OSR CHAP 1 SPINE Flashcards
(476 cards)
1
Q
What two changes occur in the vascular supply to the disk with aging?
A
Vessels begin disappearing after the age of 10 & Endplates ossify
2
Q
What is the source of nutrients to the disk?
A
Diffusion through endplates
3
Q
What two external factors decrease endplate permeability?
A
- Smoking; 2. Vibration
4
Q
What factors increase permeability?
A
Exercise
5
Q
How does aging affect the disk’s collagen content?
A
Decreased collagen content
6
Q
How does aging affect the disk’s fibril diameter?
A
Increased fibril diameter and variability
7
Q
How does aging affect the disk’s noncollagenous protein?
A
Increased noncollagenous protein
8
Q
How does aging affect the disk’s pH?
A
Decreased pH
9
Q
Magnetic resonance imaging (MRI): what are the rates of false-positive (asymptomatic) findings for patients 40 years old, and >60 years old?
A
- 40 years old: 60%; 3. >60 years old: 90%
10
Q
What is the function of the anterior column and the posterior column?
A
- Anterior column: support; 2. Posterior column: tension band
11
Q
An anteriorly placed graft is loaded in which two directions and unloaded in which two directions?
A
- Loaded in compression, flexion; 2. Unloaded in extension, traction
12
Q
What effect does an anterior plate have on the axis of rotation?
A
Moves axis of rotation anteriorly
13
Q
… on the graft in extension?
A
Loads graft in extension
14
Q
… on the graft in flexion?
A
Unloads graft in flexion
15
Q
What is the definition of terminal bending?
A
Moments at ends of a long construct
16
Q
How can terminal bending be prevented?
A
With intermediate fixation points
17
Q
How much lumbar torsional resistance is provided by facets, disk, and ligaments?
A
- Facets: 40%; 2. Disk: 40%; 3. Ligaments: 20%
18
Q
After a flexion-distraction injury, what is the status of the anterior longitudinal ligament (ALL) and the posterior longitudinal ligament (PLL disrupted)?
A
- ALL intact; 2. PLL out
19
Q
Which approach is biomechanically superior in this situation?
A
Posteriorly based fusions are superior to anteriorly based fusions
20
Q
How are the cervical spine facets oriented in the sagittal plane?
A
Cervical: 45 degrees in the sagittal plane
21
Q
Compare with thoracic and lumbar facet orientation.
A
- Thoracic: vertical in sagittal plane (essentially in the coronal plane); 2. Lumbar: sagittally aligned
22
Q
The sinuvertebral nerve originates from which structure?
A
Sympathetic chain
23
Q
What structures and elements does it supply?
A
- Supplies structures within the spinal canal; 2. Supplies posterior elements
24
Q
What other neurologic structure also innervates the posterior elements?
A
Primary dorsal ramus also contributes to innervation
25
Pattern of innervation example: the L3 nerve root innervates which facets?
L3 innervates the L3-4 facets
26
At which level is the pedicle diameter the smallest?
T5
27
What is the furcal nerve? What is its clinical significance?
1. Peripheral nerve often originating from L4 nerve root; 2. Can result in variable L4 dermatomal distribution
28
Infection versus malignancy: which generally destroys the disk?
1. Infection destroys the disk early; 2. Malignancy usually skips the disk
29
Compare with the effect of tuberculosis on the disk.
Tb skips the disk early, but may involve the disk late
30
What are the earliest plain radiographic findings of infection?
Disk space narrowing at 7 to 10 days
31
What is the natural history of disk space infection?
Spontaneous arthrodesis
32
What are the two usual treatment for osteomyelitis?
Intravenous antibiotics Brace
33
What are the three operative indications?
1. Failure of conservative treatment; 2. Progressive neurologic deficit; 3. Instability (e.g., fracture)
34
What are the two negative prognostic factors for infection?
1. Increased age; 2. More cephalad involvement
35
What is the MRI appearance of malignancy on T1 and T2 sequences?
1. T1: low; 2. T2: high
36
What three tumors classically involve the posterior elements?
1. ABC (aneurysmal bone cyst); 2. Osteoid osteoma/osteoblastoma; 3. Osteochondroma
37
Cervical spondylosis is most common at which two levels?
1. C5–6; 2. C6–7
38
Degenerative cervical spondylolisthesis is most common at which two levels?
1. C3–4; 2. C4–5
39
What are the most common levels of cervical trauma in the young?
C4 to C7
40
What are the most common levels of cervical trauma in the elderly?
C1, C2
41
What is Spurling's test? What is its clinical significance?
1. Rotation, lateral bend, vertical compression of neck; 2. To identify cervical radiculopathy
42
What arm position classically relieves the symptoms of cervical radiculopathy?
Symptoms improve with the arm overhead
43
What is the ideal therapy regimen for radiculopathy? What percentage of patients improve?
Isometric exercises 75% improve
44
What is the finger escape test? What is its clinical significance?
1. Spontaneous small finger abduction secondary to weak intrinsics; 2. Indicative of myelopathy
45
In what two ways does cervical myelopathy generally progress?
1. Long quiescent periods; 2. Stepwise deterioration
46
What is Lhermittes sign?
Lightning sensation in arms with neck flexion
47
What does the C4 nerve root innervate?
Scapular muscles
48
What three roots correspond to reflexes within the upper extremities?
1. C5: biceps; 2. C6: brachioradialis; 3. C7: triceps
49
What is the significance of a hypoactive brachioradialis (BR) reflex?
Hypoactive BR reflex = lower motor neuron involvement (radiculopathy)
50
What is the significance of an inverted radial reflex (IRR)?
1. IRR: hypoactive BR reflex + concurrent finger flexion; 2. Upper motor neuron involvement (myelopathy)
51
What is Power's ratio used for? What is its critical value?
