General Surgery Principles — MCQs

General Surgery Principles Indian Medical PG Practice Questions and MCQs

Question 391: Which of the following produces the least damage to blood elements?

A. Disc oxygenator
B. Membrane oxygenator (Correct Answer)
C. Bubble oxygenator
D. Screen oxygenator

Explanation: **Explanation:** The primary goal of an oxygenator in cardiopulmonary bypass (CPB) is to facilitate gas exchange (O₂ uptake and CO₂ removal) while minimizing trauma to blood components. **Why Membrane Oxygenator is the Correct Answer:** The **Membrane Oxygenator** is currently the gold standard because it utilizes a semi-permeable membrane (usually microporous polypropylene or silicone) to separate the blood from the gas phase. This prevents a **direct gas-blood interface**, which is the primary cause of protein denaturation, hemolysis, and platelet activation. By mimicking the natural alveolar-capillary barrier of the lung, it significantly reduces trauma to blood elements, making it the safest choice for long-term procedures. **Analysis of Incorrect Options:** * **Bubble Oxygenator:** These function by bubbling oxygen directly through the blood. The direct contact between gas and blood causes significant hemolysis and protein denaturation. They are largely obsolete due to the high risk of micro-emboli and blood damage. * **Disc Oxygenator:** This is an older "film" type oxygenator where rotating discs dip into a reservoir of blood and expose a thin film to an oxygen atmosphere. While better than bubbling, the mechanical agitation and direct interface still cause more damage than membrane types. * **Screen Oxygenator:** Blood is filmed over a series of wire screens in an oxygen-rich environment. Like the disc oxygenator, the direct gas-blood interface leads to higher rates of cellular destruction compared to membrane technology. **Clinical Pearls for NEET-PG:** * **Gold Standard:** Membrane oxygenators are preferred for any bypass surgery lasting more than 1–2 hours. * **Complications of CPB:** The "Post-perfusion syndrome" (systemic inflammatory response) is significantly reduced when using membrane oxygenators. * **Key Advantage:** Membrane oxygenators allow for independent control of O₂ and CO₂ tension, which is more difficult with bubble oxygenators.

Question 392: Which of the following is NOT required for wound healing?

A. Zinc
B. Copper
C. Vitamin C
D. None of the above (Correct Answer)

Explanation: ### Explanation The correct answer is **None of the above** because Zinc, Copper, and Vitamin C are all essential micronutrients required for the complex process of wound healing. A deficiency in any of these can lead to delayed healing or wound dehiscence. **Why the options are essential:** * **Zinc (Option A):** Zinc is a critical cofactor for **DNA polymerase and RNA polymerase**, making it essential for cell proliferation during the epithelialization phase. It also plays a vital role in **matrix metalloproteinases (MMPs)**, which are necessary for wound remodeling. * **Copper (Option B):** Copper is a cofactor for the enzyme **lysyl oxidase**. This enzyme is responsible for the cross-linking of collagen and elastin fibers, which provides the wound with its ultimate tensile strength. * **Vitamin C (Option C):** Also known as Ascorbic acid, it is required for the **hydroxylation of proline and lysine** residues during collagen synthesis. Without Vitamin C, stable collagen triple helices cannot form, leading to impaired wound healing (as seen in Scurvy). **Clinical Pearls for NEET-PG:** * **Tensile Strength:** A wound reaches approximately 3% of its final strength at 1 week, 20% at 3 weeks, and plateaus at **70-80%** by 3 months. It never regains 100% of the original tissue strength. * **Collagen Types:** Type III collagen is synthesized first (granulation tissue), which is later replaced by the stronger **Type I collagen** during the remodeling phase. * **Most Common Cause of Delayed Healing:** Local **infection** is the most common cause of wound healing failure, while **malnutrition** (protein-energy malnutrition) is a significant systemic cause. * **Steroids:** These inhibit wound healing by decreasing inflammation and collagen synthesis. Interestingly, **Vitamin A** can help reverse the inhibitory effects of steroids on wound healing.

