Week 4 Craniofacial distraction osteogenesis

Question 1

What is distraction osteogenesis

Answer 1

a surgical procedure that can be used to lengthen the bone by gradually expanding the osteotomy

Question 2

True or False?

If you want to lengthen the bone more than 1 cm, you want to consider DO instead of BSSO

Answer 2

True

Question 3

How much can Do lengthen the bone up to?

Answer 3

20-30 mm (2-3 cm)

Question 4

Distraction site bone formation is similar to….

Answer 4

fracture healing site

Question 5

4 phases of the healing phase of the bone fracture

Answer 5

1. Inflammation
2. Soft Callus
3. Hard Callus
4. Remodeling

Question 6

3 Phases of the DO site.

Answer 6

1. Latency: phase between the osteotomy and the activation of the distractor
2. Distraction: When the distractor is activated, osteotomy gap is widened
3. Consolidation : distractor maintained and new bone is being formed inside the gap

Question 7

_______ is the main driving force for new bone formation

Answer 7

distraction

Question 8

ossification modes for bone formation

Answer 8

1. intramembranous
2. endochondral
3. transchondroid: in between endo and intramembranous

Question 9

_______ is critical for DO site bone formation

Answer 9

periosteum

Question 10

DO also relies on good _______ and _______

Answer 10

angiogenesis

blood supply

Question 11

common distraction rate used nowadays?

Answer 11

1 mm/day

Question 12

General guideline of consolidation time is _____

Answer 12

has to be at least double the duration of the distraction phase

If distract the bone fore 20 days… consolidation time should be at least 40 days.

Question 13

Advantages of DO

Answer 13

• no need for bone graft
• can achieve significantly larger bone movement (>20 mm of Mandibular advancement)
• Lengthen bone in multiple dimensions simultaneously
• Surgical procedure less invasive than conventional orthognathic surgery
• Less soft tissue resistance
• Better long term stability
• Less distortion and loading of the TMJ than BSSO

Question 14

Disadvantages of DO

Answer 14

• Technique and equipment sensitive
• Less precise control for occlusion control
• Pt compliance
• Possible 2nd surgery to remove devices
• Longer treatment time
• Higher cost
• Increased chance for infection

Question 15

Indications of craniofacial DO

Answer 15

• severe micrognathia in infants and children with airway obstruction
• Max deficiency associated with cleft and lip palate
• Max deficiency associated with craniofacial dysostosis
• Mandibular lengthening more than 10 mm
• Severe sleep apnea due to Mx/Mn hypoplasia
• Widening of Constricted mandible
• Correction of syndromic and non-syndromic craniosynostosis
• Syndromic midfacial deformities

Question 16

Contraindications of craniofacial DO

Answer 16

Lack of adequate bone stock to distract

Deficiency or defect can be corrected by traditional orthognathic surgery without bone graft

Lack of pt compliance