OSM Wound Healing Flashcards
What are 2 causes of tissue damage?
- Physical
2. Chemical
What are the 3 stages of wound healing?
- Inflammatory
- Fibroplastic
- Remodeling
When does the inflammatory stage of wound healing begin?
At the time of injury
How long does the inflammatory stage of wound healing last?
3-5 days
What are the 2 phases of the Inflammatory stage of wound healing?
- Vascular
2. Cellular
What is the first phase of inflammatory stage of wound healing involving vasoconstriction and coagulation, then WBC release Histamines and Prostaglandins E1 and E2 which cause vasodilation allowing leukocytes to migrate into the interstitial tissues?
Vascular
What causes edema and how?
Fibrin causes lymphatic obstruction causing Edema
The 2nd phase of the inflammatory stage of wound healing, the Cellular phase, is triggered by what?
Activation of serum compliment (C3a & C-5a) caused by tissue trauma
What 2 complement factors are chemotactic for neutrophils to Marginate and Diapedese?
C3a and C5a
What is the term for the process by which a neutrophil sticks to the vessel wall?
Margination
What is the term for a Neutrophil migrating through vessel wall?
Diapedesis
What is the term for neutrophils releasing their lysosomal enzymes, the proteases that destroy bacteria, foreign material and digest necrotic tissue?
Degranulation
What does a Macrophage do to foreign and necrotic material?
Phagocytize
Which lymphocytes produce antibodies?
B lymphocytes
Which lymphocytes are the helper, suppressor, and killer cells?
T lymphocytes
What is the flow of the cellular phase of the Inflammatory stage of wound repair?
tissue injurystimulates split complement factors C3a & C5acause chemotaxis, margination, diapedesis of NeutrophilsNeutrophils degranulate to destroy bacteria, foreing material, and digest necrotic tissue, aided by macrophages to clear the debrisB & T lymphocytes accumulateB lymphocytes form antibodies and further aides immune system in fighting infection
What are 5 signs of inflammation?
Erythema –redness Edema –swelling
Warmth – vasodilation Pain Loss of function
What are 3 things that cause pain in wound healing?
- Histamines
- Prostaglandins
- Pressure from edema
What 2 things lead to loss of function in wound healing?
- Edema
2. Pain
In epithelialization, how does the epithelium proliferate/migrate?
The free edge of the epithelium advances over wound until it contacts other epithelial cells
What do cells without cell to cell contact do in wound healing?
Release chemical mediators that regulate cell growth.
When cells contact each other they stop releasing chemical mediators and cell proliferation stops. This is called what?
Contact inhibition
In the 2nd phase of wound healing, the Fibroplastic stage, what crisscrosses the wound as a result of coagulation forming a latticework on which fibroblasts can begin laying down ground substance and tropocollagen?
Fibrin strands
When does the fibroplastic stage of wound healing take place?
3-4 days after injury
What are the 2 phases of the Fibroblastic stage of wound healing?
- Migratory Phase
2. Proliferative Phase
During which phase of the Fibroblastic stage of wound healing does Epithelial migration continue?
Migratory Phase
What removes necrotic materials during the Migratory phase of Fibroplastic Stage of wound healing?
Leukocytes
How do capillaries in-grow to the wound area during the Migratory phase of the Fibroplastic stage of wound healing?
Bud from existing blood vessels at margin of wound and run along fibrin strands to cross wound
Fibroblasts migrate into the wound during the Migratory phase of the Fibroplastic stage of wound healing and do what?
Stimulate pluripotential mesenchymal cells to begin tropocollage production
What occurs if wound placed under early tention (no sutures) during wound healing?
Wound pulls apart, increasing the scar
What 3 things occur during the Proliferative Phase of the Fibroplastic Stage of wound healing?
- epithelial thickness increases
- Collagen fibers laid down by fibroblasts
haphazardly - Capillaries interconnect to increase vascularity
How long does the Proliferative phase of the Fibroplastic Stage of wound healing last?
2-3 weeks
What is the resulting strength of the repaired wound at the end of the Fibroplastic Stage?
75%
What do fibroblasts lay down haphazardly that ?undergoes crosslinking to become collagen
Tropocollagen
What are 2 things laid down by fibroblasts to produce collagen?
- Ground substance (mucopolysaccharides)
2. Tropocollagen
What is the 3rd stage of wound healing that results in wound maturation
Remodeling stage
What is the length of the Remodeling stage of Wound Healing?
It continues indefinitely
What happens to the epithelium during the Remodeling Stage of Wound Healing?
Epithelial stratification
What is the resulting strength of the wound after the collagen has remodeled in the Remodeling stage of of Wound Healing?
85% of original strength
When the fibroblasts disappear in the Remodeling Stage of Wound Healing, what will be the character of the scar?
The scar will be softer
When the Vascular integrity is reestablished in the Remodeling Stage of wound healing, will the volume of vessels in the wound increase or decrease, and what will be the resulting erythema?
The volume of vessels will decrease and there will be LESS erythema
Why is there a loss of flexibility in the healed tissue of a wound?
