Negative pressure wound therapy with instillation: a pilot study describing a new method for treating infected wounds

This data review reports the results of 15 patients who were treated with Vacuum-Assisted Closure (VAC) negative pressure therapy system in addition to the timed, intermittent delivery of an instilled topical solution for management of their complex, infected wounds. Prospective data for 15 patients treated with negative pressure wound therapy (NPWT)-instillation was recorded and analysed. Primary endpoints were compared to a retrospective control group of 15 patients treated with our institution's standard moist wound-care therapy. Culture-specific systemic antibiotics were prescribed as per specific patient need in both groups. All data were checked for normality of distribution and equality of variance and appropriate parametric and non parametric analyses were conducted. Compared with the standard moist wound-care therapy control group, patients in the NPWT-instillation group required fewer days of treatment (36.5 +/- 13.1 versus 9.9 +/- 4.3 days, P < 0.001), cleared of clinical infection earlier (25.9 +/- 6.6 versus 6.0 +/- 1.5 days, P < 0.001), had wounds close earlier (29.6 +/- 6.5 versus 13.2 +/- 6.8 days, P < 0.001) and had fewer in-hospital stay days (39.2 +/- 12.1 versus 14.7 +/- 9.2 days, P < 0.001). In this pilot study, NPWT instillation showed a significant decrease in the mean time to bioburden reduction, wound closure and hospital discharge compared with traditional wet-to-moist wound care. Outcomes from this study analysis suggest that the use of NPWT instillation may reduce cost and decrease inpatient care requirements for these complex, infected wounds.     

Negative-pressure wound therapy: a snapshot of the evidence

Topical negative pressure (TNP) is a mode of therapy used to encourage wound healing. It can be used as a primary treatment for chronic/complex wounds or as an adjunct to surgery. Based on the evidence to date, the clinical effectiveness of negative-pressure therapy is still unclear. Although case reports and retrospective studies have demonstrated enhanced wound healing in acute/traumatic wounds, chronic wounds, infected wounds, wounds secondary to diabetes mellitus, sternal wounds and lower limb wounds, there are very few randomised controlled trials, with unclear results. The evidence is lacking for the use of TNP therapy for other indications to enhance wound healing such as patients with decubitus ulcers, diabetes and peripheral vascular disease and to improve skin graft take. There have been, as yet, no quality-of-life studies available for negative-pressure therapy. Despite this, the usage of TNP has increased. This review provides an overview of clinical studies using TNP and proposes avenues for further research to elucidate the exact mechanism of TNP, in addition to large randomised controlled clinical trials of patients undergoing this therapy.     

A systematic review of the effectiveness of negative pressure wound therapy in the management of diabetes foot ulcers

Foot ulcers are a common complication in patients with diabetes. Negative pressure wound therapy (NPWT) is a wound care therapy that is being increasingly used in the management of foot ulcers. This article presents a systematic review examining the effectiveness of this therapy. The review question is how effective is NPWT in achieving wound healing in diabetes foot ulcers? The primary outcome for this study was the number of patients achieving complete wound healing (secondary outcomes, other markers of wound healing, adverse events and patient satisfaction). A systematic literature review and tabulative synthesis of randomised controlled trials (RCTs). The review identified four RCTs of weak to moderate quality. Only one study examining NPWT in postamputation wound healing reported data on the primary outcome. These data show a 20% improvement in wound healing [odds ratios = 2·0%, confidence interval (CI) ?1·0 to 4·0] and number needed to treat = 6 (CI 4–64). No serious treatment‐related complications were reported by any of the studies. One study suggested a reduction in the risk of secondary amputation (absolute risk reduction = 7·9%, CI 0·5–15·43). Studies also reported an increase in granulation and wound‐healing rates in patients treated with NPWT therapy. No data on patient satisfaction or experience were reported. While all the studies included in the review indicated that the NPWT therapy is more effective than conventional dressings, the quality of the studies were weak and the nature of the inquiries in terms of outcome and patient selection divergent. There is a strong need for larger trials to assess NPWT therapy in diabetes care with different groups of patients and in relation to different clinical objectives and parameters.     

