Question 1

An 18-year-old man comes to the office with a grade IV isthmic spondylolisthesis and severe left lower extremity discomfort. Which imaging study would best help identify the site of potential nerve root compression:

Explanation

An MRI scan would be the imaging study of choice to best identify the site of nerve root compression because it provides parasagittal views that can help determine the degree of narrowing of the neural foramina. Plain myelography may not accurately identify lateral recess compression. A C T scan would produce images perpendicular to the plane of nerve root compression. Bone scan and PET scan would be of little or no help in identifying nerve root compression.

Question 2

Some of the more common risk factors that could predispose a person to developing low back pain are listed below. Which risk factor has not been implicated:

Explanation

Being female has not been implicated as a risk factor in the development of low back pain. Occupations that require heavy lifting, the use of jackhammers, and operating motor vehicles, as well as the usage of tobacco products and being overweight have all been associated with a higher incidence of developing low back pain.

Question 3

When considering surgical intervention in the management of low back pain, it is crucial to try and identify the possible offending agent or pain generator. Based on awake anatomical stimulation studies, what percentage of patients should report significant discomfort when a nerve root is either compressed or stretched in an attempt to elicit pain:

Explanation

Studies have reported on diskectomies in awake patients performed under local anesthesia. Anatomic spinal structures were stimulated prior to additional local anesthesia placed into these deeper areas and patients were asked to report any pain. Compression or stretching of nerve roots caused significant pain 100% of the time. Stimulation of the posterior dura caused significant pain only 1% of the time.

Question 4

Which disorder does not represent a rheumatologic/inflammatory condition associated with causing low back pain:

Explanation

Although osteoarthritis is the most common arthritic disorder associated with low back pain, it is not a rheumatologic condition. Rheumatoid arthritis, Reiter syndrome, psoriatic arthritis, and ankylosing spondylitis are all rheumatologic or inflammatory conditions associated with the development of low back pain.

Question 5

A 57-year-old man with known lung cancer and metastatic disease complains of increasing low back pain. How often is the lumbar spine involved when a patient has known spinal metastasis:

Explanation

In 85 % of patients with metastatic disease to the spine, the lumbar region vertebral body is involved. If operable, the vertebral body lesion can be managed via an anterior approach with a corpectomy, as opposed to a posterior approach with laminectomy and removal of all involved posterior elements (if they are involved).

Question 6

A 32-year-old man develops left lower extremity discomfort following a basketball game. A magnetic resonance image of the lumbar spine reveals a posterolateral disk herniation at the level of L4/L5. All of the following conditions could be associated with this except:

Explanation

Decreased strength in the hip abductors and in the extensor hallucis longus muscle along with numbness in the lateral aspect of the leg and pain in the dorsum of the foot can all be associated with a herniation at the L4/L5 level affecting the L5 nerve root. Decreased strength in plantarflexion of the foot is present when the S1 nerve root is involved, such as with a disk herniation at the L5/S1 level.C orrect Answer: Decreased strength in plantarflexion of the foot

Question 7

A 43-year-old man develops pain radiating down his left leg from a far- lateral disk herniation at the L5/S1 level. Which is the most likely nerve root contributing to his discomfort:

Explanation

Typically, for a posterolateral disk herniation, the traversing or more distal nerve root is often involved. With a far-lateral disk herniation (as in this case), the exiting nerve root is usually involved. In this case, it would be the L5 nerve root.

Question 8

Which orthopedic test, designed to apply tension to the spinal cord producing pain, involves having the patient lie supine while the examiner flexes the patient's head to his chest:

Explanation

The Kernig test involves the patient lying supine while the examiner forcibly flexes the head to the chest applying tension to the spinal cord. The test is positive if pain is elicited and indicates meningeal irritation in conditions such as meningitis. The Hoover test can help identify a patient who is malingering. This test involves having the patient lie supine with the examiner's hands placed under both of the patient's heels. The patient is asked to lift the affected leg. If a true effort is made, the examiner should feel downward pressure in the patient's opposite foot as he attempts to lift the affected leg. If no downward pressure is felt, the patient purposely may not be trying and might be malingering. The Milgram test may be used in conditions with suspected intrathecal pathology. While lying supine, the patient is asked to perform bilateral straight leg lifts. If the patient can sustain his feet 2 inches off the ground for more 30 seconds, intrathecal pathology is less likely. The Naffziger test is designed to increase intrathecal pressure and thus pain by compressing the jugular veins. The Gaenslen test is used to determine sacroiliac joint pathology.

Question 9

A 52-year-old man sustained an L1 burst fracture after falling from a ladder 3 weeks ago. He was found neurologically intact after initial examination. He has been treated with conservative management since the accident, but he now complains of an inability to void along with numbness and tingling in both of his legs. Computed tomography scan shows worsening conus compression. On physical examination, you discover that he has weak anal sphincter tone. Your next step in the treatment of this patient should be:

Explanation

This patient has deteriorating neurological findings involving the cauda equina; therefore, surgical decompression is indicated. An anterior approach will directly decompress the neural structures. Performing a laminectomy alone is actually contraindicated as it may increase potential spinal instability. A posterior approach to achieve a fusion with instrumentation may not fully decompress the neural structures, although this is somewhat controversial.

