Wounds: an overview of the role of oxygen

A fingerprint-like supramolecular-assembled Ag3PO4/polydopamine/g-C3N4 heterojunction nanocomposite for enhanced solar-driven oxygen evolution in vivo

Biocompatible photocatalytic water-splitting systems are promising for tissue self-oxygenation. Herein, a structure-function dual biomimetic fingerprint-like silver phosphate/polydopamine/graphitic carbon nitride (Ag3PO4/PDA/g-C3N4) heterojunction nanocomposite is proposed for enhanced solar-driven oxygen (O2) evolution in vivo in situ. Briefly, a porous nitrogen-defected g-C3N4 nanovoile (CN) is synthesized as the base. Dopamine molecules are controllably inserted into the CN interlayer, forming PDA spacers (4.28 nm) through self-polymerization-induced supramolecular-assembly. Ag3PO4 nanoparticles are then in situ deposited to create Ag3PO4/PDA/CN. The fingerprint-like structure of PDA/CN enlarges the layer spacing, thereby accelerating mass transfer and increasing reaction sites. The PDA spacer roles as excellent light harvester, electronic-ionic conductor, and redox pair through conformational changes, resulting in tailored electronic band structure, optimized carrier behavior, and reduced electrochemical impedance. In physiological conditions, Ag3PO4/PDA/CN exhibits O2 evolution rate of 45.35 μmol⋅g-1⋅h-1, 9-fold of bulk g-C3N4. The biocompatibility and in vivo oxygen supply effectiveness for biomedical applications have been verified in animal models.

Wireless Battery-free and Fully Implantable Organ Interfaces

Advances in soft materials, miniaturized electronics, sensors, stimulators, radios, and battery-free power supplies are resulting in a new generation of fully implantable organ interfaces that leverage volumetric reduction and soft mechanics by eliminating electrochemical power storage. This device class offers the ability to provide high-fidelity readouts of physiological processes, enables stimulation, and allows control over organs to realize new therapeutic and diagnostic paradigms. Driven by seamless integration with connected infrastructure, these devices enable personalized digital medicine. Key to advances are carefully designed material, electrophysical, electrochemical, and electromagnetic systems that form implantables with mechanical properties closely matched to the target organ to deliver functionality that supports high-fidelity sensors and stimulators. The elimination of electrochemical power supplies enables control over device operation, anywhere from acute, to lifetimes matching the target subject with physical dimensions that supports imperceptible operation. This review provides a comprehensive overview of the basic building blocks of battery-free organ interfaces and related topics such as implantation, delivery, sterilization, and user acceptance. State of the art examples categorized by organ system and an outlook of interconnection and advanced strategies for computation leveraging the consistent power influx to elevate functionality of this device class over current battery-powered strategies is highlighted.

Oxygen-Generating Hydrogels as Oxygenation Therapy for Accelerated Chronic Wound Healing

Hypoxia in chronic wounds impairs the activities of reparative cells, resulting in tissue necrosis, bacterial infections, decreased angiogenesis, and delayed wound healing. To achieve effective oxygenation therapy and restore oxygen homeostasis, oxygen-generating hydrogels based on different oxygen sources have been developed to release dissolved oxygen in the wound bed, which not only alleviate hypoxia, but also accelerate chronic wound healing. This review first discusses the vital role of oxygen and hypoxia in the wound healing process. The advancements in oxygen-generating hydrogels, which produce oxygen through the decomposition of hydrogen peroxide, metal peroxides, glucose-activated cascade reactions, and photosynthesis of algae microorganisms for chronic wound healing, are discussed and summarized. The therapeutic effects and challenges of using oxygen-generating hydrogels for the clinical treatment of chronic wounds are concluded and prospected.

Effect of hyperbaric oxygen treatment on diabetic foot ulcers: A meta-analysis

The meta-analysis aimed to assess the effect of hyperbaric oxygen treatment on diabetic foot ulcers. Using dichotomous or contentious random or fixed effect models, the outcomes of this meta-analysis were examined and the odds ratio (OR) and the mean difference (MD) with 95% confidence intervals (CIs) were computed. 17 examinations from 1992 to 2022 were enrolled for the present meta-analysis, including 7219 people with diabetic foot ulcers. Hyperbaric oxygen treatment had a significantly higher healed ulcer (OR, 14.39; 95% CI, 4.02-51.52, p < 0.001), higher adverse event (OR, 2.14; 95% CI, 1.11-4.11, p = 0.02), lower mortality (OR, 0.22; 95% CI, 0.07-0.71, p = 0.01) and higher ulcer area reduction (MD, 23.39; 95% CI, 11.79-34.99, p < 0.001) compared to standard treatment in patients with diabetic foot ulcers. However, hyperbaric oxygen treatment and standard treatment had no significant difference in amputation (OR, 0.62; 95% CI, 0.22-1.75, p = 0.37), major amputation (OR, 0.59; 95% CI, 0.18-1.92, p = 0.38), minor amputation (OR, 0.64; 95% CI, 0.15-2.66, p = 0.54) and healing time (MD, -0.001; 95% CI, -0.76 to 0.75, p = 0.99) in patients with diabetic foot ulcers. The examined data revealed that hyperbaric oxygen treatment had a significantly higher healed ulcer, adverse event, and ulcer area reduction and lower mortality, however, there was no significant difference in amputation and healing time compared to standard treatment in patients with diabetic foot ulcers. Yet, attention should be paid to its values since most of the selected examinations had a low sample size and some of the comparisons had a low number of selected studies.

Portable Negative Pressure Wound Dressing in Oncoplastic Conservative Surgery for Breast Cancer: A Valid Ally

Background and Objectives: The use of oncoplastic techniques has spread widely in the last decade, with an expansion of the indications and demonstration of excellent oncological safety profiles. A potential downside may be the increased complication rates, which could influence the timing of adjuvant therapy. To date, there is increasing evidence that negative pressure therapy on closed wounds can reduce complication rates after surgery. From this perspective, we tested the use of portable negative pressure wound dressings (NPWDs) in oncoplastic surgery to minimize early post-operative admissions to the outpatient clinic and prevent surgical complications. Materials and Methods: An observational prospective cohort study was conducted on a population of patients who underwent quadrantectomy and wise-pattern reduction mammoplasty for breast cancer. The primary objective of the study is represented by the evaluation of the impact of NPWD on post-operative outcomes in an oncoplastic surgery setting. Patients enrolled between January 2021 and January 2023 were divided into two groups, the conventional dressing (CD) group and the NPWD group, by a simple randomization list. Results: A total of 100 patients were enrolled, with 52 in the CD group and 48 in the NPWD group. The use of NPWD significantly reduced the wound dehiscence rate (2.0% vs. 7.7% p = 0.002) and the number of one-month postoperative admissions to our clinic (3.8 ± 1.1 vs. 5.7 ± 1.3 p = 0.0009). Although not significant, it is possible to note a trend of reduction of clinically relevant postoperative total complications in patients treated with NPWDs. Conclusions: NPWDs may represent a useful tool in the post-surgical management of complex oncoplastic procedures, ensuring less wound dehiscence. Furthermore, the use of these dressings led to a significant reduction in admissions to the clinic, promoting a lower use of resources by hospitals and effective prevention of possible complications.