1. Anterior atlanto-occipital (AO) dissociation; 2. BC/AO >1: abnormal
52
What is the definition of Torg's ratio? What is its clinical significance?
1. Canal width divided by vertebral body width; 2. For the identification of congenital stenosis
53
Compare normal and critical values of Torg's ratio?
1. Normal is 1.0; 2. Critical value is <0.8
54
What three arteries contribute to the spinal cord blood supply?
1. Anterior spinal artery (two thirds from vertebral artery); 2. Two dorsal spinal arteries (one third from posterior inferior cerebellar artery [PICA])
55
The watershed area of the cervical spinal cord is at which levels?
C5 to C7
56
What are the two classic symptoms of calcified disk disease in a child?
1. Neck pain; 2. Torticollis
57
What is the treatment of choice?
Observation
58
What is the prognosis?
Likely to go on to spontaneous resolution
59
What is the most common reason for a missed cervical spine injury?
Inadequate visualization of involved levels
60
At which two levels are injuries most often missed?
1. Cervicothoracic junction; 2. Atlantooccipital junction
61
In an awake, alert patient without neck symptoms, what is required for C-spine clearance?
1. Clinical exam only; 2. No films required
62
Compare with a patient with neck pain or neurologic deficits.
Three views of cervical spine with or without computed tomography (CT)
63
What is the normal atlantodens interval (ADI) in adults and in children?
1. Adults: <4.0 mm
64
What are the normal and unstable values of a lateral mass overhang on an open mouth view? What is its clinical significance?
1. Normal = 0 mm overhang; 2. Unstable = >6.9 mm; 3. Relevant for Jefferson fracture
65
What are the two White/Panjabi instability criteria for subaxial C-spine on flexion-extension films?
1. Sagittal translation >3.5 mm or 20%; 2. Sagittal rotation >20 degrees
66
… on resting films?
1. Sagittal translation >3.5 mm or 20%; 2. Relative sagittal angulation >11 degrees
67
On a pediatric lateral C-spine film, what is the normal C2 retropharyngeal space? Retrotracheal space?
1. <14 mm retrotracheal
68
What level is most commonly involved in pseudosubluxation? What is its significance?
1. C2 on C3; 2. May be a normal finding in children
69
What is the key radiographic landmark when evaluating for pseudosubluxation?
Check spinolaminar line
70
What percentage of space is occupied by the cord? What makes up the remainder?
1. 33% cord; 2. 33% dens; 3. 33% empty (cerebrospinal fluid [CSF], fat); Steele's rule of thirds
71
What percentage of head rotation occurs at C1–2?
0.5
72
The arterial arcade around the odontoid process is supplied by which two vessels?
1. Vertebral artery; 2. External carotid artery
73
What are the anterior landmarks for levels C3, C4, C5, and C6?
1. C3: hyoid; 2. C4, C5: thyroid
74
The carotid tubercle is at which level?
C6
75
What is the C7-T1 landmark?
Sternal notch
76
With an anterior cervical discectomy and fusion (ACDF), what is the first muscle encountered? What is the innervation?
1. Platysma; 2. Facial nerve (cranial nerve [CN] VII)
77
With an ACDF, the interval for dissection lies between what two anatomical areas?
1. Carotid sheath; 2. Trachea
78
What are the four contents of the carotid sheath?
1. Internal carotid artery (ICA); 2. Common carotid artery (CCA); 3. Internal jugular vein (IJV); 4. CN X vagus
79
What artery lies at the proximal extent of exposure? What is to be done with it?
1. Superior thyroid artery; 2. It may be sacrificed
80
Where is the omohyoid muscle encountered? How should it be retracted?
1. Encountered on the medial side of the carotid sheath within pretracheal tissue; 2. Retract medially, may divide if necessary
81
What are the origin, insertion, innervation, and function of the omohyoid muscle?
1. Origin: scapula; 2. Insertion: hyoid bone; 3. Innervation: ansa cervicalis (C1 to C3); 4. Function: depress hyoid bone and larynx
82
More proximal approaches put which nerve at risk? What is its clinical significance?
1. Superior laryngeal nerve; 2. Responsible for high note phonation
83
Classically, there is increased recurrent laryngeal nerve risk with which approach? Why?
1. Right-sided approach; 2. More variable on right (left goes around the aortic arch)
84
In which interval does the recurrent laryngeal nerve ascend?
Tracheoesophageal interval
85
What do recent data indicate about the side of approach and recurrent laryngeal nerve injury rate?
Right- and left-sided approaches have equivalent injury rates
86
What approach places the thoracic duct at risk? What is the treatment if the duct is injured?
1. Left-sided approach; 2. If injured, ligate proximally and distally
87
Horner's syndrome is a risk at which level? Why?
1. C7-T1; 2. Because of the inferior cervical ganglion
88
Vocal cord paralysis may also occur by which other mechanism? How can this be prevented?
1. Compression of larynx between retractor and endotracheal (ET) tube; 2. Prevention: deflate ET tube after retractors are placed, allow tube to re-centralize
89
What does “SLAC Line” refer to?
The five capital letters in the acronym refer to the following structures (anterior to posterior):; 1. Sympathetic chain; 2. Longus coli; 3. Artery (vertebral); 4. cervical nerve root; 5. Lateral mass
90
What is the preferred proximal cervical approach for a singer?
Anterior retropharyngeal approach
91
What is the key posterior triangle for the posterior approach?
Suboccipital triangle
92
What two structures does this triangle contain?
1. Vertebral artery; 2. C1 nerve
93
What is the most superficial structure?
Greater occipital nerve (C2)
94
What is the size of the safe zone relative to the C1 spinous process?
