The Application of Bilayer Artificial Dermis Combined with VSD Technology in Chronic Wounds

Background: Bilayer artificial dermis promotes wound healing and offers a treatment option for chronic wounds. Aim: Examine the clinical efficacy of bilayer artificial dermis combined with Vacuum Sealing Drainage (VSD) technology in the treatment of chronic wounds. Method: From June 2021 to December 2023, our hospital treated 24 patients with chronic skin tissue wounds on their limbs using a novel tissue engineering product, the bilayer artificial dermis, in combination with VSD technology to repair the wounds. The bilayer artificial dermis protects subcutaneous tissue, blood vessels, nerves, muscles, and tendons, and also promotes the growth of granulation tissue and blood vessels to aid in wound healing when used in conjunction with VSD technology for wound dressing changes in chronic wounds. Results: In this study, 24 cases of chronic wounds with exposed bone or tendon larger than 1.0 cm2 were treated with a bilayer artificial skin combined with VSD dressing after wound debridement. The wounds were not suitable for immediate skin grafting. At 2 - 3 weeks post-treatment, good granulation tissue growth was observed. Subsequent procedures included thick skin grafting or wound dressing changes until complete wound healing. Patients were followed up on average for 3 months (range: 1 - 12 months) post-surgery. Comparative analysis of the appearance, function, skin color, elasticity, and sensation of the healed chronic wounds revealed superior outcomes compared to traditional skin fl repairs, resulting in significantly higher satisfaction levels among patients and their families. Conclusion: The application of bilayer artificial dermis combined with VSD technology for the repair of chronic wounds proves to be a viable method, yielding satisfactory therapeutic effects compared to traditional skin flap procedures.

Study on the effect of Shixiang plaster on the expression of CD31,serum FN,and VEGF in a rat model with chronic wounds

Background:Chronic wounds pose a significant surgical challenge,often requiring traditional treatments with limited efficacy.This study explores the promising impact of Shixiang plaster,a classic Chinese ointment,on wound healing.We investigated the cluster of differentiation 31(CD31)expression,serum fibronectin(FN),and vascular endothelial growth factor(VEGF)levels in SPF rats with induced wounds to elucidate the mechanism behind Shixiang plaster’s effectiveness.We investigated the effect and explored the role of Shixiang plaster on the expression of CD31,serum FN,and VEGF in chronic wounds.Methods:The study involved 36 SPF rats divided into model,rb-bFGF,and Shixiang plaster groups.Penicillin was injected into the rats before modelling for 3 days to prevent infection.The skin was excised 2 cm below the horizontal line of the inferior border of the shoulder bone in the middle of the rat column up to the deep fascial layer and inoculated with a certain concentration of Staphylococcus aureus;the wound was covered aseptically for 3 days.The trauma area of the rats was observed at 3,7,and 14 days,respectively.Histopathology was observed using haematoxylin eosin and Masson staining.CD31 expression was detected using immunohistochemistry staining.FN and VEGF expression was detected using serum ELISA.Statistical analyses were carried out by the method of SPSS.Results:Regarding wound morphology,at 3 days,the recovery area of the Shixiang plaster group was larger than that of the other two groups,at 7 days,the wound healing rate of the Shixiang plaster group was significantly higher,and at 14 days,the wounds of the Shixiang plaster group had been mostly healed,with a healing rate of 98.3%.Haematoxylin eosin staining revealed a large amount of granulation tissue at 3 days in the Shixiang plaster group,and the epidermal scales disappeared at 14 days,with thinner epidermal thickness at 1 lesion and a large reduction in inflammatory cell infiltration.Masson staining showed that at 3,7,and 14 days,blue staining was the most abundant and deeper in the Shixiang plaster group,with richer collagen and a compact tissue matrix.Immunohistochemical testing showed strong positive expression of CD31 in the Shixiang plaster group,with abundant neovascularisation and large official lumens extending towards the surface of the wound.Statistically significant elevated expression of FN at 7 and 14 days was determined by ELISA in the Shixiang plaster group,and VEGF expression was significantly increased at 7 days,but expression had been expressed at a low level at 14 days.Conclusion:Shixiang plaster exhibits remarkable efficacy in healing chronic wounds.The proposed mechanism involves FN’s promotion of angiogenesis and cell proliferation,VEGF’s impact on angiogenesis and inflammation,and CD31’s regulatory role in inhibiting inflammation while promoting angiogenesis.

