Wound Healing — MCQs
Wound contraction can be most effectively minimized by:
Regeneration is characterized by:
A patient has a lacerated, untidy wound of the leg and attended the casualty department after 2 hours. His wound should be:
The following statement about keloid is true:
Granulation tissue is replaced by connective tissue in what stage of wound healing?
Which of the following is TRUE about bone healing in elderly patients?
What is the mechanism of secondary healing?
Which vitamin is known to inhibit wound healing?
What is the ideal angle for Z-plasty?
The best skin graft for an open wound is
Wound Healing Indian Medical PG Practice Questions and MCQs
Question 1: Wound contraction can be most effectively minimized by:
- A. Allowing secondary granulation
- B. Full thickness grafting (Correct Answer)
- C. Split skin graft
- D. Dressing with placenta
Explanation: ***Full thickness grafting*** - **Full-thickness skin grafts** include the epidermis and full dermis, which contains **fewer myofibroblasts** than split-thickness grafts, thus minimizing contraction. - The greater amount of dermal tissue acts as a **mechanical barrier** to prevent excessive wound contraction, providing a more stable and aesthetically pleasing result. *Allowing secondary granulation* - Healing by **secondary intention** involves substantial granulation tissue formation, which is rich in **myofibroblasts** and leads to significant wound contraction. - This method of healing is often used for infected or contaminated wounds but results in the **most contraction**. *Split skin graft* - **Split-thickness skin grafts** contain only a portion of the dermis, making them prone to **moderate to significant wound contraction**. - While better than secondary intention, the thin dermal layer provides less resistance to the contractile forces of the **myofibroblasts**. *Dressing with placenta* - **Placental tissue dressings** can promote wound healing by providing growth factors and a scaffold for regeneration. - However, they do not inherently prevent or minimize **wound contraction** in the same way that a full-thickness graft mechanically does, as they do not replace the entire dermal layer.
Question 2: Regeneration is characterized by:
- A. Granulation tissue
- B. Repairing by different type of tissue
- C. Cellular proliferation is largely regulated by biochemical factors
- D. Repairing by same type of tissue (Correct Answer)
Explanation: ***Repairing by same type of tissue*** - **Regeneration** involves the replacement of damaged cells and tissues with cells of the **same type**, leading to a complete restoration of normal structure and function [1]. - This process is seen in tissues with high proliferative capacity, like the **epidermis** or the **liver**, following injury [2]. *Granulation tissue* - **Granulation tissue** is characteristic of **repair by fibrosis** (scar formation), not regeneration [1]. - It consists of proliferating fibroblasts, new blood vessels (angiogenesis), and inflammatory cells, which eventually mature into a fibrous scar. *Repairing by different type of tissue* - The replacement of damaged tissue with a **different type of tissue** (typically fibrous connective tissue) is known as **repair by fibrosis** or **scar formation** [1]. - This occurs when the tissue's regenerative capacity is limited or when the injury is severe, resulting in the loss of normal tissue architecture and function [3]. *Cellular proliferation is largely regulated by biochemical factors* - While **cellular proliferation** is indeed regulated by **biochemical factors** (growth factors, cytokines) in both regeneration and repair, this statement describes a mechanism common to cellular growth and healing in general, not a defining characteristic unique to regeneration [1]. - This regulation guides both the replacement with original tissue (regeneration) and scar formation, so it's not specific enough to define regeneration alone. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 113-115. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 112-113. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 113.
Question 3: A patient has a lacerated, untidy wound of the leg and attended the casualty department after 2 hours. His wound should be:
- A. Debrided and sutured immediately
- B. Sutured immediately
- C. Cleaned and dressed
- D. Debrided and sutured secondarily (Correct Answer)
Explanation: ***Debrided and sutured secondarily*** - An **untidy wound** indicates contamination, irregular edges, and devitalized tissue, which significantly increases the **risk of wound infection**. - The standard management involves **thorough debridement** to remove all contaminated and non-viable tissue, followed by **delayed primary closure** (suturing after 3-5 days once the wound shows healthy granulation) or **healing by secondary intention**. - This approach is especially important for **lower extremity wounds**, which have a higher infection risk due to relatively poorer blood supply compared to facial wounds. - Even though the patient presented within 2 hours (well within the "golden period"), the **untidy nature** of the wound makes **immediate primary closure risky** and secondary closure the safer, preferred option. *Debrided and sutured immediately* - While **debridement is essential** for untidy wounds, **immediate primary closure** after debridement is generally reserved for **tidy wounds** with minimal contamination. - For untidy wounds, immediate closure increases the risk of **trapping bacteria and devitalized tissue**, leading to **wound infection**, abscess formation, or dehiscence despite being within the golden period. - Primary closure may be considered in select cases with minimal contamination and excellent debridement, but this is not the standard teaching for untidy wounds. *Sutured immediately* - **Immediate suturing without debridement** of an untidy wound would be dangerous, as it would trap contaminants, foreign material, and devitalized tissue. - This approach would significantly increase the risk of **serious wound infection**, including **gas gangrene** or necrotizing fasciitis in contaminated wounds. - Proper wound preparation is mandatory before any closure is considered. *Cleaned and dressed* - Simple **cleaning and dressing** is insufficient for an untidy wound as it does not address the devitalized tissue that requires **surgical debridement**. - While this avoids the risk of premature closure, it fails to provide adequate treatment for a wound that needs formal surgical debridement to remove non-viable tissue and reduce bacterial load. - This approach might be acceptable only as a temporary measure if surgical debridement cannot be performed immediately.
