Keloids And Hypertrophic Scars Notes

Wound Keloid And Hypertrophic Scar

Differentiate the various types of wounds, and plan and observe the management of wounds.

Wound Keloid And Hypertrophic Scar Definition:

A discontinuity or break in the surface epithelium.

Types Of Wounds Classification

1. Simple vs. Complex

• Simple wounds: Involve only skin.
• Complex wounds: Involve underlying nerves, vessels and tendons.

Read And Learn More: General Surgery Notes

2. Closed vs. Open Wounds

Closed wounds

• Contusion
• Abrasion
• Haematoma

Closed wounds Contusions: These can be a minor soft tissue injury without a break in the skin, or a major injury such as when being run over by a vehicle.

Generally, they produce discolouration of the skin due to a collection of blood underneath it.

Closed wounds Abrasions: In these wounds, the epidermis of the skin is scraped away.

These wounds are painful because they expose dermal nerve endings. They require cleaning, antibiotics, and proper dressings.

Closed wounds Haematomas: These refer to a collection of blood usually following injury. These may occur spontaneously in patients who have bleeding tendencies like haemophilia.

• Depending on the site, they may be subcutaneous, intramuscular, intra-articular, or even subperiosteal.
• A knee joint haematoma may need to be aspirated followed by the application of a compression bandage. Small haematomas are usually absorbed and may get infected if they are not.

Open wounds

• Incised
• Lacerated
• Penetrating
• Crushed

Open wounds Incised wounds: These are caused by sharp objects, such as a knife, blade, or glass. They have a sharp edge and are usually less contaminated. They are ideally treated by primary suturing, which results in a neat and clean scar.

Open wounds Lacerated wounds: These are caused by blunt injury, such as a fall on a stone or a road traffic accident (RTA). The edges are jagged. The injury may either involve only skin and subcutaneous tissue or deeper structures as well.

• Due to the blunt nature of the trauma, there is crushing of the tissue which may result in a haematoma, bruising, or even necrosis.
• These wounds are treated by wound excision and primary suturing provided they are performed within six hours of the injury.

Open wounds Penetrating wounds: These are not uncommon. Stab injuries of the abdomen are a very notorious example.

• These may look like an innocent injury with a small 1–2 cm cut, but internal organs like the intestines, liver, spleen, or mesenteric blood vessels might also be damaged.
• All penetrating wounds of the abdomen should be admitted and observed for at least 24 hours. Layer-by-layer exploration and repair are recommended, but may not always be possible due to the oblique track of the injury.

Open wounds Crushed wounds: These are caused by blunt trauma due to RTAs, wall collapses, earthquakes or industrial accidents.

• These wounds are dangerous as they may cause severe haemorrhage, death of the tissues, and or crushing of blood vessels. These patients are more prone to gas gangrene and tetanus.
• Adequate treatment involves a thorough debridement to remove all dead and necrotic tissue.

3. Tidy vs. Untidy Wounds

Tidy wounds: Incised, clean, healthy tissue, seldom associated with tissue loss.

Repair in Tidy Wound

• Nerves: Fascicular repair under magnification (loupe or microscope) using 8–0 or 10–0 monofilament nylon
• Artery: To be repaired by using 6–0 proline
• Tendon repaired by monofilament nonabsorbable suture (polypropylene 3–0 or 4–0)
• Skin loss: Skin flap or skin graft

Tidy Untidy wounds: Crushed or avulsed, contaminated, devitalised tissues, often associated with tissue loss.

4.  Acute vs. Chronic Wounds

• Acute wounds: Stab wounds, RTAs, and blast injuries.
• Chronic wounds: Leg ulcers and pressure sores.

General Principles of Open Wound Management

• Admission or observation in the hospital.
• Monitoring of vitals.
• Systemic antibiotics depend on the extent of wound contamination.
• Injection of tetanus toxoid for prophylaxis against tetanus.
• Treatment of the wound by cleaning, dressing, or suturing

General Principles of Open Wound Management Healing Of The Wound

• Healing by primary intention occurs in clean, incised wounds (for example. surgical incisions) wherein there is only a potential space between the edges. It produces a clean, neat, thin scar.
• Healing by secondary intention occurs in infected wounds or in those with skin loss. It produces an ugly scar.