Efficacy of lidocaine wet compress combined with red-light irradiation for chronic wounds

BACKGROUND Chronic wounds that fail to progress through normal phases of healing present a significant healthcare burden owing to prolonged treatment and associated costs.Traditional wound care typically involves regular dressing changes,which can be painful.Recent approaches have explored the use of lidocaine to manage pain and red-light irradiation(RLI),known for its anti-inflammatory and cell proliferation effects,to potentially enhance wound healing.AIM To investigate the therapeutic efficacy of lidocaine wet compression(LWC)combined with RLI for chronic wounds.METHODS We enrolled 150 patients with chronic wounds from the Wound and Ostomy Outpatient Clinic of the Second Hospital of Anhui Medical University from April to September 2022.The wounds were treated with dressing changes.The patients were randomly assigned to the control and experimental groups using a random number table and given the same first dressing change(2%LWC for 5 min and routine dressing change).From the second dressing change,in addition to 2%LWC for 5 min and routine dressing change,the experimental group received RLI,whereas the control group continued to receive the same LWC and dressing change.The first and second dressing changes were performed on days 1 and 2,respectively.The third dressing change was performed 3 d after the second change.The frequency of subsequent dressing changes was determined based on wound exudation and pain.Pain during the first three dressing changes was evaluated in both groups.The average number of dressing changes within 28 d and the degree of wound healing on day 28 were also recorded.RESULTS During the initial dressing change,no noticeable differences were observed in the pain levels experienced by the two groups,indicating similar pain tolerance.However,during the second and third dressing changes,the experimental group reported significantly less pain than the control group.Furthermore,over 28 d,the experimental group required fewer dressing changes than the control group.CONCLUSION Notably,the effectiveness of wound healing on the 28th day was significantly higher in the experimental group than that of in the control group.The combination of LWC and RLI was effective in reducing early-stage pain,promoting wound healing,decreasing the frequency of dressing changes,and enhancing patients’overall quality of life with chronic wounds.

Antibacterial Properties of Crateva adansonii (Capparidaceae) on Strains Isolated from Chronic Wounds Diagnosed in the Commune of Ouinhi in 2021

Plants have always been used by people for therapeutic purposes. They are still the main source of therapeutic substances in developing countries. Crateva adansonii, a member of the Capparidaceae family, is a medicinal plant with antibacterial properties used in Benin. The aim of this study was to assess the efficacy of an aqueous extract of C. adansonii on bacterial strains isolated from chronic wounds in the Ouinhi population. To achieve this, the bacterial flora present in chronic wounds was identified using the Ikram method (2014) coupled with the API Remoel One method. The antibacterial properties of the aqueous extract of C. adansonii on the microbial strains isolated were then assessed by determining the Inhibition Diameters (ID), the Minimum Inhibitory Concentrations (MIC) and finally the Minimum Bactericidal Concentrations (MBC). A total of eighty (80) strains were isolated and identified on the basis of morphological, cultural and biochemical characteristics. The species S. Aureus species accounted for the largest proportion (67.5%). Other species such as Listeria sp, Pseudomonas proteus, S. epidermidis and Bacillus cereus, Citrobacter freundii, Steno maltophila;Axin calcoaceticus, E. coli, K. pneumonia, Lem. richardii, Salmonella paratyphi A, Salmonella sp, Shigella sp were determined in variable proportions. At a concentration of 10 mg/ml, only S. aureus was sensitive to contact with the extract. However, at 20 mg/ml, 89% of strains were sensitive and 11% very sensitive. The highly sensitive strains are Salmonella sp and E. coli. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) are 20 mg/ml and 40 mg/ml respectively. The MBC/MIC ratio of the aqueous mixture of Crateva adansonii (Capparidaceae) varied from 1.2 to 2, with a bactericidal effect on 100% of the strains tested.