A comparison of diabetic foot ulcer outcomes using negative pressure wound therapy versus historical standard of care

Diabetic foot ulcers (DFUs) are a leading cause of morbidity and hospitalisation among patients with diabetes. We analysed claims data for Medicare part B diabetic foot ulcer patients treated with Negative Pressure Wound Therapy at home (N = 1135) and diabetic foot ulcer patients from a published meta-analysis of randomised controlled wet-to-moist therapy. The expected costs of care for the two treatments were also compared. A significantly greater proportion of wounds treated with NPWT achieved a successful treatment endpoint compared with wet-to-moist therapy at both 12 weeks (39.5% versus 23.9%; P < 0.001) and 20 weeks (46.3% versus 32.8%; P < 0.001). NPWT-treated patients reached a successful wound treatment endpoint more rapidly, and the benefit was apparent in all wound sizes. Expected 20-week treatment costs for NPWT were similar to those for wet-to-moist therapy if one nursing visit per day for the latter is assumed but 42% less if two nursing visits per day are made. Thus, NPWT may improve the proportion of DFUs that attain a successful wound treatment endpoint and decrease resource utilisation by a given health care system compared with standard wet-to-moist therapy.     

Evaluation of vacuum‐assisted closure in patients with wound complications following tumour surgery

Covering the reconstructed area with a healthy soft‐tissue envelope is a major challenge after limb‐sparing surgery in patients with malignant bone and soft‐tissue tumours. Negative pressure wound therapy (NPWT) of open wounds hastens healing and minimises the requirement for complex reconstructive soft‐tissue surgery. The aim of this study was to investigate the effectiveness and safety of NPWT in bone and soft‐tissue malignant tumour patients with postoperative wound complications. Between January 2006 and November 2009, at a single institution, 13 patients with malignant bone and soft‐tissue tumours who had undergone wide resection were retrospectively analysed. NPWT was performed in all patients to temporarily close the soft‐tissue defects. After obtaining the culture negativity and normal infection markers, definitive soft‐tissue reconstruction was performed to close the wound with primary suturisation in two patients, split thickness grafts in four patients, full thickness grafts in two patients, rotational flaps in three patients and free flaps in two patients. Mean duration of hospitalisation was 20 (range 8–48) days and mean follow‐up period was 57·3 (range 50–74) months. There was no tumour recurrence or skip metastasis in the follow‐up period. In addition, there was no periprosthetic infection or complication associated with NPWT. In conclusion, NPWT therapy seems to be a safe and effective option in the management of local wound problems and secondary surgical site infections after musculoskeletal tumour surgery.     

Retrospective evaluation of clinical outcomes in subjects with split‐thickness skin graft: comparing V.A.C.® therapy and conventional therapy in foot and ankle reconstructive surgeries

This retrospective study compared the clinical outcomes of negative pressure wound therapy with reticulated open cell foam (NPWT/ROCF) as delivered by Vacuum‐Assisted Therapy^® (V.A.C.^® Therapy, KCI Licensing Inc., San Antonio, TX) to non‐NPWT/ROCF conventional therapy (CT) in split‐thickness skin graft (STSG) survival in all patients to determine whether NPWT/ROCF affects the outcome of the graft survival, in terms of overall graft take, duration of graft take, repeated grafts and complications. The authors conducted a 10‐year retrospective review of 142 patients admitted to a level I trauma centre and treated with an STSG in foot and ankle reconstructive surgeries. Demographic data, wound etiology, dressing type used, time to graft take, NPWT/ROCF duration, complications and outpatient treatments were analysed. There were significantly fewer repeated STSGs required in the NPWT/ROCF group compared to CT [n = 3 (3·5%) versus n = 9 (16%); P = 0·006]. In assessing safety, there were fewer complications in graft failure (seroma, hematoma and infection) in the NPWT/ROCF group as compared to the CT group at 8·9 months (range: 1–12 months). NPWT/ROCF is an excellent alternative for securing an STSG and is associated with improved graft survival as measured by a reduction in the number of repeated STSGs and graft failure complications.     

