Objective: Negative pressure wound therapy (NPWT) can be delivered in continuous or noncontinuous modes, while NPWT with instillation (NPWTi) couples NPWT with automated delivery and removal of topical wound treatment solutions and suspensions. This porcine study compared granulation response of NPWTi (instillation foam dressing with saline) to NPWT (standard foam dressing) in continuous and noncontinuous modes. Methods: Full-thickness dorsal excisional wounds in pigs were treated with continuous NPWT, intermittent NPWT, dynamic (controlled variable) NPWT, and NPWTi with saline (n = 10 per group). Wound dimensions were determined from 3D images collected on days 0, 2, 5, and 7. On day 7, animals were euthanized and specimens were harvested for histopathological review. Results: Average granulation thickness was not statistically different among continuous (3.29 ± 0.33 mm), intermittent (3.03 ± 0.47 mm), and dynamic (3.40 ± 0.34 mm) NPWT wounds at day 7. Average granulation thickness of NPWTi wounds (4.75 ± 0.54 mm), however, was statistically greater (P < .05) by 44%, 57%, and 40%, respectively, than that of wounds treated with continuous, intermittent, and dynamic NPWT. Analysis of 3D images revealed a greater reduction in wound area and perimeter in NPWTi wounds compared to all NPWT wounds (P < .05). In addition, the average wound fill rate for NPWTi wounds was faster than that for continuous (40%; P < .05), intermittent (25%; P > .05), and dynamic (65%; P < .05) NPWT wounds. Conclusions: Although not confirmed in humans, these porcine data suggest that NPWTi with saline may stimulate a faster rate of wound granulation than NPWT in continuous and noncontinuous modes.
dynamic NPWT; negative pressure wound therapy with instillation; preclinical model; variable NPWT; wound cleansing
Non healing chronic wounds are difficult to treat in patients with diabetes and can result in severe medical problems for these patients and for society. Negative-pressure wound therapy (NPWT) has been adopted to treat intractable chronic wounds and has been reported to be effective. However, the mechanisms underlying the effects of this treatment have not been elucidated. To assess the vasculogenic effect of NPWT, we evaluated the systemic mobilization of endothelial progenitor cells (EPCs) during NPWT. Twenty-two of 29 consecutive patients who presented at the clinic of Seoul National Universty Hospital between December 2009 and November 2010 who underwent NPWT for diabetic foot infections or skin ulcers were included in this study. Peripheral blood samples were taken before NPWT (pre-NPWT) and 7–14 days after the initiation of NPWT (during-NPWT). Fluorescence-activated cell sorting (FACS) analysis showed that the number of cells in EPC-enriched fractions increased after NPWT, and the numbers of EPC colony forming units (CFUs) significantly increased during NPWT. We believe that NPWT is useful for treating patients with diabetic foot infections and skin ulcers, especially when these conditions are accompanied by peripheral arterial insufficiency. The systemic mobilization of EPCs during NPWT may be a mechanism for healing intractable wounds in diabetic patients with foot infections or skin defects via the formation of increased granulation tissue with numerous small blood vessels.
diabetic foot; endothelial progenitor cell; negative-pressure wound therapy
Negative pressure wound therapy (NPWT) is a well-accepted modality for treatment of difficult wounds, but has traditionally required a bulky electrically powered pump that was difficult to procure and use for both caregivers and patients. Often times, treatment of refractory smaller-sized wounds was impractical even though they may benefit from NPWT.
Spiracur (Sunnyvale, CA) has developed a simple, easy-to-use, single-use, off-the-shelf, mechanically powered NPWT device that weighs <3 ounces. This device allows for the practical treatment of smaller-sized wounds with NPWT designed specifically for the ambulatory patient being treated at home.
The Smart Negative Pressure (SNaP®) Wound Care System is a novel light-weight NPWT device that does not require an electrically powered pump. Instead, the SNaP system utilizes specialized springs to generate a preset (−75, −100, and −125 mmHg) continuous subatmospheric pressure level to the wound bed. This technology has demonstrated similar efficacy and increased usability for both clinicians and patients when compared with electrically powered NPWT devices.
