Wound Healing Phases

Introduction

Hemostasis, inflammation, proliferation, and tissue remodeling or resolution are the four overlapping phases of wound healing. These phases and their associated biophysiological processes must occur in the appropriate order, at a precise moment, and at an optimal level for a specified length. Numerous variables can affect wound healing, interfering with one or more phases of the process and resulting in inadequate or impaired tissue repair.

 

Healing Phases

Hemostasis – (injury to 15 minutes) This phase begins within the first 15 minutes after an injury and extends into the dermis through the epidermis. Capillaries deliver blood to the dermis layer of the skin. When vessels are injured, coagulation is activated. Aggregation and activation of platelets result in the formation of clots. The release of growth factors is therefore referred to as fibrinolysis. Vasoconstriction will then complete this phase.

 

Inflammatory (1-5 days) – During the inflammatory phase, “normal” physiological changes such as erythema, warmth, pain, and localized edema may occur. This is the location of cell proliferation and activation, as well as re-epithelialization.

 

Proliferative (5 to 25 days) – This phase can take place only in a full-thickness wound. This would include a stage III and IV pressure injury/ulcer. During this phase, granulation occurs.

 

Maturation (21—24 months) – This is the concluding phase of the healing cascade for full-thickness wounds. Additionally, you may hear it referred to as the “remodeling” phase. In comparison to the original tissue, the tensile strength of scar tissue will be only about 80%.

 

Conclusion

Hemostasis, inflammation, proliferation, and remodeling all play a role in wound healing. This process involves a diverse range of cell types, including neutrophils, macrophages, lymphocytes, keratinocytes, fibroblasts, and endothelial cells. Numerous factors, classified as local and systemic factors, might hinder wound healing by altering one or more steps of the process. These influences are not mutually exclusive. Single or several factors may contribute to the overall result of the healing process in any one or more of the specific phases.

 

Further Reading and References

Guo S, Dipietro LA. Factors affecting wound healing. J Dent Res. 2010;89(3):219-229. doi:10.1177/0022034509359125

 

Bjarnsholt T, Kirketerp-Moller K, Jensen P, Kit M, Krogfelt K, Phipps R, et al. (2008). Why chronic wounds won’t heal: a novel hypothesis. Wound Repair Regen 1:2-10

 

Disclaimer

The views and opinions stated in this blog are exclusively those of the author and do not reflect those of iWound, its affiliates, or partner companies.

share

ArabicChinese (Simplified)EnglishFrenchHindiRussianSpanish