Use of negative pressure wound therapy in the management of infected abdominal wounds containing mesh: an analysis of outcomes

The purpose of this study was to examine the clinical outcomes of negative pressure wound therapy (NPWT) using reticulated open-cell foam (ROCF) in the adjunctive management of abdominal wounds with exposed and known infected synthetic mesh. A non randomised, retrospective review of medical records for 21 consecutive patients with infected abdominal wounds treated with NPWT was conducted. All abdominal wounds contained exposed synthetic mesh [composite, polypropylene (PP), or knitted polyglactin 910 (PG) mesh]. Demographic and bacteriological data, wound history, pre-NPWT and comparative post-NPWT, operative procedures and complications, hospital length of stay (LOS) and wound healing outcomes were all analysed. Primary endpoints measured were (1) hospital LOS prior to initiation of NPWT, (2) total time on NPWT, (3) hospital LOS from NPWT initiation to discharge and (4) wound closure status at discharge. A total of 21 patients with abdominal wounds with exposed, infected mesh were treated with NPWT. Aetiology of the wounds was ventral hernia repair (n = 11) and acute abdominal wall defect (n = 10). Prior to NPWT initiation, the mean hospital LOS for the composite, PP and PG meshes were 76 days (range: 21-171 days), 51 days (range: 32-62 days) and 19 days (range: 12-39 days), respectively. The mean hospital LOS following initiation of NPWT for wounds with exposed composite, PP and PG mesh were 28, 31 and 32 days, respectively. Eighteen of the 21 wounds (86%) reached full closure after a mean time of 26 days of NPWT and a mean hospital LOS of 30 days postinitiation of NPWT. Three wounds, all with composite mesh left in situ, did not reach full closure, although all exhibited decreased wound dimensions, granulating beds and decreased surface area exposure of mesh. During NPWT/ROCF, one hypoalbuminemic patient with exposed PP mesh developed an enterocutaneous fistula over a prior enterotomy site. This patient subsequently underwent total mesh extraction, takedown of the fistula and PP mesh replacement followed by reinstitution of NPWT and flap closure. In addition to appropriate systemic antibiotics and nutritional optimisation, the adjunctive use of NPWT resulted in successful closure of 86% of infected abdominal wounds with exposed prosthetic mesh. Patient hospital LOS (except those with PG mesh), operative procedures and readmissions were decreased during NPWT compared with treatment prior to NPWT. Future multi-site prospective, controlled studies would provide a strong evidence base from which treatment decisions could be made in the management of these challenging and costly cases.     

Hip ulcer secondary to foreign body reaction and vacuum-assisted closure therapy: report of a case

Patients who have a foreign body reaction are at risk of developing chronic ulcers secondary to necrosis, due to the inflammation present in the affected tissues or trauma, worsened by alterations in the vascular perfusion. These ulcers represent a therapeutic challenge for both physicians and patients.     

VAC therapy to promote wound healing after surgical revascularisation for critical lower limb ischaemia

Vacuum‐assisted closure (VAC) therapy is a new emerging non‐invasive system in wound care, which speeds up wound healing by causing vacuum, improving tissue perfusion and suctioning the exudates, and facilitating the removal of bacteria from the wound. The application of sub‐atmospheric pressure on the lesions seems to alter the cytoskeleton of the cells on the wound bed, triggering a cascade of intracellular signals that increase the rate of cell division and subsequent formation of granulation tissue. The aim of this study is to analyse the results of VAC therapy used as an adjuvant therapy for the treatment of foot wounds in patients affected by critical limb ischaemia (CLI) (Rutherford 6 class) after distal surgical revascularisation, to promote and accelerate the healing of ulcers. Twenty‐nine patients (20 males, 9 females; mean age 68·4) affected by CLI of Rutherford 6 class, after surgical revascularisation of the lower limb, underwent VAC therapy in order to speed up wound healing. Complete wound healing was achieved in 19 patients (65·51%), in an average period of 45·4 ± 25·6 days. VAC therapy is a valid aid, after surgical revascularisation, to achieve rapid healing of foot lesions in patients with CLI.     