1.5 to 2 cm lateral from C1 spinous process to vertebral artery
95
With a posterior approach, which way should the nerve root be retracted?
Elevate root superiorly
96
What nerve root is at the highest risk for traction injury? Why?
1. C5 at highest risk; 2. Straightest take-off
97
What is the best way to approach ossification of the posterior longitudinal ligament (OPLL)? What is the preferred surgical technique for decompression?
1. Posterior; 2. Laminoplasty
98
What preoperative sagittal plane requirement is necessary for laminoplasty success?
Cervical lordosis
99
What is the principal complication of laminoplasty?
Decreased cervical range of motion (ROM) by 50 to 62%
100
The lateral mass includes which two structures?
1. Pedicle; 2. Ipsilateral lamina
101
For a one-level ACDF, compare outcomes associated with allograft versus autograft use.
Equivalent outcomes
102
What two clinical conditions are the exceptions?
1. Multiple levels; 2. Smokers
103
In performing a multiple-level ACDF, what should one consider preoperatively?
1. Strut graft; 2. Plate; 3. Adjunct posterior fusion
104
For smokers, is allograft or autograft preferred for one level? What about for two levels?
1. One level: always autograft; 2. Two levels: autograft strut
105
A posterior approach should generally be included with anterior surgeries in excess of ________.
Two corpectomies
106
What are reported ACDF pseudarthrosis rates for one level?
0.12
107
What are reported ACDF pseudarthrosis rates for multiple levels?
0.3
108
What is the significance of the Hillibrand study?
25% of ACDF patients required an additional procedure within 10 years for adjacent-level disease
109
What is the principal factor in determining adjacent-level degeneration?
Preoperative adjacent-level status
110
What is the treatment if the lateral femoral cutaneous nerve (LFCN) is cut with graft harvest?
Allow it to retract into the pelvis
111
What percentage of patients develop long-term pain at the graft site?
0.25
112
For the elderly patient, is an ACDF or a posterior approach generally better tolerated?
Posterior approach
113
Increased risk of dysphagia and respiratory compromise occur with which four factors?
1. Increased number of levels; 2. Increased operative time; 3. Increased blood loss; 4. More proximal level of surgery
114
What complication is unique to an posterior approach?
Air embolism
115
When performing a multilevel posterior laminectomy, what else should one do? Why?
1. Instrumented fusion; 2. To prevent postoperative kyphosis
116
What is the order of relative frequency of the three rheumatoid-related disorders within the cervical spine?
1. 1: C1–2 instability; 2. 2: basilar invagination; 3. 3: subaxial subluxation
117
What are the criteria for atlantoaxial instability in the adult and in the child?
1. Adult: >3 mm motion; 2. Child: >4 mm motion
118
What is the significance if >7 mm motion is seen at C1–2?
1. Alar ligaments also disrupted; 2. Contraindication to elective orthopaedic surgery
119
A posterior atlanto-dens interval (PADI) smaller than ________ is an indication for surgery.
14 mm
120
What are the expected surgical outcomes if PADI is 10 to 14 mm or <10 mm?
1. 10 to 14 mm: can expect neurologic improvement postoperatively; 2. <10 mm: stabilize; improvement unlikely
121
What is the critical PADI value in flexed position?
Surgery indicated if <6 mm in flexion
122
What are the two additional operative indications at C1–2?
1. >10 mm motion; 2. Myelopathy
123
What four surgical options are appropriate if C1–2 subluxation is reducible?
1. Gallie technique; 2. Brooks technique; 3. Transarticular screws; 4. Harms technique
124
What three surgical options are appropriate if subluxation is irreducible? What is the key step to all three?
1. Posterior decompression with occiput-C2 fusion; 2. Posterior decompression with C1–2 transarticular screws; 3. Harms technique; Key step with all interventions: decompression!
125
What is the expected long-term consequence without surgery for instability?
On average, patients die within 8 years
126
What are the three criteria that indicate that surgery is less likely to be successful? What is the Ranawat category?
1. Objective weakness; 2. Upper motor neuron (UMN) signs; 3. Nonambulatory
127
Upon which two factors is the Nurick classification of myelopathy based?
1. Gait; 2. Ambulatory function
128
What anatomic line lies at the base of the foramen magnum? What is its clinical significance?
1. McRae's line across the base of the foramen magnum; 2. Odontoid should always be below this line (if not, then invagination is present)
129
What is the most important operative indication for invagination?
Neurologic compromise
130
… Migration in excess of?
>5 mm
131
… Cervicomedullary angle (CMA)?
<135 degrees
132
… Ranawat measurement?
<13 mm
133
… McRae's line?
Odontoid proximal to McRae's line
134
What two surgical options are appropriate for basilar invagination?
1. Occiput to C2 fusion; 2. Transoral odontoid resection
135
What are the only two current indications for a transoral approach?
1. Cranial nerve deficits (brainstem compromise); 2. Solid posterior C1–2 fusion with persistent anterior cord compromise
136
What are the two classic symptoms of atlantoaxial arthritis? What is the treatment?
1. Headache; 2. Rotational pain; 3. Treatment: posterior C1–2 fusion
137
What are the criteria for instability: (________ mm, ________ degrees)?
1. >3.5 mm or 20% translation; 2. >11 degrees (static film); 3. >20 degrees (flexion-extension films)
138
Which gender is most commonly affected? What are the other three primary risk factors?
1. Male; 2. History steroid use; 3. RF+; 4. Nodules
139
An increased risk of neurologic compromise exists with what two radiographic criteria?
1. Subluxation >4 mm; 2. Cervical height index >2
140
What is the treatment of choice?
Posterior fusion and wiring
141
Where is the skull thickest?
