Is Larval (Maggot) Debridement Effective for Removal of Necrotic Tissue From Chronic Wounds?

Evaluating nursing opinion and perception of maggot therapy for hard-to-heal wound management

OBJECTIVE

Maggot therapy (MT) or larval debridement therapy is a recognised, effective but underutilised treatment for the management of hard-to-heal wounds and infected ulcers. It is available on NHS prescription in the UK, where wound management is predominantly nurse-led. Anecdotal reports and published literature suggest that nurses may be reluctant to utilise the therapy. The aim of this study was to evaluate the feelings and opinions of nurses regarding the use of MT.

METHOD

The first stage of this mixed-methods study was a focus group held to discuss MT and opinions of specialist nurse clinicians. Next, an anonymised web-based online survey was launched through the Nursing Times journal and distributed through social media targeting all nurses. Finally, in-depth interviews were held with specialist and generalist nurses.

RESULTS

Awareness of MT among all nurses was extremely high. A breakdown of results showed that MT was much more highly regarded by wound specialist nurses than non-wound specialist nurses. The latter exhibited a greater level of reluctance to administer the therapy, with almost one-third of these nurses surveyed saying they found maggots disgusting and that the idea of MT made their skin crawl. In-depth interviews revealed that a lack of knowledge about MT was a prime concern.

CONCLUSION

Wound specialist nurses are more likely to embrace MT than non-wound nurse specialists, who report a varying degree of wariness to MT. Our study highlights a need for better education and training in MT for all nurses, to address issues with acceptance and willingness to treat or help treat patients with hard-to-heal wounds which are suitable for MT.

A molecular approach to maggot debridement therapy with Lucilia sericata and its excretions/secretions in wound healing

Chronic wounds caused by underlying physiological causes such as diabetic wounds, pressure ulcers, venous leg ulcers and infected wounds affect a significant portion of the population. In order to treat chronic wounds, a strong debridement, removal of necrotic tissue, elimination of infection and stimulation of granulation tissue are required. Maggot debridement therapy (MDT), which is an alternative treatment method based on history, has been used quite widely. MDT is an efficient, simple, cost-effective and reliable biosurgery method using mostly larvae of Lucilia sericata fly species. Larvae can both physically remove necrotic tissue from the wound site and stimulate wound healing by activating molecular processes in the wound area through the enzymes they secrete. The larvae can stimulate wound healing by activating molecular processes in the wound area through enzymes in their excretions/secretions (ES). Studies have shown that ES has antibacterial, antifungal, anti-inflammatory, angiogenic, proliferative, hemostatic and tissue-regenerating effects both in vivo and in vitro. It is suggested that these effects stimulate wound healing and accelerate wound healing by initiating a direct signal cascade with cells in the wound area. However, the enzymes and peptides in ES are mostly still undefined. Examining the molecular content of ES and the biological effects of these ingredients is quite important to illuminate the molecular mechanism underlying MDT. More importantly, ES has the potential to have positive effects on wound healing and to be used more as a therapeutic agent in the future, so it can be applied as an alternative to MDT in wound healing.

What is the effect of larval therapy on the debridement of venous leg ulcers? A systematic review

AIM

To determine the impact of larval therapy on the debridement of venous leg ulcers, in comparison to other debridement methods or no debridement.

METHOD

Using systematic review methodology, published quantitative studies focusing on the effect of larval therapy on the debridement of venous leg ulcers were included. The search was conducted in January 2020 and updated in May 2021 using CINAHL, PubMed, Embase, and the Cochrane library, and returned 357 records, of which six studies met the inclusion criteria. Data were extracted using a predesigned extraction tool and all studies were quality appraised using the RevMan risk of bias assessment tool.

RESULTS

Larval therapy was found to debride at a faster rate than hydrogel (p = 0.011, p < 0.001, p = 0.0039), have a similar effect to sharp debridement (p = 0.12, p = 0.62), and was a resource-effective method of debridement (p < 0.05, p < 0.001, p < 0.001). When larval therapy in combination with compression therapy was compared to compression alone, larvae had a greater effect on debridement (p < 0.05), however, it did not improve overall wound healing rates (p = 0.54, p = 0.664, p = 0.02). Pain levels increased during larval therapy and reduced after treatment, when compared to other standard debridement techniques.

