Plastic and Reconstructive Surgery Practice Questions

Q: What is the primary use of a dermatome?

To harvest skin grafts. **Explanation:** A **dermatome** is a specialized surgical instrument designed specifically to produce thin, uniform slices of skin from a donor area. The primary objective is to **harvest skin grafts** (split-thickness or full-thickness) for the reconstruction of skin defects caused by burns, trauma, or surgical excisions. * **Why Option B is correct:** Dermatomes allow the surgeon to precisely adjust the depth of the cut (usually measured in thousandths of an inch). This precision is essential for harvesting **Split-Thickness Skin Grafts (STSG)**, where only the epidermis and a portion of the dermis are taken, allowing the donor site to heal spontaneously. * **Why Option A is incorrect:** Scar tissue removal (revision) is typically performed using scalpels or lasers, not a dermatome, which is designed for harvesting healthy skin. * **Why Option C is incorrect:** Abrading pigmented skin or scars is known as **dermabrasion**, which uses a high-speed rotating brush or diamond fraise, not a dermatome. * **Why Option D is incorrect:** Approximation of tissue is achieved through suturing, stapling, or surgical adhesives. **High-Yield Clinical Pearls for NEET-PG:** 1. **Types of Dermatomes:** * **Knife/Manual:** (e.g., Humby’s knife, Blair’s knife) – Requires manual skill to maintain thickness. * **Drum:** (e.g., Padgett’s) – Uses an adhesive to lift the skin; excellent for irregular donor sites. * **Electric/Air-powered:** (e.g., Brown’s) – The most commonly used in modern practice for rapid, uniform harvesting. 2. **Thickness:** A standard STSG is usually **0.012 to 0.018 inches** thick. 3. **Donor Site:** The most common donor site is the **thigh** due to its broad surface area and ease of concealment.

Q: Skin grafting is performed on a wound using skin taken from an identical twin brother. What type of skin graft is this called?

Isograft. ### Explanation The correct answer is **Isograft (Option A)**. **1. Why Isograft is correct:** An **Isograft** (also known as a syngeneic graft) refers to the transfer of tissue between individuals who are genetically identical, such as **monozygotic (identical) twins**. Because the donor and recipient share the same Major Histocompatibility Complex (MHC) antigens, the recipient’s immune system does not recognize the graft as foreign. Consequently, there is no graft rejection, and long-term immunosuppression is not required. **2. Why the other options are incorrect:** * **Autograft (Option C):** This involves tissue transferred from one site to another on the **same individual** (e.g., taking a split-thickness skin graft from the thigh to cover a burn on the arm). This is the most common type of graft. * **Allograft (Option B):** Also called a homograft, this is a transfer between genetically different members of the **same species** (e.g., human to human). These require immunosuppression to prevent rejection. * **Xenograft (Option D):** Also called a heterograft, this involves tissue transfer between **different species** (e.g., porcine/pig skin or bovine valves used in humans). These are often used as temporary biological dressings. **3. NEET-PG High-Yield Pearls:** * **Order of Immunogenicity:** Xenograft > Allograft > Isograft/Autograft. * **First Set Rejection:** Occurs in 7–10 days in an unsensitized recipient. * **Second Set Rejection:** Occurs in 3–4 days (accelerated) due to pre-existing memory T-cells. * **Hyperacute Rejection:** Occurs within minutes to hours due to pre-formed ABO or HLA antibodies. * **Skin Graft Survival:** Relies on three stages: **Plasmatic imbibition** (first 24–48h), **Inosculation** (48–72h), and **Revascularization** (day 4 onwards).

Q: What is the ideal angle for a Z-plasty?

60 degrees. **Explanation:** Z-plasty is a versatile transposition flap technique used in plastic surgery to increase the length of a scar, change its direction, or release a contracture. **Why 60 degrees is the Correct Answer:** The gain in length in a Z-plasty is directly proportional to the angle of the flaps. A **60-degree angle** is considered the "ideal" or "standard" angle because it provides a significant and predictable **75% increase in length** while maintaining adequate blood supply to the flap tips. It offers the best balance between maximum lengthening and flap viability. **Analysis of Incorrect Options:** * **30 degrees (Option A):** While smaller angles are easier to transpose, they provide a minimal length increase (only about 25%). They are rarely used because the gain is insufficient for most clinical contractures. * **45 degrees (Option B):** This provides a moderate length increase (approx. 50%). It is used when skin tension is too high for a 60-degree flap, but it is not the "ideal" standard. * **90 degrees (Option D):** Theoretically, larger angles provide more length (a 90-degree angle would yield a 120% increase). However, they are clinically impractical because the flaps become too difficult to transpose and the resulting tension often leads to tip necrosis or wound dehiscence. **High-Yield Clinical Pearls for NEET-PG:** * **Mathematical Principle:** Z-plasty consists of one central limb and two parallel side limbs of equal length. * **Length Gain Rule:** 30° = 25% gain; 45° = 50% gain; **60° = 75% gain**. * **Primary Indication:** Linear scar contractures (e.g., post-burn contractures crossing a joint line). * **Key Complication:** Flap tip necrosis (usually due to excessive tension or narrow angles).

Q: Which anatomical location is associated with the poorest scar healing and appearance?