Wireless and battery-free technologies for neuroengineering

Tethered and battery-powered devices that interface with neural tissues can restrict natural motions and prevent social interactions in animal models, thereby limiting the utility of these devices in behavioural neuroscience research. In this Review Article, we discuss recent progress in the development of miniaturized and ultralightweight devices as neuroengineering platforms that are wireless, battery-free and fully implantable, with capabilities that match or exceed those of wired or battery-powered alternatives. Such classes of advanced neural interfaces with optical, electrical or fluidic functionality can also combine recording and stimulation modalities for closed-loop applications in basic studies or in the practical treatment of abnormal physiological processes.

Influence of Acidic pH on Wound Healing In Vivo: A Novel Perspective for Wound Treatment

There has been little understanding of acidification functionality in wound healing, highlighting the need to study the efficacy of wound acidification on wound closure and cellular activity in non-infected wounds. This study is focused on establishing the healing potential of wound acidification in non-infected wounds. Acidic buffers, constituting either phosphoric or citric acid, were employed to modify the physiological pH of non-infected full-thickness excisional murine wounds. Acidification of the wound by acidic buffers was found to be an effective strategy to improve wound healing. A significant improvement in wound healing parameters was observed as early as 2 days post-treatment with acidic buffers compared to controls, with faster rate of epithelialization, wound closure and higher levels of collagen at day 7. pH is shown to play a role in mediating the rate of wound healing, with acidic buffers formulated at pH 4 observed to stimulate faster recovery of wounded tissues than pH 6 buffers. Our study shows the importance of maintaining an acidic wound microenvironment at pH 4, which could be a potential therapeutic strategy for wound management.

Hypoxia: molecular pathophysiological mechanisms in human diseases

Hypoxia, a low O2 tension, is a fundamental feature that occurs in physiological events as well as pathophysiological conditions, especially mentioned for its role in the mechanism of angiogenesis, glucose metabolism, and cell proliferation/survival. The hypoxic state through the activation of specific mechanisms is an aggravating circumstance commonly noticed in multiple sclerosis, cancer, heart disease, kidney disease, liver disease, lung disease, and in inflammatory bowel disease. On the other hand, hypoxia could play a key role in tissue regeneration and repair of damaged tissues, especially by acting on specific tissue stem cells, but their features may result as a disadvantage when it is concerned for neoplastic stem cells. Furthermore, hypoxia could also have a potential role in tissue engineering and regenerative medicine due to its capacity to improve the performance of biomaterials. The current review aims to highlight the hypoxic molecular mechanisms reported in different pathological conditions to provide an overview of hypoxia as a therapeutic agent in regenerative and molecular therapy.

Graphical abstract

Does Higher Intraoperative Fraction of Inspired Oxygen Improve Complication Rates Following Implant-Based Breast Reconstruction?

Background

The surgical literature debates about whether an average intraoperative fractional inspired level of oxygen (FiO₂) greater than 80% confers lower postsurgical complication rates. Although some evidence demonstrates minimal or no difference in short-term mortality or surgical site infections, few studies suggest negative long-term outcomes.

Objectives

To the best of our knowledge, this is the first study examining the relationship between intraoperative FiO₂ levels and postoperative outcomes in the setting of immediate prepectoral implant-based breast reconstruction.

Methods

The authors retrospectively reviewed the complication profiles of 309 patients who underwent prepectoral 2-stage breast reconstruction following mastectomy between 2018 and 2021 at a single institution. Two cohorts were created based on whether intraoperative FiO₂ was greater than 80% or less than or equal to 80%. Complication rates between the cohorts were analyzed using Chi-squared test, Fisher's exact test, and multivariable logistic regressions. Variables examined included demographic information; smoking history; preexisting comorbidities; history of chemotherapy, radiation, or axillary lymph node dissection; and perioperative information.

Results

Chi-squared and multivariable regression analysis demonstrated no significant difference between cohorts in complication rates other than reoperation. Reoperation rates were significantly increased in the FiO₂ greater than 80% cohort (P = 0.018). Multivariable logistic regression also demonstrated that the use of acellular dermal matrix was significantly associated with increased postoperative complications (odds ratio 11.985; P = 0.034).

Conclusions

Complication rates did not statistically differ in patients with varying intraoperative FiO₂ levels outside of reoperation rates. In the setting of implant-based prepectoral breast reconstruction, hyperoxygenation likely does not lead to improved postsurgical outcomes.

Level of Evidence 3

Biofilm and Equine Limb Wounds

Simple Summary

Delayed wound healing commonly occurs in limb wounds of horses. These equine limb wounds share many similarities with chronic wounds in humans and one of them seems to be the presence of biofilm, even though equine wound biofilm research is just emerging. Biofilms are aggregates of bacteria, and within these aggregates, the bacteria are protected from both antimicrobial substances and the immune response of the host. Biofilm infections in wounds often delay healing and are impossible to detect with routine diagnostics. However, if suspected, aggressive treatment is needed and includes physically removing biofilm and unhealthy tissue from the wound during debridement and immediately applying antimicrobial compounds to kill any biofilm or bacteria not removed during debridement.

Abstract

In chronic wounds in humans, biofilm formation and wound chronicity are linked, as biofilms contribute to chronic inflammation and delayed healing. Biofilms are aggregates of bacteria, and living as biofilms is the default mode of bacterial life; within these aggregates, the bacteria are protected from both antimicrobial substances and the immune response of the host. In horses, delayed healing is more commonly seen in limb wounds than body wounds. Chronic inflammation and hypoxia are the main characteristics of delayed wound healing in equine limbs, and biofilms might also contribute to this healing pattern in horses. However, biofilm formation in equine wounds has been studied to a very limited degree. Biofilms have been detected in equine traumatic wounds, and recent experimental models have shown that biofilms protract the healing of equine limb wounds. Detection of biofilms within wounds necessitates advanced techniques that are not available in routine diagnostic yet. However, infections with biofilm should be suspected in equine limb wounds not healing as expected, as they are in human wounds. Treatment should be based on repeated debridement and application of topical antimicrobial therapy.

Following ISAPS Recommendations, Does it Really Help?

BACKGROUND

The demand for abdominoplasty procedures has increased in surgical centres as a result of patient preference and economic concerns. The International Society of Aesthetic Plastic Surgery (ISAPS) published the Facility Accreditation Guideline on 22 October 2018. It is a list of recommendations that aim to reduce the incidence of complications and increase safety standards.

