Polyurethane foam dressing with non-adherent membrane improves negative pressure wound therapy in pigs

OBJECTIVE

Negative pressure wound therapy (NPWT) is considered to be an effective technique to promote the healing of various wounds. The aim of this study was to evaluate different wound dressings combined with NPWT in treating wounds in Wuzhishan pigs.

METHOD

Excisions were made in the backs of the pigs and were covered with polyvinyl alcohol (PVA) dressing, polyurethane (PU) dressing or PU dressing with non-adherent membrane (PU-non-ad). NPWT was applied to the wound site. In the control group, basic occlusive dressing (gauze) without NPWT was applied. On days 0, 3, 7, 14, 21 and 28 post-surgery, the wound size was measured during dressing change, and wound healing rate (WHR) was calculated. In addition, blood perfusion within 2cm of the surrounding wound was measured by laser doppler flowmetry. Dressing specimen was collected and microbiology was analysed. Granulation tissues from the central part of the wounds were analysed for histology, vascular endothelial growth factor (VEGF) and cluster of differentiation 31 (CD31) mRNA expression.

RESULTS

The PU-non-ad-NPWT significantly (p<0.01) accelerated wound healing in the pigs. Further pathological analysis revealed that the non-adherent membrane effectively protected granulation tissue formation in PU-NPWT treated wounds. The blood perfusion analysis suggested that the non-adherent membrane improved the blood supply to the wound area. Microbiological analysis showed that non-adherent membrane decreased the bacterial load in the PU-NPWT dressing. VEGF and CD31 mRNA expression was upregulated in the wound tissue from the PU-non-ad-NPWT treated groups.

CONCLUSION

In this study, the PU dressing with non-adherent membrane was an ideal dressing in NPWT-assisted wound healing.

One-Stage Coverage of Leg Region Defects with STSG Combined with VAC Dressing Improves Early Patient Mobilisation and Graft Take: A Comparative Study

Lower limb skin defects are very common and can result from a wide range of aetiologies. Split thickness skin graft (STSG) is a widely used method to address these problems. The role of postoperative dressing is primary as it permits one to apply a uniform pressure over the grafted area and promote adherence. Focusing on lower limb reconstruction, our clinical study compares the application of V.A.C. (Vacuum Assisted Closure) Therapy vs. conventional dressing in the immediate postoperative period following skin grafting. We included in the study all patients who received skin grafts on the leg region between January 2015 and December 2018, despite the aetiology of the defect. Only reconstructions with complete preoperative and postoperative follow-up data were included in the study. Patients were divided into two groups depending on if they received a traditional compressive dressing or a VAC dressing in the immediate postoperative period. We could retain 92 patients, 23 in the No VAC group and 69 in the VAC group. The patients included in the VAC group showed a statistically significant higher rate of graft take together with a lower immobilisation time (p < 0.05). Moreover, a lower rate of postoperative infection was recorded in the VAC group. This study represents the largest in the literature to report in detail surgical outcomes comparing the use of VAC therapy vs. conventional dressing after STSG in the postoperative management of lower limb reconstruction using skin grafts. VAC therapy was used to secure the grafts in the leg region, increasing the early graft take rate while at the same time improving patient mobilisation.

Safeguarding Skin Grafts: An Evidence-Based Summary of Fixation Techniques

BACKGROUND

Effective skin graft fixation is vital in preventing sheering forces, seroma, and hematoma from compromising graft take. Yet, selecting the ideal technique for securing skin grafts remains a contentious subject, with significant variation in practice existing between surgeons. There is, therefore, benefit to be derived from assessing the literature for evidence-based recommendations to guide the decision-making process.

METHODS

A search of Medline and Embase was performed using appropriate key terms, yielding 419 articles. Reference lists were analyzed. Inclusion and exclusion criteria were composed. Level I to III studies, as defined by the Centre for Evidence-Based Medicine, that compared skin graft fixation methods were analyzed. Rayyan QCRI was used for abstract and title screening. After full text screening, 41 studies were included for qualitative analysis. All included randomized control trials (RCTs) were assessed for risk of bias using the Cochrane Risk-of-Bias 2 (ROB2) tool.

RESULTS

We identified 4 groups of fixation technique: "tie-over bolster" (TOB), "no TOB," "adhesive glues," and "negative pressure wound therapy" (NPWT). Twelve studies compared TOB with no TOB, with no difference in graft take demonstrated. Sixteen studies compared adhesive glues with traditional methods, with no difference in graft take demonstrated. Thirteen studies compared NPWT with traditional methods, with enhanced graft take demonstrated. Risk of bias was deemed low in 1 of 13 RCTs.

CONCLUSIONS

Based on the current evidence, only NPWT is associated with enhanced graft take. However, there is a scarcity of robust level I evidence comparing different fixation techniques, meaning that strong recommendations cannot be made. We propose examples of hypothesis-driven RCTs, in predetermined clinical settings, based on the theoretical benefits of the techniques that would add value to clinical practice.