Role of stem cell therapies in treating chronic wounds:A systematic review

BACKGROUND The impairment of cutaneous wound healing results in chronic,non-healing wounds that are caused by altered wound environment oxygenation,tissue injury,and permissive microbial growth.Current modalities for the treatment of these wounds inadequately address the complex changes involved in chronic wound pathogenesis.Consequently,stem cell therapies have emerged as a potential therapeutic modality to promote cutaneous regeneration through trophic and paracrine activity.AIM To investigate current literature regarding use of stem cell therapies for the clinical treatment of chronic,non-healing wounds.METHODS PubMed,EMBASE,Cochrane Library,Web of Science,and Scopus were queried with combinations of the search terms“mesenchymal stem cells,”“adult stem cells,”“embryonic stem cells,”“erythroid precursor cells,”“stem cell therapies,”and“chronic wounds”in order to find relevant articles published between the years of 2000 and 2019 to review a 20-year experience.Reference lists from the articles were reviewed to identify additional pertinent articles.Retrieved manuscripts(reviews,case reports/series,retrospective/prospective studies,and clinical trials)were evaluated by the authors for their depiction of clinical stem cell therapy use.Data were extracted from the articles using a standardized collection tool.RESULTS A total of 43 articles describing the use of stem cell therapies for the treatment of chronic wounds were included in this review.While stem cell therapies have been explored in in vitro and in vivo applications in the past,recent efforts are geared towards assessing their clinical role.A review of the literature revealed that adipose-derived stem cells,bone marrow-derived stem cells,bone marrowderived mononuclear cells,epidermally-derived mesenchymal stem cells,fibroblast stem cells,keratinocyte stem cells,placental mesenchymal stem cells,and umbilical cord mesenchymal stem cells have all been employed in the treatment of chronic wounds of various etiologies.Most recently,embryonic stem cells have emerged as a novel stem cell therapy with the capacity for multifaceted germ cell layer differentiation.With the capacity for self-renewal and differentiation,stem cells can enrich existing cell populations in chronic wounds in order to overcome barriers impeding the progression of wound healing.Further,stem cell therapies can be utilized to augment cell engraftment,signaling and activity,and resultant patient outcomes.CONCLUSION Assessing observed clinical outcomes,potential for stem cell use,and relevant therapeutic challenges allows wound care stakeholders to make informed decisions regarding optimal treatment approaches for their patients’chronic wounds.

Combined debridement in chronic wounds:A literature review

Wounds debridement is important for healing of chronic wounds. Combined debridement is a new technique to deal with the complex chronic wounds. This review introduces several topical methods of combined debridement according to the various color classifications. Methods include combined sharp and hydrogel debridement, combined ultrasonic and enzymatic debridement, ultrasonic debridement combined with surgical debridement and vacuum aspiration on debridement, and other types of debridement. This article also explores why each combined debridement mentioned above can achieve a good effect.

Effectiveness of fire needle combining with moist healing dressing to promote the growth of granulation tissue in chronic wounds:A case report

In this case study,we analyzed the wound-healing process of a patient with a chronic wound who underwent fire needle treatment,and we tracked the coverage of granulation tissue and decrease of slough and exudate.An 85-year-old man had repeated right shoulder and back pain,itching,and skin festering for more than 1.5 years.A fire needle was administered combined with moist dressing once every 5 days to promote wound healing.After six rounds of fire needle treatment,granulation tissue formed over the surface of the wound base,the depth of the wound had become shallow,and the wound area was reduced.No complications occurred during the intervention.Fire needle therapy combined with a moist wound-healing dressing can be an effective alternative approach in managing chronic wounds.

Research Progress of Continuous Nursing for Patients with Chronic Wounds After Discharge

The research status of continuous nursing of patients with chronic wounds is reviewed.Since the research on continuous nursing of chronic wound patients in China is still in the initial stage,if necessary,learn from foreign experience,improve relevant systems,develop corresponding evaluation tools,actively implement telemedicine,and carry out hospital-community linkage models,etc.to provide high-quality nursing services for patients with chronic wounds.

Chronic wounds:pathological characteristics and their stem cell-based therapies

Chronic wounds are characterized by prolonged healing processes and poor prognoses,which have substantially impacted human health and daily life.Traditional treatment strategies have various limitations and drawbacks.Therefore,fully effective therapeutic approaches remain urgently needed.Stem cell(SC)-based therapies have drawn significant attention for their abilities of immunomodulation and pro-regeneration.It has been demon-strated that stem cells(SCs)can improve angiogenesis,collagen deposition,and hair rejuvenation,thus facilitating wound healing.In addition,attempts were performed to facilitate the cell survival,function,retention,and en-graftment of the delivered SCs.In this review,we first introduce the pathological process involved in chronic wound healing.Following that,the mechanism of SCs in promoting chronic wound repair is discussed in detail.Then,we highlight recent SC-based therapies for chronic wound repair developments.Finally,we present our views on the remaining challenges and future trends of SC-based therapies for chronic wound treatment.

