Cyclic negative pressure wound therapy: an alternative mode to intermittent system

A case series of prophylactic negative pressure wound therapy use with purse-string closure in stoma closure wounds in infants

BACKGROUND

The study introduces the application of negative pressure wound therapy (NPWT) in pediatric stoma closure, emphasizing the importance of enhancing aesthetics and minimizing surgical site infections (SSI).

CASE PRESENTATION

The case series involves four infants undergoing non-umbilical stoma closure with a combination of purse-string closure (PSC) and NPWT, focusing on aesthetic outcomes and infection prevention. NPWT was initiated immediately after surgery, and patients were monitored every 3-4 days. Notably, none of the four infants experienced SSI or other complications. The patients adequately tolerated NPWT, with no significant adverse events. Furthermore, Manchester Scar Scale (MSS) was 9 [7-10], and Patient and Observer Scar Assessment Scale (POSAS) (observer) was 12.5 [12-19], POSAS (patient) was 12.5 [11-16] (all median values [minimum-maximum]), indicating that excellent aesthetic outcomes were achieved.

DISCUSSION

We emphasizes the significance of aesthetics in pediatric patients; in addition, our findings demonstrate that four infants who received NPWT combined with PSC achieved superior outcomes that did the most recent four infants who underwent PSC only at our institution. It also addresses the risk of SSI in stoma closure and discusses the pros and potential cons of using NPWT in pediatric cases, underlining the need for further research and the accumulation of additional reports.

CONCLUSIONS

This is the inaugural report of prophylactic NPWT for pediatric stoma closure, emphasizing the effectiveness of combining PSC and NPWT for SSI prevention and improved aesthetics. The study calls for additional research and reports on NPWT in pediatric cases to further solidify its benefits in this patient population.

A Novel Wound Therapy Modality: Autologous Wound Edge Dotted Full-Thickness Skin Grafting Improving Diabetic Foot Ulcer Healing

Aim

To explore the therapeutic efficacy of autologous wound edge-dotted full-thickness skin grafting in improving diabetic foot ulcer healing.

Methods

Sixty-three patients were divided into three groups: conventional wound therapy (CWT) (n = 23), platelet-rich plasma (PRP) (n = 20), and graft (n = 20). All participants were followed up for 12 weeks. The therapeutic efficacy of the three different wound treatment modalities was analyzed.

Results

After follow-up, 37 (58.7%) patients showed complete wound re-epithelialization, of which 10 (43.5%) occurred in the CWT group, 14 (70.0%) in the PRP group, and 13 (65.0%) in the graft group. Multivariate Cox analysis showed that the independent predictive factors for ulcer healing were different treatment modalities (graft: HR = 3.214, 95% CI=1.300-7.945, P < 0.05; platelet-rich plasma: HR = 3.075, 95% CI=1.320-7.161, P < 0.01), ABI (HR = 9.917, 95% CI=2.675-36.760, P < 0.01), and TcPO2 (HR = 1.040; 95% CI=1.005-1.076; P < 0.05). Stratified analysis showed that higher ABI in graft group or PRP group had higher wound healing rate (graft group: HR = 3.748, 95% CI=1.210-11.607, P < 0.05; PRP group: HR = 5.029, 95% CI=1.743-14.509, P < 0.05); higher TcPO2 in the graft group had higher wound healing rate (HR = 15.805, 95% CI=4.414-56.594, P < 0.01). Additionally, the wound healing time (P < 0.0167) and cumulative healing rate (P < 0.05) in both the PRP group and graft group were more advantageous. The graft group promotes wound re-epithelialization earlier and faster than in the CWT group and PRP group (P < 0.05). Meanwhile, the graft group had lower medical costs (P < 0.0167).

Conclusion

Autologous wound edge dotted full-thickness skin grafting has a higher cost-performance ratio than traditional diabetic foot ulcer wound care and is worthy of further clinical application.

