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Hello,
For small wounds that require a wound vac and have a tunnel, what is the best method for foam application? Is it best to not pack the tunnel if it is not deep or pack with white foam and black foam? Thank you
Jun 13, 2022 by Melissa Khoo,
3 replies
Elaine Horibe Song
MD, PhD, MBA
Hi Melissa,
Thanks for your question. Other colleagues might have other suggestions as well, but here are some thoughts. If the tunnel is unexplored, it is better not to place dressings into these areas and explore the tunnel first. To explore the wound, clinicians may opt to gently probe with gloved finger and try to feel hidden structures that may contraindicate use of wound vac. Then a swab may be used to measure how far the tunnel extends. If no contraindications exist, white foam may be cut to fit dimensions, ensuring contact with tunneling without tightly packing or allowing dressing medium to contact intact skin edges. White foam is hydrophilic and meant to hold moisture next to structures like bone, hardware, tendon. To prevent it from hardening, it needs to remain constantly moist. It is important to ensure you can see it from the opening of the tunnel, so that it is visible and not overlooked during dressing changes. Black foam is typically not a first option for tunnels as it may break more easily. It can still be used if no other options are available, but care must be taken to avoid breakage (e.g. by wrapping it with a single layer of gauze or wound non-contact material)
Jun 14, 2022
Elaine Horibe Song
MD, PhD, MBA
Hi Melissa,
Thanks for your question. Other colleagues might have other suggestions as well, but here are some thoughts. If the tunnel is unexplored, it is better not to place dressings into these areas and explore the tunnel first. To explore the wound, clinicians may opt to gently probe with gloved finger and try to feel hidden structures that may contraindicate use of wound vac. Then a swab may be used to measure how far the tunnel extends. If no contraindications exist, white foam may be cut to fit dimensions, ensuring contact with tunneling without tightly packing or allowing dressing medium to contact intact skin edges. White foam is hydrophilic and meant to hold moisture next to structures like bone, hardware, tendon. To prevent it from hardening, it needs to remain constantly moist. It is important to ensure you can see it from the opening of the tunnel, so that it is visible and not overlooked during dressing changes. Black foam is typically not a first option for tunnels as it may break more easily. It can still be used if no other options are available, but care must be taken to avoid breakage (e.g. by wrapping it with a single layer of gauze or wound non-contact material. 
Jun 14, 2022
Samantha Kuplicki
MSN, APRN-CNS, AGCNS-BC, CWS, CWCN-AP, CRNFA
Hi! Thanks for the question :)

First thought for me is---where is wound? Abdomen? Extremity? Is the etiology of tunneling known? (Foreign body, deep tissue abscess, bone infection, EC fistula). So, I would say pausing NPWT and packing any tunneling is based upon some of this info. If it's an explored tunnel that can be gently probed for depth, a piece of white foam can be cut to fit the area and carefully guided in as to not overpack but enough to contact the surface area of the base of the tunnel to allow it to granulate in. The tunnel should be shallower within each application. If not, reassessment should be performed as to why healing is not taking place. Black foam is much less dense than white foam and can fracture into pieces. White foam is more dense, less adherent, and stronger than black and is made for tunneling.
Jun 16, 2022
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