Surgical Treatment of Pyoderma Gangrenosum with Negative Pressure Wound Therapy and Skin Grafting, Including Xenografts: Personal Experience and Comprehensive Review on 161 Cases

Significance: Pyoderma gangrenosum (PG) is a rare debilitating autoinflammatory ulcerative skin disease. No gold standard has been established for the treatment of PG. The role of surgical interventions and negative pressure wound therapy (NPWT) was discussed controversially until recently as these procedures might pose a trigger to further aggravate the condition. Recent Advances: Recent advances confirm the paradigm change that a surgical approach of PG with split thickness skin grafting (STSG) secured by NPWT is a safe and valuable treatment if performed under adequate immunosuppression. We elaborate this on the hand of a broad literature search retrieving 101 relevant articles describing 138 patients complemented with our personal experience on 23 patients, including 2 patients treated with a porcine xenodressing. Critical Issues: A wide range of surgical approaches have been reported, including xenografts. Treatment was finally successful in 86%, including the xenotransplant cases. Ten percent improved and failures were mainly reported without immunosuppression. Despite halting the inflammatory process, NPWT alone, without skin grafting, does not much accelerate healing time. The best surgical approach appears to be STSG fixed with NPWT as this leads to higher skin graft take. There remains the problem of the chronic nature of PG and the recurrence after tapering of immunosuppression or trauma; therefore, a sustained immunosuppressive treatment is suggested. Future Directions: While surgical treatment is supported by the published data, the exact immunosuppression is still evolving. Due to deeper insights into pathogenesis and growing clinical reports, a broader utilization of biologic treatments and a shift from tumor necrosis factor (TNF)-alpha to interleukin (IL)-12/23 or IL-23 antibodies alone are predictable, as IL-12/23 antibodies show good clinical responses with fewer side effects. The positive results with porcine xenodressings might be due to immunological effects of the xenomaterial; they appear promising, but are preliminary and should be confirmed in a larger patient collective.

Full-thickness Skin Graft Fixation Techniques: A Review of the Literature

Multiple techniques for skin graft fixation have been proposed, but the evidence underlying these techniques is unclear. This study aimed to review the literature for full-thickness graft fixation techniques. PubMed was electronically searched to identify relevant studies. The search strategy identified 91 relevant articles. These consisted of 2 randomised controlled trials (RCTs), 10 observational cohort studies (8 retrospective, 2 prospective), and 79 descriptive studies (case series, case reports, or expert opinion articles). Both identified RCTs compared the tie-over dressing against a modified tie-over dressing. The tie-over dressing was also included in all identified observational studies, and comparisons were made against quilting/mattress suturing (4 studies, 181 grafts in total), simple pressure dressings (3 studies, 528 grafts), non-tie-over dressings non-specifically (1 study, 71 grafts), hydrocolloid dressings (1 study, 62 grafts), and double-tie over dressings (1 study, 43 grafts). No significant differences were found between fixation methods for graft take, haematoma rate, and infection rate. No studies have found a significant difference between tie-over dressings and alternative graft fixation technique, with the most evidence for simple pressure dressings and quilting/mattress suturing. However, the evidence base consists mostly of small, retrospective observational studies. This article describes the current evidence base and this should be considered when planning future reports in the field.

Retrospective Study on the Clinical Superiority of the Vacuum-Assisted Closure System with a Silicon-based Dressing over the Conventional Tie-over Bolster Technique in Skin Graft Fixation

Background and Objectives: The tie-over bolster technique has been conventionally used for skin graft fixation; however, long operative times and postoperative pain are the main disadvantages of this method. In this study, we introduce a new method using vacuum-assisted closure (VAC) with a silicon-based dressing as an alternative for skin graft fixation. This retrospective study aimed to evaluate the clinical effect of the VAC plus silicon-based dressing method and the conventional tie-over bolster technique for skin graft fixation in terms of pain, operative time, and skin graft take rate. Materials and Methods: Sixty patients who underwent skin graft surgery performed by a single surgeon from January 2017 to October 2018 were included in this clinical study. They were divided into two groups based on the type of treatment: tie-over bolster technique and vacuum-assisted closure (VAC), or silicon-based dressing groups. The operative times were recorded twice (during suturing or stapling of the graft and during removal of the dressing) in the two groups; similarly, pain was assessed using a numeric rating scale (NRS) after surgery and during dressing removal. Skin graft take rate was evaluated two weeks after dressing removal. Results: Twenty-six patients who met the eligibility criteria were enrolled into the study and assigned to one of the two groups (n = 13 each). No significant differences in age, gender, and graft area were noted between the two groups of patients. The VAC plus silicon-based dressing group demonstrated higher skin graft take rates (p < 0.05), shorter operation times (p < 0.05), and lower levels of pain (postoperative pain and pain during dressing removal) compared with the tie-over bolster technique group (p < 0.05). Conclusions: These findings indicate that VAC with silicon-based dressing can be used for skin graft fixation due to its superior properties when compared with the conventional method, and can improve the quality of life of patients undergoing skin graft fixation.

Role of customised negative-pressure wound therapy in the integration of split-thickness skin grafts: A randomised control study

Background:

Split-thickness skin grafting (STSG) is a time-tested technique in wound cover, but many factors lead to suboptimal graft take. Role of custom-made negative-pressure wound therapy (NPWT) is compared with conventional dress in the integration of STSG and its cost is compared with widely used commercially available NPWT.