External occipital protuberance
142
What structures are at risk with screws?
Venous sinuses
143
What is the Gallie technique?
Spinous process wiring with midline graft
144
How much relative resistance does the Gallie provide versus flexion, extension, and rotation?
1. Good versus flexion; 2. Not good versus extension and rotation; 3. Not good versus extension and rotation
145
Gallie should not be used in what situation?
Posteriorly displaced odontoid fracture
146
What is the Brooks technique?
Posterior wiring with bilateral grafts
147
How much relative resistance does the Brooks provide versus flexion, extension, and rotation?
1. Good versus flexion; 2. Better versus extension and rotation; 3. Better versus extension and rotation
148
With either the Gallie or Brooks, what must be applied postoperatively?
Halo vest
149
How effective are C1–2 transarticular screws against flexion, extension, and rotation?
Best versus flex, extension, and rotation
150
How can the vertebral artery be injured with a transarticular screw?
Screw too caudally directed
151
How can the occiput-C1 joint be injured?
Screw too cephalad
152
How can the hypoglossal nerve (CN XII) be injured?
Screw too long: too anterior to lateral mass
153
What are the two functions of the hypoglossal nerve?
1. Innervates muscles of tongue; 2. Contributes to strap muscle innervation via ansa cervicalis; 3. Contributes to strap muscle innervation via ansa cervicalis
154
If considering transarticular screws, which study must be obtained preoperatively?
Preoperative thin-cut CT scan
155
What percentage of patients have anatomy that precludes C1–2 screws?
0.15
156
If an iatrogenic injury to one vertebral artery occurs, what is the next step?
Sublaminar wires and graft (Gallie/ Brooks type)
157
Vertebral artery injury may be seen in association with trauma at what location?
Facet joint injury
158
How can it be injured intraoperatively?
Lateral bone removal with burr
159
If a vertebral artery stroke occurs, what is the name of the resultant syndrome? What are its four features?
1. Wallenberg syndrome; 2. Nystagmus; 3. Diplopia; 4. Dysphagia; 5. Pain, temperature loss
160
What is the path of the vertebral artery? Above C1?
1. C6 foramen transversarium to C1; 2. Up and medially through arcuate foramen above C1; 3. Up and medially through arcuate foramen above C1
161
Thoracic disk disease is most common at which levels?
T8 to T12 (especially T11-T12)
162
What is the classic mechanism of injury resulting in thoracic disk herniation (herniated nucleus pulposus [HNP])?
Torsion + bend
163
An HNP is most likely to be symptomatic in what two situations?
1. Scheuermann's disease; 2. Calcified disk; 3. Calcified disk
164
What are the two indications for surgery?
1. Myelopathy; 2. Pain with magnetic resonance (MR) correlation; 3. Pain with magnetic resonance (MR) correlation
165
What is the disadvantage of a posterior approach?
Decreased midline access from the posterior
166
For the approach, should the surgeon go over or under the rib? From right or left? Why?
1. Over rib; 2. From right; 3. Avoid artery of Adamkiewicz
167
Where is the watershed area for the thoracic spinal cord?
Middle T-spine
168
Where does the spinal cord end?
L1–2
169
What are the radiographic criteria for a diagnosis of disseminated idiopathic skeletal hyperostosis (DISH, diffuse idiopathic skeletal hyperostosis)?
Nonmarginal syndesmophytes >3 levels
170
Is the disk generally involved?
DISH generally spares the disk
171
What type of syndesmophytes are seen with ankylosing spondylitis?
Marginal syndesmophytes
172
Are compression fractures more common in the thoracic or lumbar spines? Why?
Thoracic spine more common because it is kyphotic
173
A vacuum sign on x-ray implies what two characteristics of the fracture?
1. Osteonecrosis; 2. Nonhealing; 3. Nonhealing
174
How can compression fracture acuity be best evaluated?
Short tau inversion recovery (STIR) MRI
175
What are the five risk factors (in descending significance) for a vertebral compression fracture?
1. Prior compression fractures; 2. Decreased bone mineral density (BMD); 3. Family history; 4. Premature menopause; 5. Smoking
176
On standing lateral films, where should the C7 plumb line fall?
Through the sacrum or within 2 cm anterior to the sacrum
177
What are the five common causes of kyphotic sagittal imbalance?
1. Scheuermann's disease; 2. Ankylosing spondylitis; 3. Neurofibromatosis; 4. Traumatic (e.g., compression, burst fractures); 5. Iatrogenic (e.g., postlaminectomy, Harrington distraction instrumentation)
178
What is an SPO? What is the effect on the posterior, middle, and anterior columns?
1. Resection of posterior column between the facet joints; 2. Posterior column shortened; 3. Middle column = hinge; 4. Anterior column lengthened
179
How much correction can be obtained, on average, per level?
10 degrees
180
What additional procedure may potentially be necessary?
Anterior grafting if a gap opens in anterior disk space
181
What is a PSO? What is the effect on the posterior, middle, and anterior columns?
1. Wedge-shaped resection with apex anterior of vertebral body, pedicle, and posterior elements; 2. Posterior column shortened; 3. Middle column shortened; 4. Anterior column = hinge
182
How much correction can be obtained, on average, per level? Which levels are preferred?
1. 30 degrees; 2. L2, L3 probably safest; 3. L2, L3 probably safest
183
In thoracolumbar compression fractures, what is the indication for surgery? Why?
Fractures at >3 consecutive levels Increased risk of kyphosis
184
What are the five surgical indications?
1. Unstable injury (posterior ligamentous complex disrupted); 2. >50% height loss; 3. >50% canal compromise; 4. >30 degrees kyphosis; 5. Incomplete or progressive neurologic deficit
185
If a neurologic deficit is present, what is the preferred surgical approach?