Hypoxia-induced CCL2/CCR2 axis in adipose-derived stem cells (ADSCs) promotes angiogenesis by human dermal microvascular endothelial cells (HDMECs) in flap tissues

Flap expansion has become an important method widely used in wound repair and organ reconstruction. However, distal skin flap ischemic necrosis remains a problematic complication. In this study, integrative bioinformatics analyses indicated the upregulation of C-C motif chemokine ligand 2 (CCL2) and C-C motif chemokine receptor 2 (CCR2) in reperfusion-exposed skin flap tissues. In adipose-derived stem cells (ADSCs, CD90-positive, CD29-positive, CD34-negative, and CD106-negative) exposed to hypoxia, HIF-1α and CCL2 levels were significantly elevated. Conditioned medium (CM) from hypoxia-stimulated ADSCs promoted HDMEC proliferation, migration, and tube formation, partially inhibited by sh-CCL2-induced CCL2 knockdown or neutralized antibody-induced CCL2 depletion in ADSCs. Consistently, CCL2, CCR2, TNF-α, TLR2, and TLR4 protein levels in HDMECs were significantly increased by hypoxia-treated ADSCs CM, and partially decreased by sh-CCL2-induced CCL2 knockdown or neutralizing antibody-induced CCL2 knockdown in ADSCs. In the flap expansion model, ADSCs transplantation significantly improved flap survival and angiogenesis by endothelial cells in flap tissues, whereas CCL2 knockdown in ADSCs partially eliminated the improvement by ADSCs transplantation; overexpression of CCL2 in ADSCs further promoted the effects of ADSCs transplantation on skin flap. In conclusion, the CCL2/CCR2 axis in ADSCs could be induced by hypoxia, promoting HDMEC proliferation, migration, and tube formation and improving flap survival and angiogenesis in flap tissues.

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

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

Novel cell culture system for monitoring cells during continuous and variable negative-pressure wound therapy

BACKGROUND

Although the clinical efficacy of negative-pressure wound therapy (NPWT) is well known, many of its molecular biological mechanisms remain unresolved, mainly due to the difficulty and paucity of relevant in vitro studies. We attempted to develop an in vitro cell culture system capable of real-time monitoring of cells during NPWT treatment.

MATERIALS AND METHODS

A novel negative-pressure cell culture system was developed by combining an inverted microscope, a stage-top incubator, a sealed metal chamber for cell culture, and an NPWT treatment device. Human keratinocytes, PSVK-1, were divided into ambient pressure (AP), continuous negative-pressure (NPc), and intermittent negative-pressure (NPi) groups and cultured for 24 h with scratch assay using our real-time monitoring system and device. Pressure inside the device, medium evaporation rate, and the residual wound area were compared across the groups.

RESULTS

Pressure in the device was maintained at almost the same value as set in all groups. Medium evaporation rate was significantly higher in the NPi group than in the other two groups; however, it had negligible effect on cell culture. Residual wound area after 9 h evaluated by the scratch assay was significantly smaller in the NPc and NPi groups than in the AP group.

CONCLUSION

We developed a negative-pressure cell culture device that enables negative-pressure cell culture under conditions similar to those used in clinical practice and is able to monitor cells under NPWT. Further experiments using this device would provide high-quality molecular biological evidence for NPWT.

Device for Negative Pressure Wound Therapy in Low-Resource Regions: Open-Source Description and Bench Test Evaluation

Background: Negative (vacuum) pressure therapy promotes wound healing. However, commercially available devices are unaffordable to most potential users in low- and middle-income countries (LMICs), limiting access to many patients who could benefit from this treatment. This study aimed to design and test a cheap and easy-to-build negative pressure device and provide its detailed open-source description, thereby enabling free replication. Methods: the negative pressure device was built using off-the-shelf materials available via e-commerce and was based on a small pump, a pressure transducer, and the simplest Arduino controller with a digital display (total retail cost ≤ 75 US$). The device allows the user to set any therapeutic range of intermittent negative pressure and has two independent safety mechanisms. The performance of the low-cost device was carefully tested on the bench using a phantom wound, producing a realistic exudate flow rate. Results: the device generates the pressure patterns set by the user (25–175 mmHg of vacuum pressure, 0–60 min periods) and can drain exudate flows within the clinical range (up to 1 L/h). Conclusions: a novel, low-cost, easy-to-build negative pressure device for wound healing displays excellent technical performance. The open-source hardware description provided here, which allows for free replication and use in LMICs, will facilitate the application and wider utilization of this therapy to patients.

