Non-healing wound: what to do?

While many types of wounds heal by themselves within a few weeks or reduce their size by 40% after four weeks of optimal treatment, some heal more slowly or not at all and do not respond to prescribed care. These are referred to as chronic wounds, wounds that are physiologically altered due to a disruption/interruption of the natural healing process. There are four common categories of slow-healing injuries.

• Pressure Sores (Bedsores): This type of wound is a hypoxic or anoxic lesion that affects the skin and underlying tissues, resulting from prolonged pressure on a body area. Pressure sores typically develop in bony areas (tailbone, buttocks, hip, heel, etc.), although they can occur on any part of the body. They arise due to a reduction in blood supply to the area, leading to the death of skin cells and the formation of an ulcer. These types of wounds only worsen if they are not treated.

• Ischaemic wounds : also known as arterial ulcers, ischaemic wounds occur in cases of arterial circulatory disorders. Indeed, arteries supply nutrients and oxygen to the body's tissues. When they are narrowed or blocked, a deficiency in tissue and skin irrigation is observed, which leads to a wound or a delay in healing. This type of wound most often appears at the tips of the toes, on the heel, or at the edge of the foot.

• Diabetic Foot Ulcers: Diabetes can cause neuropathy, which can lead to a total loss of sensation in the foot, as well as leg arthropathy, which can result in minor foot injuries, ulcers, infections, and even gangrene. These open wounds are most often found on the legs or the soles of the feet. Research suggests that 15% of people with diabetes will suffer from diabetic foot ulcers in their lifetime.

• Veinous ulcers: this type of wound most commonly develops between the knee and the ankle, and is associated with a disorder in the venous system of the legs (varicose veins, phlebitis). Indeed, veins are the blood vessels that return blood to the heart. Therefore, if the blood in these veins becomes stagnant, it creates significant and constant pressure within the veins, gradually damaging the blood vessels and leading to the formation of ulcers.

Chronic wounds can quickly deteriorate and become infected, particularly without appropriate treatment. Indeed, these slowly healing wounds can lead to long-term health issues, such as extreme pain, loss of function and mobility, or extended hospitalisation. In some cases, these types of injuries can result in amputation.

If your wound is not improving, do not hesitate to consult a vascular doctor or a specialist in chronic wounds. Treatment typically begins with a physical examination involving a wound inspection and the collection of patient information about their medical history (information about chronic health problems, recent surgical procedures, and current medication) in order to identify any underlying condition that could affect the body's ability to heal.

In many instances, it will first be necessary to address the underlying causes of the wound before healing can commence. The patient may undergo blood and urine tests, a wound biopsy and/or a wound culture to search for potential pathogenic microorganisms. That being said, here are some approaches a doctor might utilise to enhance wound healing which depend on the patient's age, health status, and the nature of the wound.

• Wound Debridement: This is a process under local anaesthesia that involves the removal of dead, devitalised, and necrotic tissues using surgical instruments (tweezers, curette, scalpel). Sometimes, a gel containing enzymes is also applied to help clean the wound. This aids in faster wound healing and ensures the growth of healthy tissues.

• Dressing the wound: Dressings can be particularly important for preparing the area for healing, removing excess fluid from the wound, protecting it from infections, and controlling humidity levels.

• Prescription of painkillers: Pain can cause a constriction of the blood vessels, which slows down healing, in addition to deteriorating the patient's quality of life. Therefore, the doctor may find it necessary to prescribe painkillers (acetaminophen, ibuprofen) to alleviate mild to moderate pain. However, if they are not sufficiently effective, the doctor may prescribe a more potent analgesic.

• Antibiotics: If a wound is infected, it has less chance of healing. Antibiotics can be prescribed to prevent and treat infection in cases of ulcers. They can either be applied to the wound using an ointment, or placed on the wound using a dressing.

• Nutritional Support: Patients suffering from significant chronic wounds may be predisposed to chronic malnutrition. Studies both experimental and clinical show promise in supporting the administration of dietary supplements (zinc, arginine, glutamine, vitamin A, vitamin B5, vitamin C, vitamin D) which may have beneficial effects on chronic wounds. However, further research is needed to better define the mechanisms of action, potential side effects, and the overall risk-benefit ratio of human application.

• Compression Therapy: If venous issues are the cause of the chronic wound, compression stockings can aid in faster healing. The pressure applied by the stockings helps to decrease venous pressure, reduce swelling, and improve circulation to promote wound healing.

• Hyperbaric Oxygen Therapy: in the context of chronic and complicated wounds, this type of treatment may be necessary. The patient is exposed to a high concentration of pure oxygen (2 to 3 times higher than normal) for 90 to 120 minutes in a pressurised chamber. This type of therapy helps to increase the concentration of oxygen in the blood, which improves blood supply to the injured area, aids in destroying harmful bacteria responsible for infection, stimulates the formation of new blood vessels and increases the rate of collagen deposition, promoting healing. It is particularly useful for people suffering from diabetic ulcers, chronic bedsores, venous ulcers or radiological wounds.

• Negative Pressure Therapy (Vacuum Assisted Closure system): In this therapy, a sealed dressing, connected to a suction device, is placed over the wound. The pump continuously draws exudates out of the wound, creating a negative pressure across the wound. This form of therapy promotes angiogenesis, helping to increase blood flow to the wound site, and enhances cellular proliferation and migration within the wound. In this therapy, the wound remains moist, which improves and accelerates the healing process.

• Ultrasound Therapy (Ultrasonotherapy): This treatment utilises ultrasonic waves, which are high-frequency mechanical vibrations (beyond 20,000 Hz) that are imperceptible to the human ear. It involves covering the wound area with a hydrogel film and emitting ultrasound waves, which warms the tissues, promotes blood circulation, and aids tissue regeneration.

• Skin grafts: In this procedure, skin is taken from another part of your body, usually your thigh, and transplanted onto the wound, increasing the chances for chronic wounds to close more quickly. There are also grafts made from human cellular products and synthetic materials.

• Adjuvant Therapy: available in gel form or impregnated on dressings, growth factors are important for wound healing. This includes platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), keratinocyte growth factor (KGF), epidermal growth factor (EGF) and granulocyte-macrophage colony-stimulating factor (GM-CSF).

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• YARMUSH M. L. & al. Co-delivery of a growth factor and a tissue-protective molecule using elastin biopolymers accelerates wound healing in diabetic mice. Biomaterials (2017).

• LEE J. W. & al. Effects of structurally stabilized EGF and bFGF on wound healing in type I and type II diabetic mice. Acta Biomaterialia (2018).

• LI M. & al. Vitamin D ameliorates impaired wound healing in streptozotocin-induced diabetic mice by suppressing NF-κB-mediated inflammatory genes. Bioscience Reports (2018).