Question 393: Which of the following is a complication of mastectomy?

A. Seroma
B. Long thoracic nerve palsy
C. Angiosarcoma
D. All of the above (Correct Answer)

Explanation: **Explanation:** Mastectomy is a major surgical procedure associated with several early and late complications. The correct answer is **All of the above** because each option represents a recognized clinical outcome following the procedure. 1. **Seroma (Option A):** This is the **most common** early complication of mastectomy. It involves a collection of serous fluid in the dead space under the skin flaps or in the axilla. It occurs due to the disruption of lymphatics and capillaries during dissection. 2. **Long Thoracic Nerve Palsy (Option B):** During axillary lymph node dissection (ALND), the long thoracic nerve (Nerve of Bell) is at risk. Injury leads to paralysis of the **Serratus Anterior** muscle, clinically presenting as **"Winging of the Scapula."** 3. **Angiosarcoma (Option C):** This is a rare but dreaded late complication known as **Stewart-Treves Syndrome**. It refers to lymphangiosarcoma arising in a limb affected by chronic lymphedema (usually 10+ years post-mastectomy). **Clinical Pearls for NEET-PG:** * **Nerve Injuries:** * *Intercostobrachial nerve:* Most commonly injured nerve; leads to numbness of the inner aspect of the upper arm. * *Thoracodorsal nerve:* Injury leads to weakness in internal rotation and adduction (Latissimus dorsi). * **Lymphedema:** Occurs in about 10-25% of patients post-ALND; risk is significantly reduced with Sentinel Lymph Node Biopsy (SLNB). * **Flap Necrosis:** Usually occurs at the edges of the skin flaps if they are tensioned or too thin.

Question 394: Intraoral vertical ramus osteotomy is done for which of the following conditions?

A. Anterior open bite
B. Mandibular advancement
C. Mandibular setback (Correct Answer)
D. Maxillary deformity

Explanation: **Explanation:** **Intraoral Vertical Ramus Osteotomy (IVRO)** is a surgical procedure used primarily for **Mandibular Setback** in patients with mandibular hyperplasia (prognathism). The procedure involves a vertical cut in the mandibular ramus, extending from the sigmoid notch down to the lower border of the mandible, posterior to the lingula. This allows the tooth-bearing segment of the mandible to be moved backward (setback) while the condylar segment remains in its original position. **Why the correct answer is right:** * **Mandibular Setback (Option C):** IVRO is specifically designed for posterior movement. It is often preferred over the Sagittal Split Osteotomy (SSO) for setbacks because it has a lower risk of inferior alveolar nerve (IAN) injury and is technically simpler for large setbacks. **Why the other options are wrong:** * **Anterior Open Bite (Option A):** This is typically corrected using a Le Fort I osteotomy (maxilla) or a Sagittal Split Osteotomy (SSO) which allows for rotational movements that IVRO cannot easily achieve. * **Mandibular Advancement (Option B):** IVRO is **not** used for advancement because the bony segments do not overlap sufficiently to allow for healing/fixation when moved forward. The **Bilateral Sagittal Split Osteotomy (BSSO)** is the gold standard for mandibular advancement. * **Maxillary Deformity (Option D):** Maxillary issues are addressed via Le Fort I, II, or III osteotomies, not mandibular ramus procedures. **High-Yield Clinical Pearls for NEET-PG:** * **Nerve Safety:** IVRO has a significantly **lower incidence of paresthesia** of the lower lip compared to BSSO because the osteotomy is posterior to the mandibular foramen. * **Fixation:** Unlike BSSO, IVRO usually requires a period of **Maxillomandibular Fixation (MMF)** because internal rigid fixation is technically difficult to apply to the vertical segments. * **Indication:** Best suited for purely posterior movements (prognathism) without the need for significant vertical or transverse changes.

Question 395: Which of the following types of shock is characterized by low peripheral resistance?