Anteriorly to decompress, fuse
186
If posterior column involvement is present, what is the preferred surgical approach? What is the significance of a lamina fracture?
1. Posteriorly to fuse; 2. Lamina fracture may entrap and compress nerve roots (go posterior)
187
What is the most common long-term complication of a thoracolumbar burst fracture?
Pain
188
Compare the reported outcomes of operative versus nonoperative treatment of stable burst fractures.
Equivalent outcomes
189
What four factors are prognostic for future back pain?
1. History of back pain; 2. Smoker; 3. >30 years old; 4. Workmen's compensation case
190
In acute low back pain, when do 50% of patients recover? When do 90% of patients recover?
1. 50% recover at 1 week; 2. 90% recover at 3 months
191
In acute sciatica, when do 50% of patients recover?
At 1 month
192
A program consisting of what two factors has been demonstrated to result in the best return to work?
1. Education; 2. Aerobic conditioning
193
What three Minnesota Multiphasic Personality Inventory (MMPI) findings are predictors of poor recovery?
1. Hysteria; 2. Hypochondriasis; 3. Depression
194
What are the aggravating positions for degenerative disk disease (DDD) and instability?
1. DDD: worse with flexion; 2. Instability: worse with extension
195
What are the general surgical treatment principles for DDD and instability?
1. DDD: treat with interbody techniques (remove painful disk); 2. Instability: treat with instrumented posterolateral fusion
196
What are the two classic symptoms of lumbar instability?
1. “Catch” with extension; 2. Back pain
197
What are the radiographic instability criteria at L1-L4?
1. >4 mm motion; 2. 10 degrees angulation
198
… at L5-S1?
1. >6 mm motion; 2. 20 degrees angulation
199
What are the five Waddell signs? What is their clinical significance?
1. Tenderness; 2. Simulation; 3. Distraction; 4. Regional disturbance (stocking-glove); 5. Overreaction; *Significance: be wary if >3 positive
200
How are impairment and disability defined? Which determines compensation?
1. Impairment: deviation from normal function; 2. Disability: inability to perform a specific function; 3. Disability more important for compensation
201
What is the proven benefit of a corset? What is its effect on motion?
1. Decreased intradiskal pressure; 2. No effect on motion
202
Compare Jewett versus thoracolumbar spinal orthosis (TLSO) for rotational control.
TLSO better
203
How can L5-S1 best be immobilized?
TLSO with thigh extension
204
Which levels are accessible in transperitoneal and retroperitoneal approaches?
1. Transperitoneal: L5-S1; 2. Retroperitoneal: L1-sacrum; 3. Retroperitoneal: L1-sacrum
205
Where does the aorta bifurcate? Above this level, where does it lie?
1. Bifurcation at L4; 2. In the midline above bifurcation
206
The inferior vena cava is on which side?
Right
207
Where do the segmental vessels come off?
Mid-body level (not at level of disk)
208
Are the parasympathetic or sympathetic fibers at risk at these levels? Which plexus?
1. Sympathetic fibers at risk; 2. Superior hypogastric plexus
209
What are the potential complications of injury to the sympathetics?
1. Retrograde ejaculation; 2. Lower extremity temperature difference (chain injury)
210
Where are the parasympathetic fibers? What is their reproductive effect?
S2–3, S3–4, usually not disturbed Control erection
211
What is the preferred direction of anterior dissection? Why?
1. Dissect from left to right; 2. Plexus is more adherent on right
212
What is the most common level of vascular injury? How is it injured? What is the consequence?
1. L4–5 most common level; 2. Injury with pituitary rongeur; 3. Most commonly leads to arteriovenous (AV) fistula, but may lead to death
213
What vessel lies in the L4–5 interspace?
Iliolumbar vein
214
… Ilioinguinal and iliohypogastric nerves?
Lateral border of psoas
215
… Genitofemoral nerve?
On psoas
216
… Obturator and femoral nerves?
Deep to psoas
217
… Sympathetic chain?
Medial to psoas
218
At what level is the genitofemoral nerve? How can it be tested?
1. Near L2–3; 2. Cremasteric reflex
219
What is the most common complication of total disk arthroplasty?
Transient radiculopathy
220
The optimal lumbar pedicle screw starting point lies at the junction of what three anatomical entities?
1. Transverse process; 2. Pars; 3. Superior articular facet
221
Should one aim more medially or laterally as one moves caudally in the lumbar spine?
More medially as one heads down
222
What is the No. 1 factor associated with lumbar screw pullout?
Osteoporosis
223
What is the No. 1 risk factor for postoperative interbody cage migration?
Posterior approach
224
What two levels have the most lumbar lordosis?
1. L4-L5; 2. L5-S1
225
Straight leg raise (SLR) versus femoral stretch tests identify HNPs at which levels?
1. Femoral stretch: L2–3 (hip flexors), L3–4 (quads, TA [tibalis anterior]); 2. SLR: L4–5, L5–S1
226
What is the most specific clinical exam for HNP? Especially true in what situation?
1. Contralateral SLR; 2. Especially for axillary herniation
227
What body position results in the lowest intradiskal pressure? Highest?
1. Lowest: supine; 2. Highest: sitting, flexed with weights in hands
228
Lumbar disk herniations occur most commonly at which location (on axial imaging)?
Paracentral
229
How can referred pain be differentiated from lumbar radicular pain?
Referred pain usually above knee
230
How does the orientation of the upper lumbar nerve roots differ from that of the lower roots?
Upper roots have more direct takeoff (less room to manipulate)
231
What is the natural history motor recovery, pain resolution, and sensory deficits in HNP?
1. Motor generally recovers; 2. Pain generally resolves; 3. 30% of sensory deficits persist
232
Pediatric herniations are not generally disk material; they consist of what?
