Full Question & Answer Text (for Search Engines)
Question 1:
Which of the following descriptions is more characteristic of tuberculosis than pyogenic spondylitis:
Options:
- Disc space is narrowed before significant bony changes occur.
- Involvement of multiple contiguous levels is uncommon.
- Bony erosions seen on computerized tomography are usually small and focal.
- Vertebral destruction exceeds disc destruction.
- Magnetic resonance imaging rarely shows significant soft tissue swelling.
Correct Answer: Vertebral destruction exceeds disc destruction.
Explanation:
Vertebral destruction exceeds disc destruction in tuberculosis. Bony changes occur earlier in tuberculosis than in pyogenic spondylitis. Involvement of multiple contiguous levels is more common in tuberculosis than pyogenic spondylitis. Bony erosions seen on computerized tomography are large in tuberclosis and small in pyogenic spondylitis. Magnetic resonance imaging often shows significant soft tissue involvement in both disorders.
Question 2:
A 5-year-old girl comes into the clinic with back pain. Her family has just moved to the United States from southeastern Asia. A lateral radiograph shows destruction of T11, T12, and L1. Magnetic resonance imaging shows a moderate posterior soft tissue mass. A neurological exam is normal. Biopsy confirms tuberculosis. For the girlâ s spinal problem, recommended treatment includes:
Options:
- A two-drug therapy for at least 6 months
- A two-drug therapy for at least 6 months along with a body cast
- A two-drug therapy and posterior spinal fusion to prevent deformity
- Anterior spinal debridement and a rib strut graft
- Anterior debridement, strut graft, and posterior fusion with instrumentation
Correct Answer: Anterior debridement, strut graft, and posterior fusion with instrumentation
Explanation:
Anterior debridement, strut graft, and posterior fusion with instrumentation provide the patient with the best chance of a positive result. This procedure minimizes graft dislodgement and posterior overgrowth. A two-drug therapy alone for at least 6 months leaves the patient at a significant risk of progressive kyphosis and neurologic deficit. A two-drug therapy for at least 6 months along with a body cast also leaves the patient with significant risk of progressive kyphosis and neurologic deficit. The lack of anterior support from a two-drug therapy and posterior spinal fusion to prevent deformity leaves the patient with significant risk of kyphosis. Even with an anterior spinal debridement and a rib strut graft, there is a risk of graft dislodgment over this large defect and of posterior growth into kyphosis.
Question 3:
A dorsal approach has which of the following characteristics with regard to a posteromedial approach in the surgical treatment of congenital vertical talus:
Options:
- The dorsal approach requires a more extensive dissection.
- The dorsal approach has a lower risk of avascular necrosis of the talus.
- The dorsal approach requires plication of the talonavicular capsule.
- The dorsal approach has a higher risk of redislocation.
- The dorsal approach requires a longer tourniquet time.
Correct Answer: The dorsal approach requires a more extensive dissection.
Explanation:
The dorsal approach has not shown evidence of avascular necrosis, whereas the posteromedial approach has shown such changes at follow-up in as many as 40% of cases. The dorsal approach requires a less extensive dissection than the posteromedial approach. The dorsal approach does not require or permit plication of the talonavicular capsule, whereas the posteromedial approach does. The dorsal approach does not appear to have a higher rate of redislocation of the talonavicular joint than the posteromedial approach. The dorsal approach requires a shorter tourniquet time than the posteromedial approach.
Question 4:
Which of the following conditions is not associated with an increased incidence of congenital vertical talus:
Options:
- C erebral palsy
- Myelomeningocele
- Arthrogryposis
- Nail patella syndrome
- Larsen syndrome
Correct Answer: C erebral palsy
Explanation:
Patients with cerebral palsy do not have an increased risk of congenital vertical talus, but they may develop an acquired neuromuscular vertical talus. Patients with myelomeningocele have approximately a 5% to 10% risk of vertical talus, far above that of the general population. Arthrogryposis is associated with an increased risk of vertical talus. Nail patella syndrome and Larsen syndrome are associated with an increased risk of vertical talus.
Question 5:
Scoliosis in Marfan syndrome is characterized by which of the following:
Options:
- Scoliosis curves are more likely to begin in the juvenile period.
- There is an increased likelihood of left thoracic curves.
- Brace treatment is more likely to be successful because of the flexibility.
- Patients are less likely to have back pain.
- C urves are more likely to be stable in adulthood.
Correct Answer: Scoliosis curves are more likely to begin in the juvenile period.
Explanation:
Scoliosis curves are much more likely to begin in the juvenile period than idiopathic scoliosis. There is no significant difference in the likelihood of left thoracic curves in Marfan syndrome. Brace treatment is less likely to be successful in Marfan syndrome than in idiopathic scoliosis. Marfan patients with scoliosis are more likely to have back pain. Marfan curves are more likely to progress in adulthood.