Vacuum-assisted closure therapy leads to an increase in plasma fibronectin level

An extensive research has been performed to investigate the mechanisms of action by which the application of subatmospheric pressure to wounds increases the rate of healing. Increased blood flow with vacuum-assisted closure (VAC) use is the most popular aspect. Fibronectin, which is an adhesion molecule, has several functional domains mediating chemotaxis, adhesion and migration. This is thereby involved in differentiation, proliferation, inflammation and thus in wound healing. In this study, plasma fibronectin levels were measured before and after VAC in patients with wounds. The results showed that there was an increase in pre- and post-VAC levels of plasma fibronectin. This statistically significant increase could be another explanation of how VAC therapy promotes wound healing.     

Evidence-based medicine: vacuum-assisted closure in wound care management

A review of the evidence base for the use of vacuum-assisted closure (VAC) therapy is presented, analysing both experimental and clinical data.     

Role of different negative pressure values in the process of infected wounds treated by vacuum‐assisted closure: an experimental study

Vacuum‐assisted closure (VAC) device is widely used to treat infected wounds in clinical work. Although the effect of VAC with different negative pressure values is well established, whether different negative pressures could result in varying modulation of wound relative cytokines was not clear. We hypothesise that instead of the highest negative pressure value the suitable value for VAC is the one which is the most effective on regulating wound relative cytokines. Infected wounds created on pigs' back were used to investigate the effects of varying negative pressure values of VAC devices. Wounds were treated with VAC of different negative pressure values or moist gauze, which was set as control. The VAC foam, semiocclusive dresses and moist gauze were changed on days 3, 5, 7 and 9 after wounds were created. When changing dressings, tissues from wounds were harvested for bacteria count and histology examination including Masson's trichrome stain and immunohistochemistry for microvessels. Western blot was carried out to test the expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Results showed that on days 3 and 5 the number of bacteria in wounds treated by VAC with 75, 150, 225 and 300 mmHg was significantly decreased compared with that in wounds treated by gauze and 0 mmHg pressure value. However, there was no difference in wounds treated with negative pressure values of 75 , 150, 225 and 300 mmHg at any time spot. Immunohistochemistry showed that more microvessels were generated in wounds treated by VAC using 75 and 150 mmHg negative pressure comparing with that using 225 and 300 mmHg on days 3 and 5. However this difference vanished on days 7 and 9. Morphological evaluation by Masson's trichrome staining showed increased collagen deposition in VAC of 75 and 150 mmHg compared with that in VAC of 225 and 300 mmHg. Western blot showed that the expression of VEGF and bFGF significantly increased when the wounds treated with 75 and 150 mmHg negative pressure values compared with the wounds treated with 225 and 300 mmHg on day 5. Treatment using VAC with different negative pressure values more than 75 mmHg has similar efficiency on reducing bacteria in the infected wound. VAC with negative pressure values of 75 and 150 mmHg promote wound healing more quickly than other pressure values. Moreover, comparing with vigorous negative pressure, relatively moderate pressures contribute to wound healing via accelerated granulation growth, increased angiogenic factor production and improved collagen fibre deposition. Further study of this model may show other molecular mechanisms.     

