Wound edge microvascular blood flow: effects of negative pressure wound therapy using gauze or polyurethane foam

Use of incisional negative pressure wound therapy in reconstructive pediatric and young adult urology to reduce surgical site occurrences: A pilot study

BACKGROUND

Surgical site occurrences (SSO) contribute to the morbidity and cost of postoperative complications. In adult and pediatric surgical literature, enthusiasm for incisional negative pressure wound therapy (iNPWT) on closed surgical incisions has been ongoing.

OBJECTIVE

The aim of this pilot study is to report the early outcomes of iNPWT in reconstructive pediatric and young adult urologic surgery.

STUDY DESIGN

This is a pilot prospective cohort study at a single, tertiary care, free-standing children's hospital. Wound complication outcomes with use of iNPWT are compared to a historical cohort that underwent routine incision closures. A multivariate logistic regression model was used to predict the risk of composite SSO within the first 30 days after surgery.

RESULTS

On univariate analysis, the percentage of patients experiencing SSO fell from 24.0 % to 6.9 % with introduction of iNPWT (p = 0.065). On multivariate analysis, compared to the pre-iNPWT group, placement of iNPWT was associated with a reduction in risk of composite SSO [OR 0.084 (0.009-0.415, p = 0.01].

DISCUSSION

Strengths of this study are that it was prospective in nature and there was consistency in iNPWT placement and management throughout the study period. Until more reliable biological markers of SSO risk are available, we believe that interventions to prevent SSO must be broadly applied. One limitation is that the financial and physical cost of having an iNPWT placed could not be measured for each individual patient.

CONCLUSION

In this pilot study, iNPWT was found to be a successful intervention to reduce SSO in reconstructive pediatric and young adult urology patients. Use of iNPWT could be considered for all, but perhaps particularly in those with a baseline high risk of SSO, including those with obesity or connective tissue disorders.

Revisiting negative pressure wound therapy from a mechanobiological perspective supported by clinical and pathological data

Negative pressure wound therapy is used often in the management of surgical incisions, chronic wounds and subacute lesions, and there are numerous publications discussing its clinical application and outcomes. However, whilst clinical use and associated literature have expanded since these systems became commercially available in the 90s, important research and discussion around the mode of action have waned, leading to a deficit in the understanding of how this important therapy influences healing. Further, much research and many publications are predominantly reflective, discussing early theorem, some of which have been proven incorrect, or at least not fully resolved leading to misunderstandings as to how the therapy works, thus potentially denying the clinician the opportunity to optimise use towards improved clinical and economic outcomes. In this narrative review, we discuss established beliefs and challenges to same where appropriate and introduce important new research that addresses the manner in which mechanical strain energy (i.e., deformations) is transferred to tissue and how this influences biological response and healing. In addition, we assess and discuss the effect of different negative pressure dressing formats, how they influence the mode of action and how this understanding can lead to more efficient and effective use and clinical economic outcomes.

In vitro evaluation of a hybrid negative pressure system for wound therapy

OBJECTIVE

The objective of this study was to assess whether negative pressure could be maintained accurately and repeatably with a wall-suction-based hybrid negative pressure wound therapy (h-NPWT) system by comparing it with a commercial negative pressure wound therapy (NPWT) device.

STUDY DESIGN

In vitro experimental study.

METHODS

A commercial NPWT device (control) and three h-NPWT devices, with 0, 3, and 6 meters of additional tubing using the hospital-wall suction (groups 1, 2, and 3 respectively), were applied sequentially to a commercial NPWT dressing on a silicone skin substrate and set to run at a continuous pressure of -125 mmHg. The pressure within the wound space was monitored at 10 second intervals for 24 h. The process was repeated five times for each group.

RESULTS

The commercial NPWT device produced an average pressure variance of 3.02 mmHg, and the h-NPWT produced average variances of 4.38, 4.24 and 4.20 mmHg for groups 1, 2 and 3, respectively. All groups produced an average pressure within 0.15 mmHg of -125 mmHg over the 24-hour period, and the h-NPWT systems produced the smallest range with all values remaining within a ±5% variation from -125 mmHg.

CONCLUSION

The h-NPWT system achieved negative pressures that were comparable to those of a commercial control NPWT device. The addition of tubing between the skin substrate and the canister did not affect the pressure applied at the wound site.

CLINICAL SIGNIFICANCE

The h-NPWT device tested in this study can be considered as an alternative for negative wound therapy when a commercial device cannot be used.

Negative Pressure Wound Therapy-A Vacuum-Mediated Positive Pressure Wound Therapy and a Closer Look at the Role of the Laser Doppler

Background: Negative pressure wound therapy (NPWT) is an intensely investigated topic, but its mechanism of action accounts for one of the least understood ones in the area of wound healing. Apart from a misleading nomenclature, by far the most used diagnostic tool to investigate NPWT, the laser Doppler, also has its weaknesses regarding the detection of changes in blood flow and velocity. The aim of the present study is to explain laser Doppler readings within the context of NPWT influence. Methods: The cutaneous microcirculation beneath an NPWT system of 10 healthy volunteers was assessed using two different laser Dopplers (O2C/Rad-97®). This was combined with an in vitro experiment simulating the compressing and displacing forces of NPWT on the arterial and venous system. Results: Using the O2C, a baseline value of 194 and 70 arbitrary units was measured for the flow and relative hemoglobin, respectively. There was an increase in flow to 230 arbitrary units (p = 0.09) when the NPWT device was switched on. No change was seen in the relative hemoglobin (p = 0.77). With the Rad-97®, a baseline of 92.91% and 0.17% was measured for the saturation and perfusion index, respectively. No significant change in saturation was noted during the NPWT treatment phase, but the perfusion index increased to 0.32% (p = 0.04). Applying NPWT compared to the arteriovenous-vessel model resulted in a 28 mm and 10 mm increase in the venous and arterial water column, respectively. Conclusions: We suspect the vacuum-mediated positive pressure of the NPWT results in a differential displacement of the venous and arterial blood column, with stronger displacement of the venous side. This ratio may explain the increased perfusion index of the laser Doppler. Our in vitro setup supports this finding as compressive forces on the bottom of two water columns within a manometer with different resistances results in unequal displacement.

