Maxillofacial Reconstruction (Strauss) Flashcards
What are 4 goals of reconstructive surgery?
- Restore facial form
- Restore bone continuity
- Restore soft tissue coverage
- Restore function
What are 3 overal goals of reconstructive surgery?
- Function
- Cosmesis
- Psychology
What are 4 causes leading to reconstructive surgery?
- Trauma
- Pathology
- Age
- Congenital
When planning reconstruction, what must be diagnosed?
What is missing (soft tissue, hard tissue, dental, or composite defect)
After diagnosing how is the restoration planned?
Plan with what is available and realize may have to restore in stages
What is the philosophy of the reconstructive ladder when considering reconstructive options?
Try what is as minimal as possible on the reconstructive ladder, e.g. the base of the ladder is healing via secondary intention
Why follow the reconstructive ladder?
As you go up the ladder both the difficulty and risks increase, so that must be accounted for
What are the the 9 steps of the reconstructive ladder starting with the bottom and ending at the top?
- Healing by secondary intention (base of ladder) 2. Primary closure
- Delayed primary closure
- Split-thickness skin graft
- Full-thickness skin graft
- Tissue expansion
- Random-pattern flap
- Pedicled flap
- Free flap
Cause of the defect, pt expectations, prognosis, pt’s health status, condition of available tissue, and surgeon’s experience all contribute to what ?
The decision of HOW to treat
When is immediate reconstructive surgery indicated (2) and its advantages (2) ?
Indicated when there is a good availability of tissue and no residual pathology
Advantages are it provides immediate function and decreases the amount of surgeries
What are 3 indications for delayed reconstruction?
- Existing pathology / infection
- Multiple defects
- Existing medical problems (risk associated with prolonged surgery, poor donor site, smoker, peripheral vascular disease)
What is the disadvantage of delayed reconstruction?
2 stage surgery
What are 4 factors influencing the choice of graft?
- Volume of tissue needed
- Type of tissue needed
- Function of tissue needed
- Availability of donor site
Which does not maintain its original blood supply and therefore depends on the blood supply from the recipient site: graft or flap?
Graft
Which does maintain its original blood supply and therefore less dependent on the recipient site blood supply?
Flap
Would a graft be indicated in an area that is poorly vascularized, such as a previously irradiated site?
No, because the graft required the recipient site’s blood supply
What is indicated to cover a poorly vascularized area, such as a previously irradiated site: a graft or a flap?
Flap because it brings its own blood supply
What is a flap type whose blood supply is derived from named blood vessels?
Axial flap
What are 2 examples of Axial flaps and their associated named blood vessels?
- Palatal island flap (greater palatine artery)
2. Abbe flap (labial artery)
What is a flap type whose blood supply is derived from unnamed blood vessels?
Random flap
What is an example of a random flap?
Tongue flap
A local / regional flap is located within the same or outside of the anatomical unit receiving the flap?
Within the same anatomical unit
A distant flap is located within the same or outside of the anatomical unit receiving the flap?
Outside of the anatomical unit
What is the first principle of flap surgery that aides in camouflaging the surgical defect?
Replace like tissue with like tissue
The second principle of flap surgery is to think of the reconstruction in terms of what?
Units
The most important aspect of a flap surgery when considering a unit is its what?
Borders
Must a partial unite defect remain a partial unit defect for reconstruction?
No, it’s always better to convert to a whole unit defect and graft for better comesis
The third principle of flap surgery requires that they should always be what 2 things?
- A pattern
2. A fall back plan
Principle IV of flap surgery discusses what aspects of suturing and what consideration for the donor site for the flap or the graft?
Sutured without tension
Donor area should not have excessive tissue loss
What are 4 factors guiding the choice of graft for bone?
- Volume of bone needed
- Type of bone needed (particulate or cortical)
- Function of bone needed
- Availability of donor site
What are the 2 phases of Axhausen’s theory of osteogenesis?
Phase I = cell proliferation and disorganized osteoid formation
Phase II = phase I disorganized osteoid resorbed and replaced with organized lamellar bone
Phase I of Axhausen’s theory of osteogenesis is most active how long after placement of bone graft?
Most active first 4-6 weeks
When is the grafted area more radiopaque, Phase I or Phase II of Axhausen’s osteogenesis?
Phase I due to disorganized osteoid
When does the disorganized osteoid from Phase I begin to resorb and be replaced by the more organized lamellar bone of Phase II of Axhausen’s osteogenesis?
2 weeks post graft, peaking at 6 weeks
New bone in the graft site is derived from what cells: graft cells or host cells?
Host cells
Is cortical bone osteoconductive or osteoinductive?
Osteoconductive because only provides a scaffold
Is particulate / cancellous bone (synonymous) osteoconductive or osteoinductive?
Osteoinductive
Longevity of graft depends on what 2 things?
Cellular quantity and quality of recipient bed
What can decrease the cellular quantity and quality of the recipient bed which will decrease graft success?
- Scarring
- Irradiation
- Fatty tissue
What is the term for a graft that is transplanted from one region to another in the same individual?
Autograft
What is the term for a graft from one individual to a genetically non- identical individual of the same species?
Allograft
What is the term for a graft transplanted from one species to another?
Xenograft
What is the term for a graft that is synthetic bone substitutes (tricalcium, phosphate, hydroxyapatite)?
Alloplasts
What is the only graft that provides living, immunocompatible cells that are essential to phase I of bone healing: autograft, allograft, xenograft, or alloplasts?
Autograft
What type of graft must be treated to reduce antigenicity, for example undergoing lyophilization [freeze drying]: autograft, allograft, xenograft, alloplasts?
Allograft
Which autogenous bone graft provides the greatest amount of viable bone-forming cells: cancellous or cortical ?
Cancellous
Which autogenous bone graft requires rigid fixation: cancellous or cortical ?
Cortical
Which autogenous bone graft has a higher concentration of bone morphogenic proteins (BMP) : cancellous or cortical ?
Cortical
Which autogenous bone graft has a more porous microstructure: cancellous or cortical?
Cancellous
Which autogenous bone graft has less osteocompetent cells and less surface area for remodeling: cancellous or cortical?
Cortical
Which autogeneous bone graft has no structural integrity: cancellous or cortical?
Cancellous
Are allogenic grafts more osteoconductive or osteoinductive?
Osteoconductive (provide the framework)
Weak osteoconductive if you have small amounts of BMP
What allograft has been processed to make BMPs more available, and the processing is thought to expedite the incorporation process once placed, and has been shown to stimulate more new bone?
Demineralized freed-dried bone (DFDB)
Alloplasts (synthetic bone substitutes) are only osteoinductive or osteoconductive?
Only osteoconduction
What is a contraindication for alloplast bone graft?
Load-bearing areas
What is a disadvantage of Alloplast bone graft use?
High incidence of tissue breakdown and secondary infection
Which is the slowest bone graft material to take?
Alloplasts. May take up to 9-12 months to see bone growth.
What are 2 areas for local bone in jaw for autogenous graft?
- Chin
2. Ramus
What are 4 areas for distant bone for autogenous graft in the jaw?
- Rib
- Calverial
- Tibial
- Ilium
What is the difference between platelet rich protein (PRP) and bone morphogenic protein (BMP)?
PRP is pt’s blood spun down and placed in graft site to provide protein regeneration chemicals to the bone. BMP is the commercial alternative
What is a positive aspect of using the rib as a distant autogenous donor site and in what demographic is this a consideration?
Rib provides both bone and cartilage. Cartilage allows the bone to continue to grow which is key for young reconstruction pts, i.e. pts still growning