The physiological polyphosphate as a healing biomaterial for chronic wounds:Crucial roles of its antibacterial and unique metabolic energy supplying properties

Insufficient metabolic energy,in the form of adenosine triphosphate(ATP),and bacterial infections are among the main causes for the development of chronic wounds.Previously we showed that the physi-ological inorganic polymer polyphosphate(polyP)massively accelerates wound healing both in animals(diabetic mice)and,when incorporated into mats,in patients with chronic wounds.Here,we focused on a hydrogel-based gel formulation,supplemented with both soluble sodium polyP(Na-polyP)and amor-phous calcium polyP nanoparticles(Ca-polyP-NP).Exposure of human epidermal keratinocytes to the gel caused a significant increase in extracellular ATP level,an effect that was even enhanced when Na-polyP was combined with Ca-polyP-NP.Furthermore,it is shown that the added polyP in the gel is converted into a coacervate,leading to encapsulation and killing of bacteria.The data on human chronic wounds showed that the administration of hydrogel leads to the complete closure of these wounds.Histological analysis of biopsies showed an increased granulation of the wounds and an enhanced microvessel forma-tion.The results indicate that the polyP hydrogel,due to its properties to entrap bacteria and generate metabolic energy,is a very promising formulation for a new therapy for chronic wounds.

Empowerment in chronic wound care——exploring the scope for patient contribution

Objective:In this study,we investigated the concept of empowerment in chronic wound care and propose to facilitate patient control by making use of degrees of freedom(DOF):that is,shaping of everyday wound care tasks initiated by patients and based on their wishes,mostly in terms of patients executing treatment steps,requesting or directing health care professionals to under take changes,or modifications of internal states.Methods:As a first step,we conducted a systematic literature search,followed by an inductive form of qualitative content analysis,which resulted in the identification of 5 dimensions as main elements of empowerment:education and shared decision making,adherence to self-care behaviors,responsibility and control,general call for empowerment,and DOF.However,the latter are noticeably absent in the literature.To investigate patients'freedom in shaping the wound care process,we conducted a second literature search.Results:A number of possibilities for patients to influence the wound care process could be identified,but experimental or clinical evidence about their effects is missing,their variety is limited,and they are only inadequately described.Conclusions:However,DOF should be an indispensable aspect of genuine empowerment,since they allow patients to occupy the role of the agent in the treatment process and give rise to the subjective experience of feeling empowered.Thus,in the third part,we develop a research proposal on how to investigate and include DOF in the clinical practice of wound care.Finally,limitations about implementations are discussed(e.g.,patients being reluctant to overcome their passive role,resulting in frustration for health care professionals).

Principles of extramural hl ealth care for chronic wounds in China

Development of extramural health care for chronic wounds is still in its infancy in China,and thus it is urgent and vital to establish a correct concept and practicable principles.The authors reviewed recent domestic and international literature and summarized the following treatment procedures and principles for extramural health care of chronic wounds.(1)The patient needs to do self-assessment of the wound by using available simple methods;(2)The patient consults with professional physicians or nurses on wound care to define the severity and etiology of the non-healing wound;(3)Professionals evaluate the existing treatment strategies;(4)Etiological treatments are given by professionals;(5)Patients buy needed dressings via the more convenient ways from pharmacies,e-commerce platform or others;(6)Professionals provide a standardized and reasonable therapeutic plan based on the patient's wound conditions;(7)Both professionals and the patient pay attention to complications to prevent adverse outcomes;(8)Professionals strengthen the public education on wound care and integrated rehabilitation.This review expected to provide new perspectives on the therapeutic strategies for chronic wounds in an extramural setting.

Discussion on the Application Effect of Simplified Vacuum Sealing Drainage(VSD)in the Treatment of Chronic Refractory Wounds

Objective:To analyze the effect of simplified vacuum sealing drainage(VSD)in the treatment of chronic refractory wounds.Methods:A total of 90 patients with chronic refractory wounds treated from May 2022 to May 2023 were randomly divided into groups.The simplified VSD treatment was employed in group A,and conventional treatment was employed in group B,and the wound healing of both groups were compared.Results:Group A showed better wound healing compared to group B,P<0.05;the wound healing rate,wound healing duration,visual analog scale(VAS)score,wound dressing times and other indicators in group A were better than those in group B,P<0.05.The SF-36 score of group A was higher than that of group B,P<0.05;the complication rate of chronic refractory wounds in group A was no different from that in group B,P>0.05.Conclusion:Simplified VSD treatment is effective in treating patients with chronic refractory wounds,and it reduces the number of wound dressing changes and promote wound healing.

