1. Introduction

Elderly patients are prone to wound healing complications after burn injuries for various reasons: First, injuries are more likely to be deep, inter alia as the skin becomes thinner with increasing age and reaction time is usually slower in the event of injury resulting in prolonged exposure to the noxious agent. Second, wound healing progresses slower and thus the risk for adverse events such as wound infection is increased. Third, elderly patients usually present with a variety of comorbidities that may compromise wound healing [1-3]. For instance, malnutrition is a common condition adversely affecting tissue repair [4].

Over the past years a variety of novel wound dressings have been added to wound specialists’ toolboxes, one of which is marine Omega3 wound matrix (KerecisÒ, Isafjordur, Iceland) that is derived from decellularized Atlantic codfish skin. Not only can this third-generation biologic dressing be handled just as any regular skin graft due to its mechanical strength, but it also has anti-inflammatory and anti-infective properties. In addition, its structure is very similar to the human skin and ingrowth of fibroblasts and capillaries is enabled by its porous microstructure. Marine Omega3 wound matrix has been seen to heal wounds faster than porcine submucosa or human amnion [5-7]. First applications chronic wounds were promising as accelerated wound closure and enhanced formation of granulation tissue was seen [8].

Whenever rapid wound healing with minimal additional donor wound surface is the desired, MEEK micrografting is a useful alternative to conventionally meshed split-thickness skin grafts (STSG). With this method, 3mm small skin squares are cut out of the graft and transferred to the wound with a silken carrier sheet. The technique allows for higher expansion rates with consistent take rates and faster wound closure relative to expansion rate when compared with the mesh technique, preparation of the grafts is however more time consuming especially when large areas have to be covered [9-11].

We present a case of an elderly, severely frail patient with a chronic wound after burn injury that was successfully treated with wound conditioning using marine Omega3 wound matrix and MEEK micrografting.

2. Case Report

An 86-year-old male patient with a medical history of stroke, prostatectomy, cardiac pacemaker implantation, arterial hypertension, dementia and alcohol abuse had sustained extensive full-thickness burns to both thighs, the right side of the abdomen and right flank averaging 15% of total body surface area (TBSA) when trying to light a coal-driven stove and falling over into the embers. The patient survived the injury and the burn wounds were treated with early epifascial excision and conventionally meshed STSG from both lower legs. Superficial Pseudomonas aeruginosa infection resulted in partial graft loss leaving a wound surface of 8% TBSA which was left to heal using conservative wound management measures. During his stay at the ICU the patient furthermore developed Covid-19 pneumonia from which he ultimately recovered.

Figure 1: Chronic wound after burn upon admission (pictures A-C). Note the detrimental wound status with scarce granulation on the right lateral thigh with partially exposed fascia (picture C).

As the wounds had not healed two months after trauma, the patient was transferred to our department for further wound care. Upon admission the patient presented with extensive residual skin defects involving the right lower abdomen, flank, hip and thigh averaging 7% TBSA with scarce formation of granulation tissue and only slight regeneration of epithelium at the wound margins. The STSGs on the left thigh had otherwise healed well, however, most of the donor sites on the lower legs were not epithelialized (Figure 1). Wound swabs were still positive for multi-resistant Pseudomonas aeruginosa indicating wound colonization, which was treated with local antiseptics and i.v. Piperacillin/Tazobactam according to resistogram. After two months of continuous hospital care, the patient was bedridden, malnourished with serum protein levels as low as 5.7 g/dl (norm: 6.6-8.3) and serum albumin of 2.3 g/dl (norm: 3.5-5.3) and not fit for surgery.

Figure 2: Wound situation after initiation of high-protein diet. Note beginning wound granulation on the exposed fascia on the lateral thigh.