Components Of Wound Healing

Wound healing

Describe normal wound healing and factors affecting healing.

1. Inflammatory (Lag) Phase

• Injury results in the release of inflammatory mediators, mainly histamine from platelets, mast cells and granulocytes. This results in increased capillary
  permeability.
• Later, kinins and prostaglandins play a chemotactic role in white blood cells and fibroblasts.
• In the first 48 hours, polymorphonuclear (PMN) leucocytes dominate and play the role of scavengers by removing dead and necrotic tissue ).

2. Proliferative (Collagen) Phase

• Between days 3–5, PMN leukocytes diminish in number, and monocytes, which play the role of specialised scavengers, increase.
• By day 5 or 6, fibroblasts appear, proliferate, and eventually give rise to a protocollagen, which is converted into collagen in the presence of protocollagen hydroxylase. O₂, ferrous ions and ascorbic acid are necessary for this step.

• Fibroplasia and capillary budding give rise to granulation tissue.
• Ground substances and mucopolysaccharides (proteoglycans) are secreted by fibroblasts and help in the binding of collagen fibres. Thus, a wound is composed of a Fibre + Gel + Fluid system (resembles Iron rods + Cement + Water used for a concrete slab).
• Epithelialisation occurs mainly from the edges of the wound through cell migration and multiplication. This is mainly brought about by marginal basal cells.
  • The entire wound is re-epithelialised within 48 hours. When there is a wound with skin loss, skin appendages also help in epithelialisation. Slowly, the
    skin surface gets keratinised.

3. Remodelling (Maturation) Phase

• It occurs between days 5 and 14.
• It is brought about by myofibroblasts (specialised fibroblasts with contractile elements). It is nature’s way of reducing the size of the defect to aid in wound healing.
• Wound contraction readily occurs in areas of loose skin like the back and gluteal region, and is greatly reduced in wounds over the tibia (shin) or malleolar surface. Corticosteroids, irradiation, and chemotherapy delay wound contraction.
• Connective tissue formation: The formation of granulation tissue is the most important and fundamental step in wound healing. (It can be compared to concrete slab laying.)

4. Phase of Scar Formation

• Fibroplasia and the laying of collagen increases
• Vascularity reduces (devascularisation)
• Epithelialisation continues
• Ingrowth of lymphatics and nerve fibres takes place
• Remodelling of collagen takes place with cicatrisation, resulting in a scar

Complications Of Wound Healing

1. Infection: It is the most important complication and results in delayed wound healing. The majority of bacteria are endogenous. Depending upon the pus or culture-sensitivity report, appropriate antibiotics are given.
2. Ugly scar: It is the result of infections.
3. Keloid and hypertrophic scar
4. Incisional hernia and wound dehiscence
5. Pigmentation of the skin
6. Marjolin’s ulcer.

Wound Closure Or Wound Suturing

1. Primary suturing: Wound suturing within a few (ideally 6) hours following an injury. Primary suturing can be done provided:

• The wound was incised or cut with a sharp object, such as a knife or razor blade.
• There is minimal injury to surrounding structures.
• There is no wound infection. If a wound is sutured in the presence of infection, the suture material is eaten away (digested) by organisms, which results in wound gaping.

Primary suturing Precautions to be taken:

• If any foreign body is present, it should be removed.
• Any associated injuries to blood vessels, nerves, or tendons should be recognised and repaired.
• Wounds over the abdomen may have associated visceral injuries—look for and treat them, if present.
• Tetanus toxoid 0.5 ml should be administered intramuscularly to prevent tetanus.

2. Wound excision and primary suturing of skin

This is indicated when:

• The wound edges are jagged.
• The wound is contaminated.
• Tissues are crushed and devitalised.
• In such situations, the wound is explored and the devitalised tissues and or foreign body, if present, are removed. The wound is irrigated with antiseptic agents. Thus, a lacerated wound is converted into an incised wound and then sutured.

