2-3 wound healing

Question 1

what is wound healing

Answer 1

mechanism whereby the body attempts to restore the integrity of the injured part.

Question 2

what is Sanatio per Primum

which kinds of wounds heal this way

Answer 2

primary intention healing

• wounds with smooth edges in close proximity
• NO infection or without scar necrosis
• surgical wounds that are surgically treated and sutured
  
  • in 6-8 days a gentle linear scar is formed
  • stitches removed in 7-10 days
  • this is called First intention closure
    
    • Wound edges opposed. Normal healing. Minimal scars
    • skin graft placement, or flap closure

Question 3

Complications of Sana per Primum

Answer 3

1. dehiscencte- reopening of the wound
2. bleeding from the wound
3. suppuration - redness - infiltrate - purulent collection

Question 4

what is Sana per Secundum

describe it’s characterisics

why is there a formation of large granulations

explain the procedure

Answer 4

wound healing by Secondary Intention

characteristics

• for larger wounds with edges that are far apart
• wounds infected with necrotic tissue and thus closure is C.I

procedure

• Wound is left open to heal by granulation, contraction and epithelialisation to seal it from the base upwards
• covered to prevent drying of wound and promote healing
• Increased inflammation and proliferation compraed to first intension results in a larger scar and less functioning tissue upon healing

Question 5

what is San Sub crustam

when is it employed

Answer 5

tertiary intention (also called delayed primary intention) used in superficial wounds

procedure

• Wound initially left open
• Edges later opposed when healing conditions are favourable

*

Question 6

what are the 3 phases of wound healing and when do they occur

Answer 6

1. inflammatory/migratory/destructive phase: 0-3 days
2. proliferation phase: day 3 - 3 weeks
3. maturation phase: 6 weeks-1-2 years

Question 7

describe the inflammatory phase

what is the initial structural support in this phase

Answer 7

• after onset of the trauma bleeding occurs and damaged epithelial tissue relases cytokines & vasoactive amines (hps)
  
  • such as histamine, prostaglandins and ,serotonin
• this is followed by vasoconstriction and thrombus formation to limit blood loss.
• Platelets stick to the damaged endothelial lining of vessels, releasing adenosine diphosphate (ADP), which causes thrombocytic aggregation to fill the wound.
• When bleeding stops, the platelets then release cytokines from their alpha granules.
  
  • plateletderived growth factor (PDGF), platelet factor IV and transforming growth factor beta (TGFβ).
• cytokines attract inflammatory cells such as polymorphonuclear lymphocytes aka neutrophils and macrophages.
• Platelets also release HSP vasoactive amines to increase vascular permeability, thereby aiding infiltration of these inflammatory cells.
• Macrophages have 2 functions
  
  1. remove dead tissue and micro-organisms
  2. regulating fibroblast activity in the proliferative phase

The initial framework for structural support of cells is provided by fibrin produced by fibrinogen.

Question 8

describe the proliferative phase

what is the wound tissue formed at the end of this stage that is also the main mechanism in secondary intention (sana per secundum

what is the nature and type of collagen in this phase and how does it affect the strength of the wound

Answer 8

• The proliferative phase lasts from the third day to the third week
• macrophages regulate this phase by doing the following
  
  • release growth factors to regulate fibroblast activity
    
    • fribroblasts make collagen using vitamin C and ground substance (glycosaminoglycans and proteoglycans),
  • release GF’s for (angioneogenesis)
  • release GF’s thgat stim epithelial mitosis for the sake of re-epithelialisation of the wound surface. .
• The wound tissue formed in the early part of this phase is called granulation tissue.
• there is an increase in the tensile strength of the wound due to increased collagen, which is at first deposited in a random fashion and consists of type III collagen.

Question 9

describe the remodelling phase

Answer 9

• The remodelling phase is characterised by maturation of collagen:
  
  • _​_type I replacing type III until a ratio of 4:1 is achieved).
• There is a realignment of collagen fibres along the lines of tension,
• decreased wound vascularity
• wound contraction due tofibroblast and myofibroblast activity.