For this, conservative wound management was commenced in first place using hypochlorous acid as topical antiseptic. A high-protein diet was administered to enhance healing capacities. On day 9 after admission wound showed beginning granulation (Figure 2). Therefore, meshed marine Omega3 wound matrix was applied and fixed to the wound bed with fibrin glue and staples to enhance granulation tissue formation (Figure 3). Fatty gauze served as secondary dressing. After four days, the matrix had largely been incorporated into the wound (Figure 4). Dressing changes were commenced on a regular basis using fatty gauze and topical povidone-iodine. Throughout the following days, rapid progression of wound healing was noted, leaving only minor areas un-epithelialized on the right lower abdomen and thigh with sufficient granulation tissue formation. On day 23, there were no clinical signs of infection and the wound surface appeared ready for skin grafting. As the patient still was not fit for surgery due to his general condition, the STSG was taken bed-side from the left thigh under topical anaesthesia with eutectic mixture of lidocaine and prilocaine (EMLA). The MEEK micrografts were secured to the wound using skin staples and -100 mmHg topical negative pressure. Areas of healed skin were meanwhile protected with silver foam dressings (Mepilex AgÒ, Mölnlycke, Gothenburg, Sweden). Good graft take was seen on day 29 (Figure 5). As wound healing progressed, the patient could be transferred to his local hospital on day 38. He was eventually discharged to home care two months after admission to our department with almost completely healed wounds and only minor residual defects (Figure 6).

Figure 3: Application of marine Omega3 wound matrix. Picture A: The product comes in sheets. The mechanical stability of the matrix allows to mesh it. Pictures B-D: Application of the wound matrix to the abdomen, right lateral thigh and right flank.

Figure 4: Almost fully incorporated matrix. Note that the mesh-pattern is still visible in the close-up.

3. Discussion

Elderly burn patients are especially prone to wound healing complications. Recent evidence suggests that conversion of superficial burns to full thickness injuries requiring epifascial debridement becomes more likely with increasing age [2]. Higher age has furthermore been identified as independent risk factor for burn wound infection [12]. Chronic wounds differ in wound melee when compared to their non-chronic counterparts in various ways. There is a pathologic upregulation of matrix-metalloproteinases, leading to continuous breakdown of newly formed extracellular matrix thus impairing wound healing. This process can furthermore be nourished by bacterial proteinases that not only destruct extracellular matrix but also stimulate host cells to excrete proteinases themselves [13]. In our patient, secondary Pseudomonas aeruginosa wound infection and subsequent chronic colonization was the likely reason for graft loss and potentially a main culprit for development of a chronic wound. Malnutrition is a known risk factor [14] and was a further hindrance of wound healing. This was addressed by adaption of the diet towards a higher protein intake. Already with these measures, slight improvement of the wound status was evident.

Figure 5: Good take of MEEK STSG, close-up of the right thigh. The skin islands are clearly viable with beginning epithelial sprouting.

Figure 6: Almost completely healed wounds two months after admission to our department. Note that the pattern of the MEEK islands is still visible in areas of full epithelialization.

Marine Omega3 wound matrix has high concentrations of long chain omega-3 fatty acids, that are largely preserved during the decellularization process. In vitro, these fatty acids have been seen to reduce bacterial growth and were even effective against several viruses, inter alia HIV and CMV [5, 6]. In their case study, Dorweiler et al. found Pseudomonas colonization as limitation of the matrix and observed premature absorption of it succeeded by enlargement of the wound surface [8]. In our patient, Pseudomonas wound colonization was addressed with application of topical antiseptics and intravenous antibiotics. Under these measures, the matrix had been largely incorporated by day 4 after application and there were no signs of absorption. We did not experience any increase of wound surface, much rather enhanced epithelialization from the wound edges and rapid formation of granulation tissue was noted.

Skin grafting with MEEK micrografts was performed to cover the residual skin defects two weeks after matrix application. As the patient was not deemed fit for surgery due to his general medical condition, skin harvest was performed under topical anaesthesia. Lumenta et al. demonstrated increased patient survival and more rapid wound closure in extensive burns when using the MEEK technique [9]. In addition, there is evidence that scar quality after healing is better when compared to conventional mesh-grafts, and the risk of infection seems to be lower [11,15]. In our patient, the MEEK technique was used mainly to limit the amount of donor area needed while a large wound surface could be treated with a relatively small graft. In case of graft failure, the procedure could easily have been repeated after another cycle of wound conditioning, possibly even using the same donor site if healed.

This case shows, that even in patients with low wound healing capacities, treatment can be successful with a holistic approach. Considering the patient’s medical history, wound situation and general condition, a stepwise procedure consisting of dietary management, wound conditioning and skin grafting under topic anaesthesia was successful. It furthermore demonstrates the potentials of currently available wound conditioning matrices in combination with well-established techniques to achieve closure of hard-to-heal wounds.

Conflict of Interest

None.

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