The Efficacy of Negative Pressure Wound Therapy (NPWT) on Healing of Diabetic Foot Ulcers: A Literature Review

BACKGROUND

Diabetes mellitus is a complex disorder that requires continuous management to control blood sugar levels and prevent complications. Diabetic foot ulcers (DFU) are the most common complication in diabetic patients. A popular therapy modality with considerable advantages in the management of diabetic foot ulcers today is negative pressure wound therapy (NPWT).

OBJECTIVE

This study aimed to review related articles about the efficacy as well as the complications or adverse effects of using NPWT on the healing of DFUs.

METHODS

Searching English databases from PubMed, Ebscohost, Proquest and Science Direct was done to identify relevant citations published between January 2017 and January 2022. A combination of terms was used with the boolean formulation of "negative pressure wound therapy OR NPWT" OR "vacuum-assisted closure or VAC" AND "diabetic foot ulcers OR diabetic foot wound" AND "wound healing" AND "Conventional dressings" and map terms were also used for the subject heading. Some potentially relevant citations of articles from the bibliographies are also reviewed.

RESULTS

This study included 8 related articles consisting of 6 RCTs, 1 cohort study and 1 Quasy experimental study. There were various methodological techniques for using NPWT and outcome measures among studies. The results of this literature review showed that NPWT was more efficacious than the other conventional or advanced moist dressings. This therapy revealed a faster healing time with complete wound healing and formation of granulation tissue and reduction in wound size. The complications or adverse effects of NPWT, such as amputation rate, bleeding and pain, were not different from conventional or advanced moist dressings, though.

CONCLUSION

NPWT was more efficacious than other conventional or advanced moist dressings for the healing of DFUs. However, complications or adverse effects of using this therapy showed no significant difference with other conventional or advanced moist dressings.

Ex vivo comparison of V.A.C.® Granufoam Silver™ and V.A.C.® Granufoam™ loaded with a first-in-class bis-dialkylnorspermidine-terphenyl antibiofilm agent

Implementation of negative pressure wound therapy (NPWT) as a standard of care has proven efficacious in reducing both the healing time and likelihood of nosocomial infection among pressure ulcers and traumatic, combat-related injuries. However, current formulations may not target or dramatically reduce bacterial biofilm burden following therapy. The purpose of this study was to determine the antibiofilm efficacy of an open-cell polyurethane (PU) foam (V.A.C.® Granufoam™) loaded with a first-in-class compound (CZ-01179) as the active release agent integrated via lyophilized hydrogel scaffolding. An ex vivo porcine excision wound model was designed to perform antibiofilm efficacy testing in the presence of NPWT. PU foam samples loaded with a 10.0% w/w formulation of CZ-01179 and 0.5% hyaluronic acid were prepared and tested against current standards of care: V.A.C.® Granufoam Silver™ and V.A.C.® Granufoam™. We observed statistically significant reduction of methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii biofilms with the CZ-01179 antibiofilm foam in comparison to current standard of care foams. These findings motivate further development of an antibiofilm PU foam loaded with CZ-01179.

Effects of Different Pressure Levels in Topical Negative Pressure Application—Analysis of Perfusion Parameters in a Clinical Skin Model Using Multimodal Imaging Techniques

The effects of topical negative pressure therapy (TNP) have been a subject of research for many years. In this study, we investigated new imaging devices to detect clinical changes that TNP causes on healthy tissue and identified differences in microcirculation created by different pressure levels. We used near-infrared spectroscopy (NIS), thermography, and a vein illuminator to measure the differences in oxygen saturation, tissue temperature, and vein pattern. A control group (−125 mmHg) and three comparison groups with only TNP dressing (Group 1), −25 mmHg (Group 2), and −175 mmHg (Group 3) were established. Thirty minutes of TNP on intact skin was followed by 30 min of resting. A total of 24 participants were measured by all imaging devices at predetermined time points. Oxygen saturation and skin temperature increased by 8.07% and 1.67 °C for the control group, 4.00% and 1.65 °C for Group 2, and 8.45% and 1.68 °C for Group 3. Group 1 showed a slight increase in oxygen saturation and a 2.7 °C increase in skin temperature. Over the 30 min following removal of TNP, oxygen saturation and temperature decreased gradually for all groups. The vein illuminator did not show significant differences in the venous pattern or flow. Our study showed that higher negative pressure values resulted in higher oxygen saturation and higher tissue temperature.

Negative pressure wound therapy versus conventional wound care in cancer surgical wounds: A meta-analysis of observational studies and randomised controlled trials

The application of negative pressure wound therapy (NPWT) in cancer surgical wounds is still controversial, despite its promising usage, because of the risks of increased tumorigenesis and metastasis. This study aimed to review the risks and benefits of NPWT in surgical wounds with the underlying malignant disease compared with conventional wound care (CWC). The first outcome was wound complications, divided into surgical site infection (SSI), seroma, hematoma, and wound dehiscence. The secondary outcome was hospital readmission. We performed a separate meta‐analysis of observational studies and randomised controlled trials (RCTs) with CI 95%. Thirteen observational studies with 1923 patients and seven RCTs with 1091 patients were included. NPWT group showed significant decrease in the risk of SSI (RR = 0.45) and seroma (RR = 0.61) in observational studies with P value <0.05, as well as RCTs but were not significant (RR = 0.88 and RR = 0.68). Wound dehiscence (RR = 0.74 and RR = 1.15) and hospital readmission (RR = 0.90 and RR = 0.62) showed lower risks in NPWT group but were not significant. Hematoma (RR = 1.08 and RR = 0.87) showed no significant difference. NPWT is not contraindicated in cancer surgical wounds and can be considered a beneficial palliative treatment to promote wound healing.

