Analysis of nerve and neuropeptide patterns in vacuum-assisted closure-treated diabetic murine wounds. Plast Reconstr Surg. 2010;126:87-96. [PMID: 20595860 DOI: 10.1097/prs.0b013e3181da86d0]

Developmental prospects of carrageenan-based wound dressing films: Unveiling techno-functional properties and freeze-drying technology for the development of absorbent films - A review

This review explores the intricate wound healing process, emphasizing the critical role of dressing material selection, particularly for chronic wounds with high exudate levels. The aim is to tailor biodegradable dressings for comprehensive healing, focusing on maximizing moisture retention, a vital element for adequate recovery. Researchers are designing advanced wound dressings that enhance techno-functional and bioactive properties, minimizing healing time and ensuring cost-effective care. The study delves into wound dressing materials, highlighting carrageenan biocomposites superior attributes and potential in advancing wound care. Carrageenan's versatility in various biomedical applications demonstrates its potential for tissue repair, bone regeneration, and drug delivery. Ongoing research explores synergistic effects by combining carrageenan with other novel materials, aiming for complete biocompatibility. As innovative solutions emerge, carrageenan-based wound-healing medical devices are poised for global accessibility, addressing challenges associated with the complex wound-healing process. The exceptional physico-mechanical properties of carrageenan make it well-suited for highly exudating wounds, offering a promising avenue to revolutionize wound care through freeze-drying techniques. This thorough approach to evaluating the wound healing effectiveness of carrageenan-based films, particularly emphasizing the development potential of lyophilized films, has the potential to significantly improve the quality of life for patients receiving wound healing treatments.

Molecular immunological mechanisms of impaired wound healing in diabetic foot ulcers (DFU), current therapeutic strategies and future directions

Diabetic foot ulcer (DFU) is a foremost cause of amputation in diabetic patients. Consequences of DFU include infections, decline in limb function, hospitalization, amputation, and in severe cases, death. Immune cells including macrophages, regulatory T cells, fibroblasts and other damage repair cells work in sync for effective healing and in establishment of a healthy skin barrier post-injury. Immune dysregulation during the healing of wounds can result in wound chronicity. Hyperglycemic conditions in diabetic patients influence the pathophysiology of wounds by disrupting the immune system as well as promoting neuropathy and ischemic conditions, making them difficult to heal. Chronic wound microenvironment is characterized by increased expression of matrix metalloproteinases, reactive oxygen species as well as pro-inflammatory cytokines, resulting in persistent inflammation and delayed healing. Novel treatment modalities including growth factor therapies, nano formulations, microRNA based treatments and skin grafting approaches have significantly augmented treatment efficiency, demonstrating creditable efficacy in clinical practices. Advancements in local treatments as well as invasive methodologies, for instance formulated wound dressings, stem cell applications and immunomodulatory therapies have been successful in targeting the complex pathophysiology of chronic wounds. This review focuses on elucidating the intricacies of emerging physical and non-physical therapeutic interventions, delving into the realm of advanced wound care and comprehensively summarizing efficacy of evidence-based therapies for DFU currently available.

Effectiveness of negative-pressure wound therapy to standard therapy in the prevention of complications after vascular surgery

Wound complications are common after vascular surgery and many may be preventable. Negative pressure wound therapy (NPWT) dressings may be able to reduce wound complications relating to closed incisions following vascular surgery and several devices are currently available along with a large body of literature. This review article will describe the use of NPWT dressings in vascular surgery. We will summarize the currently available systems, the likely mechanism of action of NWPT, the published studies to date and we will give our recommendations regarding the priorities for future research on this topic.

Molecular mechanisms of action of negative pressure wound therapy: a systematic review

Negative pressure wound therapy (NPWT) has significantly advanced wound care and continues to find new applications. Its effects at a molecular level however, remain a subject of debate. The aim of this systematic review is to summarize the current evidence regarding the molecular mechanisms of action of NPWT. Medline, Embase, EBSCO databases and clinical trial registries were searched from inception to January 2023. Clinical studies, animal models or in-vitro studies that quantitatively or semi-quantitatively evaluated the influence of NPWT on growth factors, cytokine or gene-expression in the circulation or wound-bed were included. Risk of Bias assessment was performed using the RoBANS tool for non-randomized studies, the COCHRANE's Risk of Bias 2(ROB-2) tool for randomized clinical studies, OHAT tool for in-vitro studies or the SYRCLE tool for animal model studies. A descriptive summary was collated and the aggregated data is presented as a narrative synthesis. This review included 19 clinical studies, 11 animal studies and 3 in-vitro studies. The effects of NPWT on 43 biomarkers and 17 gene expressions were studied across included studies. NPWT stimulates modulation of numerous local and circulating cytokines and growth factor expressions to promote an anti-inflammatory profile. This is most likely achieved by downregulation of TNFα, upregulation of VEGF, TGF-β and fibronectin.

