Multiple Choice Questions

Spine

Please use the comments section at the bottom of the page if you have any query or feedback about any of the questions.

 

23. The most accurate way to monitor the motor tracts during spinal surgery is to stimulate which of the following regions:

A) Tibial nerve
B) Peroneal nerve
C) Motor cortex
D) Gastrocnemius
E) Proximal spinal cord

Correct Answer: C

The most accurate way to monitor the motor tracts of the spinal cord is to stimulate the motor cortex. Stimulation at the level of the spinal cord conducts mainly antidromically through sensory pathways. Stimulation of the tibial and peroneal nerve is performed for monitoring sensory pathways only; these are an important indicator of spinal cord integrity but do not monitor the motor pathways per se. Stimulation of the gastrocnemius does not have any value for monitoring.

Author: Fouad Chaudery


22. Which part of the body is removed last in a posterior vertebral column resected via a posterior approach:

A) The lamina 
B) The pedicles
C) The anterior wall of the vertebral body
D) The posterior vertebral cortex 
E) The transverse process

Correct Answer: D

To protect and stabilize the neural elements, the posterior vertebral cortex is left intact to be resected last.

Author: Fouad Chaudery

 

21. Which of the following conditions does not have a risk of cervical deformity greater than the general population

A) Neurofibromatosis
B) Larsen syndrome
C) Diastrophic dysplasia
D) Achondroplas
E) Down syndrome

Correct Answer: D

Achondroplasia is associated with frequent stenosis of the foramen magnum in infancy, as well as lower cervical stenosis. However, it is not associated with an actual deformity of the cervical spine. By contrast, neurofibromatosis, Larsen syndrome, and diastrophic dysplasia are associated with infantile cervical kyphosis. Down syndrome is associated with the risk of upper cervical instability.

Author: Fouad Chaudery

 

20. According to National Institutes of Health (NIH) criteria, what is the minimum number of 15-mm café-au-lait macules required as a diagnostic criterion for neurofibromatosis in postpubertal patients:

An Update on Neurofibromatosis Type 1: Not Just Café-au-Lait Spots,  Freckling, and Neurofibromas. An Update. Part I. Dermatological Clinical  Criteria Diagnostic of the Disease | Actas Dermo-Sifiliográficas

A) One
B) Two 
C) Three
D) Four
E) Six

Correct Answer: E

The NIH criteria require at least six 15-mm café-au-lait macules in postpubertal patients. Café-au-lait macules must be larger than 5 mm in prepubertal patients

Author: Fouad Chaudery

 

19. Which of the following is found less often in children with lumbosacral agenesis as compared to controls:

A) Cervical spine anomalies
B) Maternal diabetes 
C) Hip dislocation 
D) Spina bifida
E) Genu recurvatum

Correct Answer: E

Patients with lumbosacral agenesis often have knee flexion contractures as compared with controls. All of the other features listed are common in patients with lumbosacral agenesis.

Author: Fouad Chaudery

18. Nine days after surgery, a 16-year-old boy with idiopathic scoliosis has a temperature of 39.5° C. Wound aspiration reveals gram-positive cocci in clusters. Your next step in management is:

A) Begin intravenous cephalosporin and monitor the response
B) Begin intravenous vancomycin and monitor the response 
C) Begin hyperbaric oxygen and intravenous antibiotics
D) Open and debride the wound, leaving the instrumentation in place 
E) Open and debride the wound, and remove the instrumentation

Correct Answer: D

Open debridement is the treatment of choice if an early deep wound infection is confirmed after spinal fusion. The instrumentation is left in place to stabilize the wound and promote fusion. The wound is closed as long as it can be cleaned up adequately during surgery, and muscle has a healthy appearance. If this cannot be achieved or if several debridements fail, the wound may be left open

Author: Fouad Chaudery

17. A patient with hemophilia A has a hematoma of the iliopsoas. He has a partial femoral nerve palsy. Treatment involves continuous factor replacement and:

A) Open drainage 
B) Decompression of the fascia over the femoral nerve
C) Percutaneous insertion of a drainage tube
D) Embolization of feeder vessels by interventional radiologist
E) Observation 

Correct Answer: E

The standard treatment of a psoas abscess is continuous factor replacement. Surgery is usually unnecessary, but it may be considered in cases of acute palsy with severe pain unresponsive to medical therapy. A percutaneous drainage tube is not recommended because the hematoma may be difficult to locate or drain.