Question 10

list the 2 types of factors that affect wound healing

Answer 10

Local:

• site of the wound
• structures involved in the wound
• mechanism of the wounding -
  
  • Crush -Incision -Crush avulsion

Systemic

• malnutrition
  
  • vit c required for collagen synthesis
  • • diseases- DB mellitus
• medications - steroids
• immune deficiencies
• smoking
• explosions causing contamination from other ppl’s tissues

Question 11

what are the 4 types of wounds

describe thr caharacteristics of each

which wounds are related to the genitourinary tract, billiary tract and viscera

Answer 11

• Clean

• Non-traumatic, uninfected operative wound
• No break in sterile technique
• Respiratory, alimentary or genitourinary tract not entered

• Clean-Contaminated

• Gastrointestinal or respiratory tract entered without significant spillage
• Oropharynx, vagina,
• non-infected genitourinary or biliary tract entered
• Minor break in sterile technique

• Contaminated

• Soft tissue lacerations, open fractures, penetrating wounds and other trauma
• Major break in sterile technique
• Traumatic wound
• Gross spillage from GI tract
• Entrance into genitourinary or biliary tracts in presence of infected urine or bile

• Dirty

• Wounds that are heavily contaminated
• Wounds that are clinically infected pre-op e.g. -Abscess -Perforated viscera
• Old traumatic wound with retained devitalized tissue or foreign body

Question 12

• Clean wound characteristics

Answer 12

• Non-traumatic, uninfected operative wound
• No break in sterile technique
• Respiratory, alimentary or genitourinary tract not entered

Question 13

Clean-Contaminated

Answer 13

• Gastrointestinal or respiratory tract entered without significant spillage
• Oropharynx, vagina,

-non-infected genitourinary or biliary tract entered

Question 14

• Contaminated

Answer 14

• Soft tissue lacerations, open fractures, penetrating wounds and other trauma
• Major break in sterile technique
• Traumatic wound
• Gross spillage from GI tract
• Entrance into genitourinary or biliary tracts in presence of infected urine or bile

Question 15

• Dirty

Answer 15

• Wounds that are heavily contaminated
• Wounds that are clinically infected pre-op e.g. -Abscess -Perforated viscera
• Old traumatic wound with retained devitalized tissue or foreign body

Question 16

list the steps required in the management of the ACUTE wound

CEDD MRS

Answer 16

1. Cleansing⇒Exploration⇒Diagnosis and Debridement( saline>knife)
2. Repair of structures and Replacement of any lost tissues
3. Skin cover/ skin closure without tenstion
4. Meticulous handling at every stage

Question 17

Management of the bleeding wound

Answer 17

• Elevate and apply pressure
  
  • torniqutte in limb damage
    
    • avoid clamping vessels ⇒ nerve damage⇒ losst anastomosing abilty
• analgesia to allow adequate dg
  *

Question 18

how to determine muscle viablilty in a acute wound

Answer 18

colour

bleeding pattern

contractility

Question 19

number 1 most important factor in preventing infection of the wound

Answer 19

host resistance to infection

Question 20

describe scars

• how long it tgakes to mature
• appearance of mature vs immature
• comparison to normal skin tissue

Answer 20

• The immature is at first pink, hard, raised and often itchy.
• disorganised collagen fibres become aligned along stress lines with their strength being in their weave rather than in their amount
• The external appearance of the scar becomes paler, while the scar becomes softer, flattens and its itchiness diminishes.
• Most of these changes occur over the first 3 months but a scar will continue to mature for 1–2 years.
• Tensile strength will continue to increase but will never reach that of normal skin.

Question 21

what are the 3 types of scars

Answer 21

• Atrophic scar
  
  • pale, flat and stretched in appearance
  • Etio: back and areas of tension.
  • stre: easily traumatised as the epidermis and dermis are thinned.
• Hypertrophic scar
  
  • app: excessive scar tissue that does not extend beyond the boundary of the original incision or wound
  • Etio:1) prolonged inflammatory phase2) unfavourable scar siting (i.e. across the lines of skin tension e.g. facial expression
  • • Keloid.
  • app: excessive scar tissue that extends beyond the boundaries of the original incision or wound.
  • etio: unknown, but it is associated with elevated levels of growth factor, deeply pigmented skin, an inherited

Question 22

histological dx between keloid and hypertrophic scar

Answer 22

• excess collagen with hypervascularity in both but keloids> hypertrophic
• keloids have more type B collagen. with random orientation
• keloids have myofibroblasts but hypertrophic does not
• hypertrophic has scant mucin- keloids are very mucinous
• Hypertrophic scars improve spontaneously with time, where as keloids do not.

Question 23

how to treat hypertrophic/ keloid scars

Answer 23

1. pressure
2. silicone gel sheets
3. excision and steroid injection to stop inflammation
4. excision and post operative radiation (beam/ brachytherapy)
5. intralesional excision-> keloids only
6. laser
7. vitamin e massage but not proven