Navigation and Robotics — MCQs
Identify the imaging modality given below.
Stereotactic Radiosurgery is a form of –
When a lumbar puncture is performed to sample cerebrospinal fluid, which of the following external landmarks is the most reliable to determine the position of the L4 vertebral spine?
To localize a supernumerary or an impacted tooth and determine its exact relationship to the other teeth, which of the following radiographs would be most effective?
The safest initial approach to open the airway of a patient with maxillofacial trauma is:
All of the following are described surgical procedures for CTE V except -
Lateral movement is produced by anterior translation of one condyle producing rotation about the
Which prosthesis is shown below in the X-ray?
Early movement following surgery for ankylosis is
Position for transport of a patient with lumbar spine fracture:
Navigation and Robotics Indian Medical PG Practice Questions and MCQs
Question 1: Identify the imaging modality given below.
- A. USG (Correct Answer)
- B. Fluoroscopy
- C. X-Ray
- D. MRI
Explanation: ***USG*** - The image displays characteristic **gray-scale imaging** with an **echogenic appearance** of tissues, typical of an ultrasound. - Presence of annotations like "10 MHz G 64%" for **frequency and gain**, and "PRC" suggest ultrasound parameters. *Fluoroscopy* - Fluoroscopy provides **real-time X-ray images** and often involves the use of contrast agents, appearing as a dynamic, darker image with high contrast. - The image lacks the distinct bone and air contrast and dynamic motion typical of fluoroscopy. *X-Ray* - X-ray images depict a **static shadowgram** of dense structures like bones as white, and air as black, with sharp delineation. - The image shows a **granular texture** and fluid-filled structures that are characteristic of soft tissue imaging through ultrasound, not X-ray. *MRI* - MRI produces **cross-sectional images** with high soft tissue contrast in multiple planes (axial, sagittal, coronal). - The image shows real-time B-mode ultrasound characteristics with **probe frequency notation**, not the slice-based imaging of MRI.
Question 2: Stereotactic Radiosurgery is a form of –
- A. Radioiodine therapy
- B. Cryosurgery
- C. Robotic Surgery
- D. Radiotherapy (Correct Answer)
Explanation: ***Radiotherapy*** - **Stereotactic radiosurgery** is a highly precise form of **radiotherapy** that delivers a single high dose or multiple fractionated high doses of radiation to a specific target area. - It uses focused **radiation beams** to treat tumors or other lesions, often as an alternative to conventional surgery, by causing damage to the DNA of target cells. *Radioiodine therapy* - **Radioiodine therapy** primarily uses **iodine-131** to treat thyroid conditions like hyperthyroidism or thyroid cancer. - This involves the patient ingesting a radioactive isotope, unlike the external radiation beams used in radiosurgery. *Cryo Surgery* - **Cryosurgery** involves the use of **extreme cold** to destroy abnormal tissues. - It is a physical method of tissue destruction and does not involve radiation. *Robotic Surgery* - **Robotic surgery** utilizes robotic systems to assist in performing surgical procedures, enhancing precision, and control for the surgeon. - This is a mode of performing traditional surgery and does not involve radiation as its primary therapeutic agent.
Question 3: When a lumbar puncture is performed to sample cerebrospinal fluid, which of the following external landmarks is the most reliable to determine the position of the L4 vertebral spine?
- A. The iliac crests (Correct Answer)
- B. The lowest pair of ribs bilaterally
- C. The inferior angles of the scapulae
- D. The posterior superior iliac spines
Explanation: ***The iliac crests*** - A line drawn between the **highest points of the iliac crests** on both sides typically intersects the L4 vertebral body or the L4-L5 intervertebral space. - This anatomical landmark provides a **safe entry point** for lumbar puncture, avoiding the spinal cord which usually ends at L1-L2. *The lowest pair of ribs bilaterally* - The lowest pair of ribs (12th ribs) corresponds to the **twelfth thoracic vertebra (T12)**, which is much higher than the desired lumbar puncture site. - Using this landmark would place the needle at a level where the **spinal cord is still present**, posing a significant risk of injury. *The inferior angles of the scapulae* - The inferior angle of the scapula typically corresponds to the **seventh thoracic vertebra (T7)**. - This landmark is also too superior for a safe lumbar puncture and does not accurately localize the lumbar spine. *The posterior superior iliac spines* - The posterior superior iliac spines (PSIS) are located at the level of the **S2 vertebra**, which is too far inferior for a standard lumbar puncture at L4-L5. - While they are important pelvic landmarks, they are not used for determining the L4 vertebral spine in this context.
Question 4: To localize a supernumerary or an impacted tooth and determine its exact relationship to the other teeth, which of the following radiographs would be most effective?
