ORAL SURG mandible fracture management Flashcards
what are the 2 parts of the condyle?
head
neck
where does the lateral pterygoid attach?
pterygoid fovea
what anatomical structure is behind the external oblique ridge?
ramus of the mandible
what anatomical structure is inferior the the external oblique ridge?
angle of the mandible
what foramen are found in the middle portion of the mandible?
lingual and mental
where does the mylohyoid muscle attach?
oblique line on the lingual surface of mandible
what part of the mandible contains teeth?
alveolar process
where does the mentalis muscle attach?
mental tubercles
what exits through the mental foramen?
terminal branch of the IAN
where is the mental foramen?
between apices of premolars
define a fracture?
a break or a breach in the continuity of normal anatomical structure of a bone by the application of excessive force resulting in 2 or more fragments of the involved bone
why does the mandible often break in more than 1 place?
due to its horseshoe shape
what structure is a known point of weakness?
condylar neck (crumple zone)
what is the aetiology of mandibular fractures?
assault
sporting injury
RTA
pathological
what types of pathology predispose the mandible to fracture?
osteolytic lesions:
cysts
tumours
what are the 5 types of fractures seen in the mandible?
simple
compound
comminuted
greenstick
pathological
define a simple fracture?
undisplaced
overlying periosteum is intact
radiograph shows crack through cortical layer of bone
describe a compound fracture?
perforated through periosteum and often skin
presents externally
involving tooth socket
why do compound fractures predispose mandible to infection?
the fracture line runs through the PDL into the oral cavity, exposing mandible to the oral microbiota
describe a comminuted fracture?
fracture pattern has multiple fracture lines
bone broken to small fragments
describe a greenstick fracture?
uncommon
outer cortices fracture and inner cortex flexes
no displacement
where are the sites in the mandible that can fracture?
dento-alveolar
condylar
coronoid
ramus
angle
body
parasymphysis
symphysis
where is the commonest area of fracture to the mandible?
condylar neck
angle
why is the condyle known as the crumple zone?
instead of driving the condyle into the skull, it will break to prevent damage to the brain
why is the angle of the mandible a point of weakness?
the presence of erupted or partially erupted lower 8s
why is the parasymphysis a point of weakness?
root of the canine
in what direction does the coronoid process usually displace and why?
superiorly due to the temporalis point of attachment
what is the relevance of the muscles attached to the mandible and fractures?
dependent on the pattern of the fracture, the muscles can pull the fracture together or apart causing displacement
causes significant pain
in what way do horizontally favourable fractures pull?
upwards
in what way do vertically favourable fractures pull?
laterally
list the muscles attached to the mandible which may affect the distraction of fracture
medial and lateral pterygoid
temporalis
masseter
digastric
geniohyoid
genioglossus
mylohyoid
what direction does the lateral pterygoid displace a condyle fracture?
anteriorly and medially
what direction does the temporalis, masseter and med. pterygoid displace a proximal segment fracture?
superiorly and medially
what direction does the digastric, geniohyoid, genioglossus and mylohyoid displace the distal segment fracture?
inferiorly and posterior
what factors determine the displacement of fractures?
pattern of fracture
degree of comminution
teeth in fracture line
muscle pull
what makes a fracture unfavourable?
muscles pulling them apart
what is a bucket handle fracture?
seen in edentulous mandibles
bilateral parasymphyseal fractures
anterior segments pulled downwards and backwards
in a bucket handle fracture, what muscles pull the anterior segment downwards and backwards?
mylohyoid
geniohyoid
digastric
genioglossus
what is a guardsman fracture of the mandible?
caused by a fall on the midpoint of the chin resulting in fracture of the symphysis as well as both condyles
what is a common finding of displaced fracture?
malocclusion
list the extraoral clinical features of mandible fractures?
pain
swelling
bruising
trismus
soft tissue injury: cut lip, dirt, tooth fragment
otorrhoea external auditory meatus tear (may accompany condylar fractures)
anaesthesia/ paraesthesia of the lip
list the intraoral clinical features seen with mandible fractures?
haematoma in FOM and buccal mucosa
malocclusion
tongue swelling
gingival laceration
mobility/ loss of teeth
fractured teeth
what intraoral finding is pathognomic of a fractured mandible?
haematoma in FOM/ buccal mucosa (Coleman’s sign)
what causes a parasymphyseal step deformity?
proximal segment displaced superiorly by muscle pull
what may be a sign of an undisplaced fracture?
small laceration in gingivae
what must be checked when suspicious of an undisplaced fracture?
mobility - if there is mobility the fracture will not heal
what are the ideal radiographic views for examination of mandible fractures?
