wounds

Presented by

Dr Azza Serry

Learning objectives:

Definition

Classification of wounds

Pathophysiology of wound healing

Types of wound healing

Factors affecting wound healing

Complications of wound healing

Evaluation &management of wounds

Definition &

classification

Wound is a breakdown of tissue continuity .

Wounds can be classified in terms of :

Depth : superficial, deep ( penetrating ) .

Mechanism : incised ,lacerated ,degloved ,burn ,missile .

Contamination :

Clean : uninfected ,GIT , genital ,urinary tracts are not entered ,eg ,hernia ,thyroidectomy ,these wounds close primarily

Clean contaminated : GIT entered under controlled conditions ,no spillage ,no acute inflammation ,eg cholecystectomy ( chronic inflammation ) .

Contaminated : acute non purulent inflammation is encountered , visible spillage from intestinal tract , open fresh accidental wound ,eg cholecystectomy wih acute inflammation ,or bile spillage, (appendix inflamed ,no rupture,no pus ) .

Dirty : old traumatic wound > 4 hours , gross pus , eg abscess ,perforated bowel ,eg rupture appendix ,incision and drainage of an abcess .

Incised wound surgical or traumatic by sharp object Edges are regular, less tissue trauma

Degloving wound:shearing forces deglove skin and subcutaneous tissue ,

Penetrating wound:

Wound is deep ,bad drainage , infection rate is high

Lacerated wound:blunt trauma , edges are irregular, devascularized ,high infection rate

Abrasion woundBlunt trauma , sloughing of superficial layers of skin, caused by friction against rough surface

Missile wound:High velocity is

more dangerous than low velocity ,bone fragments acts as a secondary missiles

Pathophysiologyof

wound healing

Wound healing is a normal response to injury .

It is a complex and dynamic process aiming at rapid restoration of tissue continuity and rapid return to normal function .

Hemostasis : vasoconstriction of torn blood vessel ,

clotting cascade activated ,platelet plug is formed ,

stabilized by fibrin .

Inflammatory phase : tissue injury → cytokines release ( I1 , TNF ) , and inflammatory mediators , recruit neutrophils → engulf bacteria ,remove dead tissues .

Monocytes : → macrophage → engulf bacteria ,remove dead tissue ,release growth factors .

Begins immediately after wounding ,lasts for 2 – 3 days

Proliferative phase : lasts from third day to third week .

Fibroblast proliferation : fibroblast form collagen and ground substance(ECM) ,vitamin C is essential for collagen .

Epithelial cell proliferation : epithelial cells migrate to close the defect from margins

Epithelial closure is complete by 48 hours .

Endothelial cells proliferation : develop new blood vessels (zinc is a cofactor )

Granulation tissue : collagen strands ,ground substance with blood vessels .

Fibroblasts acquire muscle filaments to form myofibroblasts to help wound

contraction ,which takes place in secondary intension .

Maturation phase : lasts for months after wound healing ,cross linkage between collagen fibrils form to increase tensile strength ( aided by vit C ) , lasts for monthes after clinical healing .

pathophysiology

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Management of open wounds

Airway ,breathing ,circulation .

Obtain a focused history ( time ,mechanism ,allergy ,immunization ) examine to exclude other injuries –site,careful neurological and vascular examination distal to site of injury .

feel distal pulses ,if not palpable ,urgent duplex after treatment of shock

Suspected fracture → x ray ,splint .

Prophylactic antibiotics in deep lacerated wounds ,tetanus prophylaxis .

In theatre ,thorough cleaning by saline irrigation ,remove foreign bodies ,scrub with antiseptic ,deal with injured structures ,

Major artery or vein → repair, small bleeding vessel → ligate .

Nerves or tendons can be repaired in clean incised wound ,

Defer the repair in contaminated wounds .

Viable muscles ( contract on pinching ,bleeds) →repair by sutures ,

Necrotic muscle (dark red or grey in colour ,does not contract on pinching ) → excise .

Wound closure : depend on contamination ,don’t close : old ≥ 4 hours ,puncture , gross infected , & missile injuries .