- A. A periapical and occlusal radiograph
- B. A high-angle occlusal radiograph
- C. A panoramic radiograph
- D. Multiple periapical radiographs and an occlusal radiograph (Correct Answer)
Explanation: ***Multiple periapical radiographs and an occlusal radiograph*** - Multiple **periapical radiographs** taken at different angles, along with an **occlusal radiograph**, allow for the application of the **SLOB rule (Same Lingual, Opposite Buccal)** for 3D localization of the impacted or supernumerary tooth. - The combination provides detailed images with varying perspectives, enabling precise determination of the **tooth's position** relative to adjacent structures. *A periapical and occlusal radiograph* - While a periapical and occlusal radiograph offer some information, a single periapical view lacks the necessary **angulations** for accurate 3D localization using the SLOB rule. - This combination may not provide enough visual data to definitively determine the tooth's **buccal-lingual position**. *A high-angle occlusal radiograph* - A high-angle occlusal radiograph provides a good **overall view of the arch** and can help locate a tooth within the arch, but it doesn't offer the detailed **buccal-lingual information** needed for precise localization. - It primarily shows the **anterior-posterior and medial-lateral position** but lacks the depth perception crucial for surgical planning. *A panoramic radiograph* - A panoramic radiograph offers a broad overview of the entire dentition and surrounding structures but suffers from **magnification and distortion**, making precise 3D localization challenging. - It is useful for initial screening but is not ideal for determining the exact **buccal-lingual relationship** of an impacted or supernumerary tooth.
Question 5: The safest initial approach to open the airway of a patient with maxillofacial trauma is:
- A. Head tilt-chin lift
- B. Jaw thrust technique (Correct Answer)
- C. Head lift-neck lift
- D. Heimlich procedure
Explanation: ***Jaw thrust technique*** - This technique is preferred in cases of **maxillofacial or suspected cervical spine trauma** as it minimizes neck movement, thereby reducing the risk of further injury. - It involves grasping the angles of the mandible and **lifting the jaw anteriorly**, which moves the tongue away from the posterior pharynx to clear the airway. *Head tilt-chin lift* - This maneuver is contraindicated in trauma settings where a **cervical spine injury** is suspected, as it can extend the neck and exacerbate spinal cord damage. - While effective for opening the airway in non-trauma patients, it involves **significant neck movement** which is unsafe in maxillofacial trauma. *Head lift-neck lift* - This is not a recognized or safe technique for airway management, especially in trauma patients, as it would cause **unnecessary and potentially harmful movement** of the head and neck. - There is no clinical scenario where this technique would be recommended over established airway maneuvers. *Heimlich procedure* - The Heimlich procedure (abdominal thrusts) is used to relieve **severe foreign body airway obstruction** and is not an initial approach to open an airway due to general trauma. - It is an intervention for choking, not for managing an airway in a patient with maxillofacial trauma where the primary concern is often **tongue prolapse** or significant structural injury causing obstruction.
Question 6: All of the following are described surgical procedures for CTE V except -
- A. Dwyer's osteotomy
- B. Salter's osteotomy (Correct Answer)
- C. Posteromedial soft tissue release
- D. Triple Arthrodesis
Explanation: ***Salter's osteotomy*** - **Salter's osteotomy** is a procedure primarily used for treating **developmental dysplasia of the hip (DDH)**, aiming to redirect the acetabulum. - It is not a described surgical procedure for the correction of **congenital talipes equinovarus (CTEV)**. *Dwyer's osteotomy* - **Dwyer's osteotomy** is a surgical procedure performed on the **calcaneus** to correct **hindfoot varus**, typically seen in CTEV. - It involves removing a wedge of bone from the lateral aspect of the calcaneus. *Posteromedial soft tissue release* - This is a common and traditional surgical procedure for correcting severe **CTEV** by addressing the contracted soft tissues on the medial and posterior aspects of the foot. - It involves releasing structures such as the **tibial tendon**, **flexor digitorum longus**, **flexor hallucis longus**, and the **posterior ankle joint capsule**. *Triple Arthrodesis* - **Triple arthrodesis** is a salvage procedure that involves fusing three joints in the foot: the **talonavicular**, **calcaneocuboid**, and **subtalar** joints. - It is used in older children or adolescents with severe, rigid, or recurrent CTEV, often after failed conservative or primary surgical treatments.