Materials and Methods:

This is a parallel group randomised control study. Block randomisation of 100 patients into one of the two groups (NPWT vs. non-NPWT; 50 patients each) was done. Graft take/loss, length of hospital stay post-grafting, need for regrafting and cost of custom-made negative pressure wound therapy (NPWT) dressings as compared to widely used commercially available NPWT were assessed.

Results:

Mean graft take in the NPWT group was 99.74% ± 0.73% compared to 88.52% ± 9.47% in the non-NPWT group (P = 0.004). None of the patients in the NPWT group required second coverage procedure as opposed to six cases in the non-NPWT group (P = 0.035). All the patients in the NPWT group were discharged within 4–9 days from the day of grafting. No major complication was encountered with the use of custom-made NPWT. Custom-made NPWT dressings were found to be 22 times cheaper than the widely used commercially available NPWT.

Conclusions:

Custom-made NPWT is a safe, simple and effective technique in the integration of STSG as compared to the conventional dressings. We have been able to reduce the financial burden on the patients as well as the hospital significantly while achieving results at par with other studies which have used commercially available NPWT.

Evidence-Based Clinical Practice Points for the Management of Venous Ulcers

Venous ulcer is an extremely common aetiology of lower extremity ulceration, which affects approximately 1% population in most of the countries, and the incidence rate increases with age and female gender. Proper assessment and diagnosis of both the patient and ulcer are inevitable in order to differentiate venous ulcers from other lower extremity ulceration and to frame an adequate and individualised management plan. Venous ulcers generally persist for weeks to many years and are typically recurrent in nature. This consensus aims to present an evidence-based management approach for the patients with venous ulcers. Various management options for venous ulcers include compression therapy, minimally invasive procedures like sclerotherapy and ablation techniques, surgical procedures, debridement and medical management with micronised purified flavonoid fraction (MPFF). Compression therapy is the mainstay treatment for venous ulcer. However, in failure cases, surgery can be preferred. Medical management with MPFF as an adjuvant therapy to standard treatment has been reported to be effective and safe in patients with venous ulcer. In addition to standard therapy, diet and lifestyle modification including progressive resistance exercise, patient education, leg elevation, weight reduction, maintaining a healthy cardiac status and strong psychosocial support reduces the risk of recurrence and improves the quality of life in patients with venous ulcer.

Antimicrobial-impregnated dressing combined with negative-pressure wound therapy increases split-thickness skin graft engraftment: a simple effective technique

OBJECTIVE

Immobilization and adequate surface contact to wounds are critical for skin graft take. Techniques such as the tie-over dressing, cotton bolster, and vacuum-assisted closure are used to address this, but each has its limitations. This study is designed to assess the effect of antimicrobial-impregnated dressing (AMD) combined with negative-pressure wound therapy (NPWT) on skin graft survival.

DESIGN

Retrospective case-control study

PARTICIPANTS

: Patients with chronic or contaminated wounds treated with split-thickness skin graft. A broad spectrum of wounds was included, from causes such as trauma, burns, chronic diabetic ulcers, and infection.

INTERVENTIONS

Antimicrobial-impregnated dressing, which contains 0.2% polyhexamethylene biguanide, with NPWT MAIN OUTCOME MEASURE:: Success of skin graft

MAIN RESULTS

: In the AMD group, all skin grafts achieved 100% take without secondary intervention. No infection or graft failure was observed in any patients, and no complications, such as hematoma or seroma formation, were noted, although in the control group partial loss of skin grafts was noted in 3 patients. Infection and inadequate immobilization were thought to be the main reasons. There were no hematoma or seroma formations in the control group.

CONCLUSION

Use of an AMD dressing with NPWT after split-thickness skin grafting can be an effective method to ensure good graft to wound contact and enhances skin graft take in chronic and contaminated wounds.

Skin graft secured by VAC (vacuum-assisted closure) therapy in chronic leg ulcers: A controlled randomized study

INTRODUCTION

Leg ulcers are a common condition. There have been very few studies of combined therapy involving VAC (vacuum-assisted closure) and skin graft.

METHODS

We performed a randomized controlled trial of VAC therapy vs. hydrocolloid dressings over 5 days following autologous grafting on chronic leg ulcers. The primary objective was to assess the difference in success (defined as a reduction in wound area of at least 50% at 1 month) between the two dressing methods. Forty-six patients with ulcers present for over one month were included. Following a 7-day hospitalization period, follow-up was performed for 3 months on an outpatient basis.

RESULTS

Our study does not demonstrate a statistically significant difference, with a 45.8% success rate in the VAC group vs. 40.9% in the conventional dressing group (P=0.73). In the venous ulcer group, the success rate was 57.9% for VAC vs. 40% for conventional dressings (P=0.3). The difference in favor of VAC in this group was not statistically significant, most likely due to an insufficient number of patients studied.

CONCLUSION

Our study does not demonstrate superiority of VAC associated with skin graft over conventional dressings. We observed more complications with VAC (40%) than with conventional dressings (23%) (P=0.06).