OBJECTIVES

The objective of this work was to detect the effects of the ISAPS guidelines on the morbidity associated with abdominoplasty procedures in day care surgical centres.

METHODS

The authors performed a retrospective study. Data regarding complications of abdominoplasty were collected from medical records of the last 350 cases of abdominoplasty performed in December 2018. The complications and their incidences were compared with similar previously published data of abdominoplasty operations performed by other authors and in surgical centres before initiation of the ISAPS Facility Accreditation Guideline.

RESULTS

In all cases, we achieved a significant reduction in skin and adipose tissue with improvement in body shape. The incidence of major and minor post-operative complications was lower than that reported in other literature.

CONCLUSIONS

This report shows that abdominoplasty is a safe procedure with low complication rates, which are even lower when the ISAPS Facility Accreditation Guideline is followed together with national, regional, state and other legal requirements.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A case report: Treatment of chronic diabetic foot ulcer with Hyperbaric Oxygen Therapy

Diabetes mellitus effects around 10% of the whole population and unhealed diabetic foot ulcer is one of the most debilitating and economically burdensome conditions. This condition is commonly seen by different specialists including physicians, orthopaedic surgeons and vascular surgeons. We present a case of unhealed diabetic foot ulcer which has been treated in our Hyperbaric Oxygen Therapy (HBOT) centre. We also review the literature with respect to management strategy and rationale of hyperbaric oxygen therapy for diabetic foot ulcers.

Wireless and battery-free platforms for collection of biosignals

Recent progress in biosensors have quantitively expanded current capabilities in exploratory research tools, diagnostics and therapeutics. This rapid pace in sensor development has been accentuated by vast improvements in data analysis methods in the form of machine learning and artificial intelligence that, together, promise fantastic opportunities in chronic sensing of biosignals to enable preventative screening, automated diagnosis, and tools for personalized treatment strategies. At the same time, the importance of widely accessible personal monitoring has become evident by recent events such as the COVID-19 pandemic. Progress in fully integrated and chronic sensing solutions is therefore increasingly important. Chronic operation, however, is not truly possible with tethered approaches or bulky, battery-powered systems that require frequent user interaction. A solution for this integration challenge is offered by wireless and battery-free platforms that enable continuous collection of biosignals. This review summarizes current approaches to realize such device architectures and discusses their building blocks. Specifically, power supplies, wireless communication methods and compatible sensing modalities in the context of most prevalent implementations in target organ systems. Additionally, we highlight examples of current embodiments that quantitively expand sensing capabilities because of their use of wireless and battery-free architectures.

Soft, Wireless and subdermally implantable recording and neuromodulation tools

Progress in understanding neuronal interaction and circuit behavior of the central and peripheral nervous system strongly relies on the advancement of tools that record and stimulate with high fidelity and specificity. Currently, devices used in exploratory research predominantly utilize cables or tethers to provide pathways for power supply, data communication, stimulus delivery and recording, which constrains the scope and use of such devices. In particular, the tethered connection, mechanical mismatch to surrounding soft tissues and bones frustrate the interface leading to irritation and limitation of motion of the subject, which in the case of fundamental and preclinical studies, impacts naturalistic behaviors of animals and precludes the use in experiments involving social interaction and ethologically relevant three-dimensional environments, limiting the use of current tools to mostly rodents and exclude species such as birds and fish. This review explores the current state-of-the-art in wireless, subdermally implantable tools that quantitively expand capabilities in analysis and perturbation of the central and peripheral nervous system by removing tethers and externalized features of implantable neuromodulation and recording tools. Specifically, the review explores power harvesting strategies, wireless communication schemes, and soft materials and mechanics that enable the creation of such devices and discuss their capabilities in the context of freely-behaving subjects. Highlights of this class of devices includes wireless battery-free and fully implantable operation with capabilities in cell specific recording, multimodal neural stimulation and electrical, optogenetic and pharmacological neuromodulation capabilities. We conclude with discussion on translation of such technologies which promises routes towards broad dissemination.

Oxygen-Releasing Biomaterials: Current Challenges and Future Applications

Oxygen is essential for the survival, function, and fate of mammalian cells. Oxygen tension controls cellular behaviour via metabolic programming, which in turn controls tissue regeneration, stem cell differentiation, drug metabolism, and numerous pathologies. Thus, oxygen-releasing biomaterials represent a novel and unique strategy to gain control over a variety of in vivo processes. Consequently, numerous oxygen-generating or carrying materials have been developed in recent years, which offer innovative solutions in the field of drug efficiency, regenerative medicine, and engineered living systems. In this review, we discuss the latest trends, highlight current challenges and solutions, and provide a future perspective on the field of oxygen-releasing materials.

Efficacy of hyperbaric oxygen therapy for diabetic foot ulcer, a systematic review and meta-analysis of controlled clinical trials

Studies have suggested that hyperbaric oxygen therapy (HBOT) is effective in the healing of diabetic foot ulcer (DFU); however, there is a lack of consensus. Therefore, to assess the efficacy of HBOT on diabetic foot ulcer among diabetic patients, controlled clinical trials were searched through PubMed, EMBASE, Clinical key, Ovid Discovery, ERMED, Clinical Trials.gov databases for randomized controlled trials (RCTs) and other sources until 15 September 2020. Studies that evaluated the effect of HBOT on diabetic foot ulcer, complete healing, amputation, adverse events, ulcer reduction area, and mortality rate were included. Of 1984 study records screened, 14 studies (768 participants) including twelve RCTs, and two CCTs were included as per inclusion criteria. The results with pooled analysis have shown that HBOT was significantly effective in complete healing of diabetic foot ulcer (OR = 0.29; 95% CI 0.14-0.61; I² = 62%) and reduction of major amputation (RR = 0.60; 95% CI 0.39-0.92; I² = 24%). Although, it was not effective for minor amputations (RR = 0.82; 95% CI 0.34-1.97; I² = 79%); however, less adverse events were reported in standard treatment group (RR = 1.68; 95% CI 1.07-2.65; I² = 0%). Nevertheless, reduction in mean percentage of ulcer area and mortality rate did not differ in HBOT and control groups. This review provides an evidence that hyperbaric oxygen therapy is effective as an adjunct treatment measure for the diabetes foot ulcers. These findings could be generalized cautiously by considering methodological flaws within all studies.