A. Hypovolemic
B. Cardiogenic
C. Distributive (Correct Answer)
D. Obstructive

Explanation: **Explanation:** Shock is defined as a state of cellular hypoxia due to an imbalance between oxygen supply and demand. The hemodynamic profile of shock is determined by the relationship: **MAP = CO × SVR** (Mean Arterial Pressure = Cardiac Output × Systemic Vascular Resistance). **Why Distributive Shock is Correct:** In **Distributive shock** (e.g., Septic, Anaphylactic, or Neurogenic shock), the primary pathology is massive peripheral vasodilation. This results in a significant **decrease in Systemic Vascular Resistance (SVR)** or peripheral resistance. To compensate, the heart typically increases cardiac output (except in neurogenic shock), leading to the classic clinical presentation of "warm shock." **Why Other Options are Incorrect:** * **Hypovolemic Shock:** Caused by loss of blood or fluid. The body compensates via the sympathetic nervous system, causing vasoconstriction to maintain BP. Thus, **SVR is increased**. * **Cardiogenic Shock:** Caused by pump failure (e.g., MI). Low cardiac output triggers a compensatory increase in peripheral resistance to maintain perfusion to vital organs. Thus, **SVR is increased**. * **Obstructive Shock:** Caused by physical obstruction to blood flow (e.g., Tension pneumothorax, Cardiac tamponade). Similar to cardiogenic shock, the body responds with compensatory vasoconstriction. Thus, **SVR is increased**. **High-Yield NEET-PG Pearls:** * **SVR** is the hallmark differentiator: It is **decreased** only in Distributive shock and **increased** in Hypovolemic, Cardiogenic, and Obstructive shock. * **Septic Shock** is the most common subtype of distributive shock. * **Neurogenic Shock** is unique because it presents with **bradycardia** (due to loss of sympathetic tone), whereas all other forms of shock typically present with tachycardia. * **PCWP (Pulmonary Capillary Wedge Pressure)** is elevated in Cardiogenic shock but decreased in Hypovolemic shock.

Question 396: What is true of Spigelian hernia?

A. It occurs exclusively in males.
B. It involves part of the circumference of the bowel wall.
C. It is best repaired by the classical Bassini technique of inguinal ligament repair.
D. It occurs at the lateral edge of the linea semilunaris. (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. It occurs at the lateral edge of the linea semilunaris.** A **Spigelian hernia** (also known as a spontaneous interstitial ventral hernia) occurs through the **Spigelian fascia**. This fascia is the layer of the rectus sheath found between the **linea semilunaris** (the lateral border of the rectus abdominis muscle) and the lateral edge of the abdominal muscles. Most of these hernias occur at or below the **arcuate line** (the "Spigelian hernia belt"), where the posterior rectus sheath is deficient, making it a point of anatomical weakness. #### Analysis of Incorrect Options: * **Option A:** Spigelian hernias are not exclusive to males; they occur in both sexes, often appearing in the 5th to 6th decades of life. * **Option B:** This describes a **Richter’s hernia**, where only a portion of the bowel circumference is trapped. While a Spigelian hernia *could* contain a Richter’s-type strangulation, it is not a defining characteristic. * **Option C:** The **Bassini technique** is specifically for **inguinal hernias**. Spigelian hernias are repaired via a transverse incision over the mass or laparoscopically (IPOM or TEP), usually involving mesh reinforcement. #### High-Yield Clinical Pearls for NEET-PG: * **Location:** Most common at the level of the **arcuate line** (Spigelian hernia belt). * **Clinical Presentation:** Often difficult to diagnose because the hernia sac is **interstitial** (lies deep to the external oblique aponeurosis), meaning a palpable bulge may be absent. * **Diagnosis:** **Ultrasound or CT scan** is the investigation of choice due to the vague clinical presentation. * **Risk:** They have a **high risk of strangulation** because of the narrow, rigid neck of the defect.