Wound excision and primary suturing of skin Precautions to be taken are:

• It should be done within 6 hours.
• Prophylaxis should be given for tetanus and gas gangrene.
• Repair of tendons and nerves may be done at a later date if there is excessive contamination.

3. Wound excision and delayed primary suturing This is indicated in lacerated wounds with major crush injuries. Primary suturing within 6 hours is not performed in these wounds because of:

• Gross oedema
• Increased tissue tension
• Haematoma
• Contamination with bacteria

Compartment syndrome may result if primary suturing is performed in such situations.

• All dead tissues should be excised
• The wound should be irrigated with saline and left open without suturing. A dressing should be applied.
• The wound should re-examined 4–6 days later. If there is no infection or non-viable tissues, the wound is sutured. This two-stage procedure is called delayed primary suturing.

Wound with skin loss: It may occur after surgical procedures or accidents, etc.

Complications Of Wound Healing Principles of debridement

• Ideally done under general anaesthesia
• Assess the extent of injury or tissue loss
• Control bleeding
• Excision of devitalised tissue, ideally using scissors
• Good saline wash or irrigation is better than betadine or hydrogen peroxide wash.

Complications Of Wound Healing Complications of skin loss

• Secondary wound infection.
• The underlying structures like tendons and nerves are in danger.
• Diabetic patients may develop septicaemia.
• Deformity and disability may occur at a later date.
• Hence, skin grafting should be done as soon as possible.

4. Secondary suturing

Postoperatively, sutures may give way due to persistent discharge of pus caused by severe infections. In such cases, 7–14 days later (after controlling infection), the skin is freed from the edge of the wound and the granulation tissue and skin are approximated. This type of suturing is called secondary suturing.

Characteristics Of An Ideal Wound Dressing

• Creates a moist environment
• Removes excess exudates
• Prevents desiccation
• Allows gaseous exchange
• Impermeable to microorganisms
• Thermally insulating
• Prevents particulate contamination
• Provides mechanical protection
• Non-toxic
• Non-traumatic
• Easy to use and cost-effective

Characteristics Of An Ideal Wound Types of dressings:

• Non-adherent fabrics
• Absorptive: Gauze, foams
• Occlusive:
  • Nonbiologic: Films, hydrocolloids, alginates, hydrogels
  • Biological: Homografts, xenografts
• Creams and ointments: Antibacterial, enzymatic

Hyperbaric Oxygen (HBO)

HBO uses oxygen as a drug and a hyperbaric chamber as a tool for elevating oxygen concentration to the target area.

• Transcutaneous oxygen pressure (TcPO₂ ) is used to assess wound oxygenation (<35 mmHg is significant).
• The rationale for HBO treatment is that tissue hypoxia or ischaemia results in impaired wound healing.
• Patients who benefit from HBO are those with marked hypoxic wounds.
• HBO therapy involves inhalation of 100% oxygen at a pressure of 1.9–2.5 times the atmospheric pressure for 90–120 min. Oxygenation may be up to 10 times higher than usual.
• Treatment is given once daily, 5–6 times/week.
• Complications include middle ear barotrauma, pneumothorax, seizures, and respiratory distress syndrome.
• Contraindications for HBO include pneumothorax, and treatment with doxorubicin, bleomycin or disulfiram.

Negative Pressure Assisted Wound Closure

This technique can be used to treat acute and chronic wounds.

• It may lead to a reduction in oedema, an increase in local blood flow, and stimulation of granulation tissue.
• Its exact mechanism is unknown. However, it is believed that this technique leads to wound healing by removing exudates while keeping the wound moist.
• It stimulates endothelial proliferation and angiogenesis and causes increased cellular proliferation and a higher microvessel density.
• It also alters wound fluid composition by removing proteinases and inflammatory cytokines and increases the speed of healing.
• It causes significant improvements in cost-effectiveness and a decreased length of hospital stay.
• It is particularly beneficial for large wounds.