Question 6:
Which of the following statements is true of demineralized bone matrix:
Options:
- Demineralized bone matrix is osteogenic.
- Demineralized bone matrix is strongly osteoinductive.
- Demineralized bone matrix is weakly osteoinductive.
- Demineralized bone matrix is consistent between forms and different sterilization methods.
- Demineralized bone matrix is not osteoconductive.
Correct Answer: Demineralized bone matrix is osteogenic.
Explanation:
Demineralized bone matrix is weakly osteoinductive. The term osteogenic refers to direct transmittal of cells capable of making bone. Demineralized bone matrix is not osteogenic. Demineralized bone matrix varies in efficacy between different forms and different methods of sterilization. The term osteoconduction refers to provision of a favorable scaffold and environment for bone formation. Demineralized bone matrix is osteoconductive.
Question 7:
A 16-year-old boy with type I Ehlers-Danlos syndrome has a spinal curvature that has progressed 18° in the past year. The curve is a double major type with a C obb angle of 60° in each curve. There is no associated kyphosis. The following treatment is recommend:
Options:
- Observation
- Bracing
- Anterior fusion and instrumentation
- Posterior fusion and instrumentation
- Anterior and posterior fusion with instrumentation
Correct Answer: Posterior fusion and instrumentation
Explanation:
Posterior fusion and instrumentation is the best-documented treatment. Although this form of treatment is followed by an increased incidence of wound healing problems, the problems can be treated. Observation is not recommended because the curve is highly likely to increase and cause a decrease in pulmonary function. Bracing has no role in large curves, and it is not known if bracing is successful in Ehlers-Danlos syndrome. Anterior fusion with instrumentation would be difficult with a double curve. Anterior fusion carries an increased risk due to vascular fragility. It is not necessary because there is no increased risk of crankshaft or pseudarthrosis. There is no particular reason for adding an anterior procedure in this situation in view of the vascular risk.
Question 8:
Scoliosis in osteogenesis imperfecta is characterized by which of the following:
Options:
- Scoliosis is due primarily to vertebral fractures.
- Scoliosis is due primarily to ligamentous laxity.
- Scoliosis is due primarily to associated neurologic problems.
- Scoliosis usually responds to brace treatment.
- Scoliosis rarely impairs quality of life.
Correct Answer: Scoliosis is due primarily to vertebral fractures.
Explanation:
Scoliosis in osteogenesis imperfecta (OI) is due primarily to ligamentous laxity. Scoliosis in OI is due primarily to ligamentous laxity, not bony fractures. There is no association between brainstem impression and scoliosis. Scoliosis in OI rarely responds to brace treatment. Scoliosis, when present in OI, is a major impairment of quality of life.
Question 9:
Which of the following is not a specific feature in making the diagnosis of a dystrophic curve in neurofibromatosis 1:
Options:
- Penciling of the ribs
- Scalloping of the vertebrae
- Widening of the foramen
- Thinning of the transverse processes
- Right convex apex
Correct Answer: Right convex apex
Explanation:
Right convex apex is not a specific characteristic of dystrophic curves. It is more common in dystrophic curves than in nondystrophic curves, but it is commonly present in both types of curves. Penciling of the ribs is one of the features specific for dystrophic curves in neurofibromatosis 1. Scalloping of the vertebrae anteriorly and posteriorly is characteristic of dystrophic curves in neurofibromatosis 1. Widening of the neural foramen is specific for dystrophic curves in neurofibromatosis 1. Widening of the neural foramen is due to tumorous masses passing through the foramen. Thinning of the transverse process is a characteristic of dystrophic curves in neurofibromatosis 1.
Question 10:
The spine in familial dysautonomia is characterized by which of the following:
Options:
- Rare scoliosis
- Flexible scoliosis
- Dense bone
- Increased risk of loss of fixation after surgery
- Spinal stenosis
Correct Answer: Increased risk of loss of fixation after surgery
Explanation:
There is an increased risk of loss of fixation in familial dysautonomia curves due to decreased bone density and curve rigidity. Scoliosis is common in patients with familial dysautonomia and affects up to one-half of patients with the disorder. The curves in familial dysautonomia are rigid, leading to limited correction. The bone density in familial dysautonomia is decreased. Spinal stenosis is not reported in patients with familial dysautonomia.
Question 11:
Which of the following spinal problems is most common in achondroplasia:
Options:
- Atlantoaxial instability
- Basilar invagination
- Symptomatic kyphosis
- Thoracolumbar stenosis
- Spondylolisthesis
Correct Answer: Thoracolumbar stenosis
Explanation:
Symptomatic stenosis of the thoracic and lumbar spine is seen in almost half of all achondroplastic patients, although not all patients require surgery. Atlantoaxial instability is rare in achondroplasia, although it is not uncommon in other dysplasias. Basilar invagination is not present in achondroplasia. Kyphosis is often transient in achondroplasia and rarely persists beyond the second year. Kyphosis is rarely symptomatic. Spondylolisthesis is rare in achondroplasia.