Physical therapy in diabetic foot ulcer: Research progress and clinical application

Diabetes foot ulcer (DFU) is one of the most intractable complications of diabetes and is related to a number of risk factors. DFU therapy is difficult and involves long-term interdisciplinary collaboration, causing patients physical and emotional pain and increasing medical costs. With a rising number of diabetes patients, it is vital to figure out the causes and treatment techniques of DFU in a precise and complete manner, which will assist alleviate patients' suffering and decrease excessive medical expenditure. Here, we summarised the characteristics and progress of the physical therapy methods for the DFU, emphasised the important role of appropriate exercise and nutritional supplementation in the treatment of DFU, and discussed the application prospects of non-traditional physical therapy such as electrical stimulation (ES), and photobiomodulation therapy (PBMT) in the treatment of DFU based on clinical experimental records in ClinicalTrials.gov.

Theoretical and Pre-Clinical Models of Vacuum Assisted Closure

Vacuum Assisted Closure (VAC) has changed how physicians treat complex and chronic wounds. For over 20 years, we have studied the mechanism of action of these devices in both an academic based research laboratory and in an industry-based laboratory.We performed a literature review of the theoretical and pre-clinical published studies from the two labs which related to the biomechanics of open pore reticulated polyurethane interfaces.The VAC device applies a direct mechanical interface to the wound surface. The interaction of the foam under suction with the wound surface causes surface deformation and cell stretch. The suction removes fluid from the tissues. There are increases in angiogenesis with better vessel morphology than standard dressings. The effect is dependent on the pore size of the foam, the pressure of application and the waveform of application. Undoubtedly, patient factors such as age, diabetes and radiation affect the response.Pre-clinical studies can help in the design and optimization of mechanical-based wound healing devices. Current work on the effects of these devices on lymphatics and scarring are areas of active investigation.

Diabetic wound healing approaches: an update

Diabetic wounds are of profound clinical importance. Despite immense efforts directed towards its management, it results in the development of amputations, following a diagnosis of diabetic foot. With a better understanding of the complexities of the microbalance involved in the healing process, researchers have developed advanced methods for the management of wounds as well as diagnostic tools (especially, for wound infections) to be delivered to clinics sooner. In this review, we address the newer developments that hope to drive the transition from bench to bedside in the coming decade.

Negative-Pressure Wound Therapy: What We Know and What We Need to Know

Negative-pressure wound therapy (NPWT) promotes wound healing by applying negative pressure to the wound surface. A quarter of a century after its introduction, NPWT has been used in various clinical conditions, although molecular biological evidence is insufficient due to delay in basic research. Here, we have summarized the history of NPWT, its mechanism of action, what is currently known about it, and what is expected to be known in the future. Particularly, attention has shifted from the four main mechanisms of NPWT to the accompanying secondary effects, such as effects on various cells, bacteria, and surgical wounds. This chapter will help the reader to understand the current status and shortcomings of NPWT-related research, which could aid in the development of basic research and, eventually, clinical use with stronger scientific evidence.

Autologous wound margin point columnar full‐thickness skin grafting combined with negative pressure wound therapy improves wound healing in refractory diabetic foot ulcers

Diabetic lower extremity ulcers (DLEUs) are a severe complication of diabetes mellitus (DM) and are difficult to heal. This study aimed to explore the efficacy of autologous point columnar full-thickness skin graft taken from the ulcer wound margin combined with negative pressure wound therapy (NPWT) in refractory DLEUs. This is a prospective cohort study. A total of 40 inpatients with refractory DLEUs were recruited in the Diabetes Foot Center of Guangxi Zhuang Autonomous Region People's Hospital from October 2019 to November 2021. According to the doctors' professional suggestions and the patients' personal wishes, these enrolled patients were divided into two groups based on different topical wound management: the graft group (n = 18) and the conventional wound therapeutic (CWT) group (n = 22). The efficacy evaluations included the time to complete re-epithelialization of the wound and healing speed within 14 days of graft treatment or after 14 days of graft treatment in the two groups. Before the treatment, the graft group had a significantly larger ulcer area than the CWT group [27.22 (15.28, 46.59) versus 10.92 (7.00, 24.93) cm² , P < .01]. However, the time to complete wound re-epithelialization in the graft group was shorter than in the CWT group [58.22 ± 30.60 versus 86.09 ± 49.54 d, P < .05]. Meanwhile, the healing speed in graft group was markedly faster than in CWT group, whether within 14 days [0.60 (0.40, 0.92) versus 0.16 (0.07, 0.34) cm² /d, P < .01] or after 14 days of graft treatment [0.57 (0.45, 0.91) versus 0.13 (0.08, 0.27) cm² /d, P < .01]. However, the total treatment cost in the graft group was lower than in the CWT group [419.59 ± 137.20 versus 663.97 ± 497.02 $, P < .05]. The novel treatment modality of autologous full-thickness skin graft taken from the ulcer wound margin combined with NPWT has hereby proposed for the first time, and is a safe, effective, and reliable method with a good performance-to-cost ratio to promote wound healing and shorten the healing time for DLEUs.