Indications for Use
Chronic, acute, traumatic, subacute, and dehisced wounds, partial-thickness burns, ulcers (such as diabetic or pressure), and surgically closed incisions and flaps.
Wounds with excess necrotic tissue, active infection, fistulas, exposed vital structures, untreated osteomyelitis, and that are highly exudative. The SNaP system was not designed for wounds that exceed the size of the dressing in surface area or have exudate levels greater than capacity of the cartridge.
Although there is significant evidence supporting the use of negative pressure wound therapy (NPWT) for the treatment of lower extremity diabetic ulcers, currently available electrically powered NPWT systems are not ideally suited for treating smaller diabetic foot ulcers. The Smart Negative Pressure (SNaP™) Wound Care System is a novel, ultraportable device that delivers NPWT without the use of an electrically powered pump. It was specifically designed to meet the wound care needs of patients with diabetes. The SNaP System is compact, silent, mobile, easy-to-use, and available off-the-shelf. It is fully disposable and may offer other important benefits over electrically powered systems to both the clinician and patient. We review the evidence for use of NPWT for the treatment of diabetic wounds and discuss the potential benefits of this new NPWT technology for patients with diabetes. We also present a case series of four difficult lower extremity diabetic ulcers that were successfully treated with the SNaP System. This study suggests that the SNaP System may be a useful addition to the armamentarium of the diabetic wound care clinician.
Apligraf®; chronic ulcers; diabetic foot ulcers; NPWT; negative pressure wound therapy; SNaP™ System; topical negative pressure; ultraportable negative pressure wound therapy; wound VAC®
Negative pressure wound therapy (NPWT) has gained acceptance among surgeons, for the treatment of open abdomen, since very high closure rates have been reported with this method, compared to other kinds of wound management for the open abdomen. However, the method has occasionally been associated with increased development of fistulae. We have previously shown that NPWT induces ischemia in the underlying small intestines close to the vacuum source, and that a protective disc placed between the intestines and the vacuum source prevents the induction of ischemia. In this study we compare pressure transduction and fluid evacuation of the open abdomen with conventional NPWT and NPWT with a protective disc.
Six pigs underwent midline incision and the application of conventional NPWT and NPWT with a protective disc between the intestines and the vacuum source. The pressure transduction was measured centrally beneath the dressing, and at the anterior abdominal wall, before and after the application of topical negative pressures of -50, -70 and -120 mmHg. The drainage of fluid from the abdomen was measured, with and without the protective disc.
Abdominal drainage was significantly better (p < 0. 001) using NPWT with the protective disc at -120 mmHg (439 ± 25 ml vs. 239 ± 31 ml), at -70 mmHg (341 ± 27 ml vs. 166 ± 9 ml) and at -50 mmHg (350 ± 50 ml vs. 151 ± 21 ml) than with conventional NPWT. The pressure transduction was more even at all pressure levels using NPWT with the protective disc than with conventional NPWT.
The drainage of the open abdomen was significantly more effective when using NWPT with the protective disc than with conventional NWPT. This is believed to be due to the more even and effective pressure transduction in the open abdomen using a protective disc in combination with NPWT.
Introduction: Although the use of negative pressure wound therapy (NPWT) is broadly efficacious, it may foster some potentially adverse complications. This is particularly true in patients with diabetes who have a wound colonized with aerobic organisms. Traditional antiseptics have been proven useful to combat such bacteria but require removal of some NPWT devices to be effective. Methods: In this article, we describe a method of “wound chemotherapy” by combining NPWT and a continuous infusion of Dakins' 0.5% solution either as a standardized technique in one device (ITI Sved) or as a modification of standard technique in another (KCI VAC) NPWT device. The twin goals of both techniques are to effectively reduce bacterial burden and to promote progressive wound healing. Results: We present several representative case examples of our provisional experience with continuous streaming therapy through 2 foam-based negative pressure devices. Discussion: Wound chemotherapy was successfully applied to patients with diabetes, without adverse reactions, complications, or recolonization during the course of treatment. We believe this to be a promising method to derive the benefits of NPWT without the frequent adverse sequela of wound colonization.