Question 12:
A 2-year-old girl with diastrophic dysplasia is brought into the office for an overall examination. A lateral radiograph of the spine shows a kyphosis of 35° from C 3 to C 6. A neurologic exam is normal, although she does have stiff joints. The patient is not yet walking. For management of this kyphosis, recommended treatment includes:
Options:
- Observation
- C ervicothoracic orthosis
- Halo traction
- Posterior fusion
- Anterior and posterior fusion
Correct Answer: Observation
Explanation:
Many diastrophic cervical kyphoses will correct spontaneously if the curve does not exceed 50°. In this patient, the lack of walking is most likely due to other skeletal factors. There is no evidence that orthosis will change the natural history of the disorder. There is no need for traction given the high chance of spontaneous resolution and the dangers of traction. Posterior fusion is only indicated if the kyphosis is continually progressive, or if neurologic signs or symptoms develop. Anterior and posterior surgery is only indicated in cases with severe pre- existing neurologic deficit.
Question 13:
A baby born with diastrophic dysplasia today may eventually require all of the following orthopedic procedures during childhood or adulthood except:
Options:
- C orrection of equinus or varus feet
- Arthrodesis from the occiput to the atlas or axis
- Posterior spinal fusion for scoliosis
- Arthroplasty of the hips
- Arthroplasty of the knees
Correct Answer: Arthrodesis from the occiput to the atlas or axis
Explanation:
Patients with diastrophic dysplasia rarely have instability of the upper cervical spine. Babies with diastrophic dysplasia often have rigid equinovarus feet that require surgery to become plantigrade and wear normal shoes. A number of patients with diastrophic dysplasia develop progressive scoliosis that requires surgical treatment. Degenerative disease of the hips is common and often requires arthroplasty in early adulthood. Degenerative disease of the knees is common and often requires arthroplasty in early adulthood.
Question 14:
A patient with spondyloepiphyseal dysplasia congenita reaches the age of 5 without being able to walk with a walker. She has five beats of clonus in both ankles. Her reflexes are brisk and her toes are upgoing. The most likely problem that accounts for these findings is:
Options:
- Severe scoliosis of the thoracic spine
- Foramen magnum stenosis
- Lumbar stenosis
- Thoracolumbar kyphosis
- Atlantoaxial instability
Correct Answer: Atlantoaxial instability
Explanation:
Atlantoaxial instability, sometimes combined with stenosis of the atlas, is a frequent cause of myelopathy in spondyloepiphyseal dysplasia congenita. Scoliosis does not account for developmental delay or myelopathy. Foramen magnum stenosis is rare in spondyloepiphyseal dysplasia congenita. Lumbar stenosis is rare with spondyloepiphyseal dysplasia congenita and would not account for myelopathy. Thoracolumbar kyphosis severe enough to cause myelopathy is rare in spondyloepiphyseal dysplasia congenita condition.
Question 15:
Scoliosis in cleidocranial dysplasia is frequently associated with which of the following conditions:
Options:
- Syringomyelia
- Atlantoaxial instability
- Spondylolisthesis
- Spinal stenosis
- Spinal decompensation
Correct Answer: Syringomyelia
Explanation:
Scoliosis with cleidocranial dysplasia (C C D) is frequently associated with syringomyelia. Cervical instability is rare in C C D. Spondylolisthesis is rare in C C D. Spinal stenosis is rare in C C D. Spinal decompensation is rare in C C D.
Question 16:
A 3-year-old girl with Larsen syndrome is brought into the office for examination. A spinal radiograph demonstrates a 50° kyphosis of the cervical spine. Her neurologic examination is normal. Recommended treatment includes:
Options:
- Observation
- Halo traction
- C ervical-thoracic orthosis
- Posterior cervical fusion
- Anterior and posterior fusion
Correct Answer: Posterior cervical fusion
Explanation:
Posterior cervical fusion has been proven effective in curves of 60°or less in Larsen syndrome, in preventing progression, and allowing correction with anterior growth. This curve is much more likely to worsen than to spontaneously improve, so preventive surgery is indicated. There is no role for halo traction in this situation. Bracing has not been proven effective in helping patients with Larsen syndrome. Addition of anterior fusion is not needed for this degree of curve in a neurologically normal child.
Question 17:
A 10-year-old patient with Hurler syndrome has undergone a bone marrow transplant and is currently medically stable. He has developed a painful thoracolumbar kyphosis that measures 50° with 25% subluxation T12 on L1. Recommended treatment includes which of the following:
Options:
- Exercise program for the trunk extensor muscles
- Thoracolumbar orthosis
- Halo traction followed by orthosis
- Anterior spinal fusion
- Anterior and posterior spinal fusion
Correct Answer: Anterior and posterior spinal fusion
Explanation:
Anterior and posterior fusion will correct the translation, instability, and ensure a solid fusion. In some cases, posterior fusion alone will suffice if pedicle fixation is good. Exercises will not correct the subluxation, which is the cause of the pain. A thoracolumbar orthosis is not corrective or well tolerated. There is no need for halo traction. Anterior fusion alone is not enough to control this focal instability if the patient is well enough to tolerate a more involved procedure.