Avulsion of ring apophysis of vertebral body
233
Is there a proven benefit to epidural steroids for HNP?
No
234
What patients are especially likely to have recurrent postoperative pain? What percentage of patients?
1. Large annular defect; 2. Up to 15 to 20% have long-term backache
235
What is the reported re-herniation rate? What is the imaging study of choice to identify re-herniation?
1. 0.1; 2. MRI with gadolinium
236
What are the three components of the treatment algorithm for postoperative infection after lumbar diskectomy? When should surgery be performed?
1. MRI with gadolinium; 2. Percutaneous biopsy and culture; 3. IV antibiotics
237
Better outcomes can be expected if decompression is performed within what time frame?
48
238
Does early decompression benefit bladder function, motor recovery, or pain?
1. Improves bladder and motor recovery; 2. No effect on pain resolution
239
What is the principal cause of lateral recess stenosis?
Superior articular facet hypertrophy
240
What are three causes of foraminal stenosis?
1. Foraminal HNP; 2. Decreased disk height; 3. Pars defect
241
In foraminal stenosis, what are the critical foraminal height and the critical posterior disk height?
1. Foraminal height <4 mm
242
Are tension signs present with central or lateral stenosis?
Not generally
243
Why is hyperreflexia not seen with lumbar stenosis? What is the most common neurologic deficit on exam?
1. Lower motor neuron (LMN) problem, so no hyperreflexia; 2. L5 most common root for weakness
244
Is there a proven benefit to epidural steroids?
No consistent benefit in controlled studies
245
What type of injection has most consistently demonstrated symptomatic benefit?
Transforaminal nerve block
246
What are the three indications for fusion after decompression of stenosis?
1. Degenerative spondylolisthesis; 2. Instability/iatrogenic injury; 3. Degenerative scoliosis
247
Is there a proven benefit to instrumentation for stenosis? How about symptomatic relief?
1. No proven benefit to instrumentation; 2. Improved symptom relief without instrumentation
248
What age group has poorer decompression outcomes? Are there other prognostic factors?
1. Young patients do worse; 2. Patients with multiple comorbidities do worse
249
What is the typical mechanism of extraforaminal L5 root compression? What is the ideal radiographic view to identify it?
1. L5 impingement between sacral ala and L5 transverse process; 2. Ferguson's view
250
What are the six types of spondylolisthesis, and (where applicable) which level is most commonly affected by each?
1. Dysplastic (L5-S1); 2. Isthmic (L5-S1); 3. Degenerative (L4-L5); 4. Traumatic; 5. Pathologic; 6. Postsurgical
251
What nerve root is most commonly affected by spondylolisthesis?
L5
252
What are the two classic radiographic features?
1. Trapezoidal L5; 2. Rounded S1
253
What is the normal value of sacral inclination? What is the significance of greater inclination?
1. Normal inclination >30 degrees; 2. More vertical sacrum: increased risk of slip
254
How is the slip angle measured? What values are considered normal?
1. Lordosis at L5-S1; 2. Normal <0 (kyphotic)
255
What nerve root is most commonly affected? Why are nerve root signs especially common with dysplastic spondylolisthesis?
1. L5 at risk; 2. Especially common because posterior arch is intact
256
Is there a proven clinical benefit to spondylolisthesis reduction?
No
257
If a reduction is performed, when is the nerve root most likely to be injured?
During the last 50% of reduction
258
Is there a proven benefit to decompression?
1. No; 2. Fusion with or without decompression leads to good outcomes
259
What is the most sensitive imaging study for identification of a pars defect?
Single photon emission computed tomography (SPECT) scan
260
When is the listhesis thought to occur? To what grade?
1. At ages 4 to 6 years; 2. Usually not to more than grade II
261
Which gender is most commonly affected?
Female
262
What effect does a unilateral pars defect have on risk of listhesis?
Unilateral defects generally do not result in a slip
263
Ideal brace?
Antilordotic brace
264
What are the treatment and activity restrictions for the various grades of adolescent slips?
1. Grade I: contact sports OK if patient asymptomatic; 2. Grade II: no contact sports; 3. Grade III/IV: fuse L4-S1 in situ
265
Is a laminectomy without fusion an option for children?
No!
266
Pars defect repair indications: age, grade, and level?
1. Young; 2. Grade I or less; 3. Above L5
267
For an adult patient, which levels should be fused if the L5-S1 slip is low grade or high grade?
1. Low grade: L5-S1; 2. High grade: L4-S1
268
Is there a proven clinical benefit to using instrumentation with fusion? Is there another point to consider?
1. No proven benefit; uninstrumented outcomes are equivalent to instrumented outcomes; 2. But instrumentation does increase fusion rates
269
If instrumentation is used, which approach has the best reported outcomes?
Best outcomes with circumferential instrumentation
270
What race and which gender are at highest risk? What age group?
1. African-American female; 2. >40 years
271
What radiographic feature is especially common among affected patients?
Transitional L5 vertebrae
272
What two factors may predispose to degenerative spondylolisthesis?
1. Pregnancy; 2. Diabetes mellitus
273
Is there a proven benefit to fusion at the time of surgery?
Fusion outcomes significantly better than decompression alone
274
Is there a proven benefit to instrumentation?
None proven
275
What is the long-term effect of untreated degenerative scoliosis?
Increased back pain
276
What are the two factors that curve flexibility depend on?
Curve magnitude Age
277
Compare general curve progression rates >50 degrees: thoracic versus thoracolumbar versus lumbar?
1. Thoracic: progresses 1 degree/year; 2. Thoracolumbar: progresses 0.5 degrees/year; 3. Lumbar: progresses 0.25 degrees/year
278
Are combined or staged surgical procedures generally preferred in adults?
