Wound Healing and The Problem Wound

Manal E. Alotaibi

Contents• Definition • Types of wound closure• Phases of Wound Healing• Impaired Wound Healing: Local

factors &systemic factors• Excessive Healing

Definition

A complex integrated sequence of cellular, physiologic, and biochemical events initiated by the stimulus of injury to tissue

Types of wound closurePrimary closureAll Layers are closed.

Approximation of acutely disrupted tissue with sutures, staples or tape.

The incision that heals by first intention does so in a minimum amount of time.

with no separation of the wound edges, and with minimal scar formation.

Primary closure

Delayed primary closureApproximation of wound margin

delayed for several days.Prevents wound infection in cases of

contamination/foreign bodies/tissue trauma.

Less bacterial colonization in open wound .

Normal healing progress occurs.Left open initially.Edges approximated 4-6 days later .

Delayed primary closure

Secondary wound closureOpen wound margins approximate by

biologic contraction Surfaces not approximatedDefect filled by granulationDeep layers are closed but superficial

layers are left to heal from the inside out.

Healing by second is appropriate in cases of infection, excessive trauma, tissue loss, or imprecise approximation of tissue.

Secondary closure

Secondary closure

Secondary closure

WOUND HEALING PHASES

Inflammatory

phase

Proliferative phase

Maturational

phase

Inflammatory PhaseHemostasis and InflammationKey components of this phase are

increased vascular permeability, and cellular recruitment

Days 4 - 6 Exposed collagen activates clotting

cascade and inflammatory phaseFibrin clot = scaffolding and concentrate

cytokines and growth factors

At the initial time of

tissue disruption,

platelets release

coagulation factors

and cytokines to

initiate the healing

process

Within the first day following tissue

injury, neutrophils attatch to

surrounding vessel walls and then move through the vessel walls to migrate to

the wound site

Inflammatory Phase

Proliferative phase

1. angiogenesis

2. fibroplasia

3. Epithelization. Production of collagen is hallmark 7 days to 6 weeks

Angiogenesis

The process of new blood vessel formation to support a healing wound environment .

tissue hypoxia – major stimulusTNF-α, heparin, VEGF, FGF-1, FGF-

2

The fibroplasia phase is characterized by movement of wound macrophages into the site of injury, which in turn attract fibroblasts. The fibroblasts then repair the site by producing new connective tissue matrix.

Wound ContractionActual contraction with pulling of edges

toward center making wounds smallerMyofibroblast: contractile propertiesSurrounding skin stretched, thinnedOriginal dermal thickness maintainedNo hair follicles, sweat glands

Epithelialization Basal epithelial cells

at the wound margin flatten (mobilize) and migrate into the open wound

Basal cells at margin multiply (mitosis) in horizontal direction

Basal cells behind margin undergo vertical growth (differentiation)

Epithelialization/Contraction

Epithelialization

Proliferative Phase

Maturation Phase

Day 8 through yearsType III replaced by type IWound may increase in strength for up to 2

years after injuryCollagen organizationCross linking of collagen

Maturation Phase

FACTORS AFFECTING WOUND HEALING

Systemic factorsThe most common nonhealing wounds affecting the lower

extremities are associated with peripheral artery disease, diabetes and chronic venous insufficiency. 

Peripheral artery disease Diabetes Chronic venous insufficiency Aging Sickle cell disease Cancer therapy Spinal cord disease and immobilization Malnutrition Smoking .

Excessive Healing

hypertrophy and keloid formation are an overactive response to the natural process of wound healing.

Hypertrophic Scars

raised and thickened.does not extend beyond the boundary of the

incision/scar.this process is exacerbated by tension lines on the

areaof surgery. incisions over the knee and elbow have a higher

incidence of hypertrophic reaction.Treatment: nearly all hypertrophic scars undergo a

degree of spontaneous resolvement. if still present after six months, surgical excision is indicated.

Hypertrophic Scars

KeloidsRaised and thickened. This process extends beyond the boundary of

the incision.Continues weeks to months past the initial

insult.Higher incidence in African Americans.Treatment: Pressure applied early may

decrease the extent of keloid formation.corticosteroid injection may be helpful.Excision with intramarginal borders is

reserved for intractable keloids.

Keloids

summary

A wound is a disruption of the normal structure and function of the epidermis.

Wounds may be caused by a variety of mechanisms including acute injury (abrasion, puncture, crush), surgery or other factors that cause breakdown of previously intact skin (eg, ischemia, pressure).

After hemostasis has been achieved, acute wounds normally heal in an efficient manner characterized by four overlapping phases: inflammation, epithelialization, fibroplasia, and maturation.

Many disease states alter the process of wound healing, the most common of which are peripheral artery disease, diabetes, and chronic venous disease.

References UpToDateWound-Healing-student-lecture-

May-2011, Abigail E. Chaffin, M.D. Assistant Professor of Plastic Surgery;Tulane University School of Medicine.

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