Question 18:
Aneurysmal bone cyst of the spine is most common in which of the following regions:
Options:
- C ervical
- Upper thoracic
- Lower thoracic
- Lumbar
- Sacral
Correct Answer: Lumbar
Explanation:
Aneurysmal bone cyst of the spine is most common in the lumbar spine, followed by the cervical spine. Aneurysmal bone cyst most commonly involves the anterior elements but later may expand into the posterior elements.
Question 19:
Aneurysmal bone cyst of the spine is most likely in this age group:
Options:
- First decade
- Second decade
- Third decade
- Fourth decade
- Fifth decade
Correct Answer: Second decade
Explanation:
The most common age is the second decade; the mean age is 13 years old for patients with this disorder.
Question 20:
A 14-year-old girl is examined because of a pain in her left flank. The radiographs of the lumbar spine show loss of the pedicle with expansion of the lateral wall of the third lumbar vertebral body. Magnetic resonance imaging shows multiple fluid levels with no additional areas of involvement. She is neurologically normal. Recommended treatment includes:
Options:
- Observation
- Radiation therapy
- Selective arterial embolization
- Radical en bloc resection
- C urettage plus radiation therapy
Correct Answer: Selective arterial embolization
Explanation:
This patient has an aneurysmal bone cyst. Selective arterial embolization is a minimally invasive treatment that often succeeds in arresting the lesions. Many times it is the only treatment needed. Selective arterial embolization can also be used as part of a strategy to be followed by curettage and reconstruction to decrease operative bleeding. This lesion will continue to expand and might cause neurologic compromise or mechanical instability. Radiation therapy poses risks of later malignant degeneration. There are other ways of treating this lesion. Radical en bloc resection may unnecessarily injure neurologic structures. While curettage is often necessary, there is no reason to introduce the risk of radiation therapy.
Question 21:
A 15-year-old girl has severe hip pain following slipped capital femoral epiphysis that was complicated by avascular necrosis. Recommended treatment is a hip arthrodesis. In response to questions about late effects, after surgery the patient should be told that she is most likely to experience:
Options:
- Low back pain
- C ontinued severe pain in the ipsilateral hip
- Marked limitation of activity
- Significant continued limp
- Pain in the contralateral hip
Correct Answer: Low back pain
Explanation:
Low back pain, followed closely by ipsilateral knee pain, is the most common late effect of hip arthrodesis in young patients. The tolerable pain usually occurs much later but may be treated by conversion to arthroplasty, if needed. Ipsilateral hip pain should be minimal or absent if the fusion is successful. Activity following arthrodesis is not significantly limited. Sports and heavy physical activities are feasible. The limp is usually minimal because the loss of hip motion is masked by lumbar motion. Pain in the contralateral hip is rare and is often minimal after hip arthrodesis.
Question 22:
Which of the following is a parameter that should be used in positioning arthrodesis of the hip in a young person:
Options:
- Flexion of 45°
- Abduction of 15° if there is shortening
- Adduction of 0°
- External rotation of 25°
- Shortening of at least 3 cm
Correct Answer: Adduction of 0°
Explanation:
Neutral abduction is important in preventing back pain. The flexion should be between 25° and 35°. Any abduction beyond neutral poses increases risk of back pain. External rotation beyond approximately 5° is not needed. Arthrodesis often produces some mandatory shortening; therefore, intentional shortening is not needed.
Question 23:
A 9-year-old boy with cerebral palsy has trouble sitting. His mother states that whenever his diapers are changed or his hips are moved, he begins to cry. Radiographs demonstrate high dislocations of both femoral heads. The femoral heads have an ovoid shape and superolateral flattening. Recommended treatment includes:
Options:
- Botulinum toxin injected into the adductors
- Bilateral open adductor tenotomy
- Bilateral femoral osteotomies with acetabuloplasty
- Bilateral proximal femoral resection
- Bilateral C olonna arthroplasty
Correct Answer: Bilateral proximal femoral resection
Explanation:
Bilateral proximal femoral resection is the recommended treatment. Femoral head dislocations may become painful in cerebral palsy at a much earlier age than in nonspastic individuals. Botulinum toxin or adductor tenotomy will not solve the problem. Replacing the deformed femoral heads into the acetabulum will not achieve the long-term goal of good hip range of motion.