Influence of incentive nursing intervention on recovery of burn patients after vacuum sealing drainage

To observe the effect of application of incentive nursing intervention (INI) on recovery in burn patients undergoing vacuum sealing drainage (VSD). From January 2017 to January 2020, a total of 82 consecutive burn patients were prospectively enrolled, and divided into INI group and routine nursing intervention (RNI) group according to random number table method. The causes of inadequate drainage were collected, the incidence was calculated, and the occurrence of inadequate drainage at different locations was compared. The pain degree and comfort status before and after the intervention were observed, and the wound healing time, hospital stay, and satisfaction after the intervention were recorded. The reasons for inadequate drainage during the treatment of VSD included negative pressure insufficient, drainage tube blockage because of escharosis, replacement of negative pressure internal sac not standard, loose sealing of the semi-permeable membrane, and the negative pressure tube fell off, compressed or reflexed. The baseline characteristics between the two groups were comparable (P > .05). The incidence of each cause and total incidence of inadequate drainage in INI group were lower than those in RNI group (P < .05, respectively). The incidences of inadequate drainage of all burn sites in INI group were lower than those in RNI group, and the difference of limbs wound between the two group was statistically significant (P < .05). After intervention, the pain intensity of INI group was lower than that of RNI group (P < .05), and the holistic comfort of INI group was higher than that of RNI group (P < .05). The wound healing time and hospital stay time in INI group were lower than those in RNI group, and the total satisfaction rate in INI group was higher than that in RNI group (P < .05, respectively). Applying INI can effectively reduce the incidence of insufficient drainage, reduce pain, improve comfort, shorten wound healing time and hospital stay, and thus improve the overall satisfaction rate of patients, which is worthy of clinical promotion and application.

Perioperative Interventions to Reduce Surgical Site Infections: A Review

Surgical site infections (SSIs) contribute to increased health care costs and morbidity after procedures as well as prolonged length of stay. Perioperative personnel can use a variety of interventions to help reduce SSI incidence; however, all strategies are not effective for all patients (eg, antibiotic prophylaxis). Results of randomized controlled trials show that some SSI reduction strategies are generally effective, including preoperative skin antisepsis with an alcohol-based agent, closing surgical wounds with triclosan-coated suture, and applying a negative pressure wound therapy device to open and closed wounds. Study results do not show that irrigating clean wounds with crystalloid solutions containing antibiotics or routinely using plastic drapes with or without impregnated iodophor or silver nylon-impregnated dressings significantly reduces SSI incidence. Perioperative leaders should support the implementation of strategies to prevent SSIs and work with interdisciplinary team members to develop an SSI prevention bundle that will meet the needs of their patients.

Effects of Simultaneous versus Staged VAC Placement in the Treatment of Deep Neck Multiple-Space Infections at a Tertiary Hospital Over a Four-Year Period in China

Purpose

Surgical drainage is an essential part of treatment for deep neck infections (DNIs) or deep neck multiple-space infections (DNMIs). With the emergence and application of new technologies and new materials, vacuum-assisted closure (VAC) in the treatment of DNMIs has been reported. However, reports on the timing of VAC placement are limited. Herein, we compared simultaneous versus staged VAC placement in the treatment of DNMIs.

Patients and Methods

Medical data from 24 patients with DNMIs who had received VAC treatment in the last five years were analyzed. The patients were classified into a simultaneous VAC placement group (11 patients) and a staged VAC placement group (13 patients) according to the timing of VAC placement when incision and drainage were performed.

Results

No differences in baseline characteristics were found between the two groups. All patients in the two groups survived and recovered. The hospitalization duration (days), time to wound healing (days), number of debridement procedures, and disease course (days) in the simultaneous VAC placement group and staged VAC placement group were 10 (4–18) and 22 (8–35), 21 (4–39) and 50 (9–86), one (1–2) and two (1–4), and 31.5 (11–49) and 56 (19–98), respectively. The results in the simultaneous VAC placement group were better than those in the staged VAC placement group (P = 0.001, 0.016, 0.045, and 0.016, respectively). The numbers of VAC sponge changes in the simultaneous VAC placement group and staged VAC placement group were two (1–2) and two (1–4), respectively, with no statistically significant difference (P = 0.336).

Conclusion

Simultaneous VAC placement during incision and drainage may shorten the wound healing time, hospitalization duration, and disease course and may reduce the number of debridement procedures.

Closed Incision Negative Pressure Wound Therapy for Elective Hip and Knee Arthroplasty: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Persistent wound drainage after total joint arthroplasty (TJA) increases the risk of surgical site infections (SSIs). Closed incision negative pressure wound therapy (ciNPWT) decreases infections in traumatic wounds, but evidence for its use after elective TJA is limited. The purpose of this meta-analysis of level I studies is to determine the effect of ciNPWT on risk of SSI and wound complications following TJA.

METHODS

MEDLINE, EMBASE, CINAHL, and Cochrane Library were searched for randomized controlled trials comparing ciNPWT vs standard dressings after total hip (THA) and total knee arthroplasty (TKA). Studies exclusively involving THA for femoral neck fractures were excluded. Risk of SSI and noninfectious wound complications (blisters, seroma, hematoma, persistent drainage, dehiscence, and wound edge necrosis) following TJA were analyzed.

RESULTS

SSI risk was lower with ciNPWT compared to standard dressings (3.4% vs 7%; relative risk [RR] 0.48, P = .007), specifically in revision THA and TKA (4.1% vs 10.5%; RR 0.41, P = .03). ciNPWT increased the noninfectious complication risk after primary TKA (RR 4.71, P < .0001), especially causing wound blistering (RR 12.66, P < .0001). ciNPWT decreased hospital length of stay by 0.73 days (P = .04) and reoperation rate (RR 0.28, P = .01).

CONCLUSION

ciNPWT decreases SSI risk compared to standard dressings after revision TJA, but not primary TJA. ciNPWT is associated with >12-fold increased risk of wound blistering after primary TKA. ciNPWT plays a role in revision TJA management, but additional randomized controlled trials with uniform wound assessment methods must be performed to sufficiently power findings and draw conclusions on the use of ciNPWT after primary TJA.

Evaluation of Incisional Negative Pressure Wound Therapy in the Prevention of Surgical Site Occurrences After Radical Cystectomy: A New Addition to Enhanced Recovery After Surgery Protocol

BACKGROUND

Surgical site infection (SSI) remains a significant complication after radical cystectomy (RC). Enhanced recovery after surgery (ERAS) focuses on interventions to decrease length of stay, but few address wound-related complications directly.

OBJECTIVE

To determine the impact that prophylactic incisional negative pressure wound therapy (iNPWT) will have to reduce the rate of surgical site occurrences (SSOs = SSI + seroma + superficial dehiscence) after RC.