Effect of closed incision negative pressure wound therapy on incidence rate of surgical site infection after stoma reversal: a pilot study

INTRODUCTION

The stoma reversal (SR) procedure is associated with a relatively high risk of perioperative complications with surgical site infection (SSI) as the most common. Recently closed incision negative pressure wound therapy (ciNPWT) was applied widely to prevent SSI.

AIM

To investigate the efficiency of ciNPWT in terms of the incidence rate of SSI after SR surgery.

MATERIAL AND METHODS

As an exploratory observational cohort study patients were treated either with ciNPWT (n = 15) or standard sterile dressing (SSD) (n = 15). CiNPWT was applied every 3 days whereas SSD was changed every day. Clinical evaluation for SSI signs, C-reactive protein level and pain assessment using the visual analogue scale (VAS) were analyzed.

RESULTS

The incidence rate of SSI was in 13% (2/15) in the ciNPWT group and 26% (4/15) in the SSD group (p = 0.651, OR = 0.44, 95% CI: 0.03-3.73). All patients in the SSD group who developed SSI presented both local and generalized signs of infection. Pain-VAS levels assessed on the 1st (MdnciNPWT = 4, MdnSSD = 5, p = 0.027, W = 51.5) and 3rd postoperative day (MdnciNPWT = 2, MdnSSD = 4, p = 0.014, W = 45.5) were significantly lower in the ciNPWT group than in the SSD group.

CONCLUSIONS

CiNPWT seems not to have a benefit to reduce SSI after the SR procedure. Further investigation is needed to establish firmly the benefit of using ciNPWT in this group of patients.

Cutaneous innervation in impaired diabetic wound healing

Type 2 diabetes is associated with several potential comorbidities, among them impaired wound healing, chronic ulcerations, and the requirement for lower extremity amputation. Disease-associated abnormal cellular responses, infection, immunological and microvascular dysfunction, and peripheral neuropathy are implicated in the pathogenesis of the wound healing impairment and the diabetic foot ulcer. The skin houses a dense network of sensory nerve afferents and nerve-derived modulators, which communicate with epidermal keratinocytes and dermal fibroblasts bidirectionally to effect normal wound healing after trauma. However, the mechanisms through which cutaneous innervation modulates wound healing are poorly understood, especially in humans. Better understanding of these mechanisms may provide the basis for targeted treatments for chronic diabetic wounds. This review provides an overview of wound healing pathophysiology with a focus on neural involvement in normal and diabetic wound healing, as well as future therapeutic perspectives to address the unmet needs of diabetic patients with chronic wounds.

Noncontact Phased-Array Ultrasound Facilitates Acute Wound Healing in Mice

Supplemental Digital Content is available in the text.

Background:

The authors developed a noncontact low-frequency ultrasound device that delivers high-intensity mechanical force based on phased-array technology. It may aid wound healing because it is likely to be associated with lower risks of infection and heat-induced pain compared with conventional ultrasound methods. The authors hypothesized that the microdeformation it induces accelerates wound epithelialization. Its effects on key wound-healing processes (angiogenesis, collagen accumulation, and angiogenesis-related gene transcription) were also examined.

Methods:

Immediately after wounding, bilateral acute wounds in C57BL/6J mice were noncontact low-frequency ultrasound– and sham-stimulated for 1 hour/day for 3 consecutive days (10 Hz/90.6 Pa). Wound closure (epithelialization) was recorded every 2 days as the percentage change in wound area relative to baseline. Wound tissue was procured on days 2, 5, 7, and 14 (five to six per time point) and subjected to histopathology with hematoxylin and eosin and Masson trichrome staining, CD31 immunohistochemistry, and quantitative polymerase-chain reaction analysis.

Results:

Compared to sham-treated wounds, ultrasound/phased-array–treated wounds exhibited significantly accelerated epithelialization (65 ± 27 percent versus 30 ± 33 percent closure), angiogenesis (4.6 ± 1.7 percent versus 2.2 ± 1.0 percent CD31⁺ area), and collagen deposition (44 ± 14 percent versus 28 ± 13 percent collagen density) on days 5, 2, and 5, respectively (all p < 0.05). The expression of Notch ligand delta-like 1 protein (Dll1) and Notch1, which participate in angiogenesis, was transiently enhanced by treatment on days 2 and 5, respectively.

Conclusions:

The authors’ noncontact low-frequency ultrasound phased-array device improved the wound-healing rate. It was associated with increased early neovascularization that was followed by high levels of collagen-matrix production and epithelialization. The device may expand the mechanotherapeutic proangiogenesis field, thereby helping stimulate a revolution in infected wound care.

Autonomic nerve dysfunction and impaired diabetic wound healing: The role of neuropeptides

Lower extremity ulcerations represent a major complication in diabetes mellitus and involve multiple physiological factors that lead to impairment of wound healing. Neuropeptides are neuromodulators implicated in various processes including diabetic wound healing. Diabetes causes autonomic and small sensory nerve fibers neuropathy as well as inflammatory dysregulation, which manifest with decreased neuropeptide expression and a disproportion in pro- and anti- inflammatory cytokine response. Therefore to fully understand the contribution of autonomic nerve dysfunction in diabetic wound healing it is crucial to explore the implication of neuropeptides. Here, we will discuss recent studies elucidating the role of specific neuropeptides in wound healing.