To evaluate the outcome of treatment for deep sternal wound infection (DSWI) in a nationwide patient cohort, before and after the introduction of negative-pressure wound therapy (NPWT).
This was a population-based cohort of all patients treated for DSWI in Iceland out of 2446 open heart operations performed between 2000 and 2010. Length of hospital stay, survival and reoperations were compared in (i) 23 patients treated with open and/or closed irrigation before August 2005 (conventional treatment, CvT group) and in (ii) 20 patients treated after this time with NPWT as a first-line therapy (NPWT group).
The DSWI rate was 1.8% and did not change during the study period. Demographics were similar for both groups, except for peripheral arterial disease which was less common in the NPWT group. Coagulase-negative staphylococci were also more common (as the only pathogen identified) in the NPWT group (70% vs 30%, P = 0.01). The median length of hospital stay was 43 days in both groups and the sternum could be closed with delayed primary closure in all except 2 patients, one in each group. Eight patients in the CvT group required surgical revision for re-infections, including debridement and rewiring, when compared with 1 patient in the NPWT group (P = 0.02). Furthermore, 6 patients in the CvT group developed late chronic infections of the sternum requiring surgical revision, compared with one in the NPWT group (P = 0.10). The 30-day mortality was not significantly different between groups (4% vs 0%, P > 0.1) and the same was true for 1-year mortality (17% vs 0%, P = 0.11).
NPWT significantly reduces the risk of early re-infections in patients with DSWI. There was a lower rate of late chronic sternal infections and lower mortality in the NPWT group, but the difference was not statistically significant. We conclude that NPWT should be considered as a first-line treatment for most DSWIs.
Deep sternal wound infection (DSWI); Mediastinitis; Cardiac surgery; Negative-pressure wound therapy; Outcome; Re-infection
Negative pressure wound therapy (NPWT) has remarkable effects on the healing of poststernotomy mediastinitis. Foam is presently the material of choice for NPWT in this indication. There is now increasing interest in using gauze, as this has proven successful in the treatment of peripheral wounds. It is important to determine the effects of NPWT using gauze on heart pumping function before it can be used for deep sternotomy wounds. The aim was to examine the effects of NPWT when using gauze and foam on the heart pumping function during the treatment of a sternotomy wound.
Eight pigs underwent median sternotomy followed by NPWT at -40, -70, -120 and -160 mmHg, using foam or gauze. The heart frequency, cardiac output, mean systemic arterial pressure, mean pulmonary artery pressure, central venous pressure and left atrial pressure were recorded.
Cardiac output was not affected by NPWT using gauze or foam. Heart frequency decreased during NPWT when using foam, but not gauze. Treatment with foam also lowered the central venous pressure and the left atrial pressure, while gauze had no such effects. Mean systemic arterial pressure, mean pulmonary artery pressure and systemic vascular resistance were not affected by NPWT. Similar haemodynamic effects were observed at all levels of negative pressure studied.
NPWT using foam results in decreased heart frequency and lower right and left atrial filling pressures. The use of gauze in NPWT did not affect the haemodynamic parameters studied. Gauze may thus provide an alternative to foam for NPWT of sternotomy wounds.
There are increasing reports of deaths and serious complications associated with the use of negative pressure wound therapy (NPWT), of which right ventricular heart rupture is the most devastating. The use of a rigid barrier has been suggested to offer protection against this lethal complication by preventing the heart from being drawn up against the sharp edges of the sternum. The aim of the present study was to determine whether a rigid barrier can be safely inserted over the heart with regard to the sternum wound edge movement.
Sternotomy wounds were created in eight pigs. The wounds were treated with NPWT at -40, -70, -120 and -170 mmHg in the presence and absence of a rigid barrier between the heart and the edges of the sternum. Wound contraction upon NPWT application, and wound distension under mechanical traction to draw apart the edges of the sternotomy were evaluated.