Question 10

A 27-year-old man comes in for examination. He complains of worsening pain in his lower back. He states that the pain started 4 days ago after lifting a heavy box. The patient's neurological exam is completely nonfocal. The initial management of this patient should include:

Explanation

This patient's neurological exam is normal and his injury was recent; this is most likely a soft tissue injury to his low back. Due to the patient's age and the fact that this is most likely not a serious injury, an initial conservative approach would be most appropriate. Epidural steroids or a selective nerve root block would be indicated if this patient developed worsening low back complaints or radicular pain in association with his low back pain.

Question 11

When trying to distinguish sciatic radicular pain from pain following a hamstring strain, it is important to know that pain from a hamstring strain usually only involves the posterior aspect of thigh. Sciatic nerve pain may also be associated with:

Explanation

Sciatic pain can involve all of the above complaints including radicular pain extending down the leg, low back pain, and pain into the opposite leg.

Question 12

A 42-year-old man sustained a twisting injury to his low back 5 months ago. Since the injury, he has persistent low back pain that radiates into his right thigh and down to his posterior calf. The patient underwent a magnetic resonance imaging of his lumbar spine revealing a small posterolateral lumbar disk herniation at the L4L5 level. Over the past month, the patient states that his leg pain has been getting progressively better and has almost disappeared over the past week with the use of nonsteroidal anti- inflammatory medications and occasional bed rest. The next step in the management of this patient should be:

Explanation

The patient has shown continued improvement of his symptoms including the leg pain with conservative treatment. Epidural steroids would be indicated if this patient had continued or worsening leg pain and/or low back pain.

Question 13

This radiograph shows a grade I spondylolisthesis of L5 on S1. This is due to a defect in what anatomical area:

Explanation

Orthopedic Prometric Exam Chapter 3 Image

The anatomical region involved in a spondylolisthesis is the pars interarticularis that is located between the superior and inferior articular processes and is a high stress area of relatively thinner bone.

Question 14

A 16-year-old football lineman develops unrelenting low back pain for the past 3 months. Based on the magnetic resonance image shown, the next step in the management of this patient is:

Explanation

This patient has a grade I-II spondylolisthesis of L5 on S1. The initial management should include restriction of physical activity. Once the symptoms abate, the athlete can return to the sport. If symptoms return, other interventions are indicated including possible brace wear.C orrect Answer: Restriction of the exacerbating activity

Question 15

A 50-year-old woman with 3 months of low back pain recently discovers a hard, painless lump in her breast. Due to the back discomfort, she undergoes plain radiography and subsequently a computed tomography scan (below). The most likely diagnosis is:

Explanation

The computed tomography scan reveals a destructive lesion involving the vertebral body extending into the pedicle in a patient with a suspected breast malignancy. This is a metastatic lesion until proven otherwise. This patient needs a thorough evaluation of her breast lesion, as well as her spine lesion, including biopsies. An osteoid osteoma is seen in a younger population and is seen on a computed tomography scan as a sclerotic round lesion.

Question 16

A 45-year-old construction worker with long standing low back pain now notices bilateral thigh and lower extremity discomfort for the past 6 months. He has undergone conservative treatment with little success including injection therapy. He cannot perform his work duties. Based on the lateral radiograph shown below, the next step in the management of the patient should consist of:

Orthopedic Prometric Exam Chapter 3 Image

Explanation

This patient has an isthmic L4L5 spondylolisthesis with accompanied neuroforaminal stenosis. He already failed conservative management and would benefit from operative intervention. This should consist of a decompressive procedure to alleviate his lower extremity symptomatology along with a fusion procedure of the L4-L5 level due to the listhesis. If he undergoes a laminectomy alone, he may develop increased low back pain in the future.

Question 17

A 35-year-old woman presents with severe back pain. Radiographic evaluation reveals a thoracic curve of 70° and a loss of thoracic kyphosis. Surgery is recommended to correct the deformity. Which of the following tests must be ordered as part of the preoperative evaluation:

Explanation

Thoracic curves greater than 65° may affect pulmonary function, especially when they are combined with thoracic lordosis. This patient displays a thoracic curve of 70° and a loss of the normal thoracic kyphosis; therefore, pulmonary function tests are part of the routine evaluation.

Question 18

A calcified thoracic disk in the spinal canal is pathognomonic for:

Explanation

Plain radiographs of the spine are helpful in the diagnosis of disk herniation only if they demonstrate disk calcification. However, the calcified disk is not always the disk that is herniated, but it suggests the diagnosis. Detection of a calcified disk on radiograph in the canal is pathognomonic of herniation.