DESIGN, SETTINGS, AND PARTICIPANTS

We retrospectively reviewed patients undergoing RC by a single surgeon from 2012 to 2017. As part of our ERAS pathway, we employed prophylactic iNPWT during abdominal closure and compared it with a contemporary cohort of standard wound closure.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We compared 90-d SSIs, SSOs, and readmissions between iNPWT and standard skin staple closure. Univariate and multivariate regressions were used to compare the two groups.

RESULTS AND LIMITATIONS

We identified 158 (104 iNPWT, 54 standard) patients from 2012 to 2017. The rates of SSIs and SSOs were 9.7% and 19.0%, respectively. The overall readmission rate for the cohort was 21.5%, with 4.4% of patients requiring readmission for SSI. The iNPWT group had lower rates of SSIs (5.8% vs 16.7%, p = 0.03) and SSOs (11.5% vs 33.3%, p < 0.01). There was no difference between the groups for readmission (21.1% vs 22.2%, p = 0.5). The iNPWT protected against both SSI (odds ratio [OR] 0.89, 95% confidence interval [CI]: 0.81-0.98) and 90-d SSO (OR 0.77, 95% CI: 0.68-0.87).

CONCLUSIONS

Prophylactic iNPWT is feasible after RC with a modest decrease in both 90-d SSIs and 90-d SSOs, but not readmissions. Wound closure assisted by iNPWT should be considered in RC ERAS pathways.

PATIENT SUMMARY

In this report, we looked at the impact of new vacuum suction dressing on the prevention of surgical infections after radical cystectomy (RC). We found that this wound dressing can decrease the impact of surgical infections and aid in recovery after RC.

Limb salvage procedure in immunocompromised patients with therapy-resistant leg ulcers-The value of ultra-radical debridement and instillation negative-pressure wound therapy

The purpose of this study was to analyse the outcome of our established triple treatment strategy in therapy‐resistant deep‐thickness chronic lower leg ulcers. This limb salvage approach consists of ultra‐radical surgical debridement, negative‐pressure wound therapy (NPWT) with or without instillation, and split‐thickness skin grafting. Between March 2003 and December 2019, a total of 16 patients and 24 severe cases of lower leg ulcers were eligible for inclusion in this highly selective population. A total of seven patients received immunosuppressive medication. Complete wound closure was achieved in 25% and almost 90% of included lower leg ulcer cases after 3 and 24 months of our triple treatment strategy, respectively. The overall limb salvage rate was 100%. Bacterial colonisation of these wounds was significantly reduced after multiple surgical debridements and NPWT. Fasciotomy and radical removal of devitalised tissue such as deep fascia, tendons, and muscles combined with NPWT showed promising results in terms of the overall graft take rate. This treatment strategy was considered as last resort for limb salvage in such a critically ill and immunocompromised patient population. Surgeons should be aware of its efficacy and consider the triple treatment strategy especially if no other limb salvage option remains.

Topical negative-pressure wound therapy: emerging devices and techniques

Introduction: The treatment of chronic wounds constitutes a massive financial burden to society and our health-care system. Therefore, efficient wound care is of great importance to all kinds of medical fields. The implementation and modification of negative-pressure wound therapy can be seen as a major improvement in wound healing. Many different NPWT applications evolved trying to address various wound etiologies.Areas covered: This review aims to give an overview of various NPWT applications, show its effects on wound healing, and discuss future modifications.Expert opinion: NPWT as a delivery device for cold plasma, growth factors, or targeted stem cells to the wound bed and the ability to monitor the inflammatory activity, bacterial load and wound healing factors can be seen as possible future steps to individualized wound care. In addition, it requires high-quality experimental studies to develop the ideal foam in terms of microstructure, pore size, and material properties.

Management of Surgical Incisions Using Incisional Negative-Pressure Therapy

Use of negative-pressure therapy (NPT) is a well-established therapy for chronic, open, contaminated wounds, promoting formation of granulation tissue and healing. The application of NPT after primary closure (ie, incisional NPT) has also been shown to reduce surgical site infection and surgical site occurrence in high-risk procedures across multiple disciplines. Incisional NPT is believed to decrease edema and shear stress, promote angiogenesis and lymphatic drainage, and increase vascular flow and scar formation. Incisional NPT may be considered when there is a high risk of surgical site occurrence or surgical site infection, particularly in procedures with nonautologous implants, such as hernia mesh or other permanent prosthetics. Here we discuss the proposed physiologic mechanism as demonstrated in animal models and review clinical outcomes across multiple specialties.

The Long-Term Outcomes Following the Application of Intralesional Epidermal Growth Factor in Patients With Diabetic Foot Ulcers

Epidermal growth factor is used as an adjuvant to close the wound in addition to standard care in diabetic foot ulcers. This study aimed to investigate the long-term outcomes after intralesional epidermal growth factor injections in the treatment of diabetic foot ulcers. Thirty-six feet of 34 patients (n = 34) with diabetic foot ulcers were included. Patient demographics, Wagner classifications, recurrence and amputation rates, Foot Function Index, Short Form 36, and American Academy of Orthopedic Surgeons Foot and Ankle Module scores were evaluated at the final follow-up examination. The mean age was 61.000 ± 13.743 years. The mean duration of wounds was 240.200 ± 146.385 days. A mean of 18.125 ± 4.494 (range 9 to 24) doses were applied. Wound closure was achieved in 33 of the 36 (91.7%) lesions. A complete response (granulation tissue >75% or wound closure) was observed in 29 (87.9%) lesions. The mean time to wound closure was 52.08 ± 10.65 (range 25 to 72) days. At the 5-year follow-up, 4 patients were lost to follow-up because of exitus owing to diabetic complications. Of the remaining 29 patients, 27 were ulcer free. In 2 patients (2 lesions, 6.9%) toe amputation was performed due to ischemic necrosis. The mean Foot Function Index, American Academy of Orthopedic Surgeons Foot and Ankle Core Scale, and AAOS Shoe Comfort Scale scores were 55.40 ± 12.15, 65.92 ± 17.56, and 56.42 ± 11.98, respectively. Complete wound healing and a low recurrence and amputation rates could be obtained with intralesional epidermal growth factor added to the standard treatment protocol.