Loxoscelism and negative pressure wound therapy (vacuum‐assisted closure): an experimental study

Brown recluse spider (Loxosceles) bites cause lesions ranging from chronic necrotic ulcers to acute life‐threatening sepsis. Based on our experience in treating acute and chronic wounds with negative pressure, we postulated that vacuum‐assisted closure (VAC) would be valuable in this application. Chester pigs were procured and injected with purified brown recluse spider venom, 1 µl of venom in two anterior sites and 0·1 µl of venom in two posterior sites on their dorsum. For each concentration of venom, treatment consisted of either VAC or dry, non adherent dressings (control group). Each day, the wounds were inspected and measured. For wounds receiving 1·0 µl of venom, the control wounds decreased in surface area to 50% of initial size after 7 days and none had healed, whereas VAC‐treated wounds were less than 50% after 48 hours and completely healed and reepithelialised after 8 days. Wounds with 0·1 µl of venom had 50% reduction after 5 days with no complete healing for control wounds, and the VAC wounds were 50% after 48 hours and all had closed and reepithelialised after 5 days. Our experimental study showed an accelerated healing time in the animals treated with the VAC as compared with controls.     

Management of a complex hind foot war injury with negative pressure wound therapy: A case study

We report the use of Negative Pressure Wound Therapy (NPWT) in a 39 year old patient with a complex open hind foot injury. The patient sustained an open calcaneal fracture with extensive soft tissue damage following the detonation of an explosively formed penetrating round in a confined space. A remarkable recovery was made following surgical debridement, internal fixation of the fracture and use of NPWT over the soft tissue injury. The patient returned to his normal level of function, without complications within a few months.     

A prospective randomized controlled trial comparing negative pressure dressing and conventional dressing methods on split-thickness skin grafts in burned patients

Introduction

Split-thickness skin grafting (SSG) is a technique used extensively in the care of burn patients and is fraught with suboptimal graft take when there is a less-than-ideal graft bed and/or grafting conditions. The technique of Negative Pressure Dressing (NPD), initially used for better wound healing has been tried on skin-grafts and has shown to increase the graft take rates. However, comparative studies between the conventional dressing and vacuum assisted closure on skin grafts in burn patients are unavailable. The present study was undertaken to find out if NPD improves graft take as compared to conventional dressing in burns patients.

Materials and methods

Consecutive burn patients undergoing split-skin grafting were randomized to receive either a conventional dressing consisting of Vaseline gauze and cotton pads or to have a NPD of 80 mm Hg for four days over the freshly laid SSG. The results in terms of amount of graft take, duration of dressings for the grafted area and the cost of treatment of wound were compared between the two groups.

Results

A total of 40 split-skin grafts were put on 30 patients. The grafted wounds included acute and chronic burns wounds and surgically created raw areas during burn reconstruction. Twenty-one of them received NPD and 19 served as controls. Patient profiles and average size of the grafts were comparable between the two groups. The vacuum closure assembly was well tolerated by all patients. Final graft take at nine days in the study group ranged from 90 to 100 per cent with an average of 96.7 per cent (SD: 3.55). The control group showed a graft take ranging between 70 and 100 percent with an average graft take of 87.5 percent (SD: 8.73). Mean duration of continued dressings on the grafted area was 8 days in cases (SD: 1.48) and 11 days in controls (SD: 2.2) after surgery. Each of these differences was found to be statistically significant (p < 0.001).

Conclusion

Negative pressure dressing improves graft take in burns patients and can particularly be considered when wound bed and grafting conditions seem less-than-ideal. The negative pressure can also be effectively assembled using locally available materials thus significantly reducing the cost of treatment.     