Question 4: The following statement about keloid is true:
- A. Extended excision is the treatment of choice
- B. Elevated levels of growth factor is not seen
- C. It will have more collagen and vascularity (Correct Answer)
- D. They do not extend beyond the wound
Explanation: ***It will have more collagen and vascularity*** - Keloid scars are characterized by an **overgrowth of dense, fibrous tissue**, primarily composed of **collagen fibers**, which explains the increased collagen content [1], [2]. - They also exhibit an increased number of **blood vessels (vascularity)** compared to normal skin, contributing to their often reddish or purple appearance. *Extended excision is the treatment of choice* - **Surgical excision alone** is generally **not the treatment of choice** for keloids because it has a **high recurrence rate** (often greater than 50-100%) [1]. - If excision is performed, it must be combined with **adjuvant therapies** such as corticosteroids, cryotherapy, or radiation therapy to reduce the risk of recurrence. *Elevated levels of growth factor is not seen* - Keloids are associated with **elevated levels of various growth factors**, such as **transforming growth factor-beta (TGF-$\beta$)** and ** basic fibroblast growth factor (bFGF)** [3]. - These growth factors play a crucial role in promoting **fibroblast proliferation** and **collagen synthesis**, contributing to the excessive scar formation [3]. *They do not extend beyond the wound* - This statement describes a **hypertrophic scar**, not a keloid. - **Keloids are distinctive** because they characteristically **extend beyond the boundaries of the original wound** or injury, often infiltrating surrounding healthy tissue [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 121. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 106-107. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 117-119.
Question 5: Granulation tissue is replaced by connective tissue in what stage of wound healing?
- A. 7 days (Correct Answer)
- B. 14 days
- C. 21 days
- D. 1 month
Explanation: ***21 days*** - Granulation tissue formation is prominent until about **21 days**, after which it starts to reorganize into fibrous connective tissue [1][2]. - In this stage, collagen deposition increases, contributing to **wound strength** and integrity [2]. *1 month* - By this time, connective tissue maturation continues but the primary transition from granulation tissue typically completes by **21 days** [2]. - It may lead to overestimation of healing progression as remodeling may still be ongoing. *14 days* - At **14 days**, granulation tissue is still present and not yet fully replaced by connective tissue [1]. - This stage primarily involves **vascularization** and **inflammatory responses**, not complete fibrous change [1]. *7 days* - This early phase is characterized by **hemostasis** and **inflammation**, with granulation tissue just beginning to form [1]. - Significant connective tissue replacement has not yet occurred, as the wound healing process is still at the initial stages. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 117-119. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 119-121.
Question 6: Which of the following is TRUE about bone healing in elderly patients?
- A. Enhanced Angiogenesis
- B. Better Callus Formation
- C. Faster Healing Rate
- D. Delayed Union is More Common (Correct Answer)
Explanation: ***Delayed Union is More Common*** - **Aging** is associated with a decrease in the number and activity of **osteoblasts** and stem cells, leading to a slower bone remodeling process. - Reduced **blood supply** to the fracture site and the presence of comorbidities in elderly patients contribute to delayed healing and an increased risk of complications like non-union. *Enhanced Angiogenesis* - **Angiogenesis**, the formation of new blood vessels, tends to be reduced in elderly patients due to age-related changes in growth factor production and endothelial cell function. - A compromised blood supply to the fracture site negatively impacts the delivery of essential nutrients and cells required for bone repair. *Better Callus Formation* - **Callus formation**, a crucial step in secondary bone healing, is often impaired in elderly individuals. - This impairment is due to decreased cellular activity, reduced growth factor production, and a less robust inflammatory response. *Faster Healing Rate* - Bone healing is generally **slower** in elderly patients compared to younger individuals. - This diminished healing rate is attributed to a decline in osteogenic potential, reduced vascularity, and frequently, poorer overall health status.
Question 7: What is the mechanism of secondary healing?