CONCLUSION

Larval therapy promotes rapid debridement of venous leg ulcers. However, further high quality randomised controlled trials, comparing larval therapy to other debridement methods for venous leg ulcers, incorporating the use of compression is required to determine the long term effects of larval therapy.

Practical context of enzymatic treatment for wound healing: A secreted protease approach (Review)

Skin wounds have been extensively studied as their healing represents a critical step towards achieving homeostasis following a traumatic event. Dependent on the severity of the damage, wounds are categorized as either acute or chronic. To date, chronic wounds have the highest economic impact as long term increases wound care costs. Chronic wounds affect 6.5 million patients in the United States with an annual estimated expense of $25 billion for the health care system. Among wound treatment categories, active wound care represents the fastest-growing category due to its specific actions and lower costs. Within this category, proteases from various sources have been used as successful agents in debridement wound care. The wound healing process is predominantly mediated by matrix metalloproteinases (MMPs) that, when dysregulated, result in defective wound healing. Therapeutic activity has been described for animal secretions including fish epithelial mucus, maggot secretory products and snake venom, which contain secreted proteases (SPs). No further alternatives for use, sources or types of proteases used for wound healing have been found in the literature to date. Through the present review, the context of enzymatic wound care alternatives will be discussed. In addition, substrate homology of SPs and human MMPs will be compared and contrasted. The purpose of these discussions is to identify and propose the stages of wound healing in which SPs may be used as therapeutic agents to improve the wound healing process.

Use of maggot debridement therapy in hospitalised patients in Germany

Exact data regarding the clinical role of maggot debridement therapy (MDT) for wound care in a specific country are not available. Thus, we analysed the use of MDT in hospitalised patients in Germany. Detailed lists of all hospitalised cases treated with MDT in Germany for the years 2011 to 2016 were provided by the Federal Statistical Office as well as the lists of the 15 most frequent principal and additional diagnoses, respectively, and the 10 most frequent procedures documented with MDT in 2016. Within the 6-year time period of the study, the number of cases treated with MDT increased by 11% from 4513 in 2011 to 5.017 in 2016. Lower leg and foot were the most frequent anatomic sides of treatment counting up to 83.9% of all cases. In addition, MDT procedures for temporary soft tissue coverage including negative pressure wound therapy were often performed: for treatment of large areas in 36.7% and small areas in 6.2%. 41.3% of all cases treated with MDT had infection with Escherichia coli and 35.9% of all cases with Bacillus fragilis. Our analysis shows a limited use of MDT with a small increase only in the last 6 years in German hospitals. MDT is predominately used to treat foot or leg ulcers.

Effectiveness of Chronic Wound Debridement with the Use of Larvae of Lucilia Sericata

The process of successful wound healing depends on effective debridement and infection control. One method of wound debridement, known since antiquity, is based on the use of fly larvae. Solid scientific evidence proves that maggot debridement therapy (MDT), like surgical intervention, can be effectively and safely used to remove necrotic tissue. Based on a review of the related literature, this study was designed to assess the effectiveness of chronic wound cleansing with the use of larvae of Lucilia sericata (Phaenicia sericata). Maggot therapy, applied in wound debridement and treatment, is a safe and effective method. Its benefits are associated with debridement, disinfection and faster tissue growth. MDT may reduce the duration of antibiotic therapy and the need for hospitalization, or it may decrease the number of outpatient visits required. It is a relatively cost-effective method, and, in addition to financial gains, it may reduce the frequency of inpatient treatment. In the literature, an increasing amount of scientific evidence confirms that such treatment can effectively reduce the biofilm and bacterial load in a wound.

Wound Infections in Critical Care

Patients admitted to critical care units are at high risk for increased morbidity and mortality from skin and deep wound infections. Despite considerable progress, wound healing remains a challenge to many clinicians. Nurses working in critical care environments need to understand the anatomic and physiologic basis for wound healing, distinguish wound inflammation from wound infection, recognize the presence of biofilms, and implement evidence-based wound care in order to promote successful outcomes in this patient population.