Technological Advances in Wound Treatment of Exotic Pets

Although most research about the use of technological advances for wound healing was performed in laboratory animals but oriented to human medicine, recent technological advances allowed its application not only to small animals but also to exotic pets. This article reviews the literature available about some of these techniques (negative wound pressure therapy, photobiomodulation [laser therapy], electrical stimulation therapy, therapeutic ultrasonography, hyperbaric oxygen therapy), and other advances in wound management (skin expanders, xenografts, and bioengineered autologous skin substitutes) in exotic pet species.

EWMA Document: Negative Pressure Wound Therapy

1. Introduction Since its introduction in clinical practice in the early 1990's negative pressure wounds therapy (NPWT) has become widely used in the management of complex wounds in both inpatient and outpatient care.¹ NPWT has been described as a effective treatment for wounds of many different aetiologies^2,3 and suggested as a gold standard for treatment of wounds such as open abdominal wounds,^4-6 dehisced sternal wounds following cardiac surgery^7,8 and as a valuable agent in complex non-healing wounds.^9,10 Increasingly, NPWT is being applied in the primary and home-care setting, where it is described as having the potential to improve the efficacy of wound management and help reduce the reliance on hospital-based care.¹¹ While the potential of NPWT is promising and the clinical use of the treatment is widespread, highlevel evidence of its effectiveness and economic benefits remain sparse.^12-14 The ongoing controversy regarding high-level evidence in wound care in general is well known. There is a consensus that clinical practice should be evidence-based, which can be difficult to achieve due to confusion about the value of the various approaches to wound management; however, we have to rely on the best available evidence. The need to review wound strategies and treatments in order to reduce the burden of care in an efficient way is urgent. If patients at risk of delayed wound healing are identified earlier and aggressive interventions are taken before the wound deteriorates and complications occur, both patient morbidity and health-care costs can be significantly reduced. There is further a fundamental confusion over the best way to evaluate the effectiveness of interventions in this complex patient population. This is illustrated by reviews of the value of various treatment strategies for non-healing wounds, which have highlighted methodological inconsistencies in primary research. This situation is confounded by differences in the advice given by regulatory and reimbursement bodies in various countries regarding both study design and the ways in which results are interpreted. In response to this confusion, the European Wound Management Association (EWMA) has been publishing a number of interdisciplinary documents^15-19 with the intention of highlighting: The nature and extent of the problem for wound management: from the clinical perspective as well as that of care givers and the patients Evidence-based practice as an integration of clinical expertise with the best available clinical evidence from systematic research The nature and extent of the problem for wound management: from the policy maker and healthcare system perspectives The controversy regarding the value of various approaches to wound management and care is illustrated by the case of NPWT, synonymous with topical negative pressure or vacuum therapy and cited as branded VAC (vacuum-assisted closure) therapy. This is a mode of therapy used to encourage wound healing. It is used as a primary treatment of chronic wounds, in complex acute wounds and as an adjunct for temporary closure and wound bed preparation preceding surgical procedures such as skin grafts and flap surgery. Aim An increasing number of papers on the effect of NPWT are being published. However, due to the low evidence level the treatment remains controversial from the policy maker and health-care system's points of view-particularly with regard to evidence-based medicine. In response EWMA has established an interdisciplinary working group to describe the present knowledge with regard to NPWT and provide overview of its implications for organisation of care, documentation, communication, patient safety, and health economic aspects. These goals will be achieved by the following: Present the rational and scientific support for each delivered statement Uncover controversies and issues related to the use of NPWT in wound management Implications of implementing NPWT as a treatment strategy in the health-care system Provide information and offer perspectives of NPWT from the viewpoints of health-care staff, policy makers, politicians, industry, patients and hospital administrators who are indirectly or directly involved in wound management.

Negative Pressure Therapy in the Regeneration of the Sciatic Nerve Using Vacuum - Assisted Closure in a Rabbit Model

Background

The aim of this study was to investigate the effects of negative pressure therapy in the regeneration of the rabbit sciatic nerve using vacuum assisted closure (VAC).

Material/Methods

Thirty male New Zealand white rabbits underwent surgical injury of the sciatic nerve, followed by negative pressure therapy using vacuum assisted closure (VAC), in three treatment groups: Group A: 0 kPa; Group B: −20 kPa; Group C: −40 kPa. At 12 weeks following surgery, the following factors were studied: motor nerve conduction velocity (MNCV); the number of myelinated nerve fibers; the wet weight of the gastrocnemius muscle. Gastrocnemius muscle and sciatic nerve tissue samples were studied for the expression of S100, and brain-derived neurotrophic factor (BDNF) using Western blot.