The Impact of Psychosocial Influences on Chronic Wound Healing

This comprehensive review explores the intricate dynamics between psychosocial factors and chronic wound healing processes, specifically focusing on prevalent conditions such as pressure ulcers, diabetic foot ulcers, and venous leg ulcers. By examining the roles of psychiatric conditions, including depression, anxiety, and post-traumatic stress disorder (PTSD), this paper illuminates how these factors intricately influence wound healing dynamics, including mechanisms of pain perception and inflammatory responses. Furthermore, we evaluate the effectiveness of integrated biopsychosocial interventions, which encompass a holistic approach to wound care, thereby enhancing healing outcomes for dermatology patients. Future studies should focus on investigating the specific psychosocial determinants that significantly influence wound healing, exploring novel therapeutic strategies, and implementing personalized interventions to meet the unique needs of each patient. Such endeavors hold promise in advancing the fields of psychodermatology and wound management, fostering a deeper understanding and application of psychosocial considerations in dermatological care.

Gene-activated dermal equivalents to accelerate healing of diabetic chronic wounds by regulating inflammation and promoting angiogenesis

Diabetic chronic wound,characterized by prolonged inflammation and impaired angiogenesis,has become one of the most serious challenges in clinic and pose a significant healthcare burden worldwide.Although a great variety of wound dressings have been developed,few of encouraged achievements were obtained so far.In this study,the gene-activated strategy was applied to enhance sustained expression of vascular endothelial growth factor(VEGF)and achieve better healing outcomes by regulating inflammation and promoting angiogenesis.The gene-activated bilayer dermal equivalents(Ga-BDEs),which has good biocompatibility,were fabricated by loading the nano-sized complexes of Lipofectamine 2000/plasmid DNA-encoding VEGF into a collagen-chitosan scaffold/silicone membrane bilayer dermal equivalent.The DNA complexes were released in a sustained manner and showed the effective transfection capacities to up-regulate the expression of VEGF in vitro.To overcome cutaneous contraction of rodents and mimic the wound healing mechanisms of the human,a reformative rat model of full-thickness diabetic chronic wound was adopted.Under the treatment of Ga-BDEs,speeding wound healing was observed,which is accompanied by the accelerated infiltration and phenotype shift of macrophages and enhanced angiogenesis in early and late healing phases,respectively.These proved that Ga-BDEs possess the functions of immunomodulation and pro-angiogenesis simultaneously.Subsequently,the better regeneration outcomes,including deposition of oriented collagen and fast reepithelialization,were achieved.All these results indicated that,being different from traditional pro-angiogenic concept,the up-regulated expression of VEGF by Ga-BDEs in a sustained manner shows versatile potentials for promoting the healing of diabetic chronic wounds.

Cellular senescence is a promising target for chronic wounds:a comprehensive review

Chronic wounds include,but are not limited to,radiation ulcers,pressure ulcers,vascular ulcers and diabetic foot ulcers.These chronic wounds can persist for years without healing and severe ulcers may lead to amputation.Unfortunately,the underlying pathologies of refractory chronic wounds are not fully characterized,and new treatments are urgently needed.Recently,increasing evidence has indicated that cell senescence plays an important role in the development of chronic wounds,and preventing cell senescence or removing senescent cells holds promise as a new therapeutic strategy.In this review,we aim to probe these latest findings to promote the understanding of cellular senescence in the pathological process and potential management of chronic wounds.

Immunomodulatory biomaterial-based wound dressings advance the healing of chronic wounds via regulating macrophage behavior

Successful wound healing is a process that has three overlying phases:inflammatory,proliferative and remodeling.Chronic wounds are characterized by a perpetuated inflammation that inhibits the proliferative and remodeling phases and impairs the wound healing.Macrophages are key modulators of the wound healing process.Initially,they are responsible for the wound cleaning and for the phagocytosis of pathogens and afterwards they lead to the resolution of the inflammatory response and they express growth factors important for angiogenesis and cytokines and growth factors needed for cell proliferation and deposition of extracellular matrix.The phenotype of the macrophage changes gradually throughout the healing process from the initial M1 pro-inflammatory phenotype characteristic of the acute response to the M2 pro-regenerative phenotype that allows an accurate tissue repair.In chronic wounds,M1 pro-inflammatory macrophages persist and impair tissue repair.As such,immunomodulatory biomaterials arise as promising solutions to accelerate the wound healing process.In this review,we discuss the importance of macrophages and their polarization throughout the different phases of wound healing;macrophage dysfunction in chronic wounds and the use of immunomodulatory biomaterials to overcome the critical problem of chronic wounds-the continued inflammatory phase that impairs healing.