Question 24:
A 9-year-old boy is examined due to a closed distal forearm fracture. The radius and ulna are both fractured and translated 100%. After manipulation twice with sedation, the translation cannot be reduced. There is 10-mm shortening of the radius and 5- mm shortening of the ulna. The distal radial angulation on the anteroposterior view is 5° less than normal. The next step in treatment should include:
Options:
- Closed reduction in the operating room under general anesthesia
- Open reduction and cast application
- Open reduction and percutaneous pin fixation
- Open reduction and plate fixation
- Acceptance of the reduction and maintenance with a cast
Correct Answer: Acceptance of the reduction and maintenance with a cast
Explanation:
The translation and shortening are not problems and the amount of angulation will easily remodel with this fracture. There is nothing to be gained from operative reduction.
Question 25:
When applying a halo for postoperative immobilization in a skeletally mature teenager, which of the following is the proper torque for the pins:
Options:
- 2 inch-pounds
- 4 inch-pounds
- 8 inch-pounds
- 10 inch-pounds
- 12 inch-pounds
Correct Answer: 8 inch-pounds
Explanation:
Eight inch-pounds is the currently recommended torque to provide optimal biomechanical fixation while minimizing pin penetration. This is also recommended for adults. In young children, 4- to 6-inch-pounds are preferred.
Question 26:
A posterior spine fusion with segmental hook fixation from T4-L4 is performed for idiopathic scoliosis in a 15-year-old girl. Somatosensory evoked potential monitoring is normal throughout the procedure. The patient awakens and is unable to move either lower extremity, but she does have some sensation in the lower extremities. Recommended treatment includes:
Options:
- Removal of instrumentation
- Myelogram
- Laminectomy above the conus medullaris
- Administration of corticosteroids and observation for 6 hours
- Full heparinization of the patient
Correct Answer: Removal of instrumentation
Explanation:
Spinal cord injury occurs in approximately 0.1% of patients operated upon for idiopathic scoliosis. In some cases, sensory spinal cord monitoring may be unchanged, especially if the injury preserves the dorsal columns. The instrumentation should be removed as soon as possible in case spinal traction or derotation or implant protrusion is producing effects on the cord or its blood supply. Corticosteroids should be administered at spinal cord injury doses, but this should not be the only measure. Obtaining a myelogram may delay the removal of instrumentation and should not be the first step. Heparinization has no proven effect.
Question 27:
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:
Options:
- Observation with serial radiographs every 4 months
- Postoperative brace for 6 months
- In situ fusion with bone graft
- Posterior fusion across the kyphosis with instrumentation
- Anterior corpectomy and fusion of T12
Correct Answer: Posterior fusion across the kyphosis with instrumentation
Explanation:
Extensive posterior decompression poses a high risk of postoperative increase in kyphosis because of both the patientâ 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.
Question 28:
Which of the following is true regarding brace treatment for Scheuermann kyphosis:
Options:
- The Milwaukee brace is not indicated.
- Permanent correction is usually obtainable.
- Bracing is effective in curves over 75°.
- Bracing is ineffective in curves having an apex at or above T8.
- The brace should be worn for 1 year after starting brace treatment.
Correct Answer: Permanent correction is usually obtainable.
Explanation:
Brace treatment is effective for Scheuermann kyphosis. Unlike idiopathic scoliosis, permanent correction of the deformity is the goal. The Milwaukee brace is often indicated. Brace treatment is ineffective for curves over 74°. The brace should be worn until skeletal maturity.
Question 29:
Which of the following statements is true about bone marrow transplantation in mucopolysaccharidoses:
Options:
- Bone marrow transplantation is contraindicated.
- Bone marrow transplantation does not affect the orthopedic problems.
- Bone marrow transplantation reverses the orthopedic manifestations.
- Graft-versus-host disease is rare.
- Bone marrow transplantation should be deferred until skeletal maturity.
Correct Answer: Bone marrow transplantation is contraindicated.
Explanation:
Bone marrow transplantation is effective in preventing the deposition of mucopolysaccharides in solid organs. Transplantation should be done early to prevent organ damage. Because the lysosomal enzyme does not cross the cell membrane of osteocartilaginous cells, it does not affect the orthopedic aspects. The risk of graft-versus-host disease is high but may be treated in most cases. Survival rate is 61% at 2 years for Hurler disease, which is otherwise fatal before maturity.
Question 30:
A 3-year-old girl with spina bifida is able to flex and adduct her hips, but she cannot extend her knees. The hips are both dislocated. The patientâ s parents ask how the hips must be treated to optimize function. The recommended treatment is:
Options:
- Observation
- Bilateral closed reduction
- Bilateral open reduction
- Bilateral open reduction and femoral osteotomies
- Bilateral open reduction with femoral osteotomies and muscle transfers
Correct Answer: Observation
Explanation:
Nonoperative treatment will allow the patient to retain maximum mobility of the hips. Operative treatment carries substantial risk of avascular necrosis, stiffness, and redislocation. These risks are not worth taking in view of the patientâ s limited muscle strength about the hips. In addition, the motor level alluded to (L2-L3) means that she will not have sensation of pain from the hips.