In degloved injuries ,second look after 3-4 days to assess skin viability,deep fascia and skin should be left open ,if there is a skin defect,wait till tissues are healthy,skin graft or flap may be performed .

Missile wounds : explore ,thorough debridement of entry , exit wounds .leave skin open .

• Types of wound healing

Primary intension : uncontaminated ,minimal tissue loss ,edges can be approximated without tension heals by rapid epithelialisation ,minimal granulation tissue ,sound healing scar ..

Secondary intension : contaminated wound ,extensive tissue loss ,edges cannot be approximated without tension .

Wound isI left open ,allowed to heal from the depth , by a combination of granulation , epithellialisation , & contraction

Cometic result & scar quality is inferior to healing by primary intension . .

Third intension : wound is closed several days after it’s formation , (to control infection ,or to reduce oedema .

Factors affecting wound healing

local

Blood supply : tight sutures , , previous irradiation ,and smoking .

Haematoma .

Wound infection .

Excess mobility .

general Concomitant disease : cardiac

respiratory ,diabetes .

Drugs : steroids ,chemotherapy .

Elderly patients ,obesity . .Nutritional factors :

Proteins : ECM formation .

Vitamin A : epithelial proliferation .

Vitamin B6 , vitamin C & copper : collagen cross linkage .

Zinc : affect fibroblast proliferation , collagen synthesis , affect wound strength .

Complications of wound healing

Wound failure can be minimized by attention to risk factors :

Ensure good blood &oxygen delivery to wounds .

Optimise patient nutrition .

Debride devitalized tissues .

Careful aseptic technique .

Avoid tight sutures

Wound dehiscence : partial or total disruption of any or all layers of surgical wound . → immediate elective reclosure .

Wound infection .

Evisceration :( burst abdomen ) : rupture of all layers of abdominal wall & extrusion of abdominal viscera . → resuscitate ,protect organs with moist sterile towel ,immediate closure with deep tension sutures .

Incisional hernia : occurs at site of partial wound dehiscence ,presents by visible protrusion on coughing ,corresponds to a wide defect ,so does not incarcerate ,→ surgical repair .

Malignant change : squamous cell carcinoma on top of a chronic ulcer (marjolin ulcer ).

Keloid scar Hypertrophied scarRaised scar ,extend beyond wound

Raised scar ,confined to wound

Does not settle spontaneously

Settle spontaneously within a year time

Thick collagen Thin collagen

Collagen arranged irregularly Collagen arranged parallel to wound

More in dark pigmented skin All races

Sternum ,deltoid ,ear lobe Sternum ,shoulder

Pressure garments ,intralesional steroids ,recurrence is common

Wound contracture Pathologic shortening of scar tissue ,→distortion of adjacent structures ,

& limited flexibility in joints .eg post burn contracture of neck or fingers .

Action :

Physiotherapy &splintage to prevent contractures across joint surfaces .

Multiple Z plasty

Prophylactic surgical wound care

preoperative Cigarette smoking stopped one month before elective surgery . Nutrition : depends on wound type , wounds closed by primary intention often heal in emaciated

patients as long as there is no wound infection . . Tight glycemic control .

Shaving is associated with increase risk of infection , clipping immediately before

surgery carries a lower risk . Prophylactic antibiotic s : indicated for clean : mesh or vascular graft is used ,

and patients with valvular heart disease. clean contaminated and contaminated wounds ,

pre-incision .60 minutes ,to be discontinued within 24 hours .

Operative Surgeon hand antiseptic : 2 - 6 min had scrub , use alcohol based

solution . Surgical site antisepsis : clean with 10% bovidone _ iodine or alcohol

solution . . Meticulous surgical technique : proper haemostasis , gentle handling

of tissues , avoid dead space .

Surgical wound infection

Wound infection usually appears between the fifth and tenth day postoperatively ,sometimes earlier .

Wound pain and postoperative fever are the earliest manifestations .

The wound is swollen , tender and red .

Wound discharge .

Infections deep to deep fascia are associated with fever and leucocytosis

treatment :

Liberal drainage : wound should be opened by removal of skin sutures .

Antibiotics guided by culture and sensitivity tests .

Possible source of hospital acquired infection should be traced and corrected .