Factors Affecting Wound Healing

General Factors

Describe normal wound healing and factors affecting healing.

1. Age: Wounds heal faster in children. In old age, wound healing is delayed because dermal collagen content decreases with ageing. In addition, collagen fibres in elderly patients show distorted architecture and organisation.

2. Debilitation results in malnutrition. Wound healing is delayed probably because of vitamin C deficiency. Following injury, vitamin C deficiency can occur after 3–4 weeks.

• Vitamin C is necessary for the synthesis and maintenance of collagen. Zinc deficiency is known to delay the healing of the pilonidal sinus.
• Zinc deficiency is rare—it occurs in large burns, severe polytrauma, and hepatic cirrhosis.

Factors Affecting Wound Healing Diabetes and Wound Healing Factors

• Tissue hypoxia due to atherosclerosis
• Thickened basement membrane →↓ tissue perfusion
• Trauma—repetitive due to neuropathy
• Tissue metabolism is increased—relative hypoxia
• Total failure of defence mechanism
• Observe 5 Ts

Factors Affecting Wound Healing Chemotherapeutic Drugs

• Decrease mesenchymal cell proliferation
• Reduce the number of platelets
• Reduce inflammatory cells
• Reduce growth factors
• Decrease wound-breaking strength

3. In diabetic patients, wound healing is delayed because of several factors such as microangiopathy, atherosclerosis, decreased phagocytic activity, the proliferation of bacteria due to high blood sugar, etc. Also, a poor immune response is seen in diabetic patients.

4. Jaundiced and uraemic patients have poor wound healing because fibroblastic repair is delayed.

5. Cytotoxic drugs such as doxorubicin and malignancy delay healing.

6. Systemic infection or inflammation: Infection of inflammation in some part of the body delays wound healing.

7. Corticosteroids, if given early, may delay wound healing because of their anti-inflammatory properties. However, they do not interfere once healing is established.

8. Malnutrition: This results in delayed wound healing including intestinal anastomotic leakage and wound dehiscence.

Factors Affecting Wound Healing Local Factors

1. Poor blood supply: Wounds over the knee or shin heal very slowly, but wounds on the face heal fast.

2. Local infection: Organisms eat away the suture material, destroy granulation tissue, and cause slough and purulent discharge.

• If the bacterial count exceeds 105 organisms or mg tissue or if any β-haemolytic streptococci are present, the wound will not heal.
• Collagen synthesis is reduced and collagenolysis is increased. Antibiotics should be given immediately or within 2 hours to prevent infection.

3. Haematoma precipitates infection.

4. Faulty technique of wound closure.

5. Tension while suturing.

6. Hypoxia: This may reduce the killing property of macrophages and the production of fibroblasts. If contamination occurs, the tissue oxygen level decreases.

• Collagen synthesis is affected in cases of hypoxia. In anaemic patients, wound healing is delayed because of decreased angiogenesis and decreased collagen production.
• Smoking causes vasoconstriction and elevated carbon monoxide levels.

7. Ionising radiation: It causes endothelial cell injury with endarteritis and results in atrophy and fibrosis.

8. The foreign body prevents healing because it precipitates infection.

Compartment Syndrome

Typically occurs in closed lower limb injuries.

• Following trauma, an inflammatory reaction results in gross oedema of the region.
• These occur in tight, divided compartments in the leg that contain nerves and vessels.

Compartment Syndrome Definition

• It is a serious condition characterised by increased pressure in one of the compartments of the body (for example. the lower limb in case of a fractured leg), resulting in ischaemia of the tissues.
• In the lower limb, vessels, nerves and muscles are enclosed by tight unyielding fascia. This is the reason why even a small amount of blood within a compartment can give rise to compartment syndrome.

Compartment Syndrome Types

Acute: Following trauma—especially fractures of long bones of the lower limb

Chronic: Due to repeated injury to the muscles of the leg—which may be induced by exercise.