Wound contraction resulting from NPWT was similar with and without the rigid barrier. When mechanical traction was applied to a NPWT treated sternum wound, the sternal edges were pulled apart. Wound distension upon traction was similar in the presence and absence of a the rigid barrier during NPWT.
A rigid barrier can safely be inserted between the heart and the edges of the sternum to protect the heart and lungs from rupture during NPWT. The sternum wound edge is stabilized equally well with as without the rigid barrier during NPWT.
This study was performed to evaluate the results of negative pressure wound therapy (NPWT) in patients with open wounds in the foot and ankle region.
Materials and methods
Using a NPWT device, 16 patients were prospectively treated for soft tissue injuries around the foot and ankle. Mean patient age was 32.8 years (range, 3–67 years). All patients had suffered an acute trauma, due to a traffic accident, a fall, or a crush injury, and all had wounds with underlying tendon or bone exposure. Necrotic tissues were debrided before applying NPWT. Dressings were changed every 3 or 4 days and treatment was continued for 18.4 days on average (range, 11–29 days).
Exposed tendons and bone were successfully covered with healthy granulation tissue in all cases except one. The sizes of soft tissue defects reduced from 56.4 cm2 to 42.9 cm2 after NPWT (mean decrease of 24%). In 15 of the 16 cases, coverage with granulation tissue was achieved and followed by a skin graft. A free flap was needed to cover exposed bone and tendon in one case. No major complication occurred that was directly attributable to treatment. In terms of minor complications, two patients suffered scar contracture of grafted skin.
NPWT was found to facilitate the rapid formation of healthy granulation tissue on open wounds in the foot and ankle region, and thus, to shorten healing time and minimize secondary soft tissue defect coverage procedures.
Negative pressure wound therapy (NPWT) has become a widely used modality for the treatment of complex wounds. However, patient compliance is frequently difficult due to the need to carry a bulky, noisy electronic device. In this issue of Journal of Diabetes Science and Technology, Lerman and colleagues describe a new system that uses no electricity and is about the size of a deck of cards. It is designed to be stored in the clinic and applied almost as simply as a standard wound dressing. Four cases are reviewed to demonstrate that the device is efficacious and helps to encourage patient compliance. No statistically significant outcomes are presented. By removing compliance barriers, this device may encourage more frequent NPWT applications for small wounds.
diabetic foot ulcer; negative pressure wound therapy
Higher closure rates of the open abdomen have been reported with negative pressure wound therapy (NPWT) than with other wound management techniques. However, the method has occasionally been associated with increased development of fistulae. We have previously shown that NPWT induces ischemia in the underlying small intestines close to the vacuum source, and that a protective disc placed between the intestines and the vacuum source prevents the induction of ischemia. In the present study we compare macroscopic changes after 12, 24, and 48 hours, using conventional NPWT and NPWT with a protective disc between the intestines and the vacuum source.
Twelve pigs underwent midline incision. Six animals underwent conventional NPWT, while the other six pigs underwent NPWT with a protective disc inserted between the intestines and the vacuum source. Macroscopic changes were photographed and quantified after 12, 24, and 48 hours of NPWT.
The surface of the small intestines was red and mottled as a result of petechial bleeding in the intestinal wall in all cases. After 12, 24 and 48 hours of NPWT, the area of petechial bleeding was significantly larger when using conventional NPWT than when using NPWT with the protective disc (9.7 ± 1.0 cm2 vs. 1.8 ± 0.2 cm2, p < 0.001, 12 hours), (14.5 ± 0.9 cm2 vs. 2.0 ± 0.2 cm2, 24 hours) (17.0 ± 0.7 cm2 vs. 2.5 ± 0.2 cm2 with the disc, p < 0.001, 48 hours)
The areas of petechial bleeding in the small intestinal wall were significantly larger following conventional NPWT after 12, 24 and 48 hours, than using NPWT with a protective disc between the intestines and the vacuum source. The protective disc protects the intestines, reducing the amount of petechial bleeding.