Senescence in chronic wounds and potential targeted therapies

Chronic wounds(e.g.diabetic wounds,pressure wounds,vascular ulcers,etc.)do not usually heal in a timely and orderly manner but rather last for years and may lead to irreversible adverse events,resulting in a substantial financial burden for patients and society.Recently,a large amount of evidence has proven that cellular senescence has a crucial influence on chronic nonhealing wounds.As a defensive mechanism,cell senescence is a manner of cell-cycle arrest with increased secretory phenotype to resist death,preventing cells from stress-induced damage in cancer and noncancer diseases.A growing amount of research has advanced the perception of cell senescence in various chronic wounds and focuses on pathological and physiological processes and therapies targeting senescent cells.However,previous reviews have failed to sum up novel understandings of senescence in chronic wounds and emerging strategies targeting senescence.Herein,we discuss the characteristics and mechanisms of cellular senescence and the link between senescence and chronic wounds as well as some novel antisenescence strategies targeting other diseases that may be applied for chronic wounds.

Histopathological study of chronic wounds modulated by intermittent negative pressure therapy under limited access dressing

Aim:Negative pressure wound therapy(NPWT)has achieved widespread success in the treatment of chronic wounds.However,its effects have been only partially explored,and investigations have generally concentrated on the wound-dressing interface;a detailed histopathological description of the evolution of wounds under NPWT is still lacking.The present study was performed to investigate the effect of a limited access dressing(LAD)which exerts intermittent NPWT in a moist environment on chronic wounds.Methods:A total of 140 patients were randomized into 2 groups:LAD group(n=64)and conventional dressing group(n=76).By histopathological analysis of the granulation tissue,the amount of inflammatory infiltrate,necrotic tissue,angiogenesis,and extracellular matrix(ECM)deposition was studied and compared to determine healing between the 2 groups.Results:After 10 days of treatment,histopathological analysis showed a significant decrease in necrotic tissue with LAD compared to the conventional dressing group(mean±standard error,11.5±0.48 vs.10.1±0.30,P=0.007),the number of inflammatory cells(12.6±0.60 vs.8.63±0.35,P=0.018),a significant increase in new blood vessels(12.8±0.58 vs.9.3±0.29,P=0.005)and ECM deposit(13.3±0.50 vs.9.6±0.24,P=0.001).Conclusion:LAD exerts its beneficial effects on chronic wound healing by decreasing the amount of necrotic tissue and inflammatory cells while increasing the amount of ECM deposition and angiogenesis.

Effect of limited access dressing on surface pH of chronic wounds

Aim:Changes in the pH of chronic wounds can inhibit the optimal activity of various enzymes in the wound environment,thereby delaying wound healing.The aim of the present study is to monitor the effect of limited access dressing(LAD)on the pH on the surface of chronic wounds.Methods:A total of 140 patients with chronic wounds of more than 4 weeks duration were divided into two groups by simple randomization:a LAD group(n=64)and a conventional dressing group(n=76).Fifty-six participants(22 in the LAD group and 34 in the conventional dressing group)were lost to follow-up or withdrawn from the study.Results:In the LAD group(n=42),the mean age was 38.3±10.56 years(range:12-60 years),and the mean wound size at the time of admission was 28 cm^(2)(range:19-40 cm^(2)).In the conventional dressing group(n=42),the mean age was 35.3±14.0 years(range:17-65 years),and the mean wound size at the time of admission was 26 cm^(2)(range:18-39 cm^(2)).Patients treated with LAD showed a significant decrease in the mean±standard deviation pH when compared with the conventional dressing group(0.83±0.52 vs.0.41±0.26,P=0.048).Conclusion:LAD reduces the chronic wound surface pH to a level required for the optimal function of various enzymes.This could be a factor that exerts a beneficial effect on wound healing.