Prospective randomized controlled trial comparing two methods of securing skin grafts using negative pressure wound therapy: vacuum-assisted closure and gauze suction

Negative pressure wound therapy (NPWT) has revolutionized the management of complicated wounds and has contributed an additional modality for securing split thickness skin grafts (STSG). The standard for NPWT is the vacuum-assisted closure (VAC) device. The authors' institution has accumulated experience using standard gauze sealed with an occlusive dressing and wall suction (GSUC) as their primary mode for NPWT. The authors report a randomized controlled trial comparing the efficacy of the GSUC vs the VAC in securing STSG. A prospective, randomized, controlled trial was conducted in 157 wounds in 104 patients requiring STSG from August 2009 to July 2012. All wounds were randomized to VAC or GSUC treatment and assessed for skin graft adherence/take. At postoperative day 4 or 5, NPWT was discontinued, and the size of the graft and any nonadherent areas were measured and recorded. Concomitant comorbidities, wound location, etiology, study failures, and reoperative rates were also reviewed. In all, 77 and 80 wounds were randomized to the GSUC and VAC study arms. Patient demographics were similar between both groups in terms of age, sex, comorbidities, etiology, and wound location. In all, 64 of 80 wounds in the GSUC group and 60 of 77 wounds in the VAC group had full take of the skin graft by postoperative day 4 or 5 (P = .80). The mean percent take in the GSUC group was 96.12% vs 96.21% in the VAC arm (P = .98). The use of NPWT in securing STSG is a useful method to promote adherence and healing. This study demonstrates that a low-cost, readily accessible system utilizing gauze dressings and wall suction (GSUC) results in comparable skin graft take in comparison to the VAC device.

Increased Cost of Negative Pressure Dressings Is Not Justified for Split-Thickness Skin Grafting of Low-Risk Wounds

OBJECTIVES

(1) To determine whether negative pressure dressings (NPDs) are superior to conventional compressive dressings (CDs) for split-thickness skin grafts (STSGs) placed on healthy, low-risk wounds, (2) To determine the cost difference of NPDs versus that of CDs.

DESIGN

Retrospective.

SETTING

Level I Trauma Center.

PATIENTS/PARTICIPANTS

One hundred ninety-five traumatic wounds treated with STSG.

MAIN OUTCOME MEASUREMENTS

Patients were assigned outcomes based on postoperative documentation: completely healed, incompletely healed (small areas of graft necrosis), failed, or lost to follow-up. The costs associated with each dressing type were documented.

RESULTS

Thirty five of 195 STSGs were lost to follow-up, leaving n = 120 STSG-NPD, n = 40 STSG-CD. Of the remaining 120 STSGs treated with NPD, 91 completely healed, 23 incompletely healed, and 6 failed. Of the 40 STSGs treated with a CD, 37 completely healed, 1 incompletely healed, and 2 failed. Patients treated with CDs had a higher likelihood of healing relative to those treated with the NPD (P = 0.018). Analyzing the outcomes as failed versus "not failed" revealed no significant difference between the groups (P = 1.00). There were more smokers in the CD group (P = 0.022). In this series, the mean cost associated with NPD compared with that of CD was $2370 more per patient.

CONCLUSIONS

There is a high rate of successful healing of STSGs for traumatic extremity wounds regardless of the dressing used. The increased cost of NPDs is not justified in wounds that are at a low risk of developing STSG failure.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

[Dermatologic surgery on the scalp]

Soft tissue defects of the scalp can be closed with varying techniques depending on size and depth of the defect. While small and superficial defects can be closed primarily or be left open for secondary intention healing, larger and deeper defects may need flaps or skin grafts. Extensive defects may require combined flaps or vacuum assisted closure techniques. Defects of the periosteum with denuded skull bone must be treated immediately to avoid bony complications. Usually, the tabula externa is fenestrated with holes or abraded totally to create better healing conditions. Granulation tissue may be induced on the properly prepared skull with vacuum-assisted closure, by using collagen sheets or with dermal skin substitutes. New developments in tissue engineering will surely provide new techniques for dealing with deep and extensive soft tissue defects.

Systematic review and evidence based recommendations for the use of negative pressure wound therapy in the open abdomen

INTRODUCTION

Negative Pressure Wound Therapy (NPWT) is widely used in the management of the open abdomen despite uncertainty regarding several aspects of usage. An expert panel was convened to develop evidence-based recommendations describing the use of NPWT in the open abdomen.

METHODS

A systematic review was carried out to investigate the efficacy of a range of Temporary Abdominal Closure methods including variants of NPWT. Evidence-based recommendations were developed by an International Expert Panel and graded according to the quality of supporting evidence.

RESULTS

Pooled results, in non-septic patients showed a 72% fascial closure rate following use of commercial NPWT kits in the open abdomen. This increased to 82% by the addition of a 'dynamic' closure method. Slightly lower rates were showed with use of Wittmann Patch (68%) and home-made NPWT (vac-pack) (58%). Patients with septic complications achieved a lower rate of fascial closure than non-septic patients but NPWT with dynamic closure remained the best option to achieve fascial closure. Mortality rates were consistent and seemed to be related to the underlying medical condition rather than being influenced by the choice of dressing, Treatment goals for open abdomen were defined prior to developing eleven specific evidence-based recommendations suitable for different stages and grades of open abdomen.

