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Wound Bed Preparation: Edge of Wound

Practice Accelerator
June 30, 2022


Wound bed preparation is a vital element of wound care. It ensures that the wound has the best environment for closure by addressing the needs of the wound and removing barriers. Wound bed preparation is usually achieved by following a systematic approach such as the TIMERS mnemonic, which consists of tissue, infection/inflammation, moisture management, edge of wound/epibole, repair/regeneration, and social factors.

These steps do not necessarily need to occur in order, and some or all of them may need to be repeated as the wound changes and progresses toward closure. Wound edge management is an important part of the wound healing process. Wound edges can become rolled (epibole), have tunneling or undermining, and may become dry, scaly, calloused, or hyperkeratotic. All of these conditions can impede wound healing and must be addressed before the wound can progress toward closure. Further, rolled or undermined edges can harbor bacteria, thus allowing infection to take root and potentially allowing biofilm to develop.

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Epibole Management

When wound edges become rolled instead of advancing across the surface of the wound, this condition is called epibole. Epibole occurs when epidermal cells migrate down the sides of the wound instead of across the wound. When these epidermal cells come in contact with other epidermal cells on the sides of the wound, they stop advancing and signal that the wound is closed. Therefore, wound closure cannot occur until epibole is addressed.1 Common epibole management strategies include1:

  • Sharp debridement
  • Silver nitrate application
  • Mechanical debridement (monofilament pads, gauze, etc)

Debridement of rolled wound edges allows the wound to epithelialize, preferably across the wound bed and not down the side. Interventions should be put in place to ensure proper epithelialization. Epibole can be prevented by properly packing the wound (being sure not to overpack), protecting the wound from pressure, preventing and addressing wound infection, and preserving the periwound by using gentle, nonadherent dressings and moisture barriers. Causes of epibole should also be addressed to prevent further complications. Causes include1:

  • Oxygen deficiency in the tissue
  • Presence of infection
  • Overpacking of the wound
  • Unhealthy wound bed
  • Cellular senescence
  • Prolonged inflammation

Calloused or Hyperkeratotic Wound Edges

Some wounds, such as diabetic foot ulcers and venous leg ulcers, may be more susceptible to the development of calloused or hyperkeratotic edges.2 Calluses occur in diabetic foot ulcers typically as a result of neuropathy and often precede ulceration. Calluses and hyperkeratotic tissues need to be pared or removed in all wound types to allow the wound to properly epithelialize. This is typically done with sharp debridement and should be performed by a licensed and skilled clinician.

Undermining and Tunneling

Tunneling in a wound occurs when there is destruction of the fascial planes that creates a narrow passageway of dead space. This dead space can harbor bacteria, thus allowing infection and potentially biofilm to form. Tunnels should be packed to facilitate healing.3 Undermining is erosion of the tissue under the wound edges that results in a cliff-like structure. Undermining can also lead to infection, if the undermined wound edge is not properly cleansed and maintained. Like tunnels, undermined wounds should be packed to encourage healing. Tunnels and undermining that are not packed may prevent healing, or the space may be closed off, with consequent abscess formation or infection.3

Monitoring Wound Edges

Like every other part of wound care, wound edge management should be thoroughly documented, including measurements, interventions, and complications. Proper documentation of care will result in better patient outcomes and an easier reimbursement process. Some documentation technologies allow for wound imaging and automatic measuring, which can greatly speed up the documentation process and allow for more time spent with the patient.

Some of these technologies then allow you to overlay the wound images, thereby providing a visual image of how much the wound has closed or enlarged. This method of documentation can be especially useful in wound care because it allows the clinician and patient to visualize how debridement of epibole or packing of undermining or tunneling has affected the wound healing process.


Wound bed preparation, when performed correctly, prepares the wound for advanced treatment modalities and healing. Edge management is an important part of the wound bed preparation process. It ensures that the wound edges are ready to epithelialize across the wound and removes places where bacteria can hide and proliferate. When conducting a wound assessment, it is important to evaluate the health of the wound edges and select appropriate interventions to aid in wound closure.


  1. Smith K. Wound care and epibole: it’s all about the edge. Wound Care Education Institute. 2017. Accessed June 13, 2022.
  2. Dowsett C, Newton H. Wound bed preparation: TIME in practice. Wounds UK. 2005. Accessed June 13, 2022.
  3. Meyers B. Wound Management: Principles and Practice. 2nd ed. Pearson Prentice Hall; 2008:52-53.

The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, HMP Global, its affiliates, or subsidiary companies.