Integrin-mediated adhesive properties of neutrophils are reduced by hyperbaric oxygen therapy in patients with chronic non-healing wound

In recent years, several studies suggested that the ability of hyperbaric oxygen therapy (HBOT) to promote healing in patients with diabetic ulcers and chronic wounds is due to the reduction of inflammatory cytokines and to a significant decrease in neutrophils recruitment to the damaged area. α4 and β2 integrins are receptors mediating the neutrophil adhesion to the endothelium and the comprehension of the effects of hyperbaric oxygenation on their expression and functions in neutrophils could be of great importance for the design of novel therapeutic protocols focused on anti-inflammatory agents. In this study, the α4 and β2 integrins' expression and functions have been evaluated in human primary neutrophils obtained from patients with chronic non-healing wounds and undergoing a prolonged HBOT (150 kPa per 90 minutes). The effect of a peptidomimetic α4β1 integrin antagonist has been also analyzed under these conditions. A statistically significant decrease (68%) in β2 integrin expression on neutrophils was observed during the treatment with HBO and maintained one month after the last treatment, while α4 integrin levels remained unchanged. However, cell adhesion function of both neutrophilic integrins α4β1 and β2 was significantly reduced 70 and 67%, respectively), but α4β1 integrin was still sensitive to antagonist inhibition in the presence of fibronectin, suggesting that a combined therapy between HBOT and integrin antagonists could have greater antinflammatory efficacy.

Targeting Tunable Physical Properties of Materials for Chronic Wound Care

Chronic wounds caused by infections, diabetes, and radiation exposures are becoming a worldwide growing medical burden. Recent progress highlighted the physical signals determining stem cell fates and bacterial resistance, which holds potential to achieve a better wound regeneration in situ. Nanoparticles (NPs) would benefit chronic wound healing. However, the cytotoxicity of the silver NPs (AgNPs) has aroused many concerns. This review targets the tunable physical properties (i.e., mechanical-, structural-, and size-related properties) of either dermal matrixes or wound dressings for chronic wound care. Firstly, we discuss the recent discoveries about the mechanical- and structural-related regulation of stem cells. Specially, we point out the currently undocumented influence of tunable mechanical and structural properties on either the fate of each cell type or the whole wound healing process. Secondly, we highlight novel dermal matrixes based on either natural tropoelastin or synthetic elastin-like recombinamers (ELRs) for providing elastic recoil and resilience to the wounded dermis. Thirdly, we discuss the application of wound dressings in terms of size-related properties (i.e., metal NPs, lipid NPs, polymeric NPs). Moreover, we highlight the cytotoxicity of AgNPs and propose the size-, dose-, and time-dependent solutions for reducing their cytotoxicity in wound care. This review will hopefully inspire the advanced design strategies of either dermal matrixes or wound dressings and their potential therapeutic benefits for chronic wounds.

Comparing near infrared spectroscopy and transcutaneous oxygen measurement in hard-to-heal wounds: a pilot study

Objective:

Oxygen plays an integral role in all phases of the wound healing process and tissue oxygenation is a key determinant of wound healing. A comprehensive evaluation of patients with hard-to-heal wounds must include measurement of oxygenation in and around the area of skin breakdown. The current gold standard, transcutaneous oxygen measurement (TCOM), has numerous drawbacks and as a result has fallen into disuse.

Method:

This study compared measurement of tissue oxygenation of near infrared spectroscopy (NIRS) with TCOM in patients with acute and hard-to-heal wounds. The Shapiro-Wilk test was used to evaluate the normality of the data. The level of agreement between NIRS and TCOM was determined using Bland-Altman analysis. The relationship between TCOM and NIRS was examined using Pearson correlation.

Results:

A total of 24 observations were obtained from 10 patients using TCOM and NIRS. The weighted mean partial pressure of oxygen (pO2) in the study population was 39.54mmHg (8.96 standard deviation). Bland–Altman analysis showed that mean difference was positive (18.75), suggesting an overestimation of oxygen measurements using TCOM compared with NIRS. The oxygen levels measured by TCOM and NIRS showed a strong correlation (r=0.74).

Conclusion:

The wound and hyperbaric community would benefit from a simplified procedure for measuring tissue oxygenation. These findings suggest a strong trend toward correlation between NIRS and TCOM. A further study in a larger population is recommended. NIRS offers several advantages over TCOM. Clinicians have immediate point-of-care visualisation of tissue oxygenation using a handheld device. The procedure takes minutes to perform and is less operator-dependent than TCOM. Finally, NIRS allows measurement of oxygenation in the wound bed, while TCOM does not.

Effects of topical negative pressure therapy on perfusion and microcirculation of human skin

BACKGROUND

Topical negative pressure wound therapy (TNPWT) is one of the most frequently used techniques in wound treatment. But some of the underlying mechanisms still remain unclear. One possible explanation is an improved microcirculation by TNPWT.

OBJECTIVE

This study investigated the influence of TNPWT on microcirculation on intact skin in real-time.

METHODS

In healthy individuals, we performed a combined tissue - laser/photo - spectrometry technique to monitor changes of 4 different microcirculation parameters in real-time: The local blood flow, the capillary-venous oxygen saturation, the blood flow velocity and the relative amount of hemoglobin. We compared these parameters using two different protocols: a continuously (VAC ON 60/OFF 60) and discontinuously (VAC ON 30/OFF 60/ON 5) application.

RESULTS

Our results demonstrate a significant increase of all four measured parameters during the active TNPWT and the pressure free period. The comparison of two different protocols shows an advantage of the examined parameters using a discontinuous TNPWT application.

CONCLUSIONS

Our study demonstrated the changes of the microvascular tissue perfusion in intact human skin under the conditions of negative pressure and may thereby offer a broader understanding of mechanisms underlying the TNPWT.

Is there a role for hyperbaric oxygen therapy in the treatment of refractory wounds of rare etiology?

INTRODUCTION

Delayed wound healing indicates wounds that have failed to respond to more than 4-6 weeks of comprehensive wound care. Wounds with delayed healing are a major source of morbidity and a major cost to hospital and community healthcare providers. Hyperbaric oxygen therapy (HBOT) is a treatment designed to increase the supply of oxygen to wounds and has been applied to a variety of wound types. This article reviews the place of HBOT in the treatment of non-healing vasculitic, calcific uremic arteriolopathy (CUA), livedoid vasculopathy (LV), pyoderma gangrenosum (PG) ulcers.

METHODS

We searched electronic databases for research and review studies focused on HBOT for the treatment of delayed healing ulcers with rare etiologies. We excluded HBOT for ulcers reviewed elsewhere.

RESULTS

We included a total of three case series and four case reports including 63 participants. Most were related to severe, non-healing ulcers in patients with vasculitis, CUA, LV, and PG. There was some evidence that HBOT may improve the healing rate of wounds by increasing nitric oxide (NO) levels and the number of endothelial progenitor cells in the wounds. HBOT may also improve pain in these ulcers.

CONCLUSION

We recommend the establishment of comprehensive and detailed wound care registries to rapidly collect prospective data on the use of HBOT for these problem wounds. There is a strong case for appropriately powered, multi-centre randomized trials to establish the true efficacy and cost-effectiveness of HBOT especially for vasculitis ulcers that have not improved following immunosuppressive therapy.