Question 19

Surgical treatment of thoracic disk herniation by a laminectomy is contraindicated because this procedure is associated with which of the following:

Explanation

There is a high incidence of spinal cord injury associated with thoracic disks removed by laminectomy. The advent of alternative procedures, such as costotransversectomy and transthoracic decompression, has led to a decrease in spinal cord injury admissions. Also, patients who do not improve after laminectomy are less likely to be helped by later anterior decompression.

Question 20

The most common presenting symptom of a patient with a thoracic disk herniation is:

Explanation

Brown et al reported on a series of 55 patients initially treated with conservative management. Anterior band-like chest pain occurred in 67% of his patients. Lower extremity complaints accounted for 20% and ranged from weakness (16%) to parasthesias (4%).

Question 21

A 68-year-old male presents with bilateral lower extremity aching and cramping that worsens with walking and improves when he leans forward on a shopping cart. Which of the following is the most characteristic clinical feature distinguishing this condition from vascular claudication?

Explanation

Neurogenic claudication due to lumbar spinal stenosis is typically relieved by lumbar flexion (e.g., walking uphill or leaning on a cart), which increases the spinal canal diameter. Vascular claudication is exacerbated by walking regardless of posture and is not relieved by spinal flexion.

Question 22

A 42-year-old female presents with acute onset of low back pain radiating down the posterior thigh, lateral calf, and dorsum of the foot. Physical examination reveals weakness in extensor hallucis longus (EHL) and decreased sensation over the dorsal first web space. Which disc herniation is most likely responsible?

Explanation

Weakness in the EHL and numbness in the first dorsal web space indicate an L5 radiculopathy. A paracentral disc herniation at L4-L5 compresses the traversing L5 nerve root.

Question 23

When evaluating a patient with spondylolisthesis, the Meyerding classification is commonly used to grade the severity of the slip. A Meyerding Grade III slip corresponds to what percentage of anterior translation of the superior vertebral body over the inferior one?

Explanation

The Meyerding classification grades spondylolisthesis based on the percentage of slip: Grade I (1-25%), Grade II (26-50%), Grade III (51-75%), Grade IV (76-100%), and Grade V (>100%, spondyloptosis).

Question 24

What is the primary anatomical defect responsible for the development of an isthmic spondylolisthesis?

Explanation

Isthmic spondylolisthesis (Type II) is characterized by a defect or stress fracture in the pars interarticularis. This allows the anterior column to slip forward while the posterior elements remain behind.

Question 25

On oblique lumbar radiographs, the posterior elements resemble a "Scotty dog". In the context of isthmic spondylolisthesis, a defect is often seen as a "collar" around the dog's neck. Which anatomical structure corresponds to the neck of the Scotty dog?

Explanation

On an oblique lumbar radiograph, the "neck" of the Scotty dog represents the pars interarticularis. A radiolucent line or "collar" indicates a pars defect (spondylolysis).

Question 26

A 35-year-old male presents to the emergency department with severe acute low back pain and bilateral leg weakness. Which of the following is the most sensitive clinical finding for the early diagnosis of cauda equina syndrome?

Explanation

Urinary retention is the most sensitive sign for cauda equina syndrome. A normal post-void residual bladder volume effectively rules out the condition in most cases.

Question 27

A 50-year-old male is diagnosed with a far lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is most likely to be directly compressed by this specific herniation?

Explanation

Far lateral or extraforaminal disc herniations compress the exiting nerve root at the same level. Therefore, an L4-L5 far lateral disc herniation compresses the exiting L4 nerve root.

Question 28

In a patient presenting with central lumbar spinal stenosis, which ligament undergoes characteristic hypertrophy and buckling, contributing significantly to dorsal compression of the thecal sac?

Explanation

The ligamentum flavum thickens and buckles inward as the disc space narrows with degeneration. This is a primary cause of dorsal compression in central lumbar spinal stenosis.

Question 29

Discogenic low back pain is a common entity. The outer annulus fibrosus of the lumbar intervertebral disc is capable of nociception. Which nerve provides the primary innervation to the outer posterior third of the annulus fibrosus?

Explanation

The sinuvertebral nerve (recurrent meningeal nerve) originates from the ventral ramus and sympathetic trunk, innervating the posterior aspect of the annulus fibrosus, posterior longitudinal ligament, and anterior dura.

Question 30

De novo degenerative lumbar scoliosis typically presents in older adults without a prior history of spinal curvature. What is the primary driving mechanism behind the development of this deformity?

Explanation

Degenerative lumbar scoliosis is caused by asymmetric degeneration of the intervertebral discs and facet joints. This leads to progressive instability and a scoliotic curve, most commonly in the lumbar spine.

Question 31

A 65-year-old female presents with chronic lower back pain and neurogenic claudication. Radiographs demonstrate degenerative spondylolisthesis. Which vertebral level and direction of slip is most statistically common in this condition?

Explanation

Degenerative spondylolisthesis occurs most frequently at the L4-L5 level, with L4 translating anteriorly over L5. It is up to four times more common in females than males.

Question 32

During a routine neurologic examination for back pain, the patient exhibits an absent Achilles tendon reflex but normal patellar reflexes. Motor testing shows weakness in plantar flexion. Which nerve root is primarily involved?