Negative pressure wound therapy in complex cranio‐maxillofacial and cervical wounds

The care and the management of the healing of difficult wounds at the level of the skull‐facial face many problems related to patient compliance and the need to perform multiple dressings, with long periods of healing and, occasionally, a very long hospitalisation period. The introduction and evolution of negative pressure wound therapy (NPWT) in the treatment of difficult wounds has resulted in better healing, with a drastic reduction in terms of time and biological costs to the patient and cost to the health care system. The main aim of this study is to describe and discuss, using out our experience, the usefulness of NPWT in the cranial‐facial‐cervical region. We studied 16 patients with complex wounds of the cranial‐facial‐cervical region treated with NPWT. We divided clinical cases in four groups: cervicofacial infectious disease, healing complications in oncological‐reconstructive surgery, healing complications of injury with exposure of bone and/or internal fixations and healing complications in traumatic injury with loss of substance. We evaluated complete or incomplete wound healing; application time, related also to hospitalisation time; days of intensive care unit (ICU) stay; management of the upper airways; timing of medication renewal; and patient comfort and compliance (on a scale of 1–5). Depression values were always between −75 and −125 mmHg in a continuous aspiration pattern. For every patient, we used the ActiVAC Therapy Unit, derived from the vacuum‐assisted closure system (Kinetic Concepts Inc., San Antonio, TX). Medication renewals were performed every 48–72 hours. The NPWT application time ranged from 4 to 22 days (mean of 11·57 day). Therapy was effective to gain a complete restitutio ad integrum in every patient included in the group of cervicofacial infectious disease. Therapy has, however, been well tolerated in our series; this is probably due to the decreased number of applications, the ease of use and the comfort of the system relative to traditional dressing. Results were satisfactory for most of cases treated; faster and more effective wound healing was achieved. The lower number of NPWT applications, relating to standard dressings, led to an increase in patient comfort and compliance and a decrease in the use of medical, and in some cases economic, resources according to international literature.     

Impact of negative pressure wound therapy on open diaphyseal tibial fractures: A prospective randomized trial

IntroductionOpen tibial fractures are associated with a high incidence of mainly osteomyelitis. Negative pressure wound therapy (NPWT) is a novel form of treatment that uses subatmospheric pressure to effect early wound healing.Objectives and study designTo determine the effect of NPWT on incidence of deep infections/osteomyelitis after open tibial fractures using a prospective randomized study design.Materials and methodsNinety-three open tibial fractures were randomized into two groups receiving NPWT and the second group undergoing periodic irrigation, cleaning and debridement respectively. The wounds were closed or covered on shrinkage in size and sufficient granulation. Evidence of infection was sought during the course of treatment and follow up. Also serial cultures were sent every time the wound was cleaned.Results and conclusionsPatients in the control group developed a total of 11 infections (22%) as opposed to only 2 (4.6%) in the NPWT group (p < 0.05). The relative risk was 5.5 (95% confidence interval) suggesting patients who received NPWT were 5.5 times less likely to develop infection. Twenty patients developed positive growth when samples were sent for culture with 3 (6.9%) in the NPWT group and 17 (34%) in the control group (p < 0.05). Only 5 patients (25%) went on the develop osteomyelitis, all being a part of the control group. Thus negative pressure wound therapy is indeed beneficial for preventing the incidence of both acute infections and osteomyelitis in open fractures. However a significant difference was not seen in the time required for the wound to be ready for delayed primary closure or coverage.     

Change in granulation tissue coverage and bacteriological load using Low Cost Negative Pressure Wound Therapy in acute musculoskeletal wounds