Phosphorylation of Microtubule- Associated Protein 4 Promotes Hypoxic Endothelial Cell Migration and Proliferation

Endothelial cells play a critical role in the process of angiogenesis during skin wound healing. The migration and proliferation of endothelial cells are processes that are initiated by the hypoxic microenvironment in a wound, but the underlying mechanisms remain largely unknown. Here, we identified a novel role for microtubule-associated protein 4 (MAP4) in angiogenesis. We firstly demonstrated that MAP4 phosphorylation was induced in hypoxic endothelial cells; the increase in MAP4 phosphorylation enhanced the migration and proliferation of endothelial cells. We also found that hypoxia (2% O₂) activated p38/mitogen-activated protein kinase (MAPK) signaling, and we identified p38/MAPK as an upstream regulator of MAP4 phosphorylation in endothelial cells. Moreover, we showed that the promigration and proproliferation effects of MAP4 phosphorylation were attributed to its role in microtubule dynamics. These results indicated that MAP4 phosphorylation induced by p38/MAPK signaling promotes angiogenesis by inducing the proliferation and migration of endothelial cells cultured under hypoxic conditions via microtubule dynamics regulation. These findings provide new insights into the potential mechanisms underlying the initiation of the migration and proliferation of endothelial cells.

Wireless, battery-free optoelectronic systems as subdermal implants for local tissue oximetry

Monitoring regional tissue oxygenation in animal models and potentially in human subjects can yield insights into the underlying mechanisms of local O2-mediated physiological processes and provide diagnostic and therapeutic guidance for relevant disease states. Existing technologies for tissue oxygenation assessments involve some combination of disadvantages in requirements for physical tethers, anesthetics, and special apparatus, often with confounding effects on the natural behaviors of test subjects. This work introduces an entirely wireless and fully implantable platform incorporating (i) microscale optoelectronics for continuous sensing of local hemoglobin dynamics and (ii) advanced designs in continuous, wireless power delivery and data output for tether-free operation. These features support in vivo, highly localized tissue oximetry at sites of interest, including deep brain regions of mice, on untethered, awake animal models. The results create many opportunities for studying various O2-mediated processes in naturally behaving subjects, with implications in biomedical research and clinical practice.

Immune and vascular dysfunction in diabetic wound healing

The diminished capacity for wound healing in patients with diabetes contributes to morbidity through ulceration and recurrent infections, loss of function and decreased workplace productivity, increased hospitalisation rates, and rising health-care costs. These are due to diabetes' effects on signalling molecules, cellular cascades, different cell populations, and the vasculature. The function of multiple immune system components including cellular response, blood factors, and vascular tone are all negatively impacted by diabetes. The purpose of this paper is to review the current understanding of immune and vascular dysfunction contributing to impaired wound healing mechanisms in the diabetic population. Normal wound healing mechanisms are reviewed followed by diabetic aberrations to immune and inflammatory function and atherogenesis and angiopathy.

DECLARATION OF INTEREST

The authors have no financial or personal relationships to people or organisations that could potentially and inappropriately influence their work and conclusions.

The effectiveness of hyperbaric oxygen therapy for healing chronic venous leg ulcers: A randomized, double-blind, placebo-controlled trial

Over 30% of venous leg ulcers do not heal despite evidence-based treatment. This study aimed to determine the effectiveness of Hyperbaric Oxygen Therapy (HBOT) as an adjunct treatment for nonhealing venous leg ulcers. A randomized, double-blind, parallel group, placebo-controlled trial was undertaken in three hyperbaric medicine units. Adults with a venous leg ulcer, Transcutaneous Oxygen Measurement indicative of a hypoxic wound responsive to oxygen challenge, and without contraindications for HBOT; were eligible. Of 84 eligible patients, 10 refused and 74 enrolled. 43 participants achieved over 50% ulcer Percent Area Reduction (PAR) after four weeks of evidence-based care and were thus excluded from the intervention phase. Thirty-one participants were randomized to either 30 HBOT treatments (100% oxygen at 2.4 atmospheres absolute (ATA) for 80 minutes), or 30 "placebo" treatments, receiving a validated "sham" air protocol, initially pressurized to 1.2ATA, then cycled between 1.05-1.2ATA for eight minutes before settling at 1.05ATA. The primary outcome was numbers in each group completely healed. Secondary outcomes were ulcer PAR, pain and quality of life, 12 weeks after commencing interventions. The participants' mean age was 70 years (standard deviation (SD) 12.9) and median ulcer duration at enrolment was 62 weeks (range 4-3120). At 12 weeks, there was no significant difference between groups in the numbers completely healed. The HBOT intervention group had a mean of 95 (SD 6.53) ulcer PAR, compared to 54 (SD 67.8) mean PAR for the placebo group (t = -2.24, p = 0.042, mean difference -40.8, SE 18.2) at 12 weeks. HBOT may improve refractory healing in venous leg ulcers, however patient selection is important. In this study, HBOT as an adjunct treatment for nonhealing patients returned indolent ulcers to a healing trajectory.

A dipeptidyl peptidase-4 inhibitor promotes wound healing in normoglycemic mice by modulating keratinocyte activity

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a well-known and novel class of oral antihyperglycaemic drugs. DPP-4 inhibition facilitates ulcer healing in patients with diabetes. However, the actual mechanisms, which are independent of lower blood glucose levels, are still unknown. Therefore, the aim of this study was to analyse the effect of the DPP-4 inhibitor sitagliptin on wound healing through a glucose-independent pathway. In this study, DPP-4 inhibitors facilitate keratinocyte differentiation and the proliferation, increase blood flow in the cutaneous of wounds in healthy C57BL/6 mice. Additionally, the administration of the DPP-4 inhibitor ameliorates wound healing and enhances adiponectin expression in healthy C57BL/6 mice. Taken together, our results reveal a protective role for the DPP-4 inhibitor sitagliptin in wound healing by regulating adiponectin and phospho-eNOS levels in keratinocytes. Based on these results, the DPP-4 inhibitor may have therapeutic potential for healing wounds through a diabetes-independent mechanism.

Nanomedicines and gene therapy for the delivery of growth factors to improve perfusion and oxygenation in wound healing

Oxygen plays a key role in wound healing, and hypoxia is a major cause of wound healing impairment; therefore, treatments to improve hemodynamics and increase wound oxygenation are of particular interest for the treatment of chronic wounds. This article describes the roles of oxygen and angiogenesis in wound healing as well as the tools used to evaluate tissue oxygenation and perfusion and then presents a review of nanomedicines and gene therapies designed to improve perfusion and oxygenation and accelerate wound healing.

Managing Complications in Abdominoplasty: A Literature Review

Background

Abdominoplasty, with or without liposuction, is among the most frequently performed aesthetic procedures. Its main objective is to improve the body contour by means of excising redundant skin and fat tissue. Although abdominoplasty is considered a safe procedure with high satisfaction rates, intraoperative and postoperative complications can become a challenge for the surgical team. The aim of this article is to offer a synopsis of the most common complications arising after abdominoplasty, along with evidence-based guidelines about how to prevent and treat them.