DISCUSSION AND CONCLUSION

The most efficient temporary abdominal closure techniques are NPWT kits with or without a dynamic closure procedure. Evidence-based recommendations will help to tailor its use in a complex treatment pathway for the individual patient.

Update on cutaneous calciphylaxis

Calciphylaxis is a devastating disorder with a mortality rate of 80% due to sepsis and organ failure. Hallmarks of this rare disease are arteriolar media calcification, thrombotic cutaneous ischemia, and necrotic ulcerations. Different mechanisms of vascular calcification can lead to calciphylaxis. Early diagnosis by deep cutaneous ulcer biopsy is most important for prognosis. Here, dermatologists play a significant role although treatment usually needs an interdisciplinary approach. Surgical procedures had been the cornerstone of treatment in the past including parathyroidectomy, but recently new medical treatments emerged aiming to normalize disturbances of minerals to reduce the serum concentration of sodium phosphate and to prevent precipitation and calcification. Multimodal therapy is warranted but only aggressive surgical debridement of cutaneous ulcers has shown significant outcome improvement.

Does treatment of split-thickness skin grafts with negative-pressure wound therapy improve tissue markers of wound healing in a porcine experimental model?

BACKGROUND

Negative-pressure wound therapy (NPWT) has been used for to treat wounds for more than 15 years and, more recently, has been used to secure split-thickness skin grafts. There are some data to support this use of NPWT, but the actual mechanism by which NPWT speeds healing or improves skin graft take is not entirely known. The purpose of this project was to assess whether NPWT improved angiogenesis, wound healing, or graft survival when compared with traditional bolster dressings securing split-thickness skin grafts in a porcine model.

METHODS

We performed two split-thickness skin grafts on each of eight 30 kg Yorkshire pigs. We took graft biopsies on postoperative days 2, 4, 6, 8, and 10 and submitted the samples for immunohistochemical staining, as well as standard hematoxylin and eosin staining. We measured the degree of vascular ingrowth via immunohistochemical staining for von Willenbrand's factor to better identify blood vessel epithelium. We determined the mean cross-sectional area of blood vessels present for each representative specimen, and then compared the bolster and NPWT samples. We also assessed each graft for incorporation and survival at postoperative day 10.

RESULTS

Our analysis of the data revealed that there was no statistically significant difference in the degree of vascular ingrowth as measured by mean cross-sectional capillary area (p = 0.23). We did not note any difference in graft survival or apparent incorporation on a macroscopic level, although standard hematoxylin and eosin staining indicated that microscopically, there seemed to be better subjective graft incorporation in the NPWT samples and a nonsignificant trend toward improved graft survival in the NPWT group.

CONCLUSION

We were unable to demonstrate a significant difference in vessel ingrowth when comparing NPWT and traditional bolster methods for split-thickness skin graft fixation. More studies are needed to elucidate the manner by which NPWT exerts its effects and the true clinical magnitude of these effects.

One-stage Reconstruction of Soft Tissue Defects with the Sandwich Technique: Collagen-elastin Dermal Template and Skin Grafts

Background:

A full-thickness soft tissue defect closure often needs complex procedures. The use of dermal templates can be helpful in improving the outcome.

Objective:

The objective was to evaluate a sandwich technique combining the dermal collagen–elastin matrix with skin grafts in a one-stage procedure.

Materials and Methods:

Twenty-three patients with 27 wounds were enrolled in this prospective single-centre observational study. The mean age was 74.8 ± 17.2 years. Included were full-thickness defects with exposed bone, cartilage and/ or tendons. The dermal collagen–elastin matrix was applied onto the wound bed accomplished by skin transplants, i.e. ‘sandwich’ transplantation. In six wounds, the transplants were treated with intermittent negative pressure therapy.

Results:

The size of defects was ≤875 cm². The use of the dermal template resulted in a complete and stable granulation in 100% of wounds. Seventeen defects showed a complete closure and 19 achieved a complete granulation with an incomplete closure. There was a marked pain relief. No adverse events were noted due to the dermal template usage.

Conclusions:

Sandwich transplantation with the collagen–elastin matrix is a useful tool when dealing with full-thickness soft tissue defects with exposed bone, cartilage or tendons.

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.

Wound Healing Society (WHS) venous ulcer treatment guidelines: what's new in five years?

Since the establishment of the guidelines for the treatment of venous ulcers by the Wound Healing Society in 2006, there has been an abundance of new literature, both in accord and discord with the guidelines. The goal of this update is to highlight new findings since the publication of these guidelines to assist practitioner and patient in appropriate health care decisions, as well as to drive future research endeavors.

Negative pressure wound therapy for at-risk surgical closures in patients with multiple comorbidities: a prospective randomized controlled study

PURPOSE

The purpose of this study is to evaluate the effect of Negative Pressure Wound Therapy (NPWT) on closed surgical incisions. We performed a prospective randomized controlled clinical trial comparing NPWT to standard dry dressings on surgical incisions.