There is no new elastin.
What occurs during wound contraction?
The wound edges migrate together, wound contracture
In wounds where the edges are not or will not be placed in apposition, what decreases the size of the wound?
Wound contraction
What can occur if a wound, such as a full thickness (3rd degree) burn, is not covered by a skin graft?
wound contraction that is deforming and debilitating
What can limit debilitating wound contracture?
Skin graft placed early, e.g. vestibuloplasty skin graft
What are 4 factors impairing wound healing?
- Foreign material
- Necrotic tissue
- Ischemia
- Tension
What is Anything non self, such as bacterial infection, or the foreign debris that shelters bacteria from host defenses?
Foreign material
What is a barrier to in-growth of reparative cells, also shelters bacteria from host defenses?
Necrotic tissue
What can act as a nutrient source for bacteria?
Hematoma
True or false: Ischemia can lead to further tissue necrosis
True
What is decreased and increased in Ischemia?
Decreased delivery of antibodies, WBC, antibiotics, oxygen, nutrients.
Increased risk of infection and delayed wound healing
What are 7 causes of Ischemia?
- Tight/incorrect sutures
- Improperly designed flaps(small base to height flap)
- Excessive external pressure to the wound
- Excessive internal pressure to the wound – hematoma
- Systemic hypotension
- Peripheral Vascular Disease
- Anemia
What is Anything tending to hold the wound edges apart?
Tension
What will occur if one uses tight sutures to overcome tissue tension and thereby approximate the margins of the wound?
Ischemia
Early suture removal can lead to what?
The edges pulling apart leading to excessive scar formation/contraction
What can occur if sutures are left in too long?
Epithelialized suture tracts (leading to increased scar size)
What are 2 basic methods of wound healing?
Primary intention and Secondary intention
What is the term for when wound edges are placed together in pre-injury anatomic position?
Primary intention
What is the term for the gap between tissue edges, bone fractures, nerve endings requiring increased epithelial migration, collagen deposition and increased contracture?
Secondary intention
Laceration, incision, reduced bone fracture, anatomic nerve ending anastamoses are examples of what type of wound healing: primary or secondary intention?
Primary
Extraction socket, underreduced fracture, ulcer, avulsive injury are examples of what type of wound healing: primary or secondary intention?
Secondary
Extraction sockets heal by what type of intention?
Secondary intention
What are 4 things in the extraction socket as healing begins?
- Cortical bone (the radiographic lamina dura)
- Torn PDL
- Rim of gingival epithelium
- Blood clot
Describe First week of Extraction Socket healing by Secondary Intention
WBC remove bacteria/debris/bone fragment Fibroplasia by fibroblasts, increased capillarie Epithelium migrates down walls of socket until contact inhibition
Osteoclasts accumulate along crestal bone
Describe what occurs over the 2nd, 3rd, 4th weeks of Extraction Socket healing by Secondary Intention
osteoid deposition along alveolar bone lining Cortical bone lining resorbed Trabecular bone fills socket Epithelim displaced to top of socket
Why is important to know that the lamina dura should be gone 4-6 months post extraction?
If take x-ray only a few weeks post-extraction and there is no lamina dura, that points to Osteomyelitis
What type of bone fills in the socket and displaces the epithelium to the top of the socket?
Trabecular bone
What are the three sources of osteoblasts?
- periosteum
- Endosteum
- Circulating pleuripotent mesenchymal cells
What do osteoblasts do?
Lay down osteoid and calcify if immobile
What is the only origin for osteoclasts?
Monocyte precursor cells (they “eat” stuff)
What do osteoclasts do?
Resorb necrotic bone or bone to be remodeled
Greenstick fracture would heal how, or an anatomically reduced bone that is stabilized would heal how: Primary or secondary intention?
Primary
What is the character of the primary intention bone healing?
Ossification across fracture site with minimal fibrous tissue
When is bone healing considered to be by secondary intention?
When the free ends are more than 1mm apart
What occurs during the Fibroplastic stage of secondary intention healing of bone?
Callus = excess collagen formation around free ends
What are 2 factors affecting bone healing?
- Vascularity
2. Immobility
If vascularity of bone is compromised what normally forms?
Cartilage forms instead of bone /fibrous tissue formation
How does bone form and why?
forms perpendicular to lines of tension to help withstand forces placed on it
Excess mobility as bone heals by primary intention causes what?
excess tensions causing decreased vascularity causing increased cartilage formation and increased fibrous tissue formation
What concept is based upon the fact that an inert foreign material placed through an epithelial barrier develops a biologic bond to surrounding bone, which resists epithelial migration along the surface of the material?
implant osseointegration
What are 5 things that enhance bone healing to implant?
- Short distance between bone and implant
- No soft tissue between bone and implant
- Viable bone
- No movement
- Implant surface free of contamination
Osteocytes secrete what onto the titanium oxide surface of the implant?
Glycosaminoglycans (GAGs)
Excess mobility as bone heals by primary intention causes what?
excess tensions causing decreased vascularity causing increased cartilage formation and increased fibrous tissue formation
What is deposited over the proteoglycan layer that was layed down by osteocytes on the implant titanium oxide surface?