Methods

A systematic MEDLINE search strategy was designed using appropriate Medical Subject Headings (MeSH) terms, and references were scanned for further relevant articles.

Results

According to the published case series, local complications are considerably more common than complications with systemic repercussions. Approximately 10% to 20% of patients suffer a local complication following abdominoplasty, while fewer than 1% suffer a systemic complication. Prevention and management strategies are critically discussed for complications including seroma, haematoma, infection, skin necrosis, suture extrusions, hypertrophic scars, neurological symptoms, umbilical anomalies, deep venous thrombosis and pulmonary thromboembolism, respiratory distress, and death.

Conclusions

The complications of abdominoplasty vary in severity and in the impact they have on the aesthetic outcomes. Recommendations for prevention and management are based on various levels of evidence, with a risk of observer bias. However, most complications can be treated appropriately following the current standards, with satisfactory results.

Oxygen therapies and their effects on wound healing

Oxygen is an important factor for wound healing. Although several different therapies investigated the use of oxygen to aid wound healing, the results of these studies are not unequivocal. This systematic review summarizes the clinical and experimental studies regarding different oxygen therapies for promoting wound healing, and evaluates the outcomes according the methodological details. A systematic literature search was conducted using Embase, Medline, Web of Science, Cochrane, PubMed publisher, and Google Scholar libraries. Clinical and experimental studies investigating oxygen for wound healing were selected. Included articles were categorized according to the kind of therapy, study design, and wound type. The methodological details were extracted and analyzed. Sixty-five articles were identified and divided in three different oxygen therapies: Local oxygen therapy, hyperbaric oxygen therapy, and supplemental inspired oxygen therapy. More than half of the included local oxygen and hyperbaric oxygen studies had one or more significant positive outcomes, 77 and 63%, respectively. Supplemental inspired oxygen therapy during gastrointestinal and vascular surgery was more likely to have a positive result than during other surgical interventions reducing surgical site infections. These many positive outcomes promote the use of oxygen treatment in the stimulation of wound healing. However, the lack of clinical studies and vast methodological diversity made it impossible to perform a proper comparison within and between the different therapies. Further randomized clinical studies are warranted to examine the value of these therapies, especially studies that investigate the more patient-friendly oxygen dressings and topical wound oxygen therapies. Also, to achieve more solid and consistent data, studies should use more standardized methods and subjects.

Hyperbaric Oxygen Therapy for Wound Dehiscence After Intraoral Bone Grafting in the Nonirradiated Patient: A Case Series

PURPOSE

In maxillofacial surgery, hyperbaric oxygen treatment is used almost exclusively as adjunctive therapy for osteoradionecrosis of the mandible in irradiated patients. It also is used to prevent the occurrence of osteoradionecrosis in the irradiated patient when dental surgery is indicated. Theoretically, hyperbaric oxygen therapy should benefit the nonirradiated patient in maxillofacial surgery (eg, patients with persistent intraoral wound dehiscences after bone grafting).

MATERIALS AND METHODS

Six nonirradiated patients underwent hyperbaric oxygen therapy because of compromised wound healing after intraoral bone grafting of the maxilla as a preimplant procedure. All patients were treated 7 to 26 times with hyperbaric oxygen therapy at 2.5 ATA.

RESULTS

All patients healed uneventfully. In retrospect, almost all patients had a history of chronic maxillary sinusitis or trauma to the operated area.

CONCLUSION

Hyperbaric oxygen therapy seems to be an effective adjunctive therapy in the treatment of nonirradiated patients with compromised intraoral maxillary bone graft healing. Chronic maxillary sinus problems or a history of trauma could predispose to wound dehiscence after bone grafting.

The occurrence of biofilm in an equine experimental wound model of healing by secondary intention

In humans, biofilm is a well-known cause of delayed healing and low-grade inflammation of chronic wounds. In horses, biofilm formation in wounds has been studied to a very limited degree. The objective of this study was thus to investigate the occurrence of biofilm in equine experimental wounds healing by secondary intention. Tissue biopsies from non-contaminated, experimental excisional shoulder and limb wounds were obtained on day 1-2, day 7-10 and day 14-15 post-wounding. Limb wounds were either un-bandaged or bandaged to induce exuberant granulation tissue (EGT) formation and thereby impaired healing. Presence of biofilm in tissue biopsies was assessed by peptide nucleic acid fluorescence in situ hybridization (PNA FISH) and confocal laser scanning microscopy (CLSM). Bandaged limb wounds developed EGT and displayed delayed healing, while shoulder and un-bandaged limb wounds healed normally. Biofilm was detected in limb wounds only. At day 14-15 biofilm was significantly more prevalent in bandaged limb wounds than in un-bandaged limb wounds (P=0.003). Further, bandaged limb wounds had a statistically significant increase in biofilm burden from day 7-10 to day 14-15 (P=0.009). The finding that biofilm was most prevalent in bandaged limb wounds with EGT formation suggests that biofilm may be linked to delayed wound healing in horses, as has been observed in humans. The inability to clear bacteria could be related to hypoxia and low-grade inflammation in the EGT, but the interaction between biofilm forming bacteria and wound healing in horses needs further elucidation.

Nanofiber-based paramagnetic probes for rapid, real-time biomedical oximetry

EPR (electron paramagnetic resonance) based biological oximetry is a powerful tool that accurately and repeatedly measures tissue oxygen levels. In vivo determination of oxygen in tissues is crucial for the diagnosis and treatment of a number of diseases. Here, we report the first successful fabrication and remarkable properties of nanofiber sensors for EPR-oximetry applications. Lithium octa-n-butoxynaphthalocyanine (LiNc- BuO), an excellent paramagnetic oxygen sensor, was successfully encapsulated in 300-500 nm diameter fibers consisting of a core of polydimethylsiloxane (PDMS) and a shell of polycaprolactone (PCL) by electrospinning. This core-shell nanosensor (LiNc-BuO-PDMS-PCL) shows a linear dependence of linewidth versus oxygen partial pressure (pO2). The nanofiber sensors have response and recovery times of 0.35 s and 0.55 s, respectively, these response and recovery times are ~12 times and ~218 times faster than those previously reported for PDMS-LiNc-BuO chip sensors. This greater responsiveness is likely due to the high porosity and excellent oxygen permeability of the nanofibers. Electrospinning of the structurally flexible PDMS enabled the fabrication of fibers having tailored spin densities. Core-shell encapsulation ensures the non-exposure of embedded LiNc-BuO and mitigates potential biocompatibility concerns. In vitro evaluation of the fiber performed under exposure to cultured cells showed that it is both stable and biocompatible. The unique combination of biocompatibility due to the PCL 'shell,' the excellent oxygen transparency of the PDMS core, and the excellent oxygen-sensing properties of LiNc-BuO makes LiNc-BuO-PDMS-PCL platform promising for long-term oximetry and repetitive oxygen measurements in both biological systems and clinical applications.

