Plastic and Reconstructive Surgery Practice Questions

Q: A full thickness loss of the middle one third of the upper lip is best reconstructed by which method?

Abbe flap. ### Explanation The reconstruction of lip defects is primarily determined by the **size** and **location** of the defect. For a full-thickness loss involving the **middle one-third** of either the upper or lower lip, the **Abbe flap** (also known as a cross-lip flap) is the gold standard. **Why Abbe Flap is Correct:** The Abbe flap involves transferring a full-thickness wedge of tissue from the opposite lip (in this case, the lower lip) into the defect of the upper lip. It is pedicled on the **labial artery**. This method is ideal for central defects because it replaces "like with like," restoring the vermilion border, muscle continuity (orbicularis oris), and skin, thereby maintaining both aesthetics and oral competence. **Analysis of Incorrect Options:** * **Estlander’s Flap:** This is a variation of the cross-lip flap specifically designed for defects involving the **oral commissure** (corner of the mouth). Since the question specifies the *middle* one-third, Estlander's is inappropriate. * **Nasolabial Flap:** While useful for skin defects of the lip or nose, it is typically a transposition flap that does not provide the full-thickness muscle required for a functional middle-lip reconstruction. * **Cheek Flap (e.g., Karapandzic or Bernard-Fries):** These are generally reserved for larger defects (greater than one-half to two-thirds of the lip) where local tissue advancement is necessary. **High-Yield Clinical Pearls for NEET-PG:** 1. **Rule of Thirds:** Defects 2/3 require regional flaps (Karapandzic). 2. **Two-Stage Procedure:** The Abbe flap requires a second stage (usually after 2–3 weeks) to divide the vascular pedicle once neovascularization occurs. 3. **Vascular Supply:** The success of both Abbe and Estlander flaps depends on the integrity of the **labial artery**, which runs between the oral mucosa and the orbicularis oris muscle.

Q: Which of the following mandibular positions is least likely achievable with a bilateral sagittal split osteotomy?

Transverse. **Explanation:** The **Bilateral Sagittal Split Osteotomy (BSSO)** is the most versatile and commonly performed surgical procedure for correcting mandibular deformities. The technique involves a sagittal split of the mandibular ramus, dividing it into two segments: a **proximal segment** (containing the condyle) and a **distal segment** (containing the teeth and chin). **Why Transverse is the correct answer:** The BSSO is primarily designed to move the distal segment of the mandible along the sagittal and vertical planes. While it can achieve **Advancement** (for retrognathia), **Set back** (for prognathism), and **Rotation** (to correct asymmetries or open bites), it is **least effective for Transverse (width) changes**. Significant widening or narrowing of the mandible requires a **Midline Mandibular Osteotomy (Symphyseal split)** or distraction osteogenesis, as BSSO is limited by the anatomy of the ramus and the risk of condylar displacement/TMJ dysfunction if forced transversely. **Analysis of Incorrect Options:** * **Advancement (A):** The most common indication for BSSO; the distal segment is slid forward to treat mandibular hypoplasia. * **Set back (B):** Used to treat mandibular hyperplasia (prognathism) by sliding the distal segment posteriorly. * **Rotation (C):** BSSO allows for the correction of occlusal cants or midline shifts by rotating the distal segment before fixation. **High-Yield Clinical Pearls for NEET-PG:** * **Nerve at risk:** The **Inferior Alveolar Nerve (IAN)** is the most commonly injured structure during BSSO, leading to lower lip paresthesia. * **Stability:** BSSO is more stable for advancement than for set-back procedures. * **Fixation:** Usually performed using rigid internal fixation (screws/plates), which often eliminates the need for prolonged maxillomandibular fixation (MMF).

Q: Lines of Blaschko represent:

Lines of development. **Explanation:** **Lines of Blaschko** are non-random cutaneous patterns that do not correspond to any known vascular, lymphatic, or nervous pathways. Instead, they represent the **lines of migration and proliferation of epidermal cells** (keratinocytes and melanocytes) during embryonic development. 1. **Why Option D is Correct:** During embryogenesis, precursor cells migrate from the neural crest and proliferate to cover the body surface. These lines reflect the clonal expansion of these cells. They typically follow a "V-shape" on the back, an "S-shape" on the chest and abdomen, and a linear pattern on the limbs. They become visible only in certain genetic or acquired skin diseases (e.g., Incontinentia Pigmenti, Linear Epidermal Nevus) where a mutation occurs in a subset of cells (mosaicism). 2. **Why Other Options are Incorrect:** * **A & B (Lymphatics/Blood vessels):** Vascular and lymphatic distributions follow distinct anatomical branching patterns (e.g., angiosomes) which do not match the characteristic whorled or V-shaped patterns of Blaschko lines. * **C (Nerves):** Lines following nerve distributions are called **Dermatomes**. While dermatomes are also developmental, they represent the sensory distribution of spinal nerves and differ significantly in morphology from Blaschko lines. **High-Yield Clinical Pearls for NEET-PG:** * **Langer’s Lines:** Lines of skin tension/cleavage (collagen orientation); crucial for surgical incisions to minimize scarring. * **Kraissl’s Lines:** Lines of maximum skin tension in a living, moving body (often used interchangeably with Langer's in clinical practice). * **Mosaicism:** The most common reason Blaschko lines become clinically apparent. * **Key Disease Example:** *Incontinentia Pigmenti* classically follows the Lines of Blaschko.

Q: A skin flap is used in the management of all the following conditions except:

Burn wound. The core concept in reconstructive surgery is the distinction between a **skin graft** and a **skin flap**. The choice depends on the vascularity of the recipient bed. ### Why "Burn Wound" is the Correct Answer In most cases of acute burns (specifically partial-thickness or full-thickness burns), the underlying wound bed is **vascular** (granulation tissue or dermis). Such beds can support a **skin graft**, which lacks its own blood supply and relies on the recipient site for nourishment (via plasmatic imbibition and inosculation). Using a flap for a standard burn wound is unnecessary, overly complex, and surgically inappropriate unless deep structures are exposed. ### Why the Other Options are Incorrect Flaps are mandatory when the recipient bed is **avascular** or "non-takeable" for a graft. A flap carries its own blood supply (pedicle), allowing it to survive over: * **Bone (A):** Cortical bone without periosteum cannot nourish a graft. * **Tendon (B):** Bare tendons (without paratenon) lack the vascularity required for graft survival. * **Cartilage (D):** Cartilage without perichondrium is avascular and requires flap coverage. ### High-Yield Clinical Pearls for NEET-PG * **The Reconstructive Ladder:** Always start with the simplest option. (Primary closure → Secondary intention → Skin Graft → Local Flap → Distant Flap → Free Flap). * **Graft vs. Flap:** If the bed is vascular (muscle, fat, periosteum), use a **Graft**. If the bed is avascular (bare bone, tendon, nerve), use a **Flap**. * **Exception:** If a burn is so deep that it exposes bone or tendon (4th-degree burn), a flap *would* be required, but for standard burn management, grafts are the gold standard.

Q: What is true about a dermoid cyst?

Rupture is associated with foreign body type inflammation. A **dermoid cyst** is a sequestration-type cyst formed when ectoderm is trapped along the lines of embryonic fusion. ### **Explanation of Options** * **Correct Answer (D):** Dermoid cysts contain adnexal structures like sebaceous glands, which produce **sebum and keratin**. If the cyst wall ruptures, these contents leak into the surrounding tissues, triggering a robust **foreign body giant cell reaction** and granulomatous inflammation. * **A is Incorrect:** Dermoid cysts are lined by **stratified squamous epithelium** (skin), not columnar epithelium. * **B is Incorrect:** Because they are lined by true skin, they frequently contain skin appendages such as **hair follicles**, sweat glands, and sebaceous glands. * **C is Incorrect:** The most common site for an external angular dermoid is the **lateral (outer) angle of the eye**, not the median (inner) angle. ### **High-Yield Clinical Pearls for NEET-PG** 1. **Pathology:** It is a "sequestration dermoid." Unlike sebaceous cysts, dermoid cysts are **congenital** and are **not** attached to the overlying skin (no punctum). 2. **Common Sites:** * **External Angular Dermoid:** Most common site (lateral eyebrow). * **Sublingual Dermoid:** Located in the midline of the floor of the mouth (above or below the mylohyoid). 3. **Radiology:** In the skull, they often cause a "punched-out" lucency due to pressure erosion of the bone. 4. **Differentiating Feature:** Always perform a clinical check for **fixity to underlying bone** and cough impulse (to rule out intracranial extension/meningocele).

Q: A Marjolin's ulcer, developing in a chronic burn scar, predisposes to which type of malignancy?