negative pressure wound therapy; open abdomen; macroscopic changes; intestinal wall
This is a paper reviewing the National Health Service (NHS) agenda in relation to the use of Negative Pressure Wound Therapy (NPWT) in chronic wound management and assesses the evidence behind it, its cost effectiveness and the outcome it has on patients' satisfaction and life style. Multiple studies over the last 10 years looking at clinical efficacy of NPWT with its cost effectiveness and the implementation of this service in the UK were reviewed. NPWT has showed a reasonable body of evidence to support its usage in chronic wounds with potential positive outcomes on finance and patients' satisfaction. However, the NHS system shows significant variations in the availability and implementation of this useful tool, depending on care providers and resources availabilities. The paper concluded that the NPWT can be a useful source of cutting down costs of chronic wound managements and saving money by its effect on expediting wound healing, which can address a part of the financial crises facing the NHS, however, has to be considered according to specific case needs. There should also be a national standard for the availability and indication of this tool to assure equal opportunities for different patients in different areas in the country.
Objective: The purpose of this article is to describe the treatment of injuries resulting from land mine explosions using a holistic approach that includes gauze-based negative pressure wound therapy (NPWT) and encompasses wound bed preparation, exudate management, and infection control. Method: In the treatment of 3 traumatic injuries, each requiring limb amputation, we describe the application of NPWT using the Chariker-Jeter system, which uses a single layer of saline-moistened antimicrobial gauze laid directly onto the wound bed. A silicone drain is placed on the gauze and then more gauze is placed over the drain to fill the wound. This is then covered with a clear semipermeable film, cut so that there is a 2- to 3-cm border around the wound allowing it to be sealed onto healthy skin. Results: In each of the cases described, we were able to achieve wound closure prior to successful skin grafting, and the patients have recovered well despite the severity of their injuries. Conclusion: We discuss the potential advantages of the Chariker-Jeter system over polyurethane foam as a method of delivering NPWT in highly extensive and irregular-shaped wounds created by land mine explosions while stressing the importance of thorough and effective wound bed preparation.
Negative pressure wound therapy (NPWT) is believed to initiate granulation tissue formation via macro-deformation of the wound edge. However, only few studies have been performed to evaluate this hypothesis. The present study was performed to investigate the effects of NPWT on wound contraction and wound edge tissue deformation.
Six pigs underwent median sternotomy followed by magnetic resonance imaging in the transverse plane through the thorax and sternotomy wound during NPWT at 0, -75, -125 and -175 mmHg. The lateral width of the wound and anterior-posterior thickness of the wound edge was measured in the images.
The sternotomy wound decreased in size following NPWT. The lateral width of the wound, at the level of the sternum bone, decreased from 39 ± 7 mm to 30 ± 6 mm at -125 mmHg (p = 0.0027). The greatest decrease in wound width occurred when switching from 0 to -75 mmHg. The level of negative pressure did not affect wound contraction (sternum bone: 32 ± 6 mm at -75 mmHg and 29 ± 6 mm at -175 mmHg, p = 0.0897). The decrease in lateral wound width during NPWT was greater in subcutaneous tissue (14 ± 2 mm) than in sternum bone (9 ± 2 mm), resulting in a ratio of 1.7 ± 0.3 (p = 0.0423), suggesting macro-deformation of the tissue. The anterior-posterior thicknesses of the soft tissue, at 0.5 and 2.5 cm laterally from the wound edge, were not affected by negative pressure.
NPWT contracts the wound and causes macro-deformation of the wound edge tissue. This shearing force in the tissue and at the wound-foam interface may be one of the mechanisms by which negative pressure delivery promotes granulation tissue formation and wound healing.