Influence of negative pressure wound therapy on peri-prosthetic tissue vascularization and inflammation around porous titanium percutaneous devices

Negative Pressure Wound Therapy (NPWT) has been shown to limit downgrowth around percutaneous devices in a guinea pig model. However, the influence of NPWT on peri-prosthetic tissue characteristics leading to limited downgrowth is still unclear. In order to investigate this, 12 CD hairless rats were assigned into two groups, NPWT and Untreated (n = 6/group). Each animal was implanted with a porous coated titanium percutaneous device and was dressed with a gauze and semi-occlusive base dressing. Post-surgery, animals in the NPWT Group received a regimen of NPWT treatment (-70 to -90 mmHg). After 4 weeks, tissue was collected over the device and stained with CD31 and CD68 to quantify blood vessel density and inflammation, respectively. The device with the surrounding tissue was also collected to quantify downgrowth. NPWT treatment led to a 1.6-fold increase in blood vessel densities compared to untreated tissues (p < 0.05). NPWT treatment also resulted in half the downgrowth as the Untreated Group, although not statistically significant (p = 0.19). Additionally, the results showed a trend toward increased CD68 cell densities in the NPWT Group compared to the Untreated Group (p = 0.09). These findings suggest that NPWT may influence wound healing responses in percutaneous devices by increasing blood vessel densities, limiting downgrowth and potentially increasing inflammation. Overall, NPWT may enhance tissue vascularity around percutaneous devices, especially in patients with impaired wound healing. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2091-2101, 2019.

Mechanical Forces in Cutaneous Wound Healing: Emerging Therapies to Minimize Scar Formation

Significance: Excessive scarring is major clinical and financial burden in the United States. Improved therapies are necessary to reduce scarring, especially in patients affected by hypertrophic and keloid scars. Recent Advances: Advances in our understanding of mechanical forces in the wound environment enable us to target mechanical forces to minimize scar formation. Fetal wounds experience much lower resting stress when compared with adult wounds, and they heal without scars. Therapies that modulate mechanical forces in the wound environment are able to reduce scar size. Critical Issues: Increased mechanical stresses in the wound environment induce hypertrophic scarring via activation of mechanotransduction pathways. Mechanical stimulation modulates integrin, Wingless-type, protein kinase B, and focal adhesion kinase, resulting in cell proliferation and, ultimately, fibrosis. Therefore, the development of therapies that reduce mechanical forces in the wound environment would decrease the risk of developing excessive scars. Future Directions: The development of novel mechanotherapies is necessary to minimize scar formation and advance adult wound healing toward the scarless ideal. Mechanotransduction pathways are potential targets to reduce excessive scar formation, and thus, continued studies on therapies that utilize mechanical offloading and mechanomodulation are needed.

Effects of topical negative pressure therapy on tissue oxygenation and wound healing in vascular foot wounds

OBJECTIVE

Topical negative pressure (TNP) therapy is widely used in the treatment of acute wounds in vascular patients on the basis of proposed multifactorial benefits. However, numerous recent systematic reviews have concluded that there is inadequate evidence to support its benefits at a scientific level. This study evaluated the changes in wound volume, surface area, depth, collagen deposition, and tissue oxygenation when using TNP therapy compared with traditional dressings in patients with acute high-risk foot wounds.

METHODS

This study was performed with hospitalized vascular patients. Forty-eight patients were selected with an acute lower extremity wound after surgical débridement or minor amputation that had an adequate blood supply without requiring further surgical revascularization and were deemed suitable for TNP therapy. The 22 patients who completed the study were randomly allocated to a treatment group receiving TNP or to a control group receiving regular topical dressings. Wound volume and wound oxygenation were analyzed using a modern stereophotographic wound measurement system and a hyperspectral transcutaneous oxygenation measurement system, respectively. Laboratory analysis was conducted on wound biopsy samples to determine hydroxyproline levels, a surrogate marker to collagen.

RESULTS

Differences in clinical or demographic characteristics or in the location of the foot wounds were not significant between the two groups. All patients, with the exception of two, had diabetes. The two patients who did not have diabetes had end-stage renal failure. There was no significance in the primary outcome of wound volume reduction between TNP and control patients on day 14 (44.2% and 20.9%, respectively; P = .15). Analyses of secondary outcomes showed a significant result of better healing rates in the TNP group by demonstrating a reduction in maximum wound depth at day 14 (36.0% TNP vs 17.6% control; P = .03). No significant findings were found for the other outcomes of changes in hydroxyproline levels (58.0% TNP vs 94.5% control; P = .32) or tissue perfusion by tissue oxyhemoglobin saturation (19.4% TNP vs 12.0% control; P = .07) at day 14. At 1 year of follow-up, there were no significant outcomes in the analysis of wound failure, major amputation, and overall survival rates between the two groups.

CONCLUSIONS

In this pilot study, applying TNP to acute high-risk foot wounds in patients with diabetes or end-stage renal failure improved the wound healing rate in reference to wound depth. This suggests that TNP may play a role in enhancing wound healing. This study sets the foundation for larger studies to evaluate the superiority of TNP over traditional dressings in high-risk foot wounds.

Computational modelling of wounded tissue subject to negative pressure wound therapy following trans-femoral amputation

Proof-of-concept computational models were developed and applied as tools to gain insights into biomechanical interactions and variations of oxygen gradients of wounded tissue subject to negative pressure wound therapy (NPWT), following trans-femoral amputation. A macro-scale finite-element model of a lower limb was first developed based on computed tomography data, and distributions of maximum and minimum principal stress values we calculated for a region of interest (ROI). Then, the obtained results were applied iteratively as new sets of boundary conditions for a specific spatial position in a capillary sub-model. Data from coupled capillary stress and mass- diffusion sub-models were transferred to the macro-scale model to map the spatial changes of tissue oxygen gradients in the ROI. The −70 mmHg NPWT resulted in a dramatic change of a wound surface area and the greatest relative contraction was observed at −150 mmHg. Tissue lateral to the depth of the wound cavity revealed homogenous patterns of decrease in oxygenation area and the extent of such decrease was dependent on the distance from the wound surface. However, tissue lateral to the width of the wound demonstrated heterogeneous patterns of change, as evidenced by both gradual increase and decrease in the oxygenation area. The multiscale models developed in the current study showed a significant influence of NPWT on both macro-deformations and changes of tissue oxygenation. The patterns of changes depended on the depth of the tissue, the geometry of the wound, and also the location of tissue plane.

