W7 - Orthognathic Surgery - Thomson Flashcards
What is needed for orthognathic assessment of pt (3)
Clinical examination
Radiograph (lat ceph)
Study models
Indications for orthognathic surgery (8)
Difficulty eating (chewing/swallowing)
TMD & headache
Excessive occlusal wear
Open bite
Aesthetics
Prognathism/retrognathia
Receding chin
Chronic mouth breathing
Obstructive sleep apnoea
Treatment goals of orthognathic surgery (4)
Establish better function
Improve occlusion
Optimize aesthetics
Improve overall patient health
What are the 5 surgical approaches of orthognathic surgery
Le fort 1
BSSO
Genioplasty
Bimax surgery
Segmental osteotomies
What is the fundamental surgical principle of orthognathic surgery
Osteotomy - separate the mx or md from the skull/ temporomandibular articulation and then fix bone segment to a planned new position
How is fixation achieved in orthognathic surgery
Titanium miniplates and screws to allow stabilisation
Describe the role of orthodontic prep for orthognathic surger
What you had
Pre surg ortho for 1.5 years
surg
Post surg osrtho 6 mo - 1 year
Describe the le fort 1 osteotomy (5)
Osteotomy sectioning lateral walls of mx sinus and lateral wall of nose
Sited above apices of mx teeth
Nasal septum divided from mx crest
Down-fracture & mobilization
Maxilla repositioning
Maxilla segmentalisation (if needed)
What can the BSSO achieve? (5)
- Advance/set back md
- Correct rotations
- Close small open-bite discrepancies
- Natural cleavage plane btw buccal and lingual cortical plates
- Saggital split (proximal (condylar) fragment and distal (dento-alveolar) fragment)
What is used to help reposition the floating md to mx in DJS
surgical wafer / splint
What is genioplasty? what can it do? (3)
Adjunct procedure to DJS
- Advance or set back
- Augmented or reduce vertical dimension
- Rotated L or R
What does tx of CLP potentially cause?
Restricted growth of maxilla
Scarring of soft tissues
Reduced alveolar bone = crowding
- May need orthognathic surgery later in life due to recessed mx
What craniofacial syndromes may require orthognathic surgery (4)
Craniofacial microsomia
Treacher collins
Aperts
Crouzons
Describe how distraction osteogenesis works (8)
Biological process of new bone formation
bony surfaces are separated by incremental traction
osteotomy
Latent period / early callus
Distraction phase
Consolidation phase (ossification of callus)
Simultaenous soft tissue lengthening
What happens to IAN during distraction osteogenesis?
Soft tissue and nerves lengthen simultaneously as bone is slowly separated