Superior Enhancement of Cutaneous Microcirculation Due to “Cyclic” Application of a Negative Pressure Wound Therapy Device in Humans – Local and Remote Effects

Objectives

Despite a common utilization of “Negative Pressure Wound Therapy” (NPWT) Devices in a wide range of specialties, some of the basic mechanisms of action of the techniques are still on debate. Conflicting results from prior studies demonstrate our lack of understanding how wound-bed perfusion or cutaneous microcirculation is affected by NPWT.

Methods

We conducted a prospective randomized study which included 45 healthy subjects to further investigate the acute effects of NPWT on cutaneous microcirculation underneath the applied dressing. Three modes of application, namely, continuous, intermittent, cyclic, were tested. Amongst others, measurements of elicited surface pressure and a comprehensive microcirculatory analysis were carried out by utilizing an O2C-device. For the detection of (systemic) remote effects, perfusion changes of the contra-lateral thigh were evaluated.

Results

All three tested modes of application led to a significant (p < 0.05) improvement in local tissue perfusion with an increased blood flow of max +151% and tissue oxygen saturation of +28.2% compared to baseline values. Surface pressure under the dressing significantly increased up to 29.29 mmHg due to the activation of the NPWT device. Continuous, intermittent, and cyclic application of negative pressure were accurately sensed by participants, resulting in reported pain values that mirrored the different levels of applied suction. Although the cyclic application mode showed the most pronounced effects regarding microcirculatory changes, no statistical significance between groups was observed.

Conclusion

We could demonstrate a significant improvement of cutaneous microcirculation under an applied NPWT dressing with favorable effects due to cyclic mode of application. An increased surface pressure leads to a better venous drainage of the tissue, which was shown to increase arterial inflow with a consecutive improvement of oxygen supply. Further research is warranted to evaluate our findings regarding wound bed perfusion in the clinical field with respect to formation of granulation tissue and wound healing.

Can Intralesional Epidermal Growth Factor Reduce Skin Graft Applications in Patients with Diabetic Foot Ulcer?

BACKGROUND

Diabetic foot ulcer (DFU) is a serious health problem. Major amputation increases the risk of mortality in patients with DFU; therefore, treatment methods other than major amputation come to the fore for these patients. Graft applications create an appropriate environment for the reproduction of epithelial cells. Similarly, epidermal growth factor (EGF) also stimulates epithelization and increases epidermis formation. In this study, we aimed to compare patients with DFU treated with EGF and those treated with a split-thickness skin graft.

METHODS

Patients who were treated for DFU in the general surgery clinic were included in the study. The patients were evaluated retrospectively according to their demographic characteristics, wound characteristics, duration of treatment, and treatment modalities.

RESULTS

There were 26 patients in the EGF group and 21 patients in the graft group. The mean duration of treatment was 7 weeks (4-8 weeks) in the EGF group and 5.3 weeks (4-8 weeks) in the graft group (P < .05). In the EGF group, wound healing could not be achieved in one patient during the study period. In the graft group, no recovery was achieved in three patients (14.2%) in the donor site. Graft loss was detected in four patients (19%), and partial graft loss was observed in three patients (14.2%). The DFU of these patients were on the soles (85.7%). These patients have multiple comorbidities.

CONCLUSIONS

EGF application may be preferred to avoid graft complications in the graft area and the donor site, especially in elderly patients with multiple comorbidities and wounds on the soles.

Consensus on the application of negative pressure wound therapy of diabetic foot wounds

Because China is becoming an aging society, the incidence of diabetes and diabetic foot have been increasing. Diabetic foot has become one of the main health-related killers due to its high disability and mortality rates. Negative pressure wound therapy (NPWT) is one of the most effective techniques for the treatment of diabetic foot wounds and great progress, both in terms of research and its clinical application, has been made in the last 20 years of its development. However, due to the complex pathogenesis and management of diabetic foot, irregular application of NPWT often leads to complications, such as infection, bleeding and necrosis, that seriously affect its treatment outcomes. In 2020, under the leadership of Burns, Trauma and Tissue Repair Committee of the Cross-Straits Medicine Exchange Association, the writing group for ‘Consensus on the application of negative pressure wound therapy of diabetic foot wounds’ was established with the participation of scholars from the specialized areas of burns, endocrinology, vascular surgery, orthopedics and wound repair. Drawing on evidence-based practice suggested by the latest clinical research, this consensus proposes the best clinical practice guidelines for the application and prognostic evaluation of NPWT for diabetic foot. The consensus aims to support the formation of standardized treatment schemes that clinicians can refer to when treating cases of diabetic foot.