Phase II Randomized Trial of Negative-Pressure Wound Therapy to Decrease Surgical Site Infection in Patients Undergoing Laparotomy for Gastrointestinal, Pancreatic, and Peritoneal Surface Malignancies

BACKGROUND

Surgical site infections (SSIs) remain a major source of morbidity and cost after resection of intra-abdominal malignancies. Negative-pressure wound therapy (NPWT) has been reported to significantly reduce SSIs when applied to the closed laparotomy incision. This article reports the results of a randomized clinical trial examining the effect of NPWT on SSI rates in surgical oncology patients with increased risk for infectious complications.

STUDY DESIGN

From 2012 to 2016, two hundred and sixty-five patients who underwent open resection of intra-abdominal neoplasms were stratified into 3 groups: gastrointestinal (n = 57), pancreas (n = 73), or peritoneal surface (n = 135) malignancy. They were randomized to receive NPWT or standard surgical dressing (SSD) applied to the incision from postoperative days 1 through 4. Primary outcomes of combined incisional (superficial and deep) SSI rates were assessed up to 30 days after surgery.

RESULTS

There were no significant differences in superficial SSIs (12.8% vs 12.9%; p > 0.99) or deep SSI (3.0% vs 3.0%; p > 0.99) rates between the SSD and NPWT groups, respectively. When stratified by type of surgery, there were still no differences in combined incisional SSI rates for gastrointestinal (25% vs 24%; p > 0.99), pancreas (22% vs 22%; p > 0.99), and peritoneal surface malignancy (9% vs 9%; p > 0.99) patients. When performing univariate and multivariate logistic regression analysis of demographic and operative factors for the development of combined incisional SSI, the only independent predictors were preoperative albumin (p = 0.0031) and type of operation (p = 0.018).

CONCLUSIONS

Use of NPWT did not significantly reduce incisional SSI rates in patients having open resection of gastrointestinal, pancreatic, or peritoneal surface malignancies. Based on these results, at this time NPWT cannot be recommended as a therapeutic intervention to decrease infectious complications in these patient populations.

Deconstructing negative pressure wound therapy

Since its introduction 20 years ago for the treatment of chronic wounds, negative pressure wound therapy use has expanded to a variety of other wound types. Various mechanisms of action for its efficacy in wound healing have been postulated, but no unifying theory exists. Proposed mechanisms include induction of perfusion changes, microdeformation, macrodeformation, exudate control and decreasing the bacterial load in the wound. We surmise that these different mechanisms have varying levels of dominance in each wound type. Specifically, negative pressure wound therapy is beneficial to acute open wounds because it induces perfusion changes and formation of granulation tissue. Post-surgical incisional wounds are positively affected by perfusion changes and exudate control. In the context of chronic wounds, negative pressure wound therapy removes harmful and corrosive substances within the wounds to affect healing. When skin grafts and dermal substitutes are used to close a wound, negative pressure wound therapy is effective in promoting granulation tissue formation, controlling exudate and decreasing the bacterial load in the wound. In this review, we elucidate some of the mechanisms behind the positive wound healing effects of negative pressure wound therapy, providing possible explanations for these effects in different wound types.

Negative Pressure Wound Therapy in the Management of Combat Wounds: A Critical Review

Significance: Wounds sustained in a combat trauma often result in a composite tissue loss. Combat injuries, due to high energy transfer to tissues, lead to trauma at multiple anatomical sites. An early wound cover is associated with lower rate of infections and a faster wound healing. The concept of negative pressure wound therapy (NPWT) in the management of combat-related wounds has evolved from the civilian trauma and the wounds from nontraumatic etiologies. Recent Advances: Encouraged by the results of NPWT in noncombat-related wounds, the military surgeons during Operation Iraqi Freedom and Operation Enduring Freedom used this novel method in a large percentage of combat wounds, with gratifying results. The mechanism of NPWT in wound healing is multifactorial and often complex reconstructive procedure can be avoided in a combat trauma setting. Critical Issues: Wounds sustained in military trauma are heavily contaminated with dirt, patient clothing, and frequently associated with extensive soft tissue loss and osseous destruction. Delay in evacuation during an ongoing conflict carries the risk of systemic infection. Early debridement is indicated followed by delayed closure of wounds. NPWT helps to provide temporary wound cover during the interim period of debridement and wound closure. Future Directions: Future area of research in combat wounds is related to abdominal trauma with loss of abdominal wall. The concept of negative pressure incisional management system in patients with a high risk of wound breakdown following surgery is under review, and may be of relevance in combat wounds.

Meta-analysis of negative-pressure wound therapy for closed surgical incisions

Background

Postoperative wound complications are common following surgical procedures. Negative‐pressure wound therapy (NPWT) is well recognized for the management of open wounds and has been applied recently to closed surgical incisions. The evidence base to support this intervention is limited. The aim of this study was to assess whether NPWT reduces postoperative wound complications when applied to closed surgical incisions.

Methods

This was a systematic review and meta‐analysis of randomized clinical trials of NPWT compared with standard postoperative dressings on closed surgical incisions.

Results

Ten studies met the inclusion criteria, reporting on 1311 incisions in 1089 patients. NPWT was associated with a significant reduction in wound infection (relative risk (RR) 0·54, 95 per cent c.i. 0·33 to 0·89) and seroma formation (RR 0·48, 0·27 to 0·84) compared with standard care. The reduction in wound dehiscence was not significant. The numbers needed to treat were three (seroma), 17 (dehiscence) and 25 (infection). Methodological heterogeneity across studies led to downgrading of the quality of evidence to moderate for infection and seroma, and low for dehiscence.

Conclusion

Compared with standard postoperative dressings, NPWT significantly reduced the rate of wound infection and seroma when applied to closed surgical wounds. Heterogeneity between the included studies means that no general recommendations can be made yet.