Author: Fouad Chaudery

16. A patient with L4 level myelomeningocele has developed a full-thickness pressure sore on the heel that has a central necrosis and is draining. While undergoing debridement in the local emergency department, the patient develops labored respiration and a nondetectable blood pressure. The most likely cause is:

A) Latex allergy
B) Aortic dissection 
C) Septic shock
D) Spontaneous tension pneumothorax 
E) Shunt failure

Correct Answer: A

Latex sensitivity is common in patients with spina bifida because of frequent exposure through catherizations and procedures. Latex avoidance is becoming the standard in institutions that commonly treat patients with spina bifida, but community hospitals that rarely see such patients may not always be aware of this problem.

• Dissection is not likely unless the patient has a connective tissue disorder.
• Septic shock is not likely to develop from a freely draining peripheral ulcer.
• Tension pneumothorax is not any more likely in patients with spina bifida than in the general population.
• Although it is important to be aware of shunt failure, it is not likely in this procedure which is done without anesthetic.

Author: Fouad Chaudery

15. A 12-year-old boy with achondroplasia has a gradual 40° thoracolumbar kyphosis. He is unable to walk more than two blocks. Magnetic resonance imaging reveals spinal stenosis, and the patient is scheduled to undergo posterior decompression from T12-S1. In addition to this procedure, you recommend:

A) Observation with serial radiographs every 4 months 
B) Postoperative brace for 6 months
C) In situ fusion with bone graft 
D) Posterior fusion across the kyphosis with instrumentation
E) Anterior corpectomy and fusion of T12

Correct Answer: D

Extensive posterior decompression poses a high risk of postoperative increase in kyphosis because of both the patient’s age and pre-existing kyphosis.

• Observation would not be a good idea because the risk is already known to be high.
• Neither a brace nor an uninstrumented fusion would prevent the deformity from developing.
• Corpectomy is not indicated because the kyphosis is not focal.
• Posterior instrumented fusion at the time of decompression is indicated.

Author: Fouad Chaudery

14. A 12-year-old girl is referred because of a positive school scoliosis screen. She has a curve of 16° from T5 to T12, convex to the right. She also complains of mild back pain over the region of the curve several times per week. Neurologic examination is normal. Recommended treatment includes:

A) Magnetic resonance imaging
B) Technetium bone scintigraphy with SPECT
C) Treatment with a thoracolumbosacral orthosis
D) Computed tomography of the thoracic spine 
E) Home exercises and re-examination in follow-up

Correct Answer: E

Home exercises and re-examination in follow-up is the most appropriate treatment in view of lack of any worrisome features. If this child had severe pain or significant night pain, then further imaging studies would be warranted.

• The magnetic resonance imaging is not indicated in this situation.
• The bone scan has a low likelihood of being positive.
• Bracing is not indicated for the curve or the pain.
• Computer tomography is unlikely to demonstrate any pathology.

Author: Fouad Chaudery

13. A “stinger” (transient weakness of the upper extremity commonly seen after a blow to the head and shoulder in football) most commonly affects the:

A) Spinal cord 
B) C-5/C-6 nerve roots 
C) C-7/C-8 nerve roots 
D) Axillary nerve 
E) Musculocutaneous nerve 

Correct Answer: B

"Stingers" are common in football. They generally result from a transient stretch to the C-5/C-6 nerve roots resulting in temporary loss of strength of the biceps, deltoid, and spinatus muscles. It is generally safe to allow the athlete to return to participation, provided the cervical spine examination is normal and any neurological deficits have completely resolved. 