Squamous cell carcinoma. **Explanation:** **Marjolin’s ulcer** refers to a malignancy arising in a site of chronic inflammation, trauma, or scarring. The most common precursor is a **chronic burn scar** (post-burn cicatrix), though it can also occur in chronic osteomyelitis sinuses, pressure sores, or venous ulcers. 1. **Why Squamous Cell Carcinoma (SCC) is correct:** The constant irritation, chronic infection, and poor lymphatic drainage in a scarred area lead to repeated cycles of cell damage and repair. Over time (typically a latent period of 10–25 years), this triggers malignant transformation of the keratinocytes. **Squamous cell carcinoma** is the histological type in approximately 75–90% of Marjolin’s ulcers. These are generally more aggressive and have a higher rate of metastasis than SCC arising in healthy skin. 2. **Why other options are incorrect:** * **Basal Cell Carcinoma (BCC):** While BCC is the most common skin cancer overall, it typically arises on sun-exposed skin. It occurs in Marjolin’s ulcers much less frequently than SCC. * **Adenocarcinoma:** This arises from glandular epithelium (e.g., GI tract, breast). It is not associated with cutaneous burn scars. * **Round Cell Carcinoma:** This is a category of highly undifferentiated tumors (like Ewing’s sarcoma or lymphomas) and is not related to chronic scar transformation. **High-Yield Clinical Pearls for NEET-PG:** * **Latency:** The average time for transformation is **30 years**. * **Characteristics:** Marjolin’s ulcers are typically painless (due to destroyed nerve endings in the scar), have everted edges, and a foul-smelling discharge. * **Lymph Nodes:** Despite being aggressive, lymph node metastasis may be delayed because the dense scar tissue acts as a barrier to lymphatic spread. * **Management:** Wide local excision (2 cm margin) is the treatment of choice; Mohs surgery or amputation may be required depending on depth and location.

Question 1

A full thickness loss of the middle one third of the upper lip is best reconstructed by which method?

Accepted Answer

Abbe flap

Answer

Naso labial flap

Answer

Cheek flap

Answer

Estlander's flap

Question 2

What is the most preferable graft for mandibular reconstruction?

Accepted Answer

Fibula graft.

Answer

Graft from anterior iliac crest.

Answer

Costochondral graft.

Answer

Any of the above.

Question 3

Which of the following mandibular positions is least likely achievable with a bilateral sagittal split osteotomy?

Accepted Answer

Transverse

Answer

Advancement

Answer

Set back

Answer

Rotation

Question 4

How does a skin graft vestibuloplasty prevent relapse?

Accepted Answer

By forming a barrier to reattachment of muscle to periosteum

Answer

By promoting osteogenesis to establish a bone barrier to loss of sulcus depth

Answer

By causing an inhibitory effect on fibroblasts in the underlying tissue

Answer

None of the above

Question 5

A 9 1/2-year-old girl presents with an approximately 1 1/4-cm nontender nodule in her neck, just to the left of the midline and below her cricoid cartilage. The nodule moves when she swallows. It has been enlarging over the last several months and was not noted by her pediatrician at her 9-year-old check-up. There is no family history of endocrine disorders. What is the most likely diagnosis?

Accepted Answer

Papillary thyroid cancer

Answer

Reactive viral lymphadenopathy

Answer

A brachial cleft cyst

Answer

A follicular adenoma of the thyroid

Question 6

Lines of Blaschko represent:

Accepted Answer

Lines of development

Answer

Lines along lymphatics

Answer

Lines along blood vessels

Answer

Lines of nerves

Question 7

A skin flap is used in the management of all the following conditions except:

Accepted Answer

Burn wound

Answer

Bone

Answer

Tendon

Answer

Cartilage

Question 8

What is true about a dermoid cyst?

Accepted Answer

Rupture is associated with foreign body type inflammation

Answer

Lined by columnar epithelium

Answer

Does not contain hair

Answer

The median angle of the eye is the most common site

Question 9

Skin grafting is absolutely contraindicated in which skin infection?

Accepted Answer

Streptococcus

Answer

Staphylococcus

Answer

Pseudomonas

Answer

Proteus

Question 10

A Marjolin's ulcer, developing in a chronic burn scar, predisposes to which type of malignancy?

Accepted Answer

Squamous cell carcinoma

Answer

Basal cell carcinoma

Answer

Adenocarcinoma

Answer

Round cell carcinoma

Plastic and Reconstructive Surgery — MCQs

Plastic and Reconstructive Surgery — MCQs

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