Week 7 Thomson- Facial Deformity

Question 1

What is required for assessing patient before orthognathic surgery?

Answer 1

• Clinical exam
• Study models
• Radiographs

Question 2

What are indications for orthognathic surgery? Which are most common?

Answer 2

• Difficulty chewing and swallowing
• TMD & headache
• Excessive O wear
• Open bite
• Unbalanced facial appearance
• Facial injury or congenital defects
• Receding chin
• Md prognathism
• Incompetent lips
• Chronic mouth breathing & dry mouth
• OSA

Question 3

What are tx goals for orthognathic surgery?

Answer 3

• Establish better function
• Improve dental occlusion
• Normalise/optimise facial aesthetics
• Improve overall pt health

Question 4

What are surgical approaches for orthognathic surgeries?

Answer 4

• Lefort 1 mx osteotomy
• Bilateral sagittal split osteotomy
• Bimaxillary surgery
• Genioplasty
• Segmental osteotomies

Question 5

What surgery is required for this pt?

Answer 5

• Bimaxillary osteotomy
• Genioplasty

Question 6

What is the fundamental surgical principle for orthognathic surgery?

Answer 6

• Pre-surgical ortho for 1.5 years
• Osteotomy to separate the maxilla / mandible from the skull and/or temporomandibular articulation, and then fix bone segment to a planned new position.
• Fixation using titanium miniplates/screws or IMF to allow stabilisation for bone healing
• Post surgical ortho for further 6 months-1 year.

Question 7

What is lefort I osteotomy?

Answer 7

• Mx 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 & mobilisation
• Mx repositioning
• Mx segmentalisation (correction of width, O plane, dento-alveolar relations)

Question 8

What is involved in bilateral sagittal split osteotomy?

Answer 8

• Advance set back md
• Correct rotations/adjust asymmetry
• Close small open bite discrepancies
• Natural cleavage plane between B & L cortical plates
• Sagittal split- proximal (condylar) fragment, distal (dento-alveolar) fragment

Question 9

What is the purpose of a wafer following double jaw surgery?

Answer 9

Helps reposition md against mx teeth and it can be wired into position

Question 10

What is genioplasty?

Answer 10

• Can be adjunct procedure to DJS or solitary procedure
• Can advance or set back
• Rotated L or R
• Augmented/Reduced vertical dimension

Question 11

What are some craniofacial syndromes?

Answer 11

• Apert’s syndrome (angle shaped head, bulging eyes)
• Crouzons syndrome
• Craniofacial microsomia
• Treacher-collins syndrome

Question 12

What is distraction osteogenesis?

Answer 12

Encouraging biological process of new bone formation where bones are separated by incremental traction

• Simultaneous lengthening of soft tissues
• Osteotomy → latent period → distraction phase → consolidation phase