Author: Fouad Chaudhry

 

 

12. The skin over the umbilicus is innervated by which of the following levels:

A) T2
B) T4
C) T7
D) T10
E) T12

Correct Answer: D

T4

Nipple line

T7

Xiphoid process

T10

Umbilicus

T12

Groin

Author: Fouad Chaudhry

 
 

 

11. The extensor hallucis longus muscle is innervated by which of the following nerve roots:

A) L1
B) L2
C) L3
D) L4
E) L5

Correct Answer: E

Remember that the L5 nerve root innervates the following muscles:
• Extensor hallucis longus
• Extensor digitorum longus and brevis
• Gluteus medius

Author: Fouad Chaudhry

 
 

 

10. The skin of the proximal one-third of the anterior thigh just distal to the inguinal ligament is innervated by which of the following sensory segmental levels: 

A) T12
B) L1
C) L2
D) L3
E) L4

Correct Answer: B

L1

Thigh, proximal third, and anterior

L2

Thigh, middle, and anterior

L3

Thigh, distal third, and anterior

Author: Fouad Chaudhry

 

 

9. The most common location of a chordoma is: 

A) Cervical vertebra
B) Thoracic vertebra
C) Lumbar vertebra
D) Sacrococcygeal region
E) Spheno-occipital region 

Correct Answer: D

Over 50% of the time, chordomas commonly occur in the sacrococcygeal region. Cervical, thoracic, and lumbar vertebral chordomas account for approximately 10% of chordomas. The remaining chordomas occur in the spheno-occipital region.

Author: Fouad Chaudhry

 

8. When harvesting an iliac crest bone graft from the post. approach, what anatomic structure is at greatest risk for injury if a Cobb elevator is directed too caudal?

A) Sciatic nerve
B) Cluneal nerves
C) Inferior gluteal artery
D) Superior gluteal artery
E) Sacroiliac joint

Best answer:  D

If a Cobb elevator is directed caudally while stripping the periosteum over the iliac wing, it will encounter the sciatic notch. Although this puts the sciatic nerve at risk, the fi rst structure encountered is the superior gluteal artery. Because it is tethered at the superior edge of the notch, it is very vulnerable to injury and can then retract inside the pelvis, making it diffi cult to obtain hemostasis. 

The inferior gluteal artery exits the sciatic notch below the piriformis and is more protected. The cluneal nerves are at risk only if the incision extends too anteriorly, and the sacroiliac joint can be entered while harvesting the graft.

Author: Salam Al-Abayachi

 

7. Through a retroperitoneal approach to the L4-5 disk, what structure must be ligated to safely mobilize the common iliac vessels toward the midline laterally and gain exposure?

A) Obturator vein
B) Iliolumbar vein
C) External iliac vein
D) Middle sacral artery
E) Hypogastric artery

Best answer:  B

To mobilize the common iliac vessels across the midline, the iliolumbar vein must be ligated. It has a short trunk and can be torn if mobilization is attempted without ligation. It is the only branch off the common iliac vessels (there are no arterial branches) prior to the terminal branches, and the internal (hypogastric) and external iliac vessels. 

The middle sacral vessels run distally from the axilla of the bifurcation and are a factor when accessing the L5-S1 disk.

Author: Salam Al-Abayachi

 

6. If a surgeon accidentally burrs through the midlateral wall of C5 during a anterior corpectomy, what structure is at greatest risk for injury?

A) C5 root
B) C6 root
C) Internal carotid artery
D) Vertebral artery
E) Vagus nerve

Best answer:  D

The vertebral artery is contained within the vertebral foramen and thus tethered along-side the vertebral body, making it vulnerable to injury if a drill penetrates the lateral wall. 

The C5 root passes over the C5 pedicle and is not in the vicinity. 

The C6 root passes under the C5 pedicle but is posterior to the vertebral artery and is only vulnerable at the very posterior-inferior corner. The carotid artery and the vagus nerve are both within the carotid sheath and well anterior.

