Healing

Published on 30/06/2015 by admin

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Last modified 30/06/2015

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Chapter 3 Healing

Wound Healing 49–51

Healing – Fibrosis 52

Healing – Special Situations 53–57

Fracture Healing 58–60

Healing

Healing is the final stage of the response of tissue to injury.

The capacity of a tissue for regeneration depends on its proliferative ability and on the type and severity of the damage. In particular, regeneration is not possible if the STEM CELLS are destroyed.

Three broad groups of cells are considered in the context of the cell cycle (p.3).

REGENERATION involves TWO PROCESSES:

1. proliferation of surviving cells to replace lost tissue.

2. migration of surviving cells into the vacant space.

The FACTORS which CONTROL healing and repair are complex: they include the production of a large variety of growth factors.

Wound Healing

Healing of a wound shows both epithelial regeneration (healing of the epidermis) and repair by scarring (healing of the dermis).

Two patterns are described depending on the amount of tissue damage. These are the same process varying only in amount.

1. Healing by first intention (primary union)

This occurs in clean, incised wounds with good apposition of the edges – particularly planned surgical incisions.

2. Healing by second intention (secondary union)

This occurs in open wounds, particularly when there has been significant loss of tissue, necrosis or infection.

Wound Contraction

Wound contraction, which is beneficial and begins early, is due mainly to the young, specialised ‘myofibroblasts’ in the granulation tissue exerting a traction effect at the wound edges. The exposed surface is reduced by gradual regeneration of the surface epithelium.

The remodelling of the collagen continues for many months.

Complications

1. Contracture

Later, contracture may cause serious cosmetic and functional disability, particularly in deep and extensive skin burns and around joints if muscles are badly damaged.

The formation of excess collagen in the form of thick interlacing bundles which causes marked swelling at the site of the wound is known as a KELOID. The essential cause is unknown. It is particularly common in black people.

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