- A. Neovascularization
- B. Scab formation
- C. Granuloma formation
- D. Granulation tissue (Correct Answer)
Explanation: ***Granulation tissue*** - **Secondary intention healing** involves the formation of abundant **granulation tissue** to fill the tissue defect [1]. - Granulation tissue consists of new **capillaries**, **fibroblasts**, and inflammatory cells, which lay the groundwork for wound closure [2]. *Neovascularization* - **Neovascularization** is the specific process of forming new blood vessels within the wound, which is a component of granulation tissue formation, but not the overall healing mechanism [2]. - While essential for delivering nutrients and oxygen, it's a sub-process rather than the primary mechanism for secondary healing itself. *Scab formation* - **Scab formation** is an initial protective mechanism, primarily associated with superficial wounds and not the intrinsic mechanism of tissue repair and closure in secondary healing. - A scab primarily protects the underlying wound from infection and desiccation while healing occurs beneath it. *Granuloma formation* - **Granuloma formation** is a specific type of chronic inflammatory response characterized by collections of macrophages, often seen in persistent infections or foreign body reactions, not typical secondary wound healing [2]. - It indicates a **cell-mediated immune response** to a non-degradable stimulus, aiming to wall off the offending agent. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 117-119. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 105-107.
Question 8: Which vitamin is known to inhibit wound healing?
- A. Vitamin A
- B. Vitamin E (Correct Answer)
- C. Vitamin C
- D. Vitamin B complex
Explanation: ***Vitamin E*** - **High doses** or **supraphysiologic levels** of vitamin E may potentially **impair wound healing** due to anticoagulant effects and possible interference with platelet function. - Excessive vitamin E supplementation (above recommended doses) can increase **bleeding risk** at surgical and wound sites, potentially delaying healing. - **Note:** Physiologic doses of vitamin E do not inhibit wound healing; this refers specifically to excessive supplementation. *Vitamin A* - **Vitamin A** plays a crucial role in wound healing by promoting **epithelial cell differentiation** and collagen synthesis. - It aids in **immune function** and inflammation modulation, both vital for effective wound repair. - Can even counteract steroid-induced impairment of wound healing. *Vitamin C* - **Vitamin C** is essential for **collagen synthesis** and cross-linking, which provides tensile strength to healing wounds. - Acts as an **antioxidant** and is vital for immune function, supporting tissue repair processes. - Deficiency leads to impaired wound healing (scurvy). *Vitamin B complex* - **B vitamins**, particularly **B1 (thiamine)**, **B5 (pantothenic acid)**, and **B6 (pyridoxine)**, are important cofactors in metabolic processes crucial for cell proliferation and tissue repair. - They contribute to energy production and synthesis of proteins and DNA needed for wound healing.
Question 9: What is the ideal angle for Z-plasty?
- A. 90°
- B. 45°
- C. 60° (Correct Answer)
- D. 75°
Explanation: ***60°*** - An angle of **60°** is considered ideal for Z-plasty because it provides the best balance between **lengthening the scar** and maintaining **tissue viability**. - This angle typically results in a **75% gain in length** along the central limb of the Z-plasty, while ensuring the flaps have a broad enough base for adequate blood supply. *90°* - While a **90°** angle would provide the most lengthening (around 100%), it creates very **thin, narrow flap tips** that are highly susceptible to **ischemia and necrosis** due to compromised blood supply. - This angle is generally avoided in Z-plasty due to the high risk of **flap complications**. *45°* - A **45°** angle results in less lengthening (approximately 50% gain) compared to a 60° angle, which may not be sufficient for significant release of scar contractures. - While it offers excellent flap viability due to wider bases, the **suboptimal lengthening** makes it less efficient for many Z-plasty applications. *75°* - An angle of **75°** would yield greater lengthening than 60°, but it also compromises flap viability making the flap susceptible to **necrosis**. - The benefits of increased length are often outweighed by the increased **risk of complications** when using this angle.
Question 10: The best skin graft for an open wound is
- A. Isograft
- B. Autograft (Correct Answer)
- C. Allograft
- D. Homograft
Explanation: ***Autograft*** - An autograft is tissue transferred from one site to another **within the same individual**, ensuring 100% genetic match and no immune rejection. - This makes it the ideal choice for **permanent coverage of open wounds** as it will be vascularized and incorporated into the host tissue without risk of rejection. *Isograft* - An isograft is tissue transferred between **genetically identical individuals** (e.g., identical twins). - While genetically identical, this option is generally not available for the vast majority of patients with open wounds. *Allograft* - An allograft (also known as a homograft) is tissue transferred between **genetically different individuals of the same species**. - Allografts carry a significant risk of **immune rejection** and are typically used as temporary covers for large burns or wounds, while awaiting autografting. *Homograft* - Homograft is another term for **allograft**, referring to tissue transplanted between genetically non-identical individuals of the same species. - Like allografts, homografts are primarily used for **temporary wound coverage** due to the high risk of immune rejection.
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