Question 397: All of the following statements regarding medullary carcinoma of the thyroid are true EXCEPT:

A. It arises from 'C' cells.
B. Both hematogenous and lymphatic spread are seen.
C. It is dependent on TSH. (Correct Answer)
D. Most cases are sporadic.

Explanation: **Explanation:** Medullary Carcinoma of the Thyroid (MTC) is a unique neuroendocrine tumor that differs significantly from differentiated thyroid cancers (Papillary and Follicular). **1. Why Option C is correct (The False Statement):** Unlike Papillary and Follicular carcinomas, which arise from follicular cells and are regulated by Thyroid Stimulating Hormone (TSH), MTC arises from **parafollicular 'C' cells**. These cells are of neural crest origin and do not possess TSH receptors. Therefore, MTC is **not dependent on TSH**, and TSH suppression therapy has no role in its management. **2. Analysis of other options:** * **Option A:** MTC arises from 'C' cells, which are responsible for secreting **Calcitonin**. This serves as a vital tumor marker for diagnosis and post-operative follow-up. * **Option B:** MTC is aggressive. It spreads via **lymphatics** to cervical lymph nodes (early) and via the **bloodstream (hematogenous)** to the liver, lungs, and bones. * **Option D:** Approximately **75-80% of cases are sporadic**. The remaining 20-25% are familial, associated with **MEN 2A, MEN 2B**, or Familial MTC (FMTC) syndromes. **Clinical Pearls for NEET-PG:** * **Genetics:** Familial cases are associated with the **RET proto-oncogene** mutation. Prophylactic thyroidectomy is recommended for carriers. * **Histology:** Characterized by deposits of **Amyloid** (transcribed from calcitonin) which stains with **Congo Red** (apple-green birefringence). * **Surgery:** The treatment of choice is **Total Thyroidectomy with Central Compartment Neck Dissection**, as MTC does not take up radioiodine.

Question 398: Dermoid cysts are most commonly seen in which of the following locations?

A. Finger
B. Skin
C. Skull (Correct Answer)
D. Hip

Explanation: **Explanation:** The correct answer is **Skull**. Dermoid cysts are developmental sequestration cysts that occur during embryonic development when surface ectoderm becomes trapped along the lines of embryonic fusion. **1. Why Skull is Correct:** The most common site for a sequestration dermoid is the **lateral angle of the orbit** (external angular dermoid), where the frontonasal and maxillary processes fuse. Other frequent sites include the midline of the nose, the scalp, and the post-auricular region. These cysts are often fixed to the underlying periosteum and may cause a "pressure erosion" or "pitting" of the outer table of the skull, which is a classic radiological finding. **2. Why Other Options are Incorrect:** * **Finger:** Cysts found here are typically **Implantation Dermoids** (Acquired), caused by trauma driving surface epithelium into deeper tissues. While common in manual laborers, they are not the "most common" site for dermoids in general compared to developmental sites. * **Skin:** While dermoids are subcutaneous, "skin" is too vague. Most skin-related lumps are sebaceous cysts (retention cysts), which are distinct from developmental dermoids. * **Hip:** This is an extremely rare site for dermoid cysts. **Clinical Pearls for NEET-PG:** * **Clinical Feature:** Dermoids are non-tender, fluctuate, and are **not** attached to the overlying skin (unlike sebaceous cysts), but are often attached to the underlying bone. * **Test:** They do not transilluminate (unlike cystic hygromas). * **Warning:** Midline dermoids on the skull (especially the bridge of the nose) may have an intracranial extension; always rule this out with imaging (CT/MRI) before excision to avoid a CSF leak.

Question 399: Thyroid storm after total thyroidectomy is most commonly due to which of the following factors?