METHODS

Patients presenting to a high-volume wound center were randomized to receive either a V.A.C. (KCI, San Antonio, TX) or a standard dry dressing over their incision at the conclusion of surgery. These were primarily high-risk patients with multiple comorbidities. The 2 groups were compared, and all incisions were evaluated for infection and dehiscence postoperatively.

RESULTS

Eighty-one patients were included for analysis. Thirty-seven received dry dressings, and 44 received NPWT. Seventy-four of these underwent lower extremity wound closure. Average follow-up was 113 days. There were no differences in demographic, preoperative, and operative variables between groups; 6.8% of the NPWT group and 13.5% of the dry dressing group developed wound infection, but this was not statistically significant (P = 0.46). There was no difference in time to develop infection between the groups. There was no statistical difference in dehiscence between NPWT and dry dressing group (36.4% vs 29.7%; P = 0.54) or mean time to dehiscence between the 2 groups (P = 0.45). Overall, 35% of the dry dressing group and 40% of the NPWT group had a wound infection, dehiscence, or both. Of these, 9 in the NPWT group (21%) and 8 in the dry dressing group (22%) required reoperation.

CONCLUSIONS

There is a significant rate of postoperative infection and dehiscence in patients with multiple comorbidities. There was no difference in the incidence of infection or dehiscence between the NPWT and dry dressing group. This study is registered with ClinicalTrials.gov. The unique registration number is NCT01366105.

Effective use of negative pressure wound therapy provides quick wound-bed preparation and complete graft take in the management of chronic venous ulcers

Venous ulcers are characterised by longstanding and recurrent loss of skin integrity. Once occurred, healing is slow and recurrence is high because of inappropriate conditions of the wound bed. This study involves 20 patients with chronic venous ulcers at least 6 weeks of duration treated with negative pressure wound therapy (NPWT). Patients underwent a radical debridement of all devitalised tissues in the first operation. After adequate haemostasis, silver-impregnated polyurethane foam was applied. Once the wounds were determined to be clean and adequate granulation tissue formation was achieved, split-thickness skin grafts were applied. Black polyurethane foam was applied over them. All wounds completely healed without the need for further debridement or regrafting. The mean number of silver-impregnated foam dressing changes prior to grafting was 2·9 (one to eight changes). The mean number of NPWT foam changes was 2·6 after skin grafting (two to five changes). Two patients who did not use conservative treatments for chronic venous insufficiency (CVI) after discharge from the hospital had recurrence of venous ulcers in the follow-up period. Application of NPWT provides quick wound-bed preparation and complete graft take in venous ulcer treatment.

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.

Histological evolution of chronic wounds under negative pressure therapy

BACKGROUND

Negative pressure wound therapy (NPT) has achieved widespread success in the treatment of difficult wounds. However, its effects are but partially explored, and investigations mostly concentrated at the wound-dressing interface; a detailed histological description of the evolution of wounds under NPT is still lacking.

MATERIALS AND METHODS

Subsequent punch biopsies of NPT-treated chronic wounds of human patients were analysed. Phenomena occurring in wounds were quantified by analysis of proliferating cells nuclear antigen (PCNA) (proliferating nuclei), CD31 (blood vessels), CD68p (macrophages) and CD45 (lymphocytes) stained slides.

RESULTS

Three layers were identified in day-0 wounds. Over time, under NPT, the layers behaved differently: the most superficial (1.5 mm) developed granulation tissue, constant in thickness, with high proliferation index, increased in blood vessels density and developed acute inflammation. Instead, the two deeper layers decreased in proliferation rate, maintained vessels density unchanged, were cleared of chronic inflammation and oedema and underwent progression towards stable tissue.

DISCUSSION

Indeed, while most research has focused on induction of superficial granulation tissue by NPT, deeper layers appear to be also affected, with relieving of chronic inflammation and tissue stabilisation. This may be an important and under-appreciated effect, playing a role in the known positive outcomes of NPT, such as better graft-taking rates.

Use of a collagen-elastin matrix for hard to treat soft tissue defects

As deep soft tissue defects with exposed bone, cartilage or tendons are not suitable for wound closure with skin mesh grafts, other techniques are needed. We report on six patients, one female and five males, aged between 32 and 89 years, and deep soft tissue defects with exposed tendons, cartilage or bone. The aetiology of these defects was vascular (n = 3), tumour surgery (2), and post-traumatic (1). Wounds were treated with a collagen-elastin matrix applied above the exposed structures. In five patients, the procedure was combined with mesh graft transplantation in the same setting. Follow-up varied between 12 and 40 weeks. Wound healing was uncomplicated in all transplanted patients until first dressing change after 7 days. All but one transplant showed a 100% take rate and the transplant was stable within 10-14 days. A complete wound closure was also achieved without transplantation, but this took 8 weeks. No adverse effects were noted. There was no skin contracture of the skin grafts. Collagen-elastin matrix with split-thickness skin grafts is a useful tool in deep soft tissue. The time to heal can be reduced.