Lower limb reconstruction with pedicled or free flaps can be commonly compromised by venous insufficiency. This complication often leads to partial/complete flap necrosis and increases the risk of superinfection. Negative-pressure wound therapy (NPWT) is known to increase local blood flow, decrease edema, promote tissue granulation, and reduce the likelihood of soft tissue infection. This study aims to evaluate the effectiveness of NPWT in the treatment of congested pedicled and free flaps of the lower limb after reconstructions in lower limb traumas. A retrospective analysis was performed on four congested (pedicled and free) flaps on the lower limbs. NPWT was applied in all cases after partial flap debridement. NPWT was able to improve and resolve tissue edema and venous insufficiency, avoid further flap necrosis, and promote granulation. On NPWT removal, a split-thickness skin graft was applied on the wound, achieving complete and uneventful healing. NPWT is a useful instrument in managing flaps affected by venous insufficiency in lower limb reconstruction, although larger studies are necessary to better define the effectiveness and indications of NPWT in this setting.
Flap; Lower limb; Edema; Congestion; Negative pressure
Primary study selection between systematic reviews is inconsistent, and reviews on the same topic may reach different conclusions. Our main objective was to compare systematic reviews on negative pressure wound therapy (NPWT) regarding their agreement in primary study selection.
This retrospective analysis was conducted within the framework of a systematic review (a full review and a subsequent rapid report) on NPWT prepared by the Institute for Quality and Efficiency in Health Care (IQWiG).
For the IQWiG review and rapid report, 4 bibliographic databases (MEDLINE, EMBASE, The Cochrane Library, and CINAHL) were searched to identify systematic reviews and primary studies on NPWT versus conventional wound therapy in patients with acute or chronic wounds. All databases were searched from inception to December 2006.
For the present analysis, reviews on NPWT were classified as eligible systematic reviews if multiple sources were systematically searched and the search strategy was documented. To ensure comparability between reviews, only reviews published in or after December 2004 and only studies published before June 2004 were considered.
Eligible reviews were compared in respect of the methodology applied and the selection of primary studies.
A total of 5 systematic reviews (including the IQWiG review) and 16 primary studies were analysed. The reviews included between 4 and 13 primary studies published before June 2004. Two reviews considered only randomised controlled trials (RCTs). Three reviews considered both RCTs and non-RCTs. The overall agreement in study selection between reviews was 96% for RCTs (24 of 25 options) and 57% for non-RCTs (12 of 21 options). Due to considerable disagreement in the citation and selection of non-RCTs, we contacted the review authors for clarification (this was not initially planned); all authors or institutions responded. According to published information and the additional information provided, most differences between reviews arose from variations in inclusion criteria or inter-author study classification, as well as from different reporting styles (citation or non-citation) for excluded studies.
The citation and selection of primary studies differ between systematic reviews on NPWT, particularly with regard to non-RCTs. Uniform methodological and reporting standards need to be applied to ensure comparability between reviews as well as the validity of their conclusions.
Objective: Negative pressure wound therapy (NPWT) is commonly used in the continuous mode. Intermittent pressure therapy (IPT) results in faster wound healing, but it often causes pain. Variable pressure therapy (VPT) has therefore been introduced to provide a smooth transition between 2 different pressure environments, thereby maintaining the negative pressure environment throughout the therapy. The aim of the present study was to examine the effects of IPT and VPT on granulation tissue formation. Method: A peripheral wound in a porcine model was treated for 72 hours with continuous NPWT (-80 mm Hg), IPT (0 to -80 mm Hg), or VPT (-10 to -80 mm Hg), using foam or gauze as wound filler. Wound contraction and force to remove the wound filler were measured. Biopsies from the wound bed were examined histologically for granulation tissue formation. Results: Intermittent pressure therapy and VPT produced similar results. Wound contraction was more pronounced following IPT and VPT than continuous NPWT. Intermittent pressure therapy and VPT resulted in the formation of more granulation tissue than continuous NPWT. Leukocyte infiltration and tissue disorganization were more prominent after IPT and VPT than after continuous NPWT. Granulation tissue grew into foam but not into gauze, regardless of the mode of negative pressure application, and less force was needed to remove gauze than foam. Conclusions: Wound contraction and granulation tissue formation is more pronounced following IPT and VPT than continuous NPWT. Granulation tissue grows into foam but not into gauze. The choice of negative pressure mode and wound filler is crucial in clinical practice to optimize healing while minimizing pain.
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.
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.
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.
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.