Combined preferred, because staging leads to malnutrition between stages
279
If severe osteoporosis is present, what is the most secure point of fixation?
Lamina
280
What are surgical outcomes most dependent on?
Final coronal and sagittal balance
281
What are the three benefits to interbody device use at the caudal end of long lumbosacral fusion?
1. Increased construct stiffness; 2. Decreased strain on posterior instrumentation; 3. Increased fusion rate
282
What is the No. 1 complication of adult scoliosis surgery?
Pseudarthrosis
283
What is the No. 1 medical complication?
Urinary tract infection
284
What is the pulmonary consequence of thoracotomy in the adult?
Never returns to preoperative pulmonary function test (PFT) values
285
What is delayed postoperative paraplegia most often due to?
Cord ischemia (stretch)
286
What was the main problem with Harrington instrumentation?
Positive sagittal balance = fatback
287
Pedicle subtraction osteotomy (PSO) for flatback is generally performed at which levels?
L2 or below
288
What is a contraindication to PSO?
Anterior pseudarthrosis
289
What are the three characteristic SMA syndrome symptoms?
1. Abdominal pain; 2. Distention; 3. Persistent vomiting
290
When does SMA syndrome occur? Why?
1. Within 1 week postop; 2. Compression of third part of duodenum between aorta and SMA
291
How can SMA be differentiated clinically and radiographically from postoperative ileus?
1. Clinically: bowel sounds present; 2. X-ray: upper gastrointestinal (GI) study
292
What are the two aspects to treatment for SMA syndrome?
1. Nasogastric (NG) tube; 2. Intravenous (IV) fluids/alimentation
293
What grade of muscle strength indicates active muscle function against gravity?
3 out of 5
294
What are the two ways in which the functional level of an SCI patient is determined?
1. Most distal intact sensory level; 2. Most distal intact (3/5 or greater) motor level if next level is 5/5
295
What is the Frankel classification used for?
Grades motor function below injury level (A = none to E = full)
296
For what two capabilities has the ASIA (American Spine Injury Association) motor score been shown to be prognostic?
1. Functional improvement potential; 2. Performance in rehabilitation
297
What is the significance of the jaw jerk reflex?
Indicates injury proximal to the cervical spine
298
What result or time frame characterizes the end of spinal shock?
1. Return of bulbocavernosus reflex; 2. Or 48 hours passed since injury
299
Are reflexes present in spinal shock?
No reflexes (UMN or LMN) are present
300
Neurogenic shock is associated with injuries above which level? What is it due to?
1. Injury above T5; 2. Disruption of descending sympathetics
301
What are the two components of the treatment algorithm for neurogenic shock?
1. 1st: fluids; 2. 2nd: pressors
302
What three MRI findings are poorly prognostic for recovery after SCI?
1. Hemorrhage; 2. Contusion; 3. Edema
303
What two factors are positively prognostic for recovery after SCI?
1. <30% displacement on radiographs
304
What type of injury is most often associated with further deterioration after admission?
Rotational fracture dislocation
305
If steroids are started within 3 hours, they should be continued for how long? What if they are started within 8 hours of injury? What if they are started more than 8 hours after injury?
1. Start within 3 hours, continue for 24 hours; 2. Start within 8 hours, continue for 48 hours; 3. After 8 hours, no steroids
306
Should steroids be administered with a penetrating wound?
No
307
What roots are involved with a conus medullaris injury? What functions are lost?
1. Roots S2, S3, S4; 2. Lost: bowel, bladder function only
308
What anatomic levels of injury are most likely to result in conus injury? What is the differential diagnosis?
1. Anatomic level of injury: T12-L1 or T11-T12; 2. Important differential: cauda equina syndrome
309
Motor evoked potentials (MEPs) monitor which area of the spinal cord?
Anterior column only
310
Somatosensory evoked potentials (SSEPs) monitor which area of the spinal cord? What is the downside?
1. Dorsal column only; 2. May miss anterior column injury
311
What degree of SSEP amplitude change is concerning?
50% drop
312
What degree of SSEP latency change is concerning?
10% increase
313
What does electromyography (EMG) monitor?
Nerve root irritation
314
What two modalities are best during scoliosis correction? What modality is best during spondylolisthesis reduction?
1. Scoliosis: SSEP, motor evoked potential (MEP); 2. Spondylolisthesis reduction: EMG
315
If intraoperative SSEP changes occur during scoliosis surgery, what two steps should be taken?
1. Increase blood pressure; 2. Stagnara wake-up test
316
If the changes persist, then what?
Remove instrumentation
317
What are the treatment and activity restrictions for an intraoperative dural tear? Is a drain necessary?
1. Primary watertight repair; 2. 48 hours of bedrest postoperatively; 3. No drain necessary
318
What are the treatment and activity restrictions for a dural tear discovered postoperatively? Should it be re-explored?
1. Subarachnoid drain; 2. Bedrest; 3. Re-explore if symptoms persist 3 to 4 days
319
What three symptoms are associated with dural tear?
1. Nausea; 2. Headache; 3. Photophobia
320
What test is used to determine if drain output is CSF?
CSF is b2-transferrin positive
321
Should antibiotics be administered after gunshot to the spine?
If associated with perforated viscus, broad spectrum antibiotics for 1 week
322
What are the two indications for intervention by general surgery?
1. Esophageal perforation; 2. Bowel perforation
323
What two conditions justify surgery to remove bullet fragments?
1. Incomplete SCI; 2. Bullet fragments causing compression
324
Bullet removal results in improved motor recovery below which level?
Motor recovery improves below T10
325
When should a laminectomy be performed?
Only if lamina fracture present
326
What two factors have been shown to predict motor recovery?