Compartment Syndrome Pathogenesis

• Following trauma to the leg, damage to the blood vessels results in ischaemia to the muscles, which in turn results in an inflammatory reaction that leads to diffuse oedema of the tissues. This is aggravated by bleeding within the compartment, resulting in compartment syndrome.
• Factors precipitating compartment syndrome include crush injuries, plaster cast applications, tight compression bandages, anticoagulants, burns, etc.

Compartment Syndrome Clinical Features

• Severe pain in the leg, disproportionate to the severity of the trauma.
• Sensory disturbances due to nerve compression.
• Pain, pallor, pulselessness, paraesthesia, and paralysis are other features which may occur within 12 hours of the onset of compartment syndrome.
• Painful passive stretching of the limb is characteristic of compartment syndrome.

Measurement Of Compartmental Pressure

• It is measured by introducing a transducer catheter within 5 cm of the injury zone.
• Compartment pressure >30 mmHg of the diastolic blood pressure is suggestive of increased compartmental pressure and is an indication of urgent fasciotomy.

Measurement Of Compartmental Pressure Treatment

• The lower leg has four compartments: Anterior, lateral, superficial posterior, and deep posterior. The fasciotomy of the lower leg can be done with either a single incision or two incisions (lateral and medial).
• The two-incision technique is more common. The lateral incision is made longitudinally, approximately 2 cm anterior to the fibular shaft. The medial incision is made longitudinally, 1–2 cm posterior to the subcutaneous posteromedial border of the tibia.
• The incisions are made 8 cm long. After incising the deep fascia, the muscles bulge out. The soleus muscle must be detached from the tibia to decompress the deep flexor compartment.
• The most important aim is to preserve the blood supply by relieving the compression on the posterior tibial and peroneal arteries.

Measurement Of Compartmental Pressure Complications

• Infections
• Gangrene requires amputation.

Hypertrophic Scar And Keloid

As the name suggests, there is hypertrophy of mature fibroblasts (excessive collagen) in hypertrophic scars. Blood vessels are minimal in this condition.

• However, in keloids, the proliferation of immature fibroblasts with immature blood vessels is found. These two conditions represent variations in the normal process of wound healing.
• Keloids are very common in Africans and are least common in Caucasians.
• A keloid is not a true tumour but has a marked tendency for local recurrence after excision.
• Keloids take the shape of a butterfly over the sternum, which is its most common site of occurrence. It is extremely difficult to treat keloids over the sternum.

Comparison of hypertrophic scar and keloid

Hypertrophic Scar And Keloid Types of Scar

• Atrophic
• Hypertrophic
• Keloid

Hypertrophic Scar And Keloid Aetiology of Keloid

• Key factors: Surgery, burns, vaccinations
• Elevated levels of growth factor (more of type ‘B’ collagen)
• Laceration or abrasion
• Over the sternum (incision)
• Inheritance and injection
• Deep-pigmented skin (black)
• Remember as KELOID
• We once had a patient who had undergone wide excision and grafting 6 times for a sternal keloid. The jaw and sites of vaccination are other common sites for keloids.
• Collagen bundles are virtually absent in keloids. It is extremely difficult to treat a keloid.

Hypertrophic Scar And Keloid Keloid Sites

• High chances – Least chances
• Skin of ear lobe – Eyelid
• Presternal – Genitalia
• Deltoid – Palm, sole
• Upper back – Across joint

Any form of excision has a high chance of recurrence

What is a Contracture?

When a scar crosses joints or flexion creases, a tight ‘web’ may form which is referred to as a contracture.

Miscellaneous

Healing of Specialised Tissues Once Destroyed

• Nerve cells of the brain and spinal cord
• Peripheral nerves
• Stomach and intestines
• Colon and oesophagus
• Wounds on the face
• Muscles
• Bone
• Cannot be replaced by the proliferation of other nerve cells
• Regenerative capacity is present
• Healing is good after anastomosis and rarely leaks
• Healing is precarious, and chances of leakage are high
• Healing is excellent due to good vascularity
• Can heal completely or may be replaced by fibrosis
• The rapid proliferation of osteoblasts

Surgical Wounds

Surgical wounds may be classified depending on their nature.

Classification of surgical wounds