Question 7: Lateral movement is produced by anterior translation of one condyle producing rotation about the
- A. Center in the opposite neck
- B. Center in the opposite ramus
- C. Center in the opposite condyle (Correct Answer)
- D. Center in the opposite angle
Explanation: ***Center in the opposite condyle*** - **Lateral excursion** of the mandible involves the **working side condyle** rotating around a vertical axis, while the **non-working side condyle** translates anteriorly and medially (Bennett movement). - This anterior translation of the non-working condyle causes the entire mandible to pivot, with the center of rotation for the **lateral movement** being located roughly within the **condyle** on the **working (rotating)** side of the jaw. *Center in the opposite neck* - While the neck of the condyle is anatomically close to the condyle head, the **functional center of rotation** for lateral movement is typically described as being within the condyle itself, specifically its rotating component. - Positioning the center of rotation in the neck would imply a different biomechanical axis for the movement, which is not accurately reflected in standard mandibular kinematics. *Center in the opposite ramus* - The **ramus** is a broad part of the mandible, much larger than the condyle, and locating the center of rotation here would imply a much wider arc of movement, which is not consistent with the precise articulation of the **temporomandibular joint**. - The primary movements of the mandible during lateral excursion are centered on the condyle and its articular surfaces, not the entire ramus. *Center in the opposite angle* - The **angle of the mandible** is a distant anatomical landmark from the temporomandibular joint and is primarily involved in muscle attachments, not as a point of rotation for **lateral condylar movement**. - Placing the center of rotation at the angle would be biomechanically inaccurate for describing mandibular kinematics during lateral excursion.
Question 8: Which prosthesis is shown below in the X-ray?
- A. Articular resurfacing
- B. Thompson prosthesis
- C. Austin Moore's prosthesis (Correct Answer)
- D. Birmingham hip replacement
Explanation: ***Austin Moore's prosthesis*** - The image clearly shows a **femoral stem with a long intramedullary component** and an **integrated prosthetic head** that articulates directly with the native acetabulum. This is characteristic of a hemiarthroplasty design, specifically resembling an Austin Moore prosthesis. - This type of prosthesis is commonly used for **femoral neck fractures** in older patients, replacing only the femoral head and neck rather than the entire hip joint. *Articular resurfacing* - **Articular resurfacing** involves capping the femoral head and lining the acetabulum with metallic implants, preserving more bone than a traditional total hip replacement. - The X-ray image does not show a cap on the femoral head or a separate acetabular component, which are features of resurfacing. *Thompson prosthesis* - The **Thompson prosthesis** is another type of hemiarthroplasty, but it typically has a **shorter, bulkier femoral stem** and a **relatively smaller head** compared to the Austin Moore prosthesis shown. - While both Thompson and Austin Moore prostheses are hemiarthroplasties, the specific shape and length of the stem in the X-ray are more consistent with an Austin Moore design. *Birmingham hip replacement* - The **Birmingham hip replacement** is a type of **hip resurfacing arthroplasty**, which, as explained earlier, involves capping the femoral head and is not depicted in this image. - It maintains more of the patient's original bone structure compared to conventional total hip replacement but still requires both femoral and acetabular components.
Question 9: Early movement following surgery for ankylosis is
- A. Desirable (Correct Answer)
- B. Harmful
- C. Indicated only when ankylosis is one sided
- D. Unimportant
Explanation: ***Desirable*** - Early movement following surgery for **ankylosis** is crucial for preventing **re-ankylosis** and promoting the formation of a **neocartilage-like layer**. - It helps maintain joint mobility, reduce stiffness, and improves long-term functional outcomes after procedures like **arthroplasty**. *Harmful* - Delays in movement can lead to increased fibrous tissue formation, limiting the newly created joint's mobility and potentially causing **re-ankylosis**. - Prolonged immobilization after joint surgery can also lead to muscle atrophy, contractures, and impaired circulation, hindering recovery. *Indicated only when ankylosis is one sided* - The principle of early movement applies to both **unilateral** and **bilateral ankylosis** to prevent recurrence and improve range of motion in the affected joint(s). - Focusing solely on unilateral cases overlooks the functional benefits of early mobilization for all patients undergoing such surgery. *Unimportant* - Early movement is a **critical component** of postoperative recovery, as it directly impacts the success of the surgical intervention by maintaining joint space and flexibility. - Neglecting early motion can compromise the surgical outcome, increasing the risk of stiffness, pain, and the need for further interventions.
Question 10: Position for transport of a patient with lumbar spine fracture:
- A. Hyperextension
- B. Hyper flexion
- C. Neutral (Correct Answer)
- D. Alternating
Explanation: ***Neutral*** - Maintaining a **neutral spine position** during transport is crucial to prevent further displacement of fractured vertebral fragments. - This position minimizes stress on the spinal cord and existing injuries, reducing the risk of neurological damage. *Hyperextension* - **Hyperextension** of the spine can worsen a lumbar fracture by creating a "gap" at the injury site, potentially leading to increased instability or compression of the spinal cord. - This position is generally contraindicated for spinal fractures due to the risk of further injury. *Hyper flexion* - **Hyperflexion** of the spine can compress the anterior aspect of a fractured vertebra, potentially leading to further collapse or retropulsion of fragments into the spinal canal. - This movement should be strictly avoided as it can destabilize the fracture and increase the risk of neurological compromise. *Alternating* - **Alternating positions** during transport is inappropriate and dangerous for a patient with a lumbar spine fracture. - Frequent movement or changes in position can cause unstable fracture fragments to shift, risking further spinal cord injury or exacerbating existing damage.
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