Level of Evidence
Negative-pressure wound therapy; split thickness skin graft
Negative pressure wound therapy (NPWT) is widely promoted as a treatment for full thickness wounds; however, there is a lack of high-quality research evidence regarding its clinical and cost effectiveness. A trial of NPWT for the treatment of grade III/IV pressure ulcers would be worthwhile but premature without assessing whether such a trial is feasible. The aim of this pilot randomised controlled trial was to assess the feasibility of conducting a future full trial of NPWT for the treatment of grade III and IV pressure ulcers and to pilot all aspects of the trial.
This was a two-centre (acute and community), pilot randomised controlled trial. Eligible participants were randomised to receive either NPWT or standard care (SC) (spun hydrocolloid, alginate or foam dressings). Outcome measures were time to healing of the reference pressure ulcer, recruitment rates, frequency of treatment visits, resources used and duration of follow-up.
Three hundred and twelve patients were screened for eligibility into this trial over a 12-month recruitment period and 12/312 participants (3.8%) were randomised: 6 to NPWT and 6 to SC. Only one reference pressure ulcer healed (NPWT group) during follow-up (time to healing 79 days). The mean number of treatment visits per week was 3.1 (NPWT) and 5.7 (SC); 6/6 NPWT and 1/6 SC participants withdrew from their allocated trial treatment. The mean duration of follow-up was 3.8 (NPWT) and 5.0 (SC) months.
This pilot trial yielded vital information for the planning of a future full study including projected recruitment rate, required duration of follow-up and extent of research nurse support required. Data were also used to inform the cost-effectiveness and value of information analyses, which were conducted alongside the pilot trial.
Current Controlled Trials ISRCTN69032034.
Negative pressure wound therapy; Pressure ulcer; Pilot randomised controlled trial
Deep and extensive burns of lower extremities present a difficult challenge to healthcare professionals. After debridement, bones, tendons or joints are frequently exposed and cannot be covered by simple autografts. Moreover, in the case of major burns, damage to the surrounding areas of skin and the severity of the patient’s overall condition, often count against using pedicled or microsurgical flaps. In dealing with such complex wounds, which are difficult to treat, several authors have recommended the combined use of Integra® and negative pressure wound therapy (NPWT). They emphasize that NPWT eliminates wound exudate, promotes neovascularisation and cell migration through the Integra® matrix while increasing its stability and adherence to the wound bed, as well as decreasing the time needed for its total integration. The case presented here is of a patient with major third-degree flame burns to the lower extremities. After debridement, the external and internal malleolus bilaterally became exposed as well as the partially debrided tendons (Achilles, extensor digitorum longus, long and short peroneus, anterior and posterior tibialis). After ruling out the use of local or microsurgical flaps due to the patient’s poor general condition and the presence of burns debrided to the fascia over both lower extremities, we elected to manage the patient with a combined treatment using Integra® and NPWT. After three weeks of treatment, the surface layer of the Integra® matrix was replaced with autografts. Due to partial loss of the skin grafts, a second autograft was needed. At present the patient is completely healed; he can walk with full flexion-extension of both ankles.
burns; Integra®; negative pressure wound therapy
Introduction. The open abdomen (OA) is often associated with complications. It has been hypothesized that negative pressure wound therapy (NPWT) in the treatment of OA may provoke enteral fistulas. Therefore, we analyzed patients with OA and NPWT with special regard to the occurrence of intestinal fistulas. Methods. The present study included all consecutive patients with OA treated with NWPT from April 2010 to August 2011 in two hospitals. Patients' demographics, indications for OA, risk factors, complications, outcome and incidence of fistulas before, during and after NPWT were recorded. Results. Of 81 patients with OA, 26 had pre-existing fistulas and 55 were free from a fistula at the beginning of NPWT. Nine of the 55 patients developed fistulas during (n = 5) or after NPWT (n = 4). Seventy-five patients received ABThera therapy, 6 patients other temporary abdominal closure devices. Only diverticulitis seemed to be a significant predisposing factor for fistulas. Mortality was slightly lower for patients without fistulas. Conclusion. The present study revealed no correlation between occurrence of fistulas before, during, and after NWPT, with diverticulitis being the only risk factor. Fistula formation during NPWT was comparable to reports from literature. Prospective studies are mandatory to clarify the impact of NPWT on fistula formation.