Impact of gauze-based NPWT on the patient and nursing experience in the treatment of challenging wounds

Negative pressure wound therapy is widely used in the treatment of hard-to-heal wounds; however, pain during dressing changes, which is often associated with pain on the commencement and cessation of pressure application and because of in-growth of new granulation tissue into interstices of foam dressings, is often experienced. Anecdotal reports have suggested that choice of gauze as the negative pressure wound therapy dressing may reduce the pain associated with dressing changes. A prospective, multi-center, non-comparative clinical investigation was carried out using gauze-based negative pressure wound therapy in chronic and acute wounds. Over 152 patients were evaluated. Median duration of therapy was 18 days with 91% of patients progressing towards healing at the end of therapy. Wound pain and odour were significantly reduced (P < 0.001) over the course of therapy. Wound pain during dressing changes was reported to be absent in 80% of dressing removals. No damage to the wound bed following dressing removal was observed in 96% of dressing changes. Dressing applications were considered easy in 79% of assessments and took a median of 20 min to complete. In patients susceptible to pain, gauze-based negative pressure therapy may be a viable option to maximise patient comfort.

Vacuum-assisted closure improves the incorporation of artificial dermis in soft tissue defects: Terudermis(®) and Pelnac(®)

As a dermal scaffold, artificial dermal substitutes allow the body to accomplish its own tissue regeneration through infiltration of cells and neovascularisation. However, they show not only rather lower take rates compared to autologous skin grafts alone, but they also require more time for sufficient vascular ingrowth to overlay the skin graft. To accelerate this overlaying, we applied vacuum-assisted closure negative-pressure settings over the artificial dermis: Terudermis(®) and Pelnac(®) grafts. Fourteen patients with complex tissue defects were treated, including bone exposure in two cases, tendon exposure in seven cases and soft tissue defects in five cases. Nine cases had combined wound infections. The time interval between the first artificial dermis graft and the second split-thickness skin graft over it was 7·64 days on average. Dermal substitutes took place completely in all cases and there were no graft failures.

Evidence-based recommendations for the use of Negative Pressure Wound Therapy in traumatic wounds and reconstructive surgery: steps towards an international consensus

Negative pressure wound therapy (NPWT) has become widely adopted over the last 15 years and over 1000 peer reviewed publications are available describing its use. Despite this, there remains uncertainty regarding several aspects of usage. In order to respond to this gap a global expert panel was convened to develop evidence-based recommendations describing the use of NPWT. In this paper the results of the study of evidence in traumatic wounds (including soft tissue defects, open fractures and burns) and reconstructive procedures (including flaps and grafts) are reported. Evidence-based recommendations were obtained by a systematic review of the literature, grading of evidence, drafting of the recommendations by a global expert panel, followed by a formal consultative consensus development program in which 422 independent healthcare professionals were able to agree or disagree with the recommendations. The criteria for agreement were set at 80% approval. Evidence and recommendations were graded according to the SIGN (Scottish Intercollegiate Guidelines Network) classification system. Twelve recommendations were developed in total; 4 for soft tissue trauma and open fracture injuries, 1 for burn injuries, 3 for flaps and 4 for skin grafts. The present evidence base is strongest for the use of NPWT on skin grafts and weakest as a primary treatment for burns. In the consultative process, 11/12 of the proposed recommendations reached the 80% agreement threshold. The development of evidence-based recommendations for NPWT with direct validation from a large group of practicing clinicians offers a broader basis for consensus than work by an expert panel alone.

[Cutaneous wound healing. Therapeutic interventions]

In modern medicine chronic wounds are an interdisciplinary major therapeutic and financial issue. Essential for therapy is both the causal treatment of the underlying disease and the symptomatic treatment depending on the phase of wound healing. The physiological process of cutaneous wound healing is divided into three overlapping phases: inflammation, proliferation and tissue remodelling. The choice of a suitable therapy depends on the extent of the wound, the localization, exudation and bacterial infestation. In recent years a number of novel findings were made about this complex biological process and the insights gained have resulted in new therapeutic concepts. In the following article we give an overview about possible therapeutic options and present the various modern wound dressings.

The use of negative pressure wound therapy for random local flaps at the ankle region

Local random flaps are seldom used for reconstruction of complex ankle wounds because of concern for flap failure attributable to vascular compromise and tissue edema. Negative pressure wound therapy has been shown to improve perfusion and limit tissue edema. The objective of this study was to demonstrate the utility of negative pressure wound therapy in improving outcomes for local flaps of the ankle. Ten consecutive patients presenting with complex ankle wounds and reconstructed using local flaps were treated with negative pressure wound therapy postoperatively. Type of flap, immediate and long-term outcomes, and complications were assessed. Seventeen local flaps were performed on 10 patients to reconstruct their ankle wounds. Mean follow up was 88 days. All flaps healed without tissue compromise or necrosis. Only one partial dehiscence and no infections were observed. This study demonstrates that negative pressure therapy may contribute to the viability of random local flaps by decreasing venous congestion. Our experience using negative pressure wound therapy on local flaps suggests that it may serve as a useful adjunct to ensure successful closure of high-risk wounds.

The micrograft concept for wound healing: strategies and applications

The standard of care for wound coverage is to use an autologous skin graft. However, large or chronic wounds become an exceptionally challenging problem especially when donor sites are limited. It is important that the clinician be aware of various treatment modalities for wound care and incorporate those methods appropriately in the proper clinical context. This report reviews an alternative to traditional meshed skin grafting for wound coverage: micrografting. The physiological concept of micrografting, along with historical context, and the evolution of the technique are discussed, as well as studies needed for micrograft characterization and future applications of the technique.