Results

At 12 weeks following VAC treatment, the MNCV, number of myelinated nerve fibers, and wet weight of the gastrocnemius muscle showed significant differences between the groups (p<0.05), in the following order: Group B >Group A >Group C. The sciatic nerve at 12 weeks following VAC in Group B and Group C showed a significant increase in expression of S100 and BDNF when compared with Group A; no significant differences were detected between Group B and Group C results from Western blot at 12 weeks.

Conclusions

The findings of this study, using negative pressure therapy in VAC in a rabbit model of sciatic nerve damage, have shown that moderate negative pressure was beneficial, but high values did not benefit sciatic nerve repair.

Negative Pressure Wound Therapy for Closed Surgical Wounds in Musculoskeletal Oncology Patients - A Case-Control Trial

Following excision of musculoskeletal tumours, patients are at high risk of wound issues such as infection, dehiscence and delayed healing. This is due to a multitude of factors including the invasive nature of the disease, extensive soft tissue dissection, disruption to blood and lymphatic drainage, residual cavity and adjuvant therapies. The use of negative pressure wound therapy (NPWT) has a growing body of evidence on its beneficial effect of wound healing such as promoting cell differentiation, minimising oedema and thermoregulation. Traditionally, these dressings have been used for open or dehisced wounds; however recent research has investigated its role in closed wounds.

Aim:

To evaluate the effect of NPWT in patients with closed wounds, either primarily or with flap coverage, in our high risk group. Consecutive patients who had a NPWT dressing applied were selected, and a control group was established by a blinded researcher with matching for tissue diagnosis, surgical site, gender and age. The primary outcome measured was documented for wound complications, with secondary data collected on radiotherapy and wound drainage.

Results:

Patients were well matched between the intervention (n=9) and control (n=9) groups for gender, age and tissue diagnosis. Both groups had 1 patient who underwent preoperative radiotherapy. A total of 3 wound infections occurred in the control group and none in the NPWT group. Overall there was a trend towards lower drain output and statistically significantly reduced infection rate in the NPWT group.

Conclusion:

In this short series, despite the NPWT patients having more additional risk factors for wound issues, they resulted in fewer infections. The sample size is not sufficient to have statistically significant reduction. Further evaluation on the value of NPWT in this patient group should be prospectively evaluated.

Evidence based review of negative pressure wound therapy

Vacuum-assisted closure, sometimes referred to as microdeformational wound therapy or most commonly negative pressure wound therapy (NPWT), has significantly improved wound care over the past two decades. NPWT is known to affect wound healing through four primary mechanisms (macrodeformation, microdeformation, fluid removal, and alteration of the wound environment) and various secondary mechanisms (including neurogenesis, angiogenesis, modulation of inflammation, and alterations in bioburden) which are described in this review. In addition, the technique has many established uses, for example in wound healing of diabetic and pressure ulcers, as well as burn and blast wounds. This therapy also has many uses whose efficacy has yet to be confirmed, for example the use in digestive surgery. Modifications of the traditional NPWT have also been established and are described in detail. This therapy has various considerations and contraindications which are summarized in this review. Finally, future perspectives, such as the optimal cycling of the treatment and the most appropriate interface material, are touched upon in the final segment. Overall, despite the fact that questions remain to be answered about NPWT, this technology is a major breakthrough in wound healing with significant potential use both in the hospital but also in the community.

Use of negative pressure wound therapy as an adjunct to the treatment of extremity soft-tissue sarcoma with ulceration or impending ulceration

Major wound complications of the extremities, following wide tumor resection and reconstruction for soft-tissue sarcomas (STSs), remain a challenge for limb-sparing surgery. Furthermore, STSs with ulceration or impending ulceration predispose patients to an increased risk of post-operative infection. The present study was conducted to assess the efficacy of negative pressure wound therapy (NPWT) in preventing wound complications associated with surgical treatment of STSs with ulceration or impending ulceration, in patients treated between February 2012 and January 2013. A total of 5 patients, with a mean age of 48 years (range, 24-68 years), were enrolled in the present study. The diagnoses consisted of undifferentiated pleomorphic sarcoma (n=2), leiomyosarcoma (n=1), synovial sarcoma (n=1) and epithelioid sarcoma (n=1). According to American Joint Committee on Cancer criteria, 3 cases were stage III tumors, and the remaining 2 cases were of stages IIA and IIB, respectively. A total of 3 patients exhibited ulceration at diagnosis, and the remaining patients demonstrated impending ulceration. The mean wound area following wide resection of the tumor was 73 cm² (range, 45-110 cm²). A continuous suction mode, with pressures measuring -200 to -300 mmHg, was used for 7-10 days on the soft-tissue defects as preparation for wound closure. Soft-tissue reconstruction included muscle flaps (n=2) and skin grafts (n=5). No major wound complications occurred. Post-operative functional and cosmetic outcomes were acceptable. A single patient demonstrated local recurrence 12 months after surgery and re-excision of the tumor was performed. All patients remained alive at the conclusion of follow-up, with a mean follow-up time of 26 months (range, 12-36 months). The present study demonstrated that NPWT is effective and safe when used as an adjunct to wound closure following resection of extremity STS with ulceration/impending ulceration.