BackgroundLow cost Negative Pressure Wound Therapy (NPWT) dressings have been considered as an alternative to traditional daily dressings. There is scanty literature evaluating the change in the percentage area of wound covered by granulation tissue following application of low-cost NPWT. The change in the bacteriological flora following application of low-cost NPWT devices has also not been evaluated.MethodsPatients above the age of 18 years with acute musculoskeletal injuries of <3 weeks duration which underwent a surgical debridement and required subsequent wound coverage were included in the study. Area of the wound and the area covered by the granulation tissue as well as the bacteriological count were measured before and after application of NPWT. A low cost NPWT using wall mounted vacuum device was put on the patient giving a constant negative pressure of 125 mm of Hg for 2 days. The findings before and after application of NPWT were compared and analyzed using Wilcoxin Signed-rank test.Results21 patients with mean age of 35.52±15.075 were included. The pre-NPWT granulation tissue area ranged from 122 mm² to 8483 mm² with a mean of 1648.38 mm² (SD = 1933.866). The post-NPWT granulation tissue area ranged from 234 mm² to 7847 mm² with a mean of 2364.48 mm² (SD = 1857.716). The mean increase in granulation tissue was 716.1 mm².The pre-NPWT wound area ranged from 422 mm² to 10847 mm² with a mean of 4009.62 mm² (SD = 3026.209). The post-NPWT wound area ranged from 326 mm² to 9143 mm² with a mean of 3410.33 mm² (SD = 2636.206). The mean reduction in wound size was 599.29 mm².The pre-NPWT bacteriological count ranged from 3000/ml to 130000000/ml with a mean of 12616761.90/ml (SD = 29664589.37). The post-NPWT bacteriological count ranged from 1000/ml to 380000000/ml with a mean of 26401523.81/ml. The mean increase in bacteriological count was 13784761.91/ml.ConclusionThere was a statistically significant decrease in wound size (p = 0.001) and statistically significant increase in percentage area of granulation tissue coverage (p = 0.000) following low cost NPWT application. However there was no statistically significant increase in bacteriological clearance in these patients.     

The effectiveness of topical negative pressure in the treatment of pressure ulcers: a literature review

The objective of the study was to gain insight into the effectiveness of vacuum-assisted closure (VAC) therapy or, more particularly, topical negative pressure (TNP) in the treatment of pressure ulcers. We carried out a systematic search in Medline, Embase and Cinahl for Randomized Clinical Trials (RCTs) involving topical negative pressure in pressure ulcers over the period 1992–2007. Five RCTs were included. Two studies dealt exclusively with pressure ulcers. No significant differences in wound healing were found in these studies. Three other studies (mixed etiology of wounds) did show significant differences in wound healing, in the decrease of wound treatment time, and in the decrease in number of bacteria. The quality of these studies, both in terms of methodology and otherwise, did not always match with the scientific standard. Moreover, these studies lacked subgroup analyses. The analyzed studies described positive effects of TNP, although both the control treatment and the end points varied in these studies. On the basis of the systematic assessment of these five RCTs, the conclusion is that TNP has not proven to be more effective than various control interventions. The differences between and within the studies in terms of control interventions, the differences in randomization and a number of weaknesses in the analyses do not allow a good comparison. The main recommendations for follow-up studies include: randomization of patients rather than of wounds, a homogeneous patient population, the use of a single well-defined and procedurally documented control intervention, and prior calculation of the random sample size.     

Clinical outcome and microvascular blood flow in VAC®‐ and Sorbalgon®‐treated peri‐vascular infected wounds in the groin after vascular surgery – an early interim analysis

Vacuum‐assisted wound closure (VAC®) therapy is considered to be superior to conventional dressings in the treatment of peri‐vascular groin infections after vascular surgery at our department. Therefore, we performed an early interim analysis of the clinical outcomes in these seriously ill patients at risk of amputation and death. Patients were randomised to either VAC® (n = 5) or Sorbalgon® (n = 5; best alternative treatment) therapy after surgical debridement. Non‐invasive, laser Doppler perfusion imaging (LDPI) studies of the skin adjacent to the undressed wound were performed after 14 days of wound treatment. There was no difference in LDPI values in VAC® versus Sorbalgon® treated patients (P = 0·46). One patient in the VAC® group suffered from two re‐bleeding episodes, leading to vascular resection and transfemoral amputation and in the Sorbalgon® group two had a complete wound healing time of more than 4 months and one had a visible interposition bypass graft in the groin after 1 month of treatment. No patient died of the groin infection. Although not statistically proven, fewer wound treatment failures were recorded in the VAC® group, justifying this early interim analysis. LDPI studies were feasible.