Sternum. **Explanation:** The quality of scar healing is primarily determined by the **tension** across the wound edges and the local skin thickness. The **Presternal (Sternum)** area is notorious for the poorest scar outcomes because it is a high-tension zone with minimal underlying subcutaneous fat and constant movement from respiration. 1. **Why Sternum is Correct:** The presternal region is the most common site for the development of **Hypertrophic scars** and **Keloids**. The skin here is under constant multidirectional tension. Furthermore, the sternum has a high density of myofibroblasts, which contribute to excessive collagen deposition, leading to thick, raised, and often itchy or painful scars. 2. **Analysis of Incorrect Options:** * **Shoulder:** While also a high-tension area prone to hypertrophic scarring, the incidence and severity are statistically lower than the presternal region. * **Back:** The skin on the back is very thick, which can lead to "stretched" or wide scars, but it is less prone to keloid formation compared to the sternum. * **Abdomen:** Generally heals well, especially if incisions follow **Langer’s lines** (cleavage lines). It is a low-tension area compared to the bony prominences of the chest. **Clinical Pearls for NEET-PG:** * **Best Scarring Site:** The **Eyelid** (thinnest skin, minimal tension). * **Keloids vs. Hypertrophic Scars:** Keloids extend *beyond* the boundaries of the original wound and rarely regress; hypertrophic scars stay *within* the wound boundaries and may regress over time. * **Langer’s Lines:** Incisions made parallel to these lines result in the finest scars due to minimum tension. * **Triad of Keloid Predisposition:** Darker skin pigmentation (Melanocytes), Presternal/Ear lobe location, and Genetic predisposition.

Q: Which of the following cannot accept a split-thickness skin graft?

Skull bone. **Explanation:** The success of a skin graft depends on **"take,"** a process where the graft survives via diffusion (plasmatic imbibition) and subsequent revascularization (inosculation) from the underlying recipient bed. For a graft to survive, the recipient bed must be **vascularized.** **Why Skull Bone is the Correct Answer:** Cortical bone, such as the outer table of the **skull bone** (when denuded of its periosteum), is a **relatively avascular surface.** It lacks a sufficient capillary network to provide the necessary nutrients for the graft to survive. To graft over bone, one must either ensure the **periosteum** is intact or drill holes into the outer cortex to allow granulation tissue to grow from the diploe. **Analysis of Incorrect Options:** * **Fat (Subcutaneous tissue):** While less vascular than muscle, healthy adipose tissue has enough capillary supply to support a split-thickness skin graft (STSG). * **Muscle:** This is a highly vascular bed and is considered one of the best surfaces for graft uptake. * **Deep Fascia:** Fascia is a vascularized connective tissue layer that provides an excellent bed for STSGs, often used in reconstructive procedures following debridement. **High-Yield Clinical Pearls for NEET-PG:** * **Avascular beds** that cannot accept a graft include: Bare bone (without periosteum), bare tendon (without paratenon), bare cartilage (without perichondrium), and infected/necrotic tissue. * **Stages of Graft Take:** 1. **Plasmatic Imbibition (0–48 hours):** Graft "drinks" nutrients via diffusion. 2. **Inosculation (48–72 hours):** Alignment of donor and recipient capillaries. 3. **Revascularization (Day 3–5):** Actual blood flow established. * **STSG vs. FTSG:** Split-thickness grafts have a higher "take" rate on less-than-ideal beds compared to Full-thickness grafts (FTSG) because they have lower metabolic demands.

Question 1

All of the following statements regarding cleft lip and palate are true, EXCEPT:

Accepted Answer

Isolated cleft palate can be diagnosed by ultrasound after 28 weeks gestation.

Answer

It can be associated with Treacher-Collins syndrome.

Answer

Cleft lip with cleft palate is the most common type.

Answer

Pierre Robin sequence is the most common syndrome.

Question 2

What is the primary use of a dermatome?

Accepted Answer

To harvest skin grafts

Answer

To remove scar tissue

Answer

To abrade pigmented skin

Answer

For approximation of lacerated soft tissue

Question 3

Skin grafting is performed on a wound using skin taken from an identical twin brother. What type of skin graft is this called?

Accepted Answer

Isograft

Answer

Allograft

Answer

Autograft

Answer

Xenograft

Question 4

What is the ideal angle for a Z-plasty?

Accepted Answer

60 degrees

Answer

30 degrees

Answer

45 degrees

Answer

90 degrees

Question 5

Which of the following is NOT true about rodent ulcer (basal cell carcinoma)?

Accepted Answer

It is radiosensitive.

Answer

Lymph node involvement is typically absent.

Answer

It commonly presents as a facial lesion.

Answer

Blood-borne metastasis is rare.

Question 6

In the reconstruction following excision of previously irradiated cheek cancer, which flap is most appropriate?

Accepted Answer

Pectoralis major myocutaneous flap

Answer

Local tongue flap

Answer

Cervical flap

Answer

Forehead flap

Question 7

Which anatomical location is associated with the poorest scar healing and appearance?

Accepted Answer

Sternum

Answer

Back

Answer

Shoulder

Answer

Abdomen

Question 8

What is the best treatment for a large capillary hemangioma (port wine stain)?

Accepted Answer

Laser therapy

Answer

Tattooing

Answer

Cryosurgery

Answer

Excision with split-thickness grafting

Question 9

Which of the following cannot accept a split-thickness skin graft?

Accepted Answer

Skull bone

Answer

Fat

Answer

Muscle

Answer

Deep fascia

Question 10

Orthodontic treatment in the management of cleft lip and palate is usually carried out during which stage of dentition?

Accepted Answer

Mixed and permanent dentition

Answer

Deciduous dentition and mixed dentition

Answer

Mixed dentition

Answer

Permanent dentition

Plastic and Reconstructive Surgery — MCQs

Plastic and Reconstructive Surgery — MCQs

On this page

Practice by Chapter

Want unlimited practice?