[Vacuum-therapy for complicated anterior abdominal wall wounds and intestinal fistulas in children]

AIM

To present results of VAC application in children with complicated wounds of anterior abdominal wall combined with intestinal and/or biliary fistulas.

MATERIAL AND METHODS

For the last 7 years 8 patients aged from 1.5 months to 15 years with infected postoperative wounds of anterior abdominal wall complicated by intestinal fistulas (6), biliary and intestinal fistulas (1) and biliary fistula (1) have been treated at the surgical department №2 of Russian Children's Clinical Hospital. All patients received complex medical therapy and local VAC-therapy.

RESULTS

Granulation and wound's size reduction were observed within first 7 days of VAC-therapy application in 5 (62.5%) children. In 4 (50%) patients at least 1 intestinal fistula has been closed in 15 days after VAC-therapy initiation on the average (range 7--24). Closure of all fistulas and wounds healing were observed in all patients in 28 days (range 16--42) after VAC-therapy initiation on the average.

CONCLUSION

VAC-therapy is safe and effective treatment of complicated wounds of anterior abdominal wall combined with intestinal and/or biliary fistulas in children.

Role of negative pressure wound therapy in total hip and knee arthroplasty

Negative-pressure wound therapy (NPWT) has been a successful modality of wound management which is in widespread use in several surgical fields. The main mechanisms of action thought to play a role in enhancing wound healing and preventing surgical site infection are macrodeformation and microdeformation of the wound bed, fluid removal, and stabilization of the wound environment. Due to the devastating consequences of infection in the setting of joint arthroplasty, there has been some interest in the use of NPWT following total hip arthroplasty and total knee arthroplasty. However, there is still a scarcity of data reporting on the use of NPWT within this field and most studies are limited by small sample sizes, high variability of clinical settings and end-points. There is little evidence to support the use of NPWT as an adjunctive treatment for surgical wound drainage, and for this reason surgical intervention should not be delayed when indicated. The prophylactic use of NPWT after arthroplasty in patients that are at high risk for postoperative wound drainage appears to have the strongest clinical evidence. Several clinical trials including single-use NPWT devices for this purpose are currently in progress and this may soon be incorporated in clinical guidelines as a mean to prevent periprosthetic joint infections.

Management of diabetic foot: Brief synopsis for busy orthopedist

According to available medical reports, over 10% of diabetic patients will develop foot ulcers during their lifetimes. This condition still remains great challenges to many clinicians. Various mechanisms may explain treatment-resistant entity. Treatment varies widely, relying on the severity of the ulceration as well as the presence of infection or ischemia. However, the most important things to keep in mind should consist of the following: 1) appropriate debridement; 2) off-loading of pressure; 3) effective control of infection; 4) local wound care strategy; 5) timely reconstructive surgery. The ideal flap for diabetic foot reconstruction should provide a well-vascularized tissue to control infection, adequate contour for footwear, durability, and solid anchorage to resist shearing forces. A thorough assessment of patient's general condition and voluntary motivation of the patient should be warranted to prevent any sort of postoperative recurrence.

Study on the effect of vacuum sealing drainage on the repair process of rabbit sciatic nerve injury

PURPOSE

To investigate the influence of vacuum sealing drainage on sciatic nerve repair after injury in rabbits.

MATERIALS AND METHODS

Twenty four New Zealand white rabbits were randomly divided into experimental group and control group. About 1 cm sciatic nerve was transected and sutured back in situ. The experimental group had vacuum sealing drainage assisted wound closure whereas the control group had normal wound closure. The nerve repair rate was compared based on nerve conduction velocity, lower leg triceps wet weight recovery rate, histology, immunohistochemical of brain-derived neurotrophic factor, and ultrastructure observation of regenerated nerve by electron microscopy at the 4th and 8th week after surgery.

RESULTS

At the 1st-2nd weeks after surgery, irritation and ulcers were observed on the surgical side in both the experimental group and the control group. At the 4th and 8th week after surgery, electrical nerve conduction velocity in the experimental group was faster than in the control group (p<0.05) and triceps muscle calf wet weight recovery rate in the experimental group was higher than that in the control group (p<0.05). Brain-derived neurotrophic factor immunohistochemical staining intensity in the experimental group was higher than that in the control group (p<0.05) and toluidine blue staining and electron microscopic observation showed that the nerve regeneration and repair were more pronounced in the experimental group as compared to the control group. Myelinated nerve fibers in the experimental group were more than that in the control group at the 4th week and 8th week after surgery.

CONCLUSION

Vacuum sealing drainage facilitates repair of peripheral nerve injury.

Systematic review of molecular mechanism of action of negative-pressure wound therapy

BACKGROUND

Negative-pressure wound therapy (NPWT) promotes angiogenesis and granulation, in part by strain-induced production of growth factors and cytokines. As their expression profiles are being unravelled, it is pertinent to consider the mode of action of NPWT at the molecular level.