A novel system for dynamic stretching of cell cultures reveals the mechanobiology for delivering better negative pressure wound therapy

Serious wounds, both chronic and acute (e.g., surgical), are among the most common, expensive and difficult-to-treat health problems. Negative pressure wound therapy (NPWT) is considered a mainstream procedure for treating both wound types. Soft tissue deformation stimuli are the crux of NPWT, enhancing cell proliferation and migration from peri-wound tissues which contributes to healing. We developed a dynamic stretching device (DSD) contained in a miniature incubator for applying controlled deformations to fibroblast wound assays. Prior to the stretching experiments, fibroblasts were seeded in 6-well culture plates with elastic substrata and let to reach confluency. Squashing damage was then induced at the culture centers, and the DSD was activated to deliver stretching regimes that represented common clinical NPWT protocols at two peak strain levels, 0.5% and 3%. Analyses of the normalized maximal migration rate (MMR) data for the collective cell movement revealed that for the 3% strain level, the normalized MMR of cultures subjected to a 0.1 Hz stretch frequency regime was ~ 1.4 times and statistically significantly greater (p < 0.05) than that of the cultures subjected to no-stretch (control) or to static stretch (2nd control). Correspondingly, analysis of the time to gap closure data indicated that the closure time of the wound assays subjected to the 0.1 Hz regime was ~ 30% shorter than that of the cultures subjected to the control regimes (p < 0.05). Other simulated NPWT protocols did not emerge as superior to the controls. The present method and system are a powerful platform for further revealing the mechanobiology of NPWT and for improving this technology.

Flap Preconditioning with the Cyclic Mode (Triangular Waveform) of Pressure-Controlled Cupping in a Rat Model: An Alternative Mode to the Continuous System

BACKGROUND

Improving flap survival is essential for successful soft-tissue reconstruction. Although many methods to increase the survival of the distal flap portion have been attempted, there has been no widely adopted procedure. The authors evaluated the effect of flap preconditioning with two different modes (continuous and cyclic) of external volume expansion (pressure-controlled cupping) in a rat dorsal flap model.

METHODS

Thirty rats were randomly assigned to the control group and two experimental groups (n = 10 per group). The continuous group underwent 30 minutes of preconditioning with -25 mmHg pressure once daily for 5 days. The cyclic group received 0 to -25 mmHg pressure for 30 minutes with the cyclic mode once daily for 5 days. On the day after the final preconditioning, caudally based 2 × 8-cm dorsal random-pattern flaps were raised and replaced in the native position. On postoperative day 9, the surviving flap area was evaluated.

RESULTS

The cyclic group showed the highest flap survival rate (76.02 percent), followed by the continuous and control groups (64.96 percent and 51.53 percent, respectively). All intergroup differences were statistically significant. Tissue perfusion of the entire flap showed similar results (cyclic, 87.13 percent; continuous, 66.64 percent; control, 49.32 percent). Histologic analysis showed the most increased and organized collagen production with hypertrophy of the attached muscle and vascular density in the cyclic group, followed by the continuous and control groups.

CONCLUSION

Flap preconditioning with the cyclic mode of external volume expansion is more effective than the continuous mode in an experimental rat model.

Negative Pressure Wound Therapy on Closed Surgical Wounds With Dead Space: Animal Study Using a Swine Model

Background

Closed incisional wound surgery frequently leaves dead space under the repaired skin, which results in delayed healing. The purpose of this study was to evaluate the effect of negative pressure wound therapy (NPWT) on incisional wounds with dead space after primary closure by evaluating the fluid volume through the suction drain, blood flow of the skin, tensile strength, and histology of the wounds.

Methods

Bilateral 25-cm-long incisional wounds with dead space were created on the back of 6 pigs by partially removing the back muscle and then suturing the skin with nylon sutures. NPWT (experimental group) or gauze dressing (control group) was applied over the closed incision for 7 days. Analysis of the wound included monitoring the amount of closed suction drain, blood perfusion unit, tensile strength of the repaired skin, and histology of the incision site.