Debridement for venous leg ulcers

BACKGROUND

Venous ulcers (also known as varicose or venous stasis ulcers) are a chronic, recurring and debilitating condition that affects up to 1% of the population. Best practice documents and expert opinion suggests that the removal of devitalised tissue from venous ulcers (debridement) by any one of six methods helps to promote healing. However, to date there has been no review of the evidence from randomised controlled trials (RCTs) to support this.

OBJECTIVES

To determine the effects of different debriding methods or debridement versus no debridement, on the rate of debridement and wound healing in venous leg ulcers.

SEARCH METHODS

In February 2015 we searched: The Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE and EBSCO CINAHL. There were no restrictions with respect to language, date of publication or study setting. In addition we handsearched conference proceedings, journals not cited in MEDLINE, and the bibliographies of all retrieved publications to identify potential studies. We made contact with the pharmaceutical industry to enquire about any completed studies.

SELECTION CRITERIA

We included RCTs, either published or unpublished, which compared two methods of debridement or compared debridement with no debridement. We presented study results in a narrative form, as meta-analysis was not possible.

DATA COLLECTION AND ANALYSIS

Independently, two review authors completed all study selection, data extraction and assessment of trial quality; resolution of disagreements was completed by a third review author.

MAIN RESULTS

We identified 10 RCTs involving 715 participants. Eight RCTs evaluated autolytic debridement and included the following agents or dressings: biocellulose wound dressing (BWD), non-adherent dressing, honey gel, hydrogel (gel formula), hydrofibre dressing, hydrocolloid dressings, dextranomer beads, Edinburgh University Solution of Lime (EUSOL) and paraffin gauze. Two RCTs evaluated enzymatic preparations and one evaluated biosurgical debridement. No RCTs evaluated surgical, sharp or mechanical methods of debridement, or debridement versus no debridement. Most trials were at a high risk of bias.Three RCTs assessed the number of wounds completely debrided. All three of these trials compared two different methods of autolytic debridement (234 participants), with two studies reporting statistically significant results: one study (100 participants) reported that 40/50 (80%) ulcers treated with dextranomer beads and 7/50 (14%) treated with EUSOL achieved complete debridement (RR 5.71, 95% CI 2.84 to 11.52); while the other trial (86 participants) reported the number of ulcers completely debrided as 31/46 (76%) for hydrogel versus 18/40 (45%) for paraffin gauze (RR 0.67, 95% CI 0.45 to 0.99). One study (48 participants) reported that by 12 weeks, 15/18 (84%) ulcers treated with BWD had achieved a 75% to 100% clean, granulating wound bed versus 4/15 (26%) treated with non-adherent petrolatum emulsion-impregnated gauze.Four trials assessed the mean time to achieve debridement: one (86 participants) compared two autolytic debridement methods, two compared autolytic methods with enzymatic debridement (71 participants), and the last (12 participants) compared autolytic with biosurgical debridement; none of the results achieved statistical significance.Two trials that assessed autolytic debridement methods reported the number of wounds healed at 12 weeks. One trial (108 participants) reported that 24/54 (44%) ulcers treated with honey healed versus 18/54 (33%) treated with hydrogel (RR (adjusted for baseline wound diameter) 1.38, 95% CI 1.02 to 1.88; P value 0.037). The second trial (48 participants) reported that 7/25 (28%) ulcers treated with BWD healed versus 7/23 (30%) treated with non-adherent dressing.Reduction in wound size was assessed in five trials (444 participants) in which two autolytic methods were compared. Results were statistically significant in one three-armed trial (153 participants) when cadexomer iodine was compared to paraffin gauze (mean difference 24.9 cm², 95% CI 7.27 to 42.53, P value 0.006) and hydrocolloid compared to paraffin gauze (mean difference 23.8 cm², 95% CI 5.48 to 42.12, P value 0.01). A second trial that assessed reduction in wound size based its results on median differences and, at four weeks, produced a statistically significantly result that favoured honey over hydrogel (P value < 0.001). The other three trials reported no statistically significant results for reduction in wound size, although one trial reported that the mean percentage reduction in wound area was greater at six and 12 weeks for BWD versus a non-adherent dressing (44% versus 24% week 6; 74% versus 54% week 12).Pain was assessed in six trials (544 participants) that compared two autolytic debridement methods, but the results were not statistically significant. No serious adverse events were reported in any trial.