Explanation

The S1 nerve root innervates the gastrocnemius and soleus muscles (plantar flexion) and mediates the Achilles tendon reflex. L4 mediates the patellar reflex.

Question 33

Waddell's signs are utilized during a physical examination to identify non-organic (psychological or behavioral) causes of back pain. Which of the following is NOT considered a positive Waddell's sign?

Explanation

Waddell's signs test for non-organic pain. True dermatomal sensory loss or myotomal weakness indicates a genuine organic neurological deficit, not a Waddell's sign.

Question 34

A 45-year-old male with persistent, severe lower back pain and L5 radiculopathy has a Grade II isthmic spondylolisthesis at L5-S1. He has failed extensive conservative management. What is the most appropriate surgical intervention?

Explanation

In adult patients with symptomatic Grade II isthmic spondylolisthesis and radiculopathy failing conservative care, the standard treatment is decompression of the nerve roots combined with instrumented fusion to stabilize the slipped segment. Pars repair is generally reserved for young patients without a significant slip.

Question 35

A patient complains of lateral thigh and anterior knee pain. Examination reveals distinct weakness in knee extension against resistance and an absent patellar reflex. Sensation is decreased over the medial aspect of the lower leg. Which nerve root is most likely compressed?

Explanation

The L4 nerve root mediates the patellar reflex, supplies motor innervation to the quadriceps (knee extension), and provides sensation to the medial aspect of the lower leg.

Question 36

A 58-year-old diabetic patient presents with unremitting back pain, fevers, and elevated ESR and CRP. You suspect pyogenic vertebral osteomyelitis. What is the most sensitive and specific imaging modality to confirm this diagnosis?

Explanation

MRI with gadolinium contrast is the gold standard imaging modality for evaluating spinal infection, offering high sensitivity and specificity for discitis, osteomyelitis, and epidural abscess.

Question 37

A 60-year-old male with a 30-year history of ankylosing spondylitis presents to the emergency room with new-onset mechanical back pain after a minor fall from standing height. Neurological exam is normal. What is the most critical suspected diagnosis that must be ruled out?

Explanation

Patients with ankylosing spondylitis have rigid, osteopenic spines that act like long bones. Even minor trauma can cause highly unstable transdiscal or transvertebral "chalk stick" fractures, which carry a high risk of neurologic injury.

Question 38

The normal adult intervertebral disc is the largest avascular structure in the human body. How does the central nucleus pulposus primarily receive its essential nutritional supply?

Explanation

The nucleus pulposus is avascular and relies entirely on passive diffusion of nutrients and oxygen from the capillary beds of the adjacent vertebral bodies through the cartilaginous endplates.

Question 39

An anteroposterior (AP) radiograph of the lumbar spine reveals the "winking owl" sign in a patient with a known history of breast cancer. This radiographic sign indicates the lytic destruction of which specific anatomical structure?

Explanation

The "winking owl" sign is the absence of a pedicle on an AP spinal radiograph, classically seen in metastatic bone disease or multiple myeloma due to lytic destruction of the pedicle.

Question 40

A 65-year-old male presents with bilateral leg pain exacerbated by walking and relieved by sitting or leaning forward over a shopping cart. Examination reveals normal peripheral pulses. Which imaging study is the gold standard for confirming the primary diagnosis in a patient without surgical hardware?

Explanation

MRI of the lumbar spine is the gold standard and most appropriate non-invasive confirmatory study for lumbar spinal stenosis. It excellently visualizes soft tissue structures causing compression, such as the ligamentum flavum and disc bulging.

Question 41

A 42-year-old female presents to the emergency department with acute onset of severe low back pain, bilateral sciatica, and perineal numbness. Her post-void residual bladder volume is 400 mL. What is the next most appropriate step in management?

Explanation

This patient presents with classic red flag signs of cauda equina syndrome, including saddle anesthesia and urinary retention (PVR >100-200 mL). It is a surgical emergency requiring urgent MRI and subsequent rapid surgical decompression.

Question 42

According to the Wiltse classification of spondylolisthesis, a slip that occurs secondary to an elongation of the pars interarticularis without a frank defect is classified as which type?

Explanation

Elongation of the pars interarticularis without a frank defect is classified as a Wiltse Type IIb (Isthmic) spondylolisthesis. Type II is divided into lytic (IIa), elongated (IIb), and acute fracture (IIc).

Question 43

A 60-year-old female presents with neurogenic claudication. Sagittal T2-weighted MRI demonstrates central canal stenosis at L4-L5.

Which posterior spinal element predictably undergoes hypertrophy and buckling, contributing significantly to this central canal stenosis?

Explanation

In degenerative lumbar spinal stenosis, the ligamentum flavum typically undergoes hypertrophy and buckles into the spinal canal as disc space height is lost. This is a primary soft-tissue contributor to posterior thecal sac compression.

Question 44

A 35-year-old man presents with right lower extremity radiating pain. Examination reveals weakness in extensor hallucis longus (EHL) and numbness over the dorsum of the right foot. The Achilles and patellar reflexes are symmetric and intact. Which nerve root is most likely affected?