Question 31:
A patient with spina bifida and L5 motor level undergoes tendon transfers about the ankle. After cast removal, he is lost to follow-up for 3 years. Upon re-examination, the patient has no motor power on either side below the knee. The most likely explanation is:
Options:
- The tendon transfers have all pulled out.
- His ventriculoperitoneal shunt has malfunctioned.
- His spinal cord has become tethered.
- His muscles have fatigued.
- He has sustained a silent compartment syndrome because of lack of sensation.
Correct Answer: His spinal cord has become tethered.
Explanation:
This scenario is common. The most likely explanation of the patientâ s loss of motor power on either side below the knee is a result of a tethered spinal cord. It is unlikely that all transferred tendons have pulled out and that he has lost function in all of the other L5 muscles that should be active. Shunt malfunction is a common occurrence in patients with spina bifida, but shunt malfunction does not present with a focal deficit at a distal level. Muscle fatigue is not a recognized phenomenon in spina bifida.
Question 32:
A 6-year-old boy with spina bifida and L3 motor level presents to the clinic with bilateral swollen legs (below the knees). His legs have been swollen for the past 3 days and his knees are warm. The patient has an oral temperature of 38.1°C . He denies any pain. There is no history of systemic infection or of any other trauma. The problem may be most likely diagnosed by ordering:
Options:
- A venogram of both lower extremities
- A duplex ultrasound of both lower extremities and the pelvic veins
- C ell count, gram stain, and culture of synovial fluid of both knees
- Aspirate of both distal femoral metaphyses
- Plain and stress varus-valgus radiographs of both knees
Correct Answer: Plain and stress varus-valgus radiographs of both knees
Explanation:
Low-energy fractures are the most likely cause of the patientâ s bilateral swollen legs. The fractures may occur with everyday activities, and they do not cause pain because of the patientâ s high neurologic level. If plain radiographs do not give the diagnosis, stress radiographs should be obtained to detect undisplaced physeal fractures. Deep vein thrombosis is rare in this age group, especially bilaterally. Spontaneous joint infection and spontaneous osteomyelitis are not any more likely in patients with spina bifida than in the general population.
Question 33:
A patient with spina bifida has significant symmetrical calcaneus positioning of both ankles. This is most likely due to:
Options:
- Lack of ambulatory experience
- Braces that are set in too much dorsiflexion
- Motor level at L3
- Motor level at L5
- Motor level at S1
Correct Answer: Motor level at L3
Explanation:
At motor level L5, dorsiflexors overpower plantarflexors to cause a calcaneus position. This condition occurs from muscle imbalance. Even with significant ambulation, it will persist. Brace properties do not cause fixed deformity. At L3, neither dorsiflexors nor plantarflexors of the ankle work. At S1, both dorsiflexors and plantarflexors are well innervated.
Question 34:
Correction of the congenital gibbus in spina bifida must follow which of these surgical principles:
Options:
- Long instrumentation
- Short instrumentation
- Avoidance of instrumentation
- Avoidance of bony resection
- Anterior approach to deformity
Correct Answer: Long instrumentation
Explanation:
The leverage provided by long instrumentation prevents loss of correction and junctional deformity. Short instrumentation poses a risk of junctional kyphosis or loss of fixation. Because of the severe angular deformity, fusion in situ without correction will be followed by increasing deformity. Resection of one to three of the vertebrae on the lower limb of the kyphosis is essential to allow safe correction without excessive tension on vessels and viscera. The anterior approach to the gibbus is deep and impractical. This approach does not allow mechanically efficient instrumentation.
Question 35:
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:
Options:
- Latex allergy
- Aortic dissection
- Septic shock
- Spontaneous tension pneumothorax
- Shunt failure
Correct Answer: Latex allergy
Explanation:
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.
Question 36:
The most common benign tumor of vertebral bodies is:
Options:
- Osteoid osteoma
- Osteoblastoma
- Osteochondrom
- Giant cell tumor
- Aneurysmal bone cyst
Correct Answer: Aneurysmal bone cyst
Explanation:
Aneurysmal bone cyst is the most common benign bone tumor of the vertebral body. Aneurysmal bone cysts sometimes extend into the posterior elements. Osteoid osteoma, osteoblastoma, and osteochondroma are primarily found in the posterior elements of the vertebrae. Giant cell tumor is rare in the spine.
Question 37:
A magnetic resonance image of a 7-year-old girl shows a line of high-signal intensity within the cord on T2 sequences that parallels the ventral surface of the cord and appears as a syrinx. However, on the axial images and on the T1 sequences, this finding is not evident. The most likely diagnosis is:
Options:
- C ollapsing syrinx
- Gibbs artifact
- Motion artifact
- Ependymoma
- Astrocytoma
Correct Answer: Gibbs artifact
Explanation:
A Gibbs artifact is a linear focus in the cord on T2-weighted images that parallels the ventral aspect of the cord and mimics a syrinx. The Gibbs artifact is due to the linear interface between two tissues of differing signal intensity. It is not seen on axial images or T1-weighted images. Motion artifact is a blurring of the image due to patient motion, respiration, or cerebral spinal fluid pulsation. Ependymoma and astrocytoma are seen on both the axial and the sagittal images.