A. Damage to the recurrent laryngeal nerve
B. Rough handling of thyroid tissue during surgery
C. Removal of parathyroid glands
D. Inadequate preoperative preparation (Correct Answer)

Explanation: **Explanation:** **Thyroid storm** is a life-threatening hypermetabolic state caused by a sudden, massive release of thyroid hormones ($T_3$ and $T_4$) into the circulation. In the context of surgery, the most critical factor in preventing this complication is achieving a **euthyroid state** before the patient reaches the operating table. **1. Why "Inadequate preoperative preparation" is correct:** The primary goal of preoperative management in hyperthyroid patients (e.g., Graves' disease) is to normalize hormone levels using antithyroid drugs (Propylthiouracil or Methimazole) and Beta-blockers. If a patient undergoes surgery while still biochemically toxic, the physiological stress of anesthesia and surgery triggers a massive surge of hormones, leading to a thyroid storm. This remains the most common and preventable cause. **2. Why other options are incorrect:** * **Rough handling of thyroid tissue (Option B):** While excessive manipulation can theoretically release hormones, it rarely causes a full-blown storm if the patient was properly prepared and euthyroid. * **Damage to the recurrent laryngeal nerve (Option A):** This leads to vocal cord palsy (hoarseness or airway obstruction), not a metabolic crisis. * **Removal of parathyroid glands (Option C):** This results in postoperative hypocalcemia and tetany, which is a separate metabolic complication. **High-Yield Clinical Pearls for NEET-PG:** * **Pre-op Preparation:** Lugol’s iodine or Potassium Iodide (SSKI) is often given 10 days pre-operatively to decrease the vascularity and friability of the gland. * **Clinical Features:** Hyperpyrexia (>104°F), tachycardia, arrhythmias (Atrial Fibrillation), and CNS agitation. * **Management:** The "P's" of treatment: **P**ropylthiouracil (blocks synthesis and peripheral conversion), **P**ropanolol (blocks sympathetic effects), **P**otassium Iodide (blocks release), and **P**rednisolone (blocks peripheral conversion and treats relative adrenal insufficiency).

Question 400: What defines a Spigelian hernia?

A. Hernia passing through the obturator canal
B. Hernia occurring through the linea alba
C. Hernia through the triangle of Petit
D. Hernia occurring at the level of the arcuate line (Correct Answer)

Explanation: ### Explanation **Spigelian Hernia** (also known as a lateral ventral hernia) occurs through the **Spigelian aponeurosis**. This is the layer of fascia between the lateral border of the rectus abdominis muscle and the semilunar line (the transition from the transversus abdominis muscle to its aponeurosis). **Why Option D is Correct:** The hernia most commonly occurs at or below the **arcuate line (of Douglas)**. At this level, the posterior rectus sheath is absent, and the aponeurosis is at its weakest. The defect typically lies between the layers of the abdominal wall (interparietal), meaning the hernia sac often remains hidden beneath the external oblique aponeurosis, making it difficult to diagnose clinically. **Analysis of Incorrect Options:** * **Option A (Obturator canal):** Defines an **Obturator hernia**, which passes through the obturator foramen. It is classic in elderly, thin females (Howship-Romberg sign). * **Option B (Linea alba):** Defines an **Epigastric hernia**, occurring through the midline fibers between the xiphoid process and the umbilicus. * **Option C (Triangle of Petit):** Defines an **Inferior Lumbar hernia**. The Petit triangle is bounded by the iliac crest, latissimus dorsi, and external oblique. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** Usually found at the "Spigelian Hernia Belt"—a transverse zone 0–6 cm cranial to the interspinal line. * **Diagnosis:** Often presents as a non-specific abdominal bulge or pain. **Ultrasound or CT** is the gold standard for diagnosis due to its interparietal nature. * **Management:** High risk of strangulation (due to narrow neck); therefore, surgical repair (open or laparoscopic) is always recommended.

Practice by Chapter

Wound Healing and Care

Practice Questions

Surgical Infections

Practice Questions

Fluid and Electrolyte Management

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Nutrition in Surgical Patients

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Hemostasis and Blood Transfusion

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Surgical Instruments and Equipment

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Sutures and Stapling Devices

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Minimal Access Surgery Principles

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Surgical Complications

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Anesthesia Principles for Surgeons

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Surgical Oncology Principles

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Evidence-Based Surgery

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