AUTHORS' CONCLUSIONS

There is limited evidence to suggest that actively debriding a venous leg ulcer has a clinically significant impact on healing. The overall small number of participants, low number of studies and lack of meta-analysis in this review precludes any strong conclusions of benefit. Comparisons of different autolytic agents (hydrogel versus paraffin gauze; Dextranomer beads versus EUSOL and BWD versus non-adherent dressings) and Larvae versus hydrogel all showed statistically significant results for numbers of wounds debrided. Larger trials with follow up to healing are required.

Which medical technology and/or local treatment is most conducive, as of 2012, to pressure sore debridement ? Developing French guidelines for clinical practice

INTRODUCTION

Implementation of a curative strategy at the debridement stage associates systemic therapy with local therapy.

OBJECTIVES

To determine which medical devices and technology other than support surfaces and what kinds of drugs to use in order to cleanse a pressure ulcer in 2012.

METHOD

A systematic review of the literature querying the databases PASCAL Biomed, Cochrane Library and PubMed from 2000 to 2010 along with a compendium of prevailing professional practices.

RESULTS

Pressure sore debridement is based on local care and on the use of alginates, hydrogels and hydrocolloids.

DISCUSSION

The analyzed articles do not take into account any specific stage of pressure ulcer debridement. Data that might favor some kinds of dressings show a low level of evidence. Were it possible to decide on the dressing to be used for a given indication, professionals would be better able to orient and narrow down their choices.

CONCLUSION

Use of alginates and hydrogels in pressure ulcer debridement is of real interest. According to expert opinion, other dressings (irrigo-absorbents, for instance) seem promising, but have yet to receive adequate scientific validation.

The efficacy of maggot debridement therapy--a review of comparative clinical trials

Over the last decade, maggot debridement therapy (MDT) has been recognized by many clinicians as a potential adjunct to conventional therapy, and many patients with non healing, chronic ulcers have been treated. Numerous case reports and case series have described the successful use of MDT in a variety of ulcers. However, comparative clinical trials and in particular randomized controlled trials investigating the efficacy of MDT are sparse. A systematic search in the literature showed three randomized clinical trials and five non randomized studies evaluating the efficacy of sterile Lucilia sericata applied on ulcers with various aetiologies. Of these, seven studies had debridement and/or healing as an outcome variable. When evaluating maggots as debriding agents, the studies report MDT as being significantly more effective than hydrogel or a mixture of conventional therapy modalities, including hydrocolloid, hydrogel and saline moistened gauze. However, the design of the studies was suboptimal, with important differences in the use of other therapies, such as compression, that may influence both debridement and healing between the compared groups, as well as inappropriately short follow-up times. The quality of the studies therefore makes it difficult to conclude that MDT shortens healing time. The poor quality of the data used for evaluating the efficacy of MDT highlights the need for more and better designed investigations.

Anti-biofilm strategies and the need for innovations in wound care

With an aging and obese population, chronic wounds such as diabetic ulcers, pressure ulcers, and venous leg ulcers are of an increasingly relevant medical concern in the developed world. Identification of bacterial biofilm contamination as a major contributor to non-healing wounds demands biofilm-targeted strategies to treat chronic wounds. While the current standard of care has proven marginally effective, there are components of standard care that should remain part of the wound treatment regime including systemic and topical antibiotics, antiseptics, and physical debridement of biofilm and devitalized tissue. Emerging anti-biofilm strategies include novel, non-invasive means of physical debridement, chemical agent strategies, and biological agent strategies. While aging and obesity will continue to be major burdens to wound care, the emergence of wounds associated with war require investigation and biotechnology development to address biofilm strategies that manage multi-drug resistant bacteria contaminating the chronic wound. The article presents some of the recent patents related to anti-biofilm strategy in wound care.