Question 38:
Which of the following statements correctly represents the definitions of C hiari I and C hiari II malformations:
Options:
- A C hiari I malformation is displacement of the brainstem through the foramen magnum; a C hiari II malformation also includes the cerebellum.
- A C hiari I malformation is displacement of the cerebellum through the foramen magnum; a C hiari II malformation also includes the brainstem.
- A C hiari I malformation is a cyst in the pons; a C hiari II malformation is a cyst including the cerebellum.
- A C hiari I malformation is an absence of the fourth ventricle; a C hiari II malformation also includes the presence of hydrocephalus.
- A C hiari I malformation is a split in the spinal cord; a C hiari II malformation also includes a tight filum terminale.
Correct Answer: A C hiari I malformation is displacement of the brainstem through the foramen magnum; a C hiari II malformation also includes the cerebellum.
Explanation:
A Chiari I malformation involves displacement of the cerebellum through the foramen magnum. A C hiari II malformation involves similar displacement of the brainstem, as well. In a C hiari II malformation, there is almost always a myelomeningocele in the lower cord. Sometimes a syrinx is also present.
Question 39:
The conus medullaris is always termed abnormal if it terminates below this level:
Options:
- L1
- L1-2 disk
- L2
- L2-3 disk
- L3
Correct Answer: L3
Explanation:
The vertebral bodies grow faster than the spinal cord. A more caudal placement of the conus medullaris is considered normal in an older patient. However, a conus medullaris below L3 at any age is abnormal and may represent a tethered and/or dysplastic cord.
Question 40:
Regardless of age, the tonsils of the cerebellum should not extend more than this distance below the foramen magnum:
Options:
- 1 mm
- 2 mm
- 3 mm
- 5 mm
- Any protrusion is abnormal
Correct Answer: 5 mm
Explanation:
Displacement of the cerebellar tonsils below the foramen magnum is termed a C hiari malfomation. A C hiari I malformation is an isolated malformation; a C hiari II malformation is associated with a syrinx. Symptoms may include headache, vomiting, and nystagmus. Although the normal protrusion allowed decreases with age, 5 mm is abnormal at any age.
Question 41:
When applying a halo, the use of six pins instead of four has which of the following effects:
Options:
- Increase in the infection rate
- Increased rate of pin loosening
- Increased rate of dural puncture
- Increase in load to failure by 50%
- Increase in risk of injury of the supraorbital nerve
Correct Answer: Increase in the infection rate
Explanation:
With an increase from four to six pins, the load to failure is increased by more than 50%. Additional pins decrease many of the complications, such as loosening and pin tract infection. The risk of dural puncture is not measurably increased because it is a rare complication.
Question 42:
Which of the following findings is an indication for the Bernese (Ganz) osteotomy:
Options:
- Acetabular dysplasia in a 10-year-old boy.
- A 20-year-old woman with a complete developmental dislocation of the hip.
- A 19-year-old man with osteonecrosis (Stulberg-Stage 4) secondary to Perthes disease.
- A 30-year-old woman with an anteroposterior (AP) center-edge angle of 10° and a joint space of 1 mm.
- A 35-year-old woman with an AP center-edge angle of 0° and a joint space of 2 mm
Correct Answer: A 35-year-old woman with an AP center-edge angle of 0° and a joint space of 2 mm
Explanation:
The Bernese (Ganz) osteotomy is contraindicated in patients with open triradiate cartilages because it crosses the cartilage. The procedure is also contraindicated in complete dislocations, incongruous hips, and advanced osteoarthritis with a joint space of 1 mm or less.
Question 43:
The false profile radiographic view of the hip is taken with the patient in which of the following positions:
Options:
- The effected hip is against the film and the pelvis is rotated 65° away from the plane of the film.
- The uneffected hip is against the film and the pelvis is rotated 65° away from the plane of the film.
- The patient is supine and the beam is angled 45° cephalad.
- The patient is supine and the beam is angled 45° caudally.
- The patient is supine and the affected hip is maximally internally rotated.
Correct Answer: The effected hip is against the film and the pelvis is rotated 65° away from the plane of the film.
Explanation:
The false profile radiographic view assesses anterior coverage and is obtained with the affected hip against the film and the pelvis rotated 65° away from the plane of the film.