METHODS

MEDLINE (January 1997 to present), Embase (January 1997 to present), PubMed (no time limit), the Cochrane Database of Systematic Reviews and the Cochrane Controlled Trials Register were searched for articles that evaluated the influence of NPWT on growth factor expression quantitatively.

RESULTS

Sixteen studies met the inclusion criteria. Tumour necrosis factor expression was reduced in acute and chronic wounds, whereas expression of interleukin (IL) 1β was reduced in acute wounds only. Systemic IL-10 and local IL-8 expression were increased by NPWT. Expression of vascular endothelial growth factor, fibroblast growth factor 2, transforming growth factor β and platelet-derived growth factor was increased, consistent with mechanoreceptor and chemoreceptor transduction in response to stress and hypoxia. Matrix metalloproteinase-1, -2, -9 and -13 expression was reduced but there was no effect on their enzymatic inhibitor, tissue inhibitor of metalloproteinase 1.

CONCLUSION

Cytokine and growth factor expression profiles under NPWT suggest that promotion of wound healing occurs by modulation of cytokines to an anti-inflammatory profile, and mechanoreceptor and chemoreceptor-mediated cell signalling, culminating in angiogenesis, extracellular matrix remodelling and deposition of granulation tissue. This provides a molecular basis for understanding NPWT.

Negative pressure wound therapy: past, present and future

Negative pressure wound therapy (NPWT), which was introduced as a commercial product (V.A.C. Therapy, KCI USA, Inc., San Antonio, TX) less than 20 years ago, has revolutionised the treatment of complex wounds. Indicated for wide variety of wound types, NPWT is an adjunctive therapy that can be used safely in a range of care settings. Current research indicates that there are four primary NPWT mechanisms of action: macrodeformation, microdeformation, fluid removal and environmental control of the wound. The interaction of the primary mechanisms results in secondary effects through cell signalling (e.g. granulation tissue formation, cell proliferation and modulation of inflammation). Better understanding of the mechanisms of action also provides insight into future directions for NPWT research that could create better solutions for patients with complex wounds.

Effect of negative pressure wound therapy on wound healing

The efficacy of NPWT in promoting wound healing has been largely accepted by clinicians, yet the number of high-level clinical studies demonstrating its effectiveness is small and much more can be learned about the mechanisms of action. In the future, hopefully we will have the data to assist clinicians in selecting optimal parameters for specific wounds including interface material, waveform of suction application, and the amount of suction to be applied. Further investigation into specific interface coatings and instillation therapy are also needed. We believe that advances in mechanobiology, the science of wound healing, the understanding of biofilms, and advances in cell therapy will lead to better care for our patients.

Role of neuropeptides, neurotrophins, and neurohormones in skin wound healing

Due to the close interactions between the skin and peripheral nervous system, there is increasing evidence that the cutaneous innervation is an important modulator of the normal wound healing process. The communication between sensory neurons and skin cells involves a variety of molecules (neuropeptides, neurohormones, and neurotrophins) and their specific receptors expressed by both neuronal and nonneuronal skin cells. It is well established that neurotransmitters and nerve growth factors released in skin have immunoregulatory roles and can exert mitogenic actions; they could also influence the functions of the different skin cell types during the wound healing process.

Influence of continuous or intermittent negative pressure on bacterial proliferation potency in vitro

Negative pressure wound therapy is helpful and effective in the treatment of intractable skin ulcers and defects, not only acute wounds. However, application of negative pressure wound therapy for an infected wound is still controversial. The authors developed an in-vitro model of negative pressure wound therapy and investigated the influence of various types of negative pressure environment on the proliferation potency of non-pathogenic Escherichia coli. E. coli in Luria-Bertani liquid media was cultured at 37°C under different environments, which were normal atmosphere in group 1, continuous negative pressure of 75 mmHg in group 2, intermittent negative pressure of 75 mmHg with cycle time of 1 minute aspiration and 1 minute abeyance in group 3, with the one of 3 minutes aspiration and 3 minutes abeyance in group 4. The relative amounts of E. coli in each group were investigated at different times. The proliferation potency of E. coli was higher under negative pressure than under normal atmosphere; higher under intermittent negative pressure than under continuous negative pressure; and higher under intermittent negative pressure with a short cycle than with a long cycle. It is important to consider the possibility that the intermittent and continuous mode of negative pressure wound therapy may promote proliferation of bacteria in an infected wound with no blood flow like necrotic tissue.

Mechanisms of action of microdeformational wound therapy

Microdeformational Wound Therapy (MDWT) is a class of medical devices that have revolutionized the treatment of complex wounds over the last 20 years. These devices, are a subset of Negative Pressure Wound Therapy (NPWT), in which there is a highly porous interface material placed between the wound and a semi-occlussive dressing and connected to suction. The porous interface material acts to deform the wound on a micro scale promoting cellular proliferation. These devices appear to significantly improve the speed of healing in many wounds, facilitate granulation tissue formation and reduce the complexity of subsequent reconstructive operations. The mechanisms through which such effects are obtained are beginning to be better understood through basic research and clinical trials. Further work in this field is likely to yield devices that are designed to treat specific wound types.