Results

The drainage amount was significantly reduced in the experimental group (49.8 mL) compared to the control group (86.2 mL) (P = 0.046). Skin perfusion was increased in the experimental group with statistical significance compared to the control group (P = 0.0175). Collagen staining was increased in the experimental group. The tensile strength of the incision site was significantly higher in the experimental group (24.6 N at 7 days, 61.67 N at 21 days) compared to the control group (18.26 N at 7 days, 50.05 N at 21 days) (P = 0.02).

Conclusion

This study explains some of the mechanism for using NPWT in closed incision wounds with dead space. It demonstrates that NPWT significantly reduces drainage amount, increases skin perfusion, increases tensile strength, and has the tendency to promote collagen synthesis for closed wound with dead space indicating enhanced healing.

Effects of Incisional Negative-Pressure Wound Therapy on Primary Closed Defects after Superficial Circumflex Iliac Artery Perforator Flap Harvest: Randomized Controlled Study

BACKGROUND

Prolonged hematoma or seroma after primary closure is a causative element in wound complications. This study evaluated the effects of negative-pressure wound therapy on primary closed wounds after superficial circumflex iliac artery perforator flap harvest.

METHODS

This study was a prospective, randomized, clinical trial comparing conventional dressing against a single application of negative-pressure wound therapy for 5 days after primary closure. A total of 100 patients who had superficial circumflex iliac artery perforator flap harvest were enrolled.

RESULTS

There was no statistical difference between the incisional negative-pressure wound therapy and conventional dressing groups in the distribution of risk factors. Significant findings were noted for duration and amount of closed suction drainage: 6.12 ± 4.99 days (median, 4 days; range, 3 to 8 days) and 100.47 ± 140.69 cc (median, 42 cc) for wounds treated with conventional dressing versus 3.34 ± 1.35 days (median, 3 days; range, 2 to 4 days) and 23.28 ±18.36 cc (median, 20 cc) for wounds in treatment group (p = 0.0077 and p = 0.0004), respectively. After closure, an increase in skin perfusion were noted on day 5 in the treatment group (p = 0.0223). There was one case of wound dehiscence in the conventional dressing group.

CONCLUSION

The incisional negative-pressure wound therapy has a positive effect over primary closed surgical defects by significantly reducing the amount of fluid collected by closed suction drains, allowing earlier removal of drains and enhancing the skin perfusion on the repaired skin.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Innovations in diabetic foot reconstruction using supermicrosurgery

The treatment of diabetic foot ulceration is complex with multiple factors involved, and it may often lead to limb amputation. Hence, a multidisciplinary approach is warranted to cover the spectrum of treatment for diabetic foot, but in complex wounds, surgical treatment is inevitable. Surgery may involve the decision to preserve the limb by reconstruction or to amputate it. Reconstruction involves preserving the limb with secure coverage. Local flaps usually are able to provide sufficient coverage for small or moderate sized wound, but for larger wounds, soft tissue coverage involves flaps that are distantly located from the wound. Reconstruction of distant flap usually involves microsurgery, and now, further innovative methods such as supermicrosurgery have further given complex wounds a better chance to be reconstructed and limbs salvaged. This article reviews the microsurgery involved in reconstruction and introduces the new method of supermicrosurgery.

Using a Contradictory Approach to Treat a Wound Induced by Hematoma in a Patient With Antiphospholipid Antibody Syndrome Using Negative Pressure Wound Therapy: Lessons Learnt

A 48-year-old woman with antiphospholipid syndrome (APS) had multiple skin necrosis caused by massive bleeding and hematoma collection at the right lower leg, left thigh, and abdomen. During the first month, we did surgical debridement every 2 to 3 days with meticulous coagulation and applied negative pressure wound therapy (NPWT). Then as the base showed initial granulation, we changed the NPWT every 4 days. NPWT was used with lower pressure and cyclic mode (-40 to -75 mm Hg) to minimize trauma and to reduce the possibility of bleeding from the wounds. After 2 months of NPWT treatment, all the wounds eventually healed with secondary intension despite the patient's condition with diabetes, hemodialysis, anticoagulant use, and corticosteroid therapy. This report supports the idea that if accompanied by conservative debridement with meticulous bleeding control, application of NPWT in low pressures and close monitoring of the patient, NPWT is possible to use even in wounds of patients with risk for bleeding.