1. Age; 2. Injury type
327
Is there a proven benefit to early surgical intervention?
No
328
Is there a proven benefit to decompressing stenosis not associated with fracture?
No
329
Which incomplete SCI syndrome has the best prognosis? Which has the worst prognosis?
1. Best: Brown-Séquard (ipsilateral motor/sensory loss, contralateral pain/temperature loss); 2. Worst: anterior column
330
With posterior cord syndrome, what is required for successful postinjury ambulation? Why?
Requires intact vision for ambulation Because proprioception is absent
331
The presence of which sensory quality is a good prognostic factor after SCI?
Pinprick sensation
332
With complete SCI, is erection possible? Is ejaculation possible?
1. Reflex erection possible, not psychogenic; 2. Normal ejaculation not possible
333
After 1 year, how much additional recovery is expected with cervical SCI versus thoracolumbar SCI?
1. Cervical: 1 additional level; 2. Thoracolumbar: 0 additional levels
334
What adaptive equipment is required for a patient with an SCI level of C4?
C4: high back, head support
335
… of C5?
C5: mouth-driven electric wheelchair
336
… of C6?
C6: manual wheelchair with wrist/ hand orthoses
337
… of C7?
C7: can live independently
338
For C5 SCI patients, which tendon transfers will provide C6- or C7-type function?
1. C6: BR to extensor carpi radialis brevis (ECRB) transfer; BR = brachioradialis; 2. C7: deltoid to triceps transfer
339
What is the treatment of an open skull fracture? Why? If closed?
1. Elevate depressed fragment if open; 2. Decrease risk of infection; 3. If closed, leave alone
340
What is the anticipated recovery period after traumatic brain injury?
84
341
What extremities are most affected by an anterior cerebellar artery (ACA) stroke? What extremities are most affected by a middle cerebellar artery (MCA) stroke?
1. ACA stroke: lower extremities most affected; 2. MCA stroke: upper extremities most affected
342
What is the definition of a mild concussion?
No loss of consciousness (LOC)
343
What are the three grades of mild concussion?
1. I: confusion, no amnesia; 2. II: retrograde amnesia; 3. III: amnesia after impact
344
What is the recommended time period before return to play (RTP) for each grade?
1. I: when patient is asymptomatic; 2. II: 1 week; 3. III: 1 month
345
What is the definition of classic concussion?
Associated with loss of consciousness
346
What circumstance justifies a postconcussion head CT?
LOC lasts longer than 5 minutes
347
What is the recommended time period before return to play (RTP) after first classic concussion?
1 week to 1 month
348
What is the recommended time period before RTP after second classic concussion?
No RTP that season
349
What is the definition of diffuse axonal injury? What is the RTP recommendation?
LOC >6 hours No RTP
350
Compare the symptoms of a burner to those of transient quadriplegia?
1. Burner: unilateral, upper plexus; 2. Transient quadriplegia: axial load, bilateral, lasts up to 36 hours
351
What four factors may predispose to the development of transient quadriplegia?
1. Stenosis; 2. Instability; 3. Herniated nucleus pulposus (HNP); 4. Congenital fusions
352
If a patient sustains a traumatic HNP, what is the timing for RTP?
May return when asymptomatic
353
What are the two contraindications to return to play?
1. Instability; 2. Neurologic symptoms >36 hours
354
Does prior transient quadriplegia predict future injury?
No
355
What are the two key features of spear tackler's spine?
1. Stenosis; 2. Loss of lordosis
356
Once spear tackler's spine has been diagnosed, are contact sports allowed?
No
357
What is the most common SCI mechanism in an athlete?
Flexion-compression (burst)
358
What is an absolute contraindication to contact sports? Example?
1. Congenital anomalies of the upper cervical spine; 2. Example: os odontoideum
359
What is a safe alternative to endotracheal (ET) intubation in C-spine trauma patients? Is there an exception?
1. Nasotracheal intubation; 2. Exception: patients in respiratory arrest
360
What is a safe alternative to ET intubation in a patient with spine trauma and facial fractures?
Cricothyroidotomy
361
What is the recommended treatment for Jefferson fracture? What must be checked at the conclusion of treatment?
1. Halo with or without traction; 2. Once treatment is completed, check C1–2 stability with flexion-extension films
362
How is traumatic spondylolisthesis classified?
1. I: minimally displaced; 2. II: anterior translation >3 mm, angulated; 3. IIa: increased angulaion with minimal translation; 4. III: also C2–3 facet dislocation
363
Type I: What are the two criteria for acceptable reduction? What is the recommended treatment?
1. <10 degrees angulation; 3. Collar for treatment
364
Type II/IIa: What is the recommended treatment? What is a critical consideration in a type IIa patient?
1. Treat with halo; 2. IIa: Do not apply traction!
365
Type III: What are the three acceptable treatment options?
1. Anterior C2–3 fusion; 2. Posterior C1 to C3 fusion; 3. Bilateral pars screws
366
In odontoid fractures, what two factors increase the risk of nonunion?
1. Displacement >5 mm; 2. Angulation >10 degrees
367
What is a salvage option for odontoid nonunion?
Posterior fusion, no screws
368
How should a cervical facet fracture be treated? Compare nondisplaced versus foating facet injuries.
1. Nondisplaced facet fracture: collar; 2. Floating facet: open reduction with internal fixation (ORIF) with lateral mass plate
369
What mechanism of injury most commonly results in facet dislocation?
Flexion-distraction
370
How can unilateral and bilateral dislocations be distinguished radiographically?
1. Unilateral <50% translation; 2. Bilateral ≥50% translation
371
If a pre-reduction MRI shows herniated disk, what is the necessary treatment?
Must approach anteriorly to decompress