Question 44:
A 15-year-old boy has a history of excessive bleeding when he is cut. His maternal uncle passed away during a tonsillectomy. The boy presents with severe hip pain (worse in extension than in flexion) and some weakness in his knee extension. The most likely cause of the patients symptoms is:
Options:
- Septic arthritis of the hip
- Psoas abscess
- Lumbar epidural hematoma
- Iliopsoas hematoma
- Hip hemarthrosis
Correct Answer: Iliopsoas hematoma
Explanation:
The patient has features suggesting mild hemophilia A or B including x- linked inheritance and occasional bleeding episodes. Iliopsoas hematoma is a complication of hemophilia. Bleed into the hip or the lumbar epidural space is less common and there are no signs to suggest infection.
Question 45:
A patient with hemophilia A has a hematoma of the iliopsoas. He has a partial femoral nerve palsy. Treatment involves continuous factor replacement and:
Options:
- Open drainage
- Decompression of the fascia over the femoral nerve
- Percutaneous insertion of a drainage tube
- Embolization of feeder vessels by interventional radiologist
- Observation
Correct Answer: Observation
Explanation:
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.
Question 46:
Which of the following best predicts the risk of nonaccidental injury in young children who sustain a fracture of the femur:
Options:
- The fracture pattern
- The location of the fracture
- The socioeconomic status of the family
- Whether the child was previously able to walk
- C oexistence of other disabilities
Correct Answer: Whether the child was previously able to walk
Explanation:
Although a spiral fracture is classically consistent with nonaccidental injury, this is not always true. A spiral fracture is often seen in accidental injuries. The location of the fracture in the femur, the socioeconomic status of the family, and the coexistence of other disabilities are all poor predictors. The ability of the child to walk has predictive ability. In one study, nonaccidental injury accounted for 42% of all femur fractures in children before walking age vs. only 2% of fractures after walking age.
Question 47:
Which of the following is known about the genetics of multiple hereditary exostosis (MHE):
Options:
- There is no genetic pattern for this condition.
- MHE follows an x-linked inheritance pattern.
- MHE follows an autosomal recessive pattern.
- MHE encodes glycosyltransferases needed for biosynthesis of heparan sulfate.
- MHE involves a defect in fibroblast growth factor.
Correct Answer: MHE encodes glycosyltransferases needed for biosynthesis of heparan sulfate.
Explanation:
Multiple hereditary exostosis (MHE) is inherited as an autosomal dominant condition. There are three genes known to be involved: EXT 1, 2, and 3. EXT 1 and 2 encode glycosyltransferases needed for biosynthesis of heparan sulfate. Fibroblast growth factor receptor is abnormal in achondroplasia.
Question 48:
A 10-year-old patient has a painful lytic lesion replacing 75% of the distal femoral metaphysis. The lesion has indistinct margins, but there is not any periosteal reaction. Biopsy reveals a benign histiocytic tumor with multiple eosinophils. Physical exam and skeletal survey reveal no other abnormalities. Which of the following would be the most appropriate treatment method:
Options:
- Radiation therapy
- Methotrexate, ifosfamide and adriamycin followed by resection
- Oral prednisone treatment for one month
- Resection and reconstruction
- C urettage and bone graft
Correct Answer: C urettage and bone graft
Explanation:
This patient has an eosinophilic granuloma, which is an isolated form of Langerhans cell histiocytosis. Patients with isolated involvement may be treated with observation, curettage, bone grafting, or steroid injection. For a lesion of this size, the risk of fracture is high and curettage with bone grafting is recommended. C hemotherapy and/or systemic steroids are reserved for patients with systemic disease.
Question 49:
Which of the following methods has the highest sensitivity in detecting skeletal lesions in patients with Langerhans cell histiocytosis:
Options:
- Physical examination
- Skeletal survey
- Ultrasound
- Bone scan
- Indium labeled white blood cell study
Correct Answer: Skeletal survey
Explanation:
Skeletal survey is the most sensitive means of detecting lesions of eosinophilic granuloma (Langerhans cell histiocytosis). Bone scan detects most, but not all, of the lesions. Some lesions lack enough osteoblastic activity to appear on bone scan. Lesions are not detected on physical exam unless they are large enough to cause pain or tenderness. Indium labeled white cell studies are not used in this condition.
Question 50:
A 15-year-old girl presents with pain and a 17°-scoliosis curve. The film suggests an enlargement and sclerosis of the transverse process of L2. The best study to further evaluate the nature and anatomic extent of the lesion is:
Options:
- Coned radiographs
- Bone scintigraphy
- Bone scan with SPEC T (single photon emission computed tomography)
- Magnetic resonance imaging
- Computed tomography
Correct Answer: Bone scan with SPEC T (single photon emission computed tomography)
Explanation:
This lesion is most likely to be an osteoid osteoma or an osteoblastoma. The best study to further evaluate the nature and anatomic extent is with computed tomography. Magnetic resonance imaging may overestimate the lesion because of sensitivity to edema in the marrow and surrounding soft tissue. Bone scintigraphy with or without SPEC T does not provide enough anatomic detail. C oned radiographs do not provide the needed multidimensional detail for this condition, as well as many other spinal problems.