Explanation

The L5 nerve root innervates the extensor hallucis longus and provides sensation to the dorsum of the foot. Unlike L4 (patellar) and S1 (Achilles), there is no reliable primary muscle stretch reflex exclusively for the L5 nerve root.

Question 45

A 24-year-old man is brought to the trauma bay following a high-speed motor vehicle collision where he was wearing only a lap belt. Radiographs reveal a flexion-distraction injury of the thoracolumbar spine (Chance fracture). What concomitant injury is highly associated with this fracture pattern?

Explanation

Chance fractures (flexion-distraction injuries) are historically associated with lap belt wear. Up to 40-50% of these patients have concomitant intra-abdominal injuries, particularly to hollow viscous organs.

Question 46

A 65-year-old woman presents with lower back and leg pain. Imaging shows an L4-L5 anterior translation with an intact pars interarticularis.

Which of the following structural characteristics most directly predisposes this specific spinal level to degenerative spondylolisthesis?

Explanation

Degenerative spondylolisthesis most commonly occurs at the L4-L5 level. This is primarily because the facet joints at this level are oriented more sagittally, conferring less resistance to anterior shear forces.

Question 47

A 40-year-old male presents with chronic stiffness and back pain. Radiographs reveal bridging syndesmophytes and bilateral fusion of the sacroiliac joints.

This classic "bamboo spine" radiographic appearance is most highly correlated with which human leukocyte antigen (HLA)?

Explanation

Ankylosing spondylitis presents radiographically with syndesmophytes leading to a bamboo spine appearance. It is a seronegative spondyloarthropathy with a strong genetic association with HLA-B27.

Question 48

A 60-year-old diabetic patient presents with unrelenting back pain and fever. Blood tests show an elevated CRP and ESR. MRI of the lumbar spine is obtained. Which of the following MRI findings is most characteristic of pyogenic spondylodiscitis as opposed to a neoplastic process?

Explanation

Pyogenic spondylodiscitis typically crosses the disc space, destroying adjacent endplates and causing T2 hyperintensity in the disc. Neoplastic processes generally involve the vertebral body and pedicles while initially sparing the avascular disc.

Question 49

In evaluating a 12-year-old female with adolescent idiopathic scoliosis (AIS), which of the following combinations of factors represents the highest risk for curve progression?

Explanation

The risk of curve progression in AIS is highest in patients with significant remaining growth (pre-menarchal, Risser 0-1) and larger magnitude curves (>25-30 degrees) at the time of presentation.

Question 50

According to the Denis three-column theory of the spine, a classic burst fracture is radiographically characterized by failure of which columns under axial loading?

Explanation

A burst fracture occurs from axial loading and involves failure of both the anterior and middle columns. Disruption of the middle column differentiates it from a simple anterior wedge compression fracture.

Question 51

A patient who underwent an uncomplicated posterior lumbar spinal fusion 10 days ago presents with increasing incisional pain, wound erythema, and a temperature of 38.5 C. There is purulent drainage from the incision. What is the most appropriate initial management?

Explanation

Acute deep postoperative spinal infections require prompt surgical irrigation and debridement (I&D) to obtain deep cultures and reduce bioburden. Spinal instrumentation is typically retained if it is stable, especially in the acute setting.

Question 52

A 45-year-old patient presents with acute right-sided L4 radiculopathy. MRI reveals a far lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is typically compressed by a far lateral disc herniation at this specific anatomical level?

Explanation

Far lateral (extraforaminal) disc herniations impinge the exiting nerve root at the same level. Therefore, an L4-L5 far lateral herniation compresses the L4 nerve root, whereas a paracentral herniation would compress the traversing L5 nerve root.

Question 53

A 15-year-old male gymnast presents with a 4-month history of localized low back pain exacerbated by extension. Oblique radiographs of the lumbar spine are obtained.

A defect in which anatomical structure represents the collar on the "Scotty dog"?

Explanation

The 'collar' on the Scotty dog sign seen on oblique lumbar radiographs represents a defect (fracture or lysis) in the pars interarticularis, indicating spondylolysis.

Question 54

A 62-year-old female presents with severe neurogenic claudication and a grade I degenerative spondylolisthesis at L4-L5. Which nerve root is most likely to be compressed in this condition?

Explanation

In degenerative spondylolisthesis, the slip most commonly occurs at L4-L5 with intact pars interarticularis. The central canal and lateral recess stenosis primarily compresses the traversing L5 nerve root.

Question 55

A 16-year-old elite gymnast complains of lower back pain exacerbated by extension. Plain radiographs are normal. What is the most appropriate next imaging modality to detect an acute pars interarticularis stress reaction without radiation exposure?

Explanation

MRI is highly sensitive for detecting marrow edema associated with acute pars stress reactions and avoids ionizing radiation, making it the preferred initial advanced imaging in pediatric patients. SPECT is also highly sensitive but involves significant radiation.