DPT + PA mandible/ facial
when do mandibular fractures merit tx?
displacement (mobility noted) and malocclusion
what complication arise due to a delay in tx of mandibular fractures?
wound dehiscence
infection
exposure of hardware
non-union or fibrous union
what time frame should mandibular fractures be treated within?
72 hours
what happens to a tooth involved in the line of a fracture?
it becomes non-vital
needs endo tx
what are the 2 types of treatment for mandible fractures?
open technique
closed technique
describe the open technique for treating mandibular fractures?
fracture margins are visualised intraorally or extraorally via an incision
why is the open technique preferred for mandible fractures?
the fracture is immobilised to allow a period of healing
describe the closed technique for treating mandibular fractures?
fracture margins are not directly visualised - no incision - intermaxillary fixation (wiring jaws together)
in the open technique, describe reduction?
aligns the bone ends anatomically
recreates the normal anatomy
in the open technique, what is the purpose of fixation?
prevents movement of the bone whilst healing occurs
describe load bearing fixation in the open technique?
100% of the functional load is supported by the fixation e.g., 2 large plates
describe load sharing in the open technique?
the load is distributed between the hardware and the bone margins e.g., one upper boarder plate and arch bars
why do we want fixation in the open technique to be load bearing?
not replying on adjacent bone to hold 2 ends together
what are the 2 methods of fixation?
open
closed (intermaxillary)
what is used for the open method of fixation?
mini-plates
reconstruction plates
compression plates (old fashioned)
lag screws
what materials are used for closed intermaxillary fixation?
arch bars
eyelet wires
leonard buttons
cast cap splints
gunning splints
what are mini-plates used for and made from?
open fixation - made of titanium (they osseointegrate) - they do not get removed
when fixating an edentulous mandible, what material do you use?
gold reconstruction plates - very rigid
list the indications for closed reduction?
non-displaced favourable fractures
grossly comminuted fractures
significant loss of overlying soft tissue
edentulous mandible fractures
fractures in children
coronoid process fractures
undisplaced condylar fractures
what are the advantages of closed reduction?
inexpensive
simple procedure
no foreign body so reduced risk of infection
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 (aspiration pneuomonia)
where do IMF screws engage?
labial cortex
what is a gunning splint?
used for edentulous fractures
anterior teeth removed from denture for oral intake
denture is wired in place for up to 6 weeks
what are indications for open reduction?
displaced unfavourable fractures
multiple fractures
edentulous displaced fractures
bilateral displaced condylar fractures
what are the advantages of open reduction?
improved alignment and occlusion
fracture immobilised
avoid IMF
low rate of malunion or non-union
lower rate of infection
what are the disadvantages of open reduction?
morbidity of surgical procedure
expensive hardware
need for GA
what are Champy’s principles?
miniplate osteosynthesis = placement of a plate along the so-called ideal line of osteosynthesis, thereby counteracting distraction forces that occur along the fracture line
in the mandibular angle region, this line indicated that a plate may be placed either along or just below the oblique line of the mandible
between the mental foramina, 2 plates are recommended below the apices of the teeth
why may extra-oral open reduction be used for edentulous mandible fractures?
to avoid stripping the periosteum as it is less vascular
what type of plates may you want to use for edentulous mandible fractures?
large reconstruction plates that are load bearing
what are complications of management of mandibular fractures?
non-union, fibrous union, mal-union
altered occlusion
distracted TMJ
scars
infection
necrosis
numb lip
exposed plate
what are the 2 types of condylar fractures?
extra-capsular
intra-capsular
describe an intra-capsular condyle fracture?
within the capsule, small fragments
describe an extra-capsular condylar fracture?
nearer the neck
how are condylar fractures usually treated?
soft diet and NSAIDs
what is TMJ effusion?
inflammation
what is the treatment for a displaced/ dislocated condylar fracture?
open reduction and internal fixation
how is a intracapsular condylar fracture treated?
closed approach
what is of concern with paediatric fractures?
tooth germs and condylar growth plates
how are paediatric fractures treated?
conservative management with splints