Higher closure rates of the open abdomen have been reported with negative pressure wound therapy (NPWT) compared with other wound therapy techniques. However, the method has occasionally been associated with increased development of intestinal fistulae. The present study measures microvascular blood flow in the intestinal wall and the omentum before and during NPWT.
Six pigs underwent midline incision and application of NPWT to the open abdomen. The microvascular blood flow in the underlying intestinal loop wall and the omentum was recorded before and after the application of NPWT of −50, −70, −100, −120, −150, and −170 mmHg respectively, using laser Doppler velocimetry.
A significant decrease in microvascular blood flow was seen in the intestinal wall during application of all negative pressures levels. The blood flow was 2.7 (±0.2) Perfusion Units (PU) before and 2.0 (±0.2) PU (*p < 0.05) after application of −50 mmHg, and 3.6 (±0.6) PU before and 1.5 (±0.2) PU (**p < 0.01) after application of −170 mmHg.
In the present study, we show that negative pressures between −50 and −170 mmHg induce a significant decrease in the microvascular blood flow in the intestinal wall. The decrease in blood flow increased with the amount of negative pressure applied. One can only speculate that a longstanding decreased blood flow in the intestinal wall may induce ischemia and secondary necrosis in the intestinal wall, which, theoretically, could promote the development of intestinal fistulae. We believe that NPWT of the open abdomen is a very effective treatment but could probably be improved.
Negative pressure wound therapy; Open abdomen; Microvascular blood flow; Intestinal wall; Omentum
Objectives: Negative pressure wound therapy (NPWT) is a useful therapy in the preparation of wounds prior to application of a split-thickness skin graft (STSG) both “pregraft” and “postgraft” on top of the STSG. Customarily, a foam-based NPWT has been used, but gauze-based therapy is finding an increasing use. Gauze is easy to apply and forgiving of complicated wound geometries so it can be an ideal material in this indication. The aim of this study was to quantitatively assess the clinical efficacy of gauze-based NPWT as an adjunctive therapy to STSG procedures. Methods: A prospective, noncomparative, multicenter evaluation was carried out to assess the performance of gauze-based NPWT. Twenty-one patients had NPWT applied prior to definitive closure by STSG or flap techniques (pregraft group). A further 21 patients underwent an STSG procedure and had gauze-based NPWT placed immediately on top of the STSG (postgraft group). Negative pressure was applied at −80 mm Hg. Results: In the pregraft group, NPWT was used for a median of 12 days. Improvement in quality of wound bed with decreased nonviable tissue (from 20% to 0% median wound area) and increased granulation tissue (from 20% to 90% median wound area) was observed. In the postgraft group, median duration of therapy was 5 days at which point median percentage skin graft-take was 96%. Conclusions: Gauze-based NPWT appears to be an effective addition to the care and management of wounds intended for definitive closure by STSG.
The purpose of this study was to evaluate the use of negative pressure wound therapy (NPWT) to improve wound healing after total hip arthroplasty (THA) and its influence on the development of postoperative seromas in the wound area.
The study is a prospective randomised evaluation of NPWT in patients with large surgical wounds after THA, randomising patients to either a standard dressing (group A) or a NPWT (group B) over the wound area. The wound area was examined with ultrasound to measure the postoperative seromas in both groups on the fifth and tenth postoperative days.
There were 19 patients randomised in this study. Ten days after surgery, group A (ten patients, 70.5 ± 11.01 years of age) developed seromas with an average size of 5.08 ml and group B (nine patients, 66.22 ± 17.83 years of age) 1.97 ml. The difference was significant (p = 0.021).
NPWT has been used on many different types of traumatic and non traumatic wounds. This prospective, randomised study has demonstrated decreased development of postoperative seromas in the wound and improved wound healing.