Question 56

Which of the following physical examination findings is NOT considered one of Waddell's signs for nonorganic back pain?

Explanation

Waddell's signs screen for nonorganic or psychological components to back pain. Bilateral absent Achilles reflexes represent a hard objective neurologic finding, not a nonorganic sign.

Question 57

A 45-year-old male presents with acute severe back pain, bilateral leg radicular symptoms, and perineal numbness. What is the most sensitive clinical symptom or sign for the diagnosis of cauda equina syndrome?

Explanation

Urinary retention is the most sensitive finding (approximately 90%) in cauda equina syndrome. Its absence can be heavily relied upon to help rule out the condition.

Question 58

A 50-year-old male is diagnosed with a far lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is most likely affected?

Explanation

Far lateral disc herniations compress the exiting nerve root at the level of the herniation. Therefore, an L4-L5 far lateral disc compresses the exiting L4 nerve root.

Question 59

A 70-year-old male presents with neck and back stiffness. Radiographs demonstrate flowing anterior osteophytes over six contiguous vertebral bodies. Which of the following is a requisite radiographic criterion for the diagnosis of Diffuse Idiopathic Skeletal Hyperostosis (DISH)?

Explanation

DISH requires flowing ossification along the anterolateral aspect of at least four contiguous vertebral bodies with relative preservation of intervertebral disc height. Sacroiliac and facet joint fusion or erosions are notably absent, distinguishing it from Ankylosing Spondylitis.

Question 60

A 68-year-old woman complains of bilateral leg pain that worsens with walking and improves when sitting or leaning over a shopping cart. What is the most likely mechanism providing relief in this patient?

Explanation

Lumbar flexion increases the cross-sectional area of the central spinal canal and neural foramina, relieving compression on the cauda equina and traversing nerve roots in neurogenic claudication.

Question 61

A 35-year-old male experiences acute radicular leg pain following heavy lifting. An MRI reveals a massive paracentral disc herniation at L5-S1. Which of the following physical examination findings is most anticipated?

Explanation

A paracentral disc herniation at L5-S1 typically compresses the traversing S1 nerve root. S1 radiculopathy presents with weakness in plantar flexion, decreased Achilles reflex, and sensory loss over the lateral foot.

Question 62

Patients with ankylosing spondylitis who sustain minor trauma are at high risk for highly unstable spinal fractures. What unique associated complication is significantly more common in these patients following such fractures?

Explanation

The ankylosed spine fractures like a long bone, leading to highly unstable, shearing fractures. These patients are at an exceptionally high risk of developing a spinal epidural hematoma due to the highly vascular fractured epidural bone and altered spinal biomechanics.

Question 63

A 22-year-old male presents with axial back pain.

Based on a lateral lumbar spine radiograph showing isthmic spondylolisthesis, what is the primary anatomical defect responsible for this specific etiology?

Explanation

Isthmic spondylolisthesis is characterized by a defect in the pars interarticularis (spondylolysis), which allows the anterior column to translate forward while the posterior elements remain behind.

Question 64

A 65-year-old male presents with leg pain on walking.

MRI commonly demonstrates severe central canal stenosis. Which of the following anatomical structures is LEAST likely to be a primary contributor to acquired degenerative central spinal stenosis?

Explanation

Central canal stenosis is typically caused by anterior disc bulging, posterior ligamentum flavum hypertrophy, and posterolateral facet joint arthropathy. The anterior longitudinal ligament is located on the ventral aspect of the vertebral bodies and does not narrow the spinal canal.

Question 65

According to the Meyerding classification system for spondylolisthesis, what percentage of vertebral body slip defines a Grade III slip?

Explanation

The Meyerding classification grades the degree of forward translation. Grade I is 0-25%, Grade II is 25-50%, Grade III is 50-75%, Grade IV is 75-100%, and Grade V (spondyloptosis) is >100%.

Question 66

A 40-year-old male undergoes an Anterior Lumbar Interbody Fusion (ALIF) at L5-S1. Postoperatively, he has no motor or sensory deficits in his legs. What is a specific, well-documented risk uniquely associated with this surgical approach?

Explanation

ALIF at L5-S1 puts the superior hypogastric sympathetic plexus at risk during anterior exposure. Injury to this plexus can cause retrograde ejaculation, occurring in 1-2% of cases.

Question 67

In evaluating adult spinal deformity, achieving appropriate sagittal balance is critical. Which of the following equations represents the fixed relationship between key pelvic parameters?

Explanation

Pelvic Incidence (PI) is a fixed morphological parameter unique to each individual. It dictates the functional parameters, specifically that PI = Pelvic Tilt (PT) + Sacral Slope (SS).

Question 68

A 55-year-old intravenous drug user presents with fever, back pain, and progressive bilateral leg weakness over the last 12 hours. MRI shows a large posterior epidural fluid collection at T10 causing severe cord compression. What is the most appropriate management?

Explanation

A spinal epidural abscess presenting with profound or progressive neurologic deficits is an absolute indication for urgent surgical decompression and debridement to salvage neurologic function.

