What is granulation?
Granulation tissue is formed as a result of secondary wound healing, or spontaneous wound closure.[1]
In primary healing the wound edges are approximated.
In secondary healing, the wound is left open to heal spontaneously, without approximating the wound edges.
The wound in secondary healing closes by processes of wound contraction and epithelialization. Granulation tissue forms generally in the middle of the open wound, where the inflammatory phase of wound healing is occurring (see figure). Granulation tissue consists of inflammatory cells and proliferating capillaries.
Allowing wounds to heal by secondary healing, rather than primary closure, is suitable for contaminated wounds (wounds with high bacterial inoculum), a long time lapse since initial injury, and severe crush injury.[1] This reduces the incidence of wound infections.
During wartime, a high proportion of wounds would fall into these categories. Therefore, an understanding of the benefits of secondary healing was important to reducing morbidity and mortality that had previously occurred as a result of wound sepsis.
_________________________________
1. Smith, D., K. Chung, and M. Robson, Wounds and Wound Healing, in Essentials of General Surgery, P. Lawrence, Editor. 2000, Lippincott Williams & Wilkins: Philadelphia