Osteoid
What is a woven membrane placed around implant to inhibit fibrous tissue ingrowth?
woven membrane for guided tissue regeneration
Why is pore size important in woven membrane for guided tissue regeneration?
allows oxygen/nutrients in while keeping fibroblasts out
What does the alveolar epithelium do to the implant?
Secretes ground substance to coat implant
What forms at this implant-epithelium surface that now has the ground substance on it?
A hemidesmosomal basal lamina system
What are 3 forms of traumatic facial neuropathology?
- Neurapraxia
- Axonotmesis
- Neurotmesis
What is a nerve injury in which there is neural compression but no disruption. The epineurial sheath and axons maintain continuity.
Neurapraxia
What are 3 causes of Neurapraxia?
- contusion from trauma
- Inflammation
- Ischemia
What is the expected recovery from Neurapraxia?
Spontaneous recovery within few days/weeks
What is nerve injury where the continuity of the axons is disrupted but the epineural sheath is not disrupted?
Axonotmesis
What are 2 causes of axonotmesis?
- Crushing injury
2. Excess traction
What is the expected recovery from axonotmesis?
Axon regeneration w/in 2-6 months possible
What is a nerve injury where there is severe trauma causing both axon and nerve sheath disruption. Complete loss of nerve continuity?
Neurotmesis
What are 2 causes of neurotmesis?
- Fracture (e.g. fractured mandible)
2. Iatrogenic transaction
What are the 2 phases of Nerve Healing?
- Degeneration phase
2. Regeneration phase
What are the 2 types of Degeneration?
- Segmental Degeneration
2. Wallerian Degeneration
What is the nerve healing degeneration type where myelin sheat dissolved in segements?
Segmental degeneration
What is the nerve healing degeneration where myelin sheath/axons distal to the injury disintegrate (everything past the injury dies/stops getting innervations)?
Wallerian degeneration
What is the term for altered sensation?
Paresthesia
What is the term for painful sensation?
Dysesthesia
What is the term for excessive sensitivity?
Hyperesthesia
What is the term for decreased sensitivity?
Hypesthesia
Paresthesia, Dysesthesia, Hyperesthesia, Hypesthesia can all result from what type of nerve injury?
Neurapraxia injury
Is there any nerve conduction in Wallerian degeneration?
No
Wallerian degeneration can result from what type of nerve injury?
Neurotmesis injury
When does the regeneration phase of nerve healing begin?
Immediately after injury
How much can nerve grow per day during the regeneration phase?
1.0 to 1.5 mm per day
Does a new myeling sheath form during regeneration phase?
Yes
Nerve regeneration will continue till one of what 2 things occurs?
- Area of innervations reached
2. Fibrous tissue obstructs growth
What will be experienced before normal feeling returns as nerve heals?
Paresthesia/dyesthesa
What may form if nerve healing is obstructed?
Traumatic neuroma, painful ball of nerve ending
Nerve repair suture is what zero thickness, and what type of suture is done to repair it?
9-0, mattress suture
What are good signs for regeneration?
Tingling or itching
What are the guidelines for gauze pressure to control bleeding?
- Moist or dry gauze can be used
- Change every 30-60 minutes
- Oozing for 24 hours with saliva to be expected
What must a patient not do while an extraction socket heals?
No smoking for 12 hours No use of a straw No spitting No strenuous exercise No hot foods/liquids for 24 hours
What are the diet guidelines for a patient recovering from tooth extraction?
High volume of liquids
Foods: soft/cool/high calorie
Diabetics should return to their normal diet and insulin routine as soon as possible
What oral hygiene instructions should be given to a patient who has just had a tooth extracted?
Brush carefully and rinse with warm salt water starting the day after surgery
What are four common sequela of tooth extraction?
- Edema
- Infection
- Trismus
- Ecchymosis
What is the usual timeframe for recovery from edema?
It reaches its maximum in 3-4 days and resolves in 3-4 beyond that.
What guidelines should be given for icing swelling after surgery?
Apply ice packs for 20 minutes on and 20 minutes off for the 1st 24 hours.
What guidelines should be given for applying heat to swelling?
Moist heat should be applied POD 2,3
How quickly after surgery does infection usually set in?
3-4 days
What antibiotics should be prescribed?
Pen VK 500 mg po qid for 7 days
Clindamycin 300 mg po tid for 7 days
When should incision and drainage be used?
In cases of abscess but NOT with cellulitis
What is the muscle most likely to become sour with trismus?
Medial pterygoid
What is the onset for suspected “deep space infection”?
2-4 days after surgery
What patients are more susceptible for ecchymosis?
Older patients and those with weakened intercellular attachments
What is the progression of color in ecchymosis?
Purple/blue to green to yellow
What is the onset of ecchymosis and then the resolution?
Onset 2-4 days after surgery and resolves in 7-10 days
Which direction does ecchymosis travel?
Spreads out and goes inferiorly due to gravity