Good for closed wounds too

Video Abstract

Clinical evaluation of improvised gauze-based negative pressure wound therapy in military wounds

The use of negative pressure wound therapy (NPWT) in civilian and military wounds is found effective in promoting granulation tissue, decreasing exudate and improving patient comfort. The Use of gauze-based NPWT is increasing in civilian trauma cases with availability of proprietary systems using gauze as filler material rather than the traditionally used reticulated open-cell foam. Military trauma wounds differ from civilian trauma wounds in energy of impact, degree and nature of contamination as well as the hostile environments. The Use of gauze as filler material for NPWT in military trauma wounds is less well studied. This study is a retrospective analysis of use of improvised gauze-based NPWT in military trauma wounds. The whole assembly was constructed from commonly available operation theatre supplies and no proprietary system was used. Results were very encouraging and the use of this improvised method can be useful and cheap alternative to costly proprietary systems.

The flaws of laser Doppler in negative-pressure wound therapy research

Recent studies, using modalities other than laser Doppler, have indicated that perfusion during negative-pressure wound therapy (NPWT) is reduced, contrary to world literature. The aim of the present study was to evaluate whether the measuring technique of the laser Doppler could be influenced by the compressive nature of NPWT dressings and whether this could explain the conflicting findings. A hypothesis that it may be possible for laser Doppler to record similar readings to those obtained during NPWT by merely compressing tissues manually was tested on 12 NPWT dressings, with each undergoing an alternating series of manual compressive forces and NPWT (-125 mmHg). During the periods of NPWT (n = 12), the mean perfusion recording increased in five experiments, reduced in six, and remained unchanged in one. During the period when manual pressure was applied (n = 12), there was a mean increase in perfusion in six experiments and a reduction in six. The type of change in perfusion (increase or decrease) was the same for both NPWT and manual pressure in 10 of the 12 experiments. In conclusion, laser Doppler can incorrectly record increased perfusion when tissues are compressed, implying that it is flawed in the field of NPWT research as tissues are always compressed to some degree by the NPWT dressing.

Negative pressure wound therapy: experience in 45 dogs

OBJECTIVE

To report experience with negative pressure wound therapy (NPWT) in 45 consecutive dogs admitted with extensive cutaneous wounds and to determine if NPWT is feasible in veterinary hospital practice.

STUDY DESIGN

Prospective descriptive study.

ANIMALS

Dogs (n = 45).

METHODS

Collected data were organized into 6 categories: patient data, wound data, NPWT data, adjunctive treatments, complications, and final outcome.

RESULTS

Wounds (53 in 45 dogs) were largely traumatic in origin, and distributed fairly evenly to the trunk, proximal and distal aspects of the limbs. Most wounds (34 dogs, 76%) had no granulation tissue and were treated a mean of 4.2 days after wounding, whereas 11 dogs had granulating wounds that were initially treated a mean of 87 days after wounding. Median NPWT use was 3 days with a mean hospitalization of 7.8 days. Most wounds (33; 62%) were closed surgically after NPWT and were healed by 14 days. The other 18 wounds healed (mean, 21 days) by second intention after hospital discharge. Overall, 96% of the wounds healed; 2 dogs died before definitive closure could be attempted.

CONCLUSION

NPWT is applicable to a wide variety of canine wounds, is well tolerated, allows for several days between dressing changes, and can used to optimize the wound bed for surgical closure or second intention healing.

Negative pressure wound therapy for managementof the surgical incision in orthopaedic surgery: A review of evidence and mechanisms for an emerging indication

Objectives

The period of post-operative treatment before surgical wounds are completely closed remains a key window, during which one can apply new technologies that can minimise complications. One such technology is the use of negative pressure wound therapy to manage and accelerate healing of the closed incisional wound (incisional NPWT).

Methods

We undertook a literature review of this emerging indication to identify evidence within orthopaedic surgery and other surgical disciplines. Literature that supports our current understanding of the mechanisms of action was also reviewed in detail.

Results

A total of 33 publications were identified, including nine clinical study reports from orthopaedic surgery; four from cardiothoracic surgery and 12 from studies in abdominal, plastic and vascular disciplines. Most papers (26 of 33) had been published within the past three years. Thus far two randomised controlled trials – one in orthopaedic and one in cardiothoracic surgery – show evidence of reduced incidence of wound healing complications after between three and five days of post-operative NPWT of two- and four-fold, respectively. Investigations show that reduction in haematoma and seroma, accelerated wound healing and increased clearance of oedema are significant mechanisms of action.

Conclusions

There is a rapidly emerging literature on the effect of NPWT on the closed incision. Initiated and confirmed first with a randomised controlled trial in orthopaedic trauma surgery, studies in abdominal, plastic and vascular surgery with high rates of complications have been reported recently. The evidence from single-use NPWT devices is accumulating. There are no large randomised studies yet in reconstructive joint replacement.

Cite this article: Bone Joint Res 2013;2:276–84.

Should infected laparotomy wounds be treated with negative pressure wound therapy?

A best evidence topic in surgery was written according to a structured protocol. The question addressed whether there is any benefit in treating infected laparotomy wounds with negative pressure wound therapy (NPWT). Forty-five papers were found using the reported search; of which 4 represented the best evidence to answer the question. The evidence on this subject is limited; there is a single non-randomised controlled trial, 2 prospective cohort studies, and 1 retrospective cohort study discussed in this paper. From the available literature, the use of NPWT in infected laparotomy wounds does reduce the length of hospital stay, the number of dressing changes required and promote faster wound healing.

Effects of negative pressure wound therapy on healing of free full-thickness skin grafts in dogs

OBJECTIVE

To compare healing of free, full-thickness, meshed skin grafts under negative pressure wound therapy (NPWT) with bolster dressings in dogs.

STUDY DESIGN

Randomized, controlled experimental study, paired design.

ANIMALS

Dogs (n = 5) METHODS: Full-thickness skin wounds (4 cm × 1.5 cm) were created bilaterally on the antebrachia of 5 dogs (n = 10). Excised skin was grafted to the contralateral limb. Grafts were randomized to NPWT or bolster dressings (control; CON). NPWT was applied continuously for 7 days. Grafts were evaluated on Days 2, 4, 7, 10, 14, and 17, biopsied on days 0, 4, 7, and 14, and had microbial culture on Day 7. Outcome variables were: time to first appearance of granulation tissue, percent graft necrosis, and percent open mesh. Significance was set at P < .05. Histologic findings, culture results, and graft appearance were reported.

RESULTS

Granulation tissue appeared earlier in the NPWT grafts compared with CON grafts. Percent graft necrosis and remaining open mesh area were both greater in CON grafts compared with NPWT grafts at most time points. Histologic results showed no significant difference in all variables measured, and all cultures were negative.