Question 69

A patient develops severe back pain two weeks after a lumbar discectomy. MRI suggests postoperative discitis. Which laboratory marker is the most reliable and rapid indicator for monitoring response to antibiotic therapy?

Explanation

CRP peaks within 48-72 hours of inflammation and normalizes rapidly with successful treatment, making it the most sensitive and dynamic marker to track the response to therapy. ESR can remain elevated for weeks.

Question 70

A patient presents with a right-sided L5 radiculopathy due to a foraminal disc herniation at L5-S1. Which of the following motor functions is most predictably weakened?

Explanation

The L5 nerve root supplies the extensor hallucis longus (EHL). Consequently, L5 radiculopathy typically causes weakness in great toe extension and potentially foot drop (tibialis anterior, shared with L4).

Question 71

An AP radiograph of the thoracic spine in a 60-year-old male with a history of prostate cancer reveals the "winking owl" sign at T9. What does this radiographic sign represent?

Explanation

The 'winking owl' sign on an AP view is caused by the absent cortical outline of one pedicle. In the context of malignancy, this highly suggests metastatic destruction of the pedicle.

Question 72

A 45-year-old presents with back pain and leg weakness.

If imaging demonstrates a large L4-L5 paracentral disc extrusion, which physical exam finding is most likely?

Explanation

A paracentral disc herniation at L4-L5 compresses the traversing L5 nerve root. This results in weakness of ankle dorsiflexion (tibialis anterior) and great toe extension, with sensory changes in the first web space.

Question 73

In evaluating a patient for lumbar spinal instability,

flexion-extension radiographs are obtained. Which translation distance in the lumbar spine is generally considered indicative of radiographic instability requiring stabilization?

Explanation

Radiographic instability in the lumbar spine is classically defined by the White and Panjabi criteria as a dynamic sagittal translation of greater than 4.5 mm or sagittal angulation greater than 15 degrees.

Question 74

A 45-year-old male presents with severe left anterior thigh pain and weakness in knee extension. MRI of the lumbar spine reveals an extraforaminal (far lateral) disc herniation at the L4-L5 level. Which nerve root is most likely compressed in this scenario?

Explanation

An extraforaminal (far lateral) disc herniation compresses the exiting nerve root at that level. At the L4-L5 level, the exiting nerve root is L4.

Question 75

A 14-year-old female presents with severe mechanical back pain and a wide-based waddling gait. Radiographs reveal a Grade III L5-S1 isthmic spondylolisthesis with a slip angle of 55 degrees and a high pelvic incidence. What is the most appropriate surgical management?

Explanation

High-grade dysplastic or isthmic spondylolisthesis in adolescents with a high slip angle typically requires reduction and fusion extending to L4 to restore sagittal balance and prevent progressive deformity.

Question 76

A 50-year-old male with long-standing ankylosing spondylitis presents to the emergency department after a minor ground-level fall. He complains of new, severe lower cervical neck pain. Plain radiographs of the cervical spine show no obvious fracture. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are at extremely high risk for unstable, occult spinal fractures even after minor trauma. Advanced imaging (CT or MRI) of the entire spine is mandatory if plain films are negative.

Question 77

A 68-year-old male presents with bilateral neurogenic claudication. Based on a typical sagittal MRI of the lumbar spine showing central canal stenosis

, which of the following structures is the primary contributor to dorsal compression of the thecal sac?

Explanation

In degenerative central canal stenosis, dorsal compression of the thecal sac is primarily caused by buckling and hypertrophy of the ligamentum flavum, often combined with facet arthropathy.

Question 78

A 42-year-old female presents with severe acute low back pain radiating to both legs. Which of the following is considered the most sensitive early clinical symptom or sign of cauda equina syndrome?

Explanation

Urinary retention is the most sensitive symptom of cauda equina syndrome, with a sensitivity of approximately 90%. An intact post-void residual effectively rules out early cauda equina compression.

Question 79

An 82-year-old male with severe COPD and coronary artery disease presents after a fall. Imaging reveals a non-displaced Type II odontoid fracture. Which of the following is the most appropriate initial management?

Explanation

In elderly patients (octogenarians), halo vest placement is associated with a high rate of morbidity and mortality. A rigid cervical collar is the safest initial non-operative treatment for non-displaced or stable patterns in patients with significant comorbidities.

Question 80

A 55-year-old male undergoes an MRI for chronic low back pain. The radiologist notes Modic Type 1 changes at the L4-L5 vertebral endplates. What do these changes represent histologically?

Explanation

Modic Type 1 changes (hypointense on T1, hyperintense on T2) represent bone marrow edema and inflammation. Type 2 represents fatty replacement, and Type 3 represents subchondral sclerosis.

Question 81

According to the Wiltse classification of spondylolisthesis, Type 1 (Dysplastic) is most commonly associated with which of the following anatomic abnormalities?

Explanation

Dysplastic (Type 1) spondylolisthesis is caused by congenital abnormalities of the upper sacrum or the arch of L5, primarily involving deficient or abnormally oriented facet joints that allow forward slippage.

