are the methods of external fixation?
intermaxillary fixation
- arch bars
- eyelet wires
- leonard buttons
- cast cap splits
- gunning splints
85
What are the indications for closed reduction techniques?
- non-displaced favourable fractures
- grossly comminuted fractures
- significant loss of overlying soft tissue
- edentulous mandibular fractures
- fractures in children
- coronoid process fractures
- undisplaced condylar fractures
86
What are the advantages of closed reduction?
- inexpensive
- simple procedure
- no foreign body so reduced risk of infection
87
What are the disadvantages of closed reduction?
- not absolutely stable
- prolonged period of IMF up to 6 weeks
- possible TMJ sequelae
- decreased oral intake
- possible pulmonary considerations
88
What are Ericht arch bars?
preformed arch bars cut to size, wired to each individual tooth and then the upper and lower arch bound together with ortho bands
89
What are IMF screws?
screws that go into the labial cortex which are then wired together
90
Are all arch bars preformed and cut to size?
no, can be custom made from impressions and occlusal registration etc
91
What are gunning splits?
- used for edentulous patients with dentures
- take away the anterior teeth and add cleats onto the denture, the dentures are then wired in place
- not common anymore
92
When is open reduction indicated?
- displaced unfavourable fractures
- multiple fractures
- edentulous displaced fractures
- bilateral displaced condylar fractures
overall this is the preferred technique
93
What are the advantages of open reduction?
- improved alignment and occlusion
- fracture immobilised
- avoid IMF
- low rate of malunion or nonunion
- lower rate of infection
94
What are the disadvantages of open reduction?
- morbidity of surgical procedure
- expensive hardware
- need for GA
95
What are the disadvantages of open reduction?
- morbidity of surgical procedure
- expensive hardware
- need for ga
96
What is dictated by Champy’s principles?
the number and position of plates
97
What do Champy’s Principles tell us about miniplate osteosynthesis?
miniplate osteosynthesis = placement of a plate along the so-called ideal line of osteosyntehsis, thereby counteracting distraction forces that occur along the fracture line
98
What to Champy’s Principles tell us about the mandibular angle region?
in the mandibular angle region, this line indicates that a plate may be placed either long or just below the oblique line of the mandible
99
What do Champy’s principles tell us about the mental foramina?
between the mental foramina 2 plates are recommended below the apices of the teeth
100
According to Champy’s Principles where are the compression and tension lines of the mandible?
lines of tension - along the necks of the teeth
lines of compression - along the inferior border of the mandible
101
What is the blue arrow point at?
mental bundle after exiting the mental foramen
102
What Champy’s principle does this align with?
1 plate above the mental foramen and 1 below
103
In what kind of fracture is an extra-oral sub-mandibular approach to open reduction often used?
displaced fractures involving the lower border, where the most appropriate place to plate the fracture is inferiorly
104
For what kind of patients is an extra-oral approach usually advocated?
edentulous patients, to avoid stripping of the periosteum as if a ridge is atrophic it has a limited vascular supply
105
Why can fractures of an edentulous mandible be quite challenging?
- the more atrophic they are the less bone there is to try and reduce and fix
- the more atrophic they are the less vascularised they are so there is poor healing capacity
- lack of anatomical landmarks
- the less bone height the greater the complication rate
106
What would typically be used to manage a fracture of an edentulous mandible?
use large reconstruction plates that are load bearing, usually placed from an extra-oral approach
107
What can be involved in the post-operative care of mandibular fracture management?
- ward vs ITU
- open vs closed reduction
- wire cutters or scissors - and instructions on how/when to release IMF
- antibiotics - oral; IV; IM
- steroids
- fluids
- post op x-rays - not now routinely taken
108
What complications can occur after managing fractures of the mandible?
- non-union, fibrous union, mal-union
- altered occlusion
- distracted TMJ
- scars - trauma and iatrogenic
- infection - 0.4-32%
- necrosis
- numb lip
- exposed plate
109
What does inadequate fixations of a mandibular fracture lead to?
non-union, fibrous union, or mal-union
110
What are the 2 types of condylar fractures?
- extra-capsular (more common, neck of condyle etc.)
- intra-capsular (less common, harder to treat due to smaller fragments)
111
When would a fracture of the condylar neck need open reduction and internal fixation?
if they have been displaced or dislocated, as this will cause shortening of the height of mandible from the point of the condylar head to the angle of the mandible, which causes deviation of the mandible to the affected side when the pt occludes and premature contact of the teeth on the affected side
112
When would a fractured condyle be treated conservatively?
if the condyle isn’t badly displaced and the occlusion isn’t significantly effected
113
When would a fractured condyle be treated actively?
if there is a displacement or dislocation
114
How is a fractured condyle treated conservatively?
- soft diet
- analgesics/anti-inflammatory
115
How is a fractured condyle treated actively?
- open reduction and plating
- closed - leonard buttons and elastic traction
116
What limits where you can place plates in a paediatric fracture (uncommon)?
tooth germs and condylar growth plate
117
How are paediatric fractures of the mandible, which are uncommon, usually managed?
conservative management with splints