A Comparison of the Effects of Alpha and Medical-Grade Honey Ointments on Cutaneous Wound Healing in Rats

Introduction. This study compared the healing efficacy and possible adverse effects of topical Alpha and medical-grade honey ointments on cutaneous wounds in rats. Methods. To conduct the study, 22 male Sprague-Dawley rats were randomly allocated into two equal groups: (1) rats with Alpha ointment applied to the wound surface area and (2) rats with medical-grade honey ointment applied to their wounds. The ointments were applied daily during the 21-day study period. Wound contraction was examined photographically with images taken on days 0, 7, and 21 after wounding. The healing process was histopathologically assessed using skin biopsies taken from the wound sites on days 7 and 21. Results. No statistically significant difference in mean wound surface area was observed between the two study groups. According to histopathological assessment, a significant reduction in the amount of collagen deposition (P value: 0.007) and neovascularisation (P value: 0.002) was seen in the Alpha-treated rats on day 21. No tissue necrosis occurred following the application of Alpha ointment. Conclusion. Daily topical usage of Alpha ointment on a skin wound can negatively affect the healing process by inhibiting neovascularization. Topical Alpha ointment can reduce the possibility of excessive scar formation by reducing collagen deposition.

Increased oxygen exposure alters collagen expression and tissue architecture during ligature-induced periodontitis

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate the effects of increased oxygen availability on gene expression and on collagen deposition/maturation in the periodontium following disease.

MATERIAL AND METHODS

Male Wistar rats had ligatures placed around their molars to induce periodontal disease, and a subset of animals underwent hyperbaric oxygen (HBO) treatment for 2 h twice per day. At 15 and 28 d, tissue gene expression of COL1A1, transforming growth factor-β1 and alkaline phosphatase was determined; other histological samples were stained with Picrosirius red to evaluate levels of collagen deposition, maturation and thickness.

RESULTS

In animals that underwent HBO treatment, type I collagen expression was higher and collagen deposition, maturation and thickness were more robust. Reduced mRNA levels of transforming growth factor-beta1 and alkaline phosphatase in HBO-treated rats on day 28 suggested that a quicker resolution in both soft tissue and bone remodeling occurred following oxygen treatment. No differences in inflammation were observed between groups.

CONCLUSIONS

The extracellular matrix regenerated more quickly in the HBO-treated group as evidenced by higher collagen expression, deposition and maturation.

Lack of association between arterial oxygen tensions in horses during exploratory coeliotomy and post-operative incisional complications: A retrospective study

The aim of this retrospective study was to determine if there was an association between the lowest arterial blood oxygen tensions (PaO2) measured during anaesthesia and post-operative incisional complications in horses. Clinical records of 278 horses undergoing ventral midline coeliotomy from 1 January 2010 to 31 December 2013 were examined. The frequency of incisional complications was 32.0% (n = 89). In a multivariable model, intra-operative arterial blood oxygen tensions (PaO2) were not significantly associated with development of an incisional complication (P = 0.351). Using hypertonic (7.2%) saline (P = 0.028, OR 3.167, 95% CI 1.132-8.861), increasing total plasma protein concentration (TP) (P = 0.002, OR 1.061 per g/L, 95% CI 1.021-1.102), an intestinal resection (P <0.001, OR 4.056, 95% CI 2.231-9.323), increasing body mass (P = 0.004, OR 1.004 per kg, 95% CI 1.001-1.006) and the use of penicillin alone compared with penicillin and gentamicin pre-operatively (P = 0.009, OR 4.145, 95% CI 1.568-10.958) increased the risk of incisional complications. The study was unable to demonstrate a link between low intra-operative PaO2 and increased risk of post-operative incisional complications.

The external microenvironment of healing skin wounds

The skin wound microenvironment can be divided into two main components that influence healing: the external wound microenvironment, which is outside the wound surface; and the internal wound microenvironment, underneath the surface, to which the cells within the wound are exposed. Treatment methods that directly alter the features of the external wound microenvironment indirectly affect the internal wound microenvironment due to the exchange between the two compartments. In this review, we focus on the effects of temperature, pressure (positive and negative), hydration, gases (oxygen and carbon dioxide), pH, and anti-microbial treatment on the wound. These factors are well described in the literature and can be modified with treatment methods available in the clinic. Understanding the roles of these factors in wound pathophysiology is of central importance in wound treatment.

Response of endothelial cells and pericytes to hypoxia and erythropoietin in a co-culture assay dedicated to soft tissue repair

The increasing mean life expectancy of the citizens of the western world countries leads to an increase of the age-related diseases, among them soft tissue defects exhibiting inadequate healing. In order to develop new therapeutic strategies to support disturbed soft tissue repair, there is a strong need of sophisticated in vitro assays. A new assay combining scratch wounding with co-cultures of primary human microvascular endothelial cells (HDMEC) and pericytes (HPC) focuses on basic characteristics of cell interaction against the background of soft tissue repair. The cell parameters proliferation, migration and differentiation, and the release of monocyte chemoattractant protein-1 (MCP-1) were analysed in response to hypoxia (pO2 < 5 mmHg) and to erythropoietin (EPO; 50 IU/ml), a glycoprotein hormone having shown promising effects in soft tissue repair. As basic characteristics of the assay, direct cell contact in co-culture led to a weakened proliferation of both cell types, an increase of the percentage of myofibroblast-like pericytes and to a higher release of MCP-1. Hypoxia caused a proliferation decrease of HPC in co-culture, which was slightly attenuated by EPO. Hypoxia also reduced the MCP-1 release of co-cultured cells, when EPO had been added. In addition, EPO had a rather positive effect on HPC migration under hypoxia. These in vitro results allow new insights into the interaction of pericytes with endothelial cells in the context of soft tissue repair.

Intra-operative tissue oxygen tension is increased by local insufflation of humidified-warm CO2 during open abdominal surgery in a rat model

INTRODUCTION

Maintenance of high tissue oxygenation (PtO2) is recommended during surgery because PtO2 is highly predictive of surgical site infection and colonic anastomotic leakage. However, surgical site perfusion is often sub-optimal, creating an obstructive hurdle for traditional, systemically applied therapies to maintain or increase surgical site PtO2. This research tested the hypothesis that insufflation of humidified-warm CO2 into the abdominal cavity would increase sub-peritoneal PtO2 during open abdominal surgery.

MATERIALS AND METHODS

15 Wistar rats underwent laparotomy under general anesthesia. Three sets of randomized cross-over experiments were conducted in which the abdominal cavity was subjected to alternating exposure to 1) humidified-warm CO2 & ambient air; 2) humidified-warm CO2 & dry-cold CO2; and 3) dry-cold CO2 & ambient air. Sub-peritoneal PtO2 and tissue temperature were measured with a polarographic oxygen probe.

RESULTS

Upon insufflation of humidified-warm CO2, PtO2 increased by 29.8 mmHg (SD 13.3; p<0.001), or 96.6% (SD 51.9), and tissue temperature by 3.0°C (SD 1.7 p<0.001), in comparison with exposure to ambient air. Smaller, but significant, increases in PtO2 were seen in experiments 2 and 3. Tissue temperature decreased upon exposure to dry-cold CO2 compared with ambient air (-1.4°C, SD 0.5, p = 0.001).

CONCLUSIONS

In a rat model, insufflation of humidified-warm CO2 into the abdominal cavity during open abdominal surgery causes an immediate and potentially clinically significant increase in PtO2. The effect is an additive result of the delivery of CO2 and avoidance of evaporative cooling via the delivery of the CO2 gas humidified at body temperature.

Systemic administration of hemoglobin improves ischemic wound healing

BACKGROUND

Oxygen plays multifaceted roles in wound healing, including effects on cell proliferation, collagen synthesis, angiogenesis, and bacterial killing. Oxygen deficit is a major factor in the pathogenesis of chronic wounds.

MATERIALS AND METHODS

We present a novel mechanism for oxygen delivery to ischemic wounds by systemic administration of an oxygen carrier substitute derived from bovine hemoglobin (IKOR 2084) in our ischemic rabbit ear wound model. The wound healing indexes, including epithelial gap and neo-granulation tissue area, were histologically analyzed. In situ expression of endothelial cells (CD31+) and proliferative cells (Ki-67+) were examined by immunohistochemistry analysis. The messenger RNA expression of collagen I, III, and vascular endothelial growth factor was measured by quantitative RT-PCR. Sirius Red staining was implemented for detection of collagen deposition, and terminal deoxynucleotidyl transferase dUTP nick end labeling analysis was performed to examine dermal cellular apoptosis.

RESULTS

Systemic administration of IKOR 2084 significantly improved oxygen tension of ischemic tissue. When compared with saline controls, IKOR 2084 treatment enhanced wound repair as demonstrated by a reduced epithelial gap and increased granulation tissue area. The expression of Ki-67+, CD31+, vascular endothelial growth factor and collagen was also enhanced by IKOR 2084 administration. Moreover, apoptosis analysis in the wounds showed that cell survival in the dermis was increased by systemic IKOR 2084 administration.

CONCLUSIONS

Our study suggests that systemic delivery of IKOR 2084 ameliorates hypoxic state, subsequently promotes angiogenesis, cellular proliferation, and collagen synthesis, attenuates hypoxia-induced apoptosis, and improved ischemic wound healing.

Can hyperbaric oxygen be used to prevent deep infections in neuro-muscular scoliosis surgery?

BACKGROUND

The prevalence of postoperative wound infection in patients with neuromuscular scoliosis surgery is significantly higher than that in patients with other spinal surgery. Hyperbaric oxygen has been used as a supplement to treat postsurgical infections. Our aim was to determine beneficiary effects of hyperbaric oxygen treatment in terms of prevention of postoperative deep infection in this specific group of patients in a retrospective study.

METHODS

Forty two neuromuscular scoliosis cases, operated between 2006-2011 were retrospectively reviewed. Patients who had presence of scoliosis and/or kyphosis in addition to cerebral palsy or myelomeningocele, postoperative follow-up >1 year and posterior only surgery were the subjects of this study. Eighteen patients formed the Hyperbaric oxygen prophylaxis (P-HBO) group and 24, the control group. The P-HBO group received 30 sessions of HBO and standard antibiotic prophylaxis postoperative, and the control group (received standard antibiotic prophylaxis).

RESULTS

In the P-HBO group of 18 patients, the etiology was cerebral palsy in 13 and myelomeningocele in 5 cases with a mean age of 16.7 (11-27 yrs). The average follow-up was 20.4 months (12-36mo). The etiology of patients in the control group was cerebral palsy in 17, and myelomeningocele in 7 cases. The average age was 15.3 years (8-32 yrs). The average follow-up was 38.7 months (18-66mo). The overall incidence of infection in the whole study group was 11.9% (5/42). The infection rate in the P-HBO and the control group were 5.5% (1/18), and 16.6% (4/24) respectively. The use of HBO was found to significantly decrease the incidence of postoperative infections in neuromuscular scoliosis patients.

CONCLUSION

In this study we found that hyperbaric oxygen has a possibility to reduce the rate of post-surgical deep infections in complex spine deformity in high risk neuromuscular patients.

A novel model of chronic wounds: importance of redox imbalance and biofilm-forming bacteria for establishment of chronicity

Chronic wounds have a large impact on health, affecting ∼6.5 M people and costing ∼$25B/year in the US alone. We previously discovered that a genetically modified mouse model displays impaired healing similar to problematic wounds in humans and that sometimes the wounds become chronic. Here we show how and why these impaired wounds become chronic, describe a way whereby we can drive impaired wounds to chronicity at will and propose that the same processes are involved in chronic wound development in humans. We hypothesize that exacerbated levels of oxidative stress are critical for initiation of chronicity. We show that, very early after injury, wounds with impaired healing contain elevated levels of reactive oxygen and nitrogen species and, much like in humans, these levels increase with age. Moreover, the activity of anti-oxidant enzymes is not elevated, leading to buildup of oxidative stress in the wound environment. To induce chronicity, we exacerbated the redox imbalance by further inhibiting the antioxidant enzymes and by infecting the wounds with biofilm-forming bacteria isolated from the chronic wounds that developed naturally in these mice. These wounds do not re-epithelialize, the granulation tissue lacks vascularization and interstitial collagen fibers, they contain an antibiotic-resistant mixed bioflora with biofilm-forming capacity, and they stay open for several weeks. These findings are highly significant because they show for the first time that chronic wounds can be generated in an animal model effectively and consistently. The availability of such a model will significantly propel the field forward because it can be used to develop strategies to regain redox balance that may result in inhibition of biofilm formation and result in restoration of healthy wound tissue. Furthermore, the model can lead to the understanding of other fundamental mechanisms of chronic wound development that can potentially lead to novel therapies.

Influence of oxygen on wound healing

Oxygen has an important role in normal wound healing. This article reviews the evidence concerning the role of oxygen in wound healing and its influence on the different stages of wound healing. The evidence reviewed has demonstrated that improving oxygenation may be helpful in limiting wound infection, although there is a lack of good quality studies on the role of oxygen in the proliferative phase and in reepithelialisation. Overall, the relationship between oxygen and wound healing is complex. Knowledge of this aspect is important as many treatment modalities for refractory wounds are based on these principles.