The reinnervation pattern of wounds and scars after treatment with transforming growth factor β isoforms

BACKGROUND

Wounds deprived of innervation fail to heal normally, and hypertrophic scars may be abnormally innervated. Manipulation of wounds alters the subsequent degree of scarring, and isoforms of transforming growth factor beta (TGFβ) are well established in this role, whilst TGFβ3 is undergoing clinical trials as an antiscarring agent for clinical use. It is unclear if treated wounds show changes in their innervation patterns as they mature into scars.

METHODS

Mice underwent 1cm(2) full thickness skin excisions which were treated with TGFβ1 or TGFβ3. Wounds were harvested between 5 and 84 days (n=6 at each time point). Sections underwent histological scar assessment and immunohistochemical staining for protein gene product 9.5 (PGP9.5), a pan-neuronal marker, and the sensory neuropeptides calcitonin gene related peptide (CGRP) and substance P (SP).

RESULTS

There was no difference in the reinnervation pattern between the peripheral and central parts of the wounds. Wounds treated with TGFβ3 healed with dermal collagen organised more like normal skin, whereas TGFβ1 treated wounds had abnormally orientated collagen within the scar compared to control treated wounds. Nerve fibre growth into the wounds followed a similar pattern in control and treated wounds, with only one significant difference during the healing process- at 42 days, the density of nerve fibres immunostained with PGP9.5 within the scar was greater than in control wounds. By 84 days, the density of PGP9.5, CGRP and SP immunopositive fibres were similar in control wounds and those treated with TGFβ isoforms.

CONCLUSIONS

Changes in reinnervation patterns of wounds treated with TGFβ isoforms were only slightly different from those of control wounds, and by 84 days, the patterns were similar.

Complex lower extremity wounds treated with skin grafts and NPWT: a retrospective review

OBJECTIVE

To evaluate a single centre experience with the use of NPWT for securing split-thickness skin grafts in the management of specifically lower extremity chronic wounds, including revascularised arterial wounds, amputations, diabetic and venous leg ulcers.

METHOD

A seven-year retrospective review of a prospectively maintained database of all the patients who underwent primary split-thickness skin grafts (STSGs) with immediate postoperative NPWT for at least 96 hours was carried out. The percentage graft take after removal of NPWT device and clinical follow-up date were reviewed.

RESULTS

A total of 59 skin grafts procedures had adequate follow up to be reviewed. This included 39% post-debridement/ amputation wounds in patients who presented with diabetic foot infection/gangrene, 31% venous leg ulcers, and 31% other post-surgical wounds (arterial ulcers that had undergone revascularisation). The mean percentage graft survival after removal of V.A.C. was 94%; 63% of cases had complete graft survival, 25% had 90-99% survival, and 8.5% had 80-89% survival. Outpatient follow up ranged from 2 weeks to 5 years (mean of 10 months). Fifteen per cent of patients were lost to follow up, and, of the remaining patients, 76% remained completely healed, 10% remained partially healed, and 14% lost the entire STSG.

CONCLUSION

Patients with STSGs secured with NPWT required fewer repeated grafting procedures, had very high initial graft survival with complete recipient bed coverage, and had good long-term wound closure rates compared with historical controls. While retrospective reviews, such as this, support NPWT as a good method of STSG affixation, the paucity of reviews with other study designs does not allow for good historic comparison, so a well-enrolled prospective trial would be of use.

DECLARATION OF INTEREST

Dr J.C. Lantis is a member of the speakers' bureau, has been a site principal investigator of four multicentre trials and has been a consultant for KCI Inc. The same author has no equity in the company and has no financial benefit from positive results for the company's product(s). No external funding was sought nor obtained for this study.

Update on negative-pressure wound therapy

BACKGROUND

Over the last 15 years, negative-pressure wound therapy has become commonly used for treatment of a wide variety of complex wounds. There are now several systems marketed, and additional products will be available in the near future. Many clinicians have noted a dramatic response when negative-pressure wound therapy technology has been used, prompting a number of scientific investigations related to its mechanism of action and clinical trials determining its efficacy.

METHODS

The peer-reviewed literature within the past 5 years was reviewed, using an evidence-based approach.

RESULTS

Negative-pressure wound therapy works through mechanisms that include fluid removal, drawing the wound together, microdeformation, and moist wound healing. Several randomized clinical trials support the use of negative-pressure wound therapy in certain wound types. Serious complications, including bleeding and infection, have recently been reported by the U.S. Food and Drug Administration in a small number of patients.

CONCLUSIONS

Negative-pressure wound therapy has dramatically changed the way complex wounds are treated. The rapid introduction of this technology has occurred faster than large-scale randomized controlled studies or registry studies have been conducted. Further clinical studies and basic science studies will help surgeons to better understand the evidence and use this technology in the future.