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Micro-contouring in Clinical Practice: the Impact on Infection
One of the key challenges in wound management is infection prevention. This can be achieved through control of the superficial bioburden — ie, wound microbial colonization. One consideration in infection prevention is that antimicrobial effectiveness may be a factor of the different physical properties of dressings.1 The ability of a dressing to conform to the wound surface appears to be a factor in the prevention of wound infection as a result of the antimicrobial protection provided at the wound-dressing interface.2 However, the choice of the optimal dressing for skin ulcers, diabetic lesions, or surgical wounds remains controversial.3Previous studies have demonstrated that the physical properties of hydrofiber interact with exudate components,4 modulating inflammatory cells and permitting a higher number of macrophages to populate the wound lesion.5 It is also known that hydrofiber dressings promote and maintain a moist wound interface, a key factor for an optimal healing process,6 due to the conformability of their cohesive gel. In our experience, use of this hydrofiber dressing, both with and without silver, facilitates the formation of a “biological wall,” micro-contouring at the wound edge (see Figure 1). This wall forms as the result of the interaction between the re-keratinization of the lesion margin and the hydrofiber in the dressing, and provides both a barrier for the residual exudate and a protective barrier.
Observation with digital microscopy shows that the biological wall is located at the external border of the wound, sealing the lesion margins and acting as a natural barrier to prevent bacterial contamination (from the wound periphery toward the wound bed). Removal of the biological wall reveals an already active wound-margin of newly forming keratinocytes moving towards the center of the wound during the re-epithelialization process (see Figure 2).
Histological examination of the biological wall found it to contain approximately 80% keratin (corneocytes with ortho- and parakeratosis), with sparse amorphous, oval, slightly eosinophilic structures. Following the dressing change, the formation of a new protective micro-contouring biological wall adjacent to the new line of developing keratinocytes wall is observed. (see Figure 3). We hypothesize that the structure formation induced only by the silver-containing hydrofiber dressing drives the centripetal direction of the wound repair process and keratynocite migration, preserving lesion border from exudate cytolytic activity— that is, micro-contouring seems to promote the ongoing process of wound healing by inducing natural wound sealing through a specific conformability mechanism, ensuring the ideal conditions for wound repair via optimal moisture balance. In addition, the histological barrier induced by the interaction between silver-containing hydrofiber and lesion border prevents infection from possible pathogens on periwound skin. The specific wound healing-mechanism induced by this dressing may be a predictive factor for the effectiveness of the dressing. To explore the healing potential of this hydrofiber dressing, a 62-patient study was conducted. Patients with venous leg ulcers, posttraumatic wounds, vasculitis, and mixed ulcers were treated using this dressing and etiologically appropriate care. They were followed-up once weekly for a mean period of 12 weeks. Results suggest that the properties of a specific hydrofiber dressing (Aquacel®, ConvaTec, Skillman, NJ) — the only hydrofiber dressing currently available in our geographic area — may induce healing. These preliminary observations support the need for further investigation, via controlled studies, to address the possible correlation between the formation of a biological wall on the lesion border and an accelerated healing process. A difference may exist in healing mechanism between core and border lesions.
References
1. Parsons D, Bowler P, Myles V, Jones S. Silver antimicrobial dressings in wound management: a comparison of antibacterial, physical and chemical characteristics. WOUNDS. 2005;17:222–232. 2. Jones S, Bowler P, Walker M. Antimicrobial activity of silver-containing dressings is influenced by dressing conformability with a wound surface. WOUNDS. 2005;17:263–270. 3. Chaby G, Senet P, Vaneau M, Martel P, Guillaume JC, Meaume S, et al. Dressings for acute and chronic wounds. Arch Dermatol. 2007;143:1297–1304. 4. Coutts P, Sibbald G. The effect of a silver-containing hydrofiber dressing on superficial wound bed and bacterial balance of chronic wounds. Int Wound J. 2005;2:348–356. 5. Hoekstra MJ, Hermans MH, Richters CD, Dutrieux RP. A histological comparison of acute inflammatory responses with a hydrofiber or tulle gauze dressing. J Wound Care. 2002;11:113–117. 6. Richters CD, du Pont JS, Mayen I, Kamperdijk EWA, Dutrieux RP, Kreis RW, et al. Effects of a hydrofiber dressing on inflammatory cells in rat partial-thickness wounds. WOUNDS. 2004;16:63–70.
Dr. Greco is a dermatologist and Chief of the Centre of Specialization for Treatment and Prevention of Cutaneous Ulcers, Frosinone ASL, Italy; email: firstauthor-greco@yahoo.com.
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