CONCLUSIONS

Variables of graft acceptance were superior when NPWT was used in the first week post-grafting. Fibroplasia was enhanced, open meshes closed more rapidly and less graft necrosis occurred with NPWT application. More preclinical studies are required to evaluate histologic differences.

Soft tissue mechanotransduction in wound healing and fibrosis

Recent evidence suggests that mechanical forces can significantly impact the biologic response to injury. Integrated mechanical and chemical signaling networks have been discovered that enable physical cues to regulate disease processes such as pathologic scar formation. Distinct molecular mechanisms control how tensional forces influence wound healing and fibrosis. Conceptual frameworks to understand cutaneous repair have expanded beyond traditional cell-cytokine models to include dynamic interactions driven by mechanical force and the extracellular matrix. Strategies to manipulate these biomechanical signaling networks have tremendous therapeutic potential to reduce scar formation and promote skin regeneration.

Comparative effectiveness of mechanically and electrically powered negative pressure wound therapy devices: a multicenter randomized controlled trial

This study was designed to compare the ultraportable mechanically powered Smart Negative Pressure (SNaP) Wound Care System (Spiracur, Sunnyvale, CA) with the electrically powered Vacuum-Assisted Closure (VAC) Therapy System (Kinetic Concepts, Inc. [KCI], San Antonio, TX) in a multicenter, comparative efficacy, noninferiority-powered, randomized controlled trial. We enrolled 132 people with noninfected, nonischemic, nonplantar lower extremity diabetic and venous wounds. Each subject was randomly assigned (1:1) to treatment with either system in conjunction with appropriate off-loading and compression therapy. The trial evaluated treatment for up to 16 weeks or complete wound closure (defined as complete reepithelialization without drainage). Primary end point analysis of wound size reduction found that SNaP-treated subjects demonstrated noninferiority to the VAC-treated subjects at 4, 8, 12, and 16 weeks (p = 0.0030, 0.0130, 0.0051, and 0.0044, respectively). Kaplan-Meier analysis showed no significant difference in complete wound closure between SNaP- and VAC-treated subjects at all time points. Device related adverse events and complications such as infection were also similar between treatment groups. These data support similar wound healing outcomes between the SNaP system and the VAC system in the population studied.

Use of negative pressure wound therapy for abdominal wounds in neonates and infants

BACKGROUND

Negative pressure wound therapy (NPWT) is an established and effective tool in the management of complicated abdominal wounds. This management approach has been used in infants, but few large series reports exist in the literature.

METHODS

The outcomes of infants with abdominal wounds receiving NPWT over the last 10 years at our institution were evaluated. Overall survival, time between initiation of NPWT, and discharge/death were examined.

RESULTS

We identified 18 infants who had abdominal wounds treated with NPWT. Diagnoses were varied, as was the duration of therapy. The median NPWT duration of treatment was 34.0 ± 92.1 days. Forty-four percent of the infants had a stoma before application of NPWT, and 22% of the infants had enterocutaneous fistulas before use of NPWT. There were only 2 cases in which a new fistula developed during the use of NPWT, and both of these omphalopagus conjoined twins had undergone the Bianchi procedure. No additional NPWT-related complications were identified. Of 18 infants, 6 died in this cohort.

CONCLUSION

Negative pressure wound therapy is an important therapeutic tool for the management of abdominal wounds in infants.

Non-invasive assessment of negative pressure wound therapy using high frequency diagnostic ultrasound: oedema reduction and new tissue accumulation

Tissue oedema plays an important role in the pathology of chronic and traumatic wounds. Negative pressure wound therapy (NPWT) is thought to contribute to active oedema reduction, yet few studies have showed this effect. In this study, high frequency diagnostic ultrasound at 20 MHz with an axial resolution of 60 µm was used to assess the effect of NPWT at - 80 mmHg on pressure ulcers and the surrounding tissue. Wounds were monitored in four patients over a 3-month period during which changes in oedema and wound bed thickness (granulation tissue) were measured non-invasively. The results showed a rapid reduction of periwound tissue oedema in all patients with levels falling by a mean of 43% after 4 days of therapy. A 20% increase in the thickness of the wound bed was observed after 7 days due to new granulation tissue formation. Ultrasound scans through the in situ gauze NPWT filler also revealed the existence of macrodeformation in the tissue produced by the negative pressure. These preliminary studies suggest that non-invasive assessment using high frequency diagnostic ultrasound could be a valuable tool in clinical studies of NPWT.

The challenges of managing a complex stoma with NPWT

This paper reports the clinical experience of a 71-year-old female with resection of the colon, who subsequently developed postoperative complications. A colostomy was carried out; necrosis of the colostomy edges and stoma retraction complicated optimal stoma appliance placement. It was possible to treat the resulting cavity with negative pressure wound therapy (NPWT) by isolating the stoma and treating the peristomal wound area. The wound was treated with NPWT for 30 days; at day 20, the patient was discharged to home to continue with NPWT for a further 10 days by community nurses, with regular follow-up visits in the outpatient clinic. The patient improved steadily and achieved complete closure of the wound.

Skin disinfection by plasma-tissue interaction: comparison of the effectivity of tissue-tolerable plasma and a standard antiseptic

Wound healing disorders frequently occur due to biofilm formation on wound surfaces requiring conscientious wound hygiene. Often, the application of conventional liquid antiseptics is not sufficient and sustainable as (1) the borders and the surrounding of chronic wounds frequently consist of sclerotic skin, impeding an effectual penetration of these products, and (2) the hair follicles representing the reservoir for bacterial recolonization of skin surfaces are not affected. Recently, it has been reported that tissue-tolerable plasma (TTP), which is used at a temperature range between 35 and 45°C, likewise has disinfecting properties. In the present study, the effectivity of TTP and a standard liquid antiseptic was compared in vitro on porcine skin. The results revealed that TTP was able to reduce the bacterial load by 94%, although the application of the liquid antiseptic remained superior as it reduced the bacteria by almost 99%. For in vivo application, however, TTP offers several advantages. On the one hand, TTP enables the treatment of sclerotic skin as well, and on the other hand, a sustainable disinfection can be realized as, obviously, also the follicular reservoir is affected by TTP.

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.