Author: Salam Al-Abayachi

 

5. What structure is located at the tip of the arrow in the figure attached?

A) Left L3 nerve root
B) Right L3 nerve root
C) Right L4 segmental artery
D) Right L4 nerve root
E) Left lateral disk herniation

Best answer:  B

Explanation: The structure shown is the exiting nerve root at the L3-4 disk, which is the right L3 root.

Author: Salam Al-Abayachi

 

4. What structure is most at risk for injury from a retractor against the tracheoesophageal junction during an ant. approach to the cervical spine?

A) Esophagus
B) Trachea
C) Superior laryngeal nerve
D) Recurrent laryngeal nerve
E) Sympathetic chain

Best answer:  D

Although any of these structures can be injured by pressure from the medial blade of a self-retaining retractor, the recurrent laryngeal nerve runs cephalad in the interval between the esopha-gus and trachea and is vulnerable to pressure if caught between the retractor and an infl ated endotra-cheal tube balloon.

Author: Salam Al-Abayachi

 

3.  A 55 year old male presented with urinary retention and saddle paraesthesia. His symptoms began 12 hours ago. He has a cardiac pacemaker inserted. Examination revealed reduced anal tone.

What is the next step in management?

A) MRI scan of the lumbar Spine
B) CT myelogram of the lumbar spine
C) Immediate surgical decompression of the cervical spine
D) Physiotherapy, analgesia, and outpatient follow up
E) High dose corticosteroid

Best answer: B

This patient has classic symptoms of cauda equina syndrome. The most important next step is to identify the source of compression in the lumbar spine. The study of choice is an MRI; however in patients who are unable to undergo an MRI such as those with pacemakers, a CT myelogram should be performed.  

Cauda equina syndrome is a complex of low back pain, bilateral or unilateral sciatica, saddle anaesthesia, motor weakness and bowel/bladder dysfunction.

Cauda equina a surgical emergency. Decompression of the lumbar spine should be performed within 48 hours from the onset of symptoms

Ref :Kostuik JP, Harrington I, Alexander D, Rand W, Evans D: Cauda equina syndrome and lumbar disc hemiation. J Bone Joint Surg Am 1986; 68:386-391

Author : Firas Arnaout

 

2.  A 40 years old man is involved in a road traffic accident and sustains neck injury with C4/C5 dislocation. On examination he has loss of motor function on one side and loss of pain and temperature sensation on the contralateral side. 

Which spinal cord syndrome is associated with these findings?

A) Central cord syndrome
B) Anterior cord syndrome
C) Brown-Sequard syndrome
D) Posterior cord syndrome
E) Neurologic shock

Best answer: C

 

Brown-Sequard syndrome is caused by complete cord hemitransection. On examination; patients have loss of motor power, proprioception and vibration sensation on one side. And contralateral loss of pain and temperature sensation. This syndrome has the best prognosis of all spinal cord injuries.

Ref: Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 179-187

Author :Firas Arnaout


1.   A 65 years old man presented with bilateral buttocks and legs pain, worse with standing and walking, and better with leaning forword.On examination, he has normal power in his legs, straight leg raising and pedal pulses normal. 

What is this clinical presentation consistent with?

A) Peripheral vascular disease
B) Disc prolapsed
C) Cauda equine syndrome
D) Spinal stenosis
E) Osteomylitis of the spine

Best answer: D

Spinal stenosis is due to narrowing of the spinal canal by either bony or soft tissue structures. Patients present with neurogenic claudication.MRI is the best investigation. 

Treatment is with analgesia and steroid injection, or surgical with decompression. It is important to differentiate between neurogenic and vascular claudication.

Ref: Weinstein JN, Tosteson TD, Lurie JD, Tosteson AN, Blood E, Hanscom B, Herkowitz H, Cammisa F, Albert T, Boden SD, Hilibrand A, Goldberg H, Berven S, An H; SPORT Investigators. Surgical versus nonsurgical therapy for lumbar spinal stenosis. N Engl J Med. 2008 Feb 21; 358(8):794-810

Author :Firas Arnaout

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