Question 82

A comatose 25-year-old male is brought to the trauma bay after a high-speed motor vehicle collision. Radiographs

reveal a bilateral C5-C6 facet dislocation. What is the most appropriate next step in management prior to definitive reduction?

Explanation

In a patient who is unexaminable (comatose) with a cervical facet dislocation, an MRI must be obtained prior to closed or open reduction to rule out a large herniated disc that could cause iatrogenic spinal cord injury upon reduction.

Question 83

The Lenke classification system for Adolescent Idiopathic Scoliosis (AIS) utilizes a sagittal modifier. Which specific radiographic measurement determines this modifier?

Explanation

The Lenke sagittal thoracic modifier is determined by measuring the kyphosis between T5 and T12. It is classified as hypokyphotic (-), normal (N), or hyperkyphotic (+).

Question 84

During a posterior lumbar spinal fusion, the surgeon prepares for pedicle screw insertion using the intersection technique. The typical entry point for a lumbar pedicle screw is located at the intersection of the transverse process and which other anatomic landmark?

Explanation

In the lumbar spine, the pedicle starting point is typically at the intersection of a line bisecting the transverse process and a vertical line along the lateral border of the superior articular process/facet.

Question 85

A 40-year-old patient undergoes emergency laminectomy and discectomy for cauda equina syndrome secondary to a massive L4-L5 disc herniation. Postoperatively, what is the most common long-term persistent deficit in these patients?

Explanation

Even with prompt surgical decompression, a significant percentage of patients with cauda equina syndrome experience long-term residual genitourinary, sexual, and bowel dysfunction due to irreversible damage to the sacral nerve roots.

Question 86

A 30-year-old male presents after a diving accident. Imaging

demonstrates a traumatic spondylolisthesis of the axis (Hangman's fracture). What is the classic mechanism of injury for this fracture pattern?

Explanation

A traumatic spondylolisthesis of the axis (Hangman's fracture) typically occurs via a hyperextension and axial loading mechanism, leading to bilateral fractures through the pars interarticularis of C2.

Question 87

In the assessment of adult spinal deformity, Pelvic Incidence (PI) is a key morphological parameter that is fixed for each individual after skeletal maturity. It is mathematically defined as the sum of which two parameters?

Explanation

Pelvic incidence (PI) is a fixed anatomical parameter defined as the sum of the pelvic tilt (PT) and the sacral slope (SS). Thus, PI = PT + SS.

Question 88

According to the Thoracolumbar Injury Classification and Severity Score (TLICS), which of the following findings contributes the most points towards the indication for surgical intervention?

Explanation

In the TLICS system, an incomplete neurologic deficit awards the highest points (3 points). Complete deficit is 2 points, burst morphology is 2 points, and suspected PLC injury is 2 points.

Question 89

The Nurick classification for cervical spondylotic myelopathy is heavily utilized in clinical assessment. It is primarily based on which of the following patient features?

Explanation

The Nurick grading scale focuses specifically on ambulatory status and gait impairment, ranging from Grade 0 (no root or cord signs) to Grade 5 (chair-bound or bedridden).

Question 90

Following a rigid L4-S1 posterior spinal fusion, the adjacent L3-L4 segment is at risk for accelerated degeneration (adjacent segment disease). Which biomechanical alteration primarily occurs at this adjacent level?

Explanation

Fusion restricts motion at the operated levels, leading to compensatory increased segmental mobility, mechanical stress, and elevated intradiscal pressure at the adjacent unfused segments, thereby accelerating degeneration.

Question 91

A 60-year-old diabetic male with an L3-L4 pyogenic spondylodiscitis caused by Staphylococcus aureus has been on targeted IV antibiotics for 2 days. What is the primary absolute indication for urgent surgical decompression?

Explanation

While medical management with IV antibiotics is the first line for spondylodiscitis, the development of an epidural abscess with progressive neurologic deficit is an absolute indication for urgent surgical decompression.

Question 92

A 72-year-old male with severe pre-existing cervical spondylosis presents after a fall resulting in a hyperextension injury to his neck

. Examination reveals profound motor weakness in his upper extremities with relatively preserved strength in his lower extremities. What is the most likely diagnosis?

Explanation

Central cord syndrome classically occurs in elderly patients with pre-existing cervical stenosis who sustain a hyperextension injury. It presents with disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 93

When evaluating a patient with lower extremity claudication symptoms, which of the following historical findings is most indicative of neurogenic claudication (due to spinal stenosis) rather than vascular claudication?

Explanation

Neurogenic claudication is characteristically relieved by lumbar flexion (leaning forward on a shopping cart or sitting), which opens the spinal canal and neuroforamina. Vascular claudication is relieved simply by resting (standing still) and worsens with increased metabolic demand like walking uphill.

Orthopedic Prometric MCQs - Chapter 3 Part 1

Orthopedic Prometric MCQs - Chapter 3 Part 24

Orthopedic Prometric MCQs - Chapter 3 Part 24

Chapter Index