Fibromyxoid sarcoma of the leg

A 48-year-old female with an atypical plaque-like lesion of the lower leg is presented in this article. Histologic investigation revealed a rare low-grade fibromyxoid sarcoma (pT1a cN0 cM0; stage Ia) of suprafascial localization. Staging of the patient did not reveal metastatic spread. The tumor was surgically removed with wide safety margins. The defect was closed using a mesh graft transplant and vacuum-assisted closure. Healing was complete. Regular follow-up for at least 5 years is recommended. Besides the rareness of this tumor, this case is also remarkable because of the localization on the lower leg and the suprafascial soft tissue.

Using VAC to facilitate healing of traumatic wounds in patients with chronic lymphoedema

Healing of traumatic injuries in patients with chronic lymphoedema is often delayed. This article describes how topical negative pressure was used to promote healing in two such cases. It also eliminated pain and prevented re-infection.

An overview of negative pressure wound therapy for the lower extremity

Since its introduction into the market, negative pressure wound therapy (NPWT), also known as topical negative pressure, has become an important adjuvant therapy for the treatment of many types of wounds. Surgeons and physicians of all subspecialties have adopted NPWT into their practices. NPWT has become a mainstay in the management of lower extremity soft tissue pathology, especially in patients with traumatic, diabetic, postsurgical, and peripheral vascular disease-associated wounds. This article reviews the background, currently understood mechanisms of action, applications, contraindications, reported complications, advantages, criticisms, and techniques in the lower extremity.

Analysis of Effective Interconnectivity of DegraPol-foams Designed for Negative Pressure Wound Therapy

Many wounds heal slowly and are difficult to manage. Therefore Negative Pressure Wound Therapy (NPWT) was developed where polymer foams are applied and a defined negative pressure removes wound fluid, reduces bacterial burden and increases the formation of granulation tissue. Although NPWT is used successfully, its mechanisms are not well understood. In particular, different NPWT dressings were never compared. Here a poly-ester urethane Degrapol^® (DP)-foam was produced and compared with commercially available dressings (polyurethane-based and polyvinyl-alcohol-based) in terms of apparent pore sizes, swelling and effective interconnectivity of foam pores. DP-foams contain relatively small interconnected pores; PU-foams showed large pore size and interconnectivity; whereas PVA-foams displayed heterogeneous and poorly interconnected pores. PVA-foams swelled by 40 %, whereas DP- and PU-foams remained almost without swelling. Effective interconnectivity was investigated by submitting fluorescent beads of 3, 20 and 45 μm diameter through the foams. DP- and PU-foams removed 70-90 % of all beads within 4 h, independent of the bead diameter or bead pre-adsorption with serum albumin. For PVA-foams albumin pre-adsorbed beads circulated longer, where 20 % of 3 μm and 10 % of 20 μm diameter beads circulated after 96 h. The studies indicate that efficient bead perfusion does not only depend on pore size and swelling capacity, but effective interconnectivity might also depend on chemical composition of the foam itself. In addition due to the efficient sieve-effect of the foams uptake of wound components in vivo might occur only for short time suggesting other mechanisms being decisive for success of NPWT.

Soft Tissue Management in Open Fractures of the Lower Leg: The Role of Vacuum Therapy

The management of severe open fractures of the lower leg continues to challenge the treating surgeon. Major difficulties include high infection rates as well as adequate temporary soft tissue coverage. In the past, these injuries were commonly associated with loss of the extremity. Today, vacuum therapy provides not only safe temporary wound coverage but also conditioning of the soft tissues until definitive wound closure. Amongst other advantages, bacterial clearance and increased formation of granulation tissue are attributed to vacuum therapy, making it an extremely attractive tool in the field of wound healing. However, despite its clinical significance, which is underlined by a constantly increasing range of indications, there is a substantial lack of basic research and well-designed studies documenting the superiority of vacuum therapy compared to alternative wound dressings. Vacuum therapy has been approved as an adjunct in the treatment of severe open fractures of the lower leg, complementing repeated surgical debridement and soft tissue coverage by microvascular flaps, which are still crucial in the treatment of these limb-threatening injuries. Vacuum therapy has in general proven useful in the management of soft tissue injuries and, since it is generally well tolerated and has low complication rates, it is fast becoming the gold standard for temporary wound coverage in the treatment of severe open fractures of the lower leg.

[Vacuum-therapy of chronic wounds in dermatologic departments]

Although the positive effects of negative pressure-therapy in wound-healing has been well known for several decades, the first paper on the now widely used vacuum systems was published ten years ago. Since then vacuum-therapy has been widely used in patients with"hard-to-heal" wounds, including dermatologic patients. Although there is still a lack of relevant comparative prospective controlled clinical trials, vacuum-therapy seems to accelerate the healing process in chronic wounds in both the granulation and epithelialization phases. Therefore, following debridement, vacuum-therapy can be considered as the therapy of choice for many patients with chronic wounds.