Innovations and Emerging Technologies in Wound Care

Amit Gefen

• Publisher: Academic Press
• Year: 2019
• ISBN:
  9780128150290
• Topic: Sciences biologiques
• Subtopic: Biotechnologie

Innovations and Emerging Technologies in Wound Care is a pivotal book on the prevention and management of chronic and non-healing wounds. The book clearly presents the research and evidence that should be considered when planning care interventions to improve health related outcomes for patients. New and emerging technologies are discussed and identified, along with tactics on how they can be integrated into clinical practice. This book offers readers a bridge between biomedical engineering and medicine, with an emphasis on technological innovations. It includes contributions from engineers, scientists, clinicians and industry professionals.

Users will find this resource to be a complete picture of the latest knowledge on the tolerance of human tissues to sustained mechanical and thermal loads that also provides a deeper understanding of the risk for onset and development of chronic wounds.

• Describes the state-of-knowledge in wound research, including tissue damage cascades and healing processes
• Covers all state-of-the-art technology in wound prevention, diagnosis, prognosis and treatment
• Discusses emerging research directions and future technology trends in the field of wound prevention and care
• Offers a bench-to-bedside exploration of the key issues that affect the practice of prevention and management of non-healing wounds

Chapter 1

Mathematical models of healing of burns

F.J. Vermolen Delft Institute of Applied Mathematics, Delft University of Technology, Delft, The Netherlands

Abstract

This chapter reviews the advantages and shortcomings of several classes of mathematical models that are used for the simulation of skin evolution after serious burn trauma. The models that are considered range from purely phenomenological formalisms to agent-based models, where each cell is dealt with individually, to continuum-based models that are based on partial differential equations, and to cellular automata models. Most of the work has been published elsewhere; however, this chapter treats the relation between cellular automata models and the Fisher–Kolmogorov equation, which is an elementary continuum-based model, and several correlations between the intensity of the final contraction and several evolutionary stages during the contraction process. These matters are part of original research and have not been published anywhere else.

Keywords

Agent-based modeling; Burn injuries; Cellular automata; Continuuum-based modeling; Mathematical modeling; Uncertainty quantification

1. 1. Introduction
2. 2. Biological mechanisms
3. 3. Methodologies
   1. 3.1 Agent-based models
   2. 3.2 Continuum-based models
   3. 3.3 Cellular automata models
4. 4. Discussion
5. 5. Conclusions
6. References
7. Further reading

1. Introduction

Serious burn injuries and other deep tissue injuries often accompany with problematic complications on the patient's skin. These complications can be the formation of hypertrophic scar tissue, which worsens the appearance of the skin, and can leave itchy sometimes painful sensations. Another major complication is the development of a severe contraction that in the worse cases leads to disability of the patient. If this is the case, then the contraction is usually referred to as a contracture. Combinations of development of excessive scar tissue and contractures are very frequent. Contractures are often treated by splinting, applying flaps, or skin grafting (skin transplantation) (see Refs. [1,2] and references therein).

To optimize therapy that is applied to treat burn injuries, a thorough understanding of the physiological processes that are occurring in the skin after trauma is crucially important. Developing such understanding requires experimental studies, where these studies contain patient (clinical) data, as well as animal experiments and in vitro experimental studies. Clinical data involve patient data, which are very useful, but highly uncontrollable because each patient has his or her own genetic pattern, gender, pigmentation, lifestyle, and age. Another complicating factor arises from the fact that burn traumas are often the result of accidents, which makes the wound architecture more unpredictable. In vitro studies, although very useful and very well controllable, focus only on few aspects, and it is questionable whether the observations from these in vitro experiments are representative for the wound behavior in human skin. All these experimental observations should be seen as models for the evolution of posttrauma human skin. Animal-based studies for therapy are receiving less and less support because of ethical concerns, and it is not sure whether experimental results observed on animals are transferrable to humans.

A recent development is the construction of in silico (computer-based) models for (human) skin evolution after trauma. Although in silico models cannot entirely replace experimental studies, we do believe that these models can be used to reduce the number of (animal-based) experiments and that these models can contribute to the understanding of various phenomena in biological medicine. Furthermore, these models can be of great value for the prediction of different scenarios that patients may be faced with. The computer models can be used to retrieve, quantify, and analyze scenarios that have not been measured. The collaboration between sciences such as mathematics and physics has existed for centuries. This differs largely from the collaboration between biologists, physicians, and mathematics. The last-mentioned collaboration only exists during the latest past decades. A complicating factor that arises in biological sciences is the large amount of uncertainty. The success rate of a therapy often varies from patient to patient. Possible reasons for the variability of the success rate are not only gender, lifestyle, and age but also genetic constitution or the presence of (unknown) other diseases. All these aspects render many biological processes in the human body even more unpredictable. These uncertainties imply that the various input parameters that are needed for the computer simulations contain uncertainties as well. Appropriate mathematical formalisms will have to deal with this degree of uncertainty.

This chapter reports on a review about various modeling studies and approaches in the context of skin evolution after serious burn trauma. The work that has been done in our group will be paid most attention. The models that have been studied will entail agent-based modeling, in which each cell is treated individually, as well as continuum-scale models. Some new results from cellular automata models will be presented as well. This modeling type is applied to wound closure, but it can be extended very easily to other phenomena. We will end up with some conclusions and discussion regarding modeling and the current models.

2. Biological mechanisms

In the introduction, it has been mentioned that various mathematical modeling approaches exist for the simulation of posttrauma skin evolution. Before the description of the various mathematical methodologies, we first review the sequence of the most important biological processes that occur during skin evolution after serious trauma, such as wounding or burn injury. A more detailed description of the physiology of wound healing processes, such as contraction, angiogenesis, wound closure, and chains of other biological subprocesses, can be found in Ref. [3].

Wound healing is a very complicated process, in which many biological processes interact, and therefore we can only briefly summarize the sequence of processes. In very superficial wound, only the epidermis (upper layer of skin) is damaged and repair amounts to restoring the epidermis. The epidermis consists of several layers, but most importantly keratinocytes constitute this layer and this layer is restored by a combination of keratinocyte migration and proliferation. To this extent, this repair mechanism is relatively straightforward compared to the restoration of deeper wounds. If it comes to deep tissue injury, then the dermis is damaged. The dermis consists of tiny blood vessels (capillaries), immune cells (macrophages), collagen (extracellular matrix), and fibroblasts. The first step in wounds that have been caused by cuts or incisions is the flow and loss of blood from the capillaries. The blood cells, platelets, make the blood coagulate and this (temporarily) closes the wound such that further loss of blood and ingress of contaminants and pathogens is prevented. This phase is referred to as hemostasis. The formed connective tissue (fibrin), which is th...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Foreword
• Chapter 1. Mathematical models of healing of burns
• Chapter 2. Ultrasound and magnetic resonance imaging methods for determining pressure injury risk
• Chapter 3. Computational modeling of the thin muscle layer, panniculus carnosus, demonstrates principles of pressure injury and prophylactic dressings
• Chapter 4. Lower leg compression and its biomechanical effects on the soft tissues of the leg
• Chapter 5. Real-time computer modeling in prevention of foot pressure ulcer using patient-specific finite element model and model order reduction techniques
• Chapter 6. Bioengineering studies of cell migration in wound research
• Chapter 7. Heel ulcers: investigating injurious tissue load thresholds in humans, based on a patient-specific computational heel model
• Chapter 8. Shape memory polymers for design of smart stocking
• Chapter 9. Emerging electroporation-based technologies for wound care
• Chapter 10. Deep tissue pressure injury: a clinical perspective regarding a condition that evolves under the skin
• Chapter 11. Skin health and integrity
• Chapter 12. Animal models in chronic wound healing research: for innovations and emerging technologies in wound care
• Chapter 13. Smart technologies in wound prevention and care
• Chapter 14. Method for improving skin color accuracy of three-dimensional printed training models for early pressure ulcer recognition
• Chapter 15. Effects of friction and pressure on skin in relation to pressure ulcer formation
• Chapter 16. Silver–enzyme hybrids as wide-spectrum antimicrobial agents
• Chapter 17. Biomechanical aspects of skin aging—the risk of skin breakdown under shear loading increases with age
• Chapter 18. Developing standard test methods for assessment of medical devices in the fields of wound prevention and care
• Index