os - trauma

Question 1

symptoms of # zygoma

Answer 1

1. ocular symptoms due to proximity of zygoma to orbital floor
2. maxillary sinus fills with blood so epistaxis as max sinus drains through nose via semi lunar hiatus

Question 2

supply of eye muscles

Answer 2

CN VIII oculomotor
except
LR7 - lateral rectus CN VII
SO4 - superior oblique CN IV trochlear

Question 3

clinical symptoms of zygomatico-orbital trauma (8)

Answer 3

1. step deformity
2. epistaxis - unilateral
3. periorbital bruising & swelling
4. subconjunctival ecchymoses
5. sensory defect via infraorbital nerve i.e. numbness in the cheek
6. diplopia
7. subcutaneous emphysema
8. flatness of the face

Question 4

inital mx of ZO #

Answer 4

1. exclude ocular injury - warn signs re retrobulbar haemorrhage
2. prophylactic ABs
3. avoid nose blowing

Question 5

definitive mx of ZO #

Answer 5

1. r/v when swelling subsided
2. CBCT / occipitomental 15 & 30 degree views
3. informed consent
4. closed reduction +/- fixation
5. OR +/- IF

Question 6

muscles that close mandible

Answer 6

masseter
medial pterygoid
temporalis

Question 7

muscles that open mandible

Answer 7

anterior belly digastric
mylohyoid
geniohyoid

Question 8

damage to IAN manifests as

Answer 8

numbness of lower lip & chin

Question 9

causes of numbness to IAN (4)

Answer 9

1. direct trauma
2. impacted M3M
3. infection of bone i.e. osteomyelitis
4. resorption of bone due to pathology i.e. cyst

Question 10

signs & symptoms of mandibular #

Answer 10

pain, swelling, loose / mobile teeth, deviation of mandible to opp side of #, facial asymmetry, AOB (# can cause shortened ramus), numbness of lip, bleeding limited to # site
important to look at FoM for sublingual haematoma

Question 11

to classify mandibular # (5)

Answer 11

1. involvement of surrounding tissue i.e. simple / compound / comminuted
2. no of # i.e. single / multiple
3. site of # lines i.e. uni / bi / multi
4. direction of # line i.e. favourable / unfavourable
5. if displaced or undisplaced

Question 12

involvement of surrounding tissue

Answer 12

1. simple = everything intact
2. compound = soft tissue damaged thus exposing # to environment
3. comminuted = bone broken into may small pieces

Question 13

what causes displacement of #

Answer 13

1 group of muscles will pull the segment up and the other group of muscles will pull the segment down therefore causing displacement

Question 14

direction of # line

Answer 14

favourable - minimises displacement
unfavourable - encourages further displacement

Question 15

causes of # displacement (6)

Answer 15

1. magnitude of force
2. mechanism of injury
3. other associated #s
4. opposing occlusion; if v good displacement minimal as acts as stopper
5. direction of # line
6. if soft tissues intact# unlikely to be displaced

Question 16

pathological causes of # (3)

Answer 16

expanding cystic lesions
osteoporosis
osteomyelitis

Question 17

greenstick #

Answer 17

in children where bone is softer due to organic content so bends rather than breaks

Question 18

mx of mandibular #

Answer 18

1. clinical exam
2. radiographs i.e. OPT & PA // CBCT
3. control pain & infection i.e. compound requires ABs
4. undisplaced potentially no tx but displaced requires tx

Question 19

any # in tooth bearing area

Answer 19

is a COMPOUND #
why ? direct communication with pd which is in communication with oral cavity
only not the case in edentulous pt

Question 20

to identify # on radiograph (3)

Answer 20

1. radiolucent line
2. loss / deformity of medial border of mandible
3. step in occlusion

Question 21

2 main methods of tx for any #

Answer 21

1. reduction = putting segment back into correct position
2. fixation = if displaced it MUST be reduced and fixed

Question 22

closed reduction & fixation

Answer 22

no cutting or raising of flaps, do not open #, depends on pt occlusion to guide process
uses intramaxillary fixation to assume if teeth are re placed in correct position then mandible must be in correct position
involves wiring jaw shut for 6wks

Question 23

CR & intermaxillary fixation contraindicated in pts with

Answer 23

epilepsy

Question 24

open reduction & internal fixation

Answer 24

expose bony edges surgically i.e. raise flap and reduce directly with vision then fixed with plates & screws

Question 25

indications for ORIF of condylar #

Answer 25

1. bilateral subcondylar # with AOB 2. displaced # middle cranial fossa 3. displaced # causing occlusal derangement 4. displaced condylar # causing limited mouth opening 5. displaced # causing ramus shortening

Question 26

le fort I

Answer 26

# line passes through alveolar ridge / lateral nose / inferior wall of maxillary sinus horizontal maxillary # separating teeth from upper face MAXILLA ONLY

Question 27

le fort II

Answer 27

pyramidal # with teeth at base & nasofrontal suture at apex inferior orbital rim = type II; if not then excludes this MAXILLA & NOSE

Question 28

le fort III

Answer 28

zygomatic arch involved = type III if not then excludes this type risk to temporalis MAXILLA, NASAL BONE, ZYGOMA

Question 29

any combination of le fort

Answer 29

is possible # of pterygoid plates is mandatory to diagnose le fort

Question 30

basic principles of distraction osteogenesis (5)

Answer 30

1. osteotomy (location & direction) 2. latency 3. remodelling 4. consolidation 5. distraction (vector / rate / rhythm - want 1mm / day)

Question 31

where you get bone for graft from

Answer 31

chin / ramus / hip (iliac ridge)

Question 32

signs of retrobulbar haemorrhage

Answer 32

pain proptosis blurred vision tx lateral canthotomy to decrease pressure behind eye

Question 33

initial mx of zygomatico orbital #

Answer 33

conservative exclude ocular injury antibiotic prophylaxis nose blow instructions / anything that creates pressure i.e. same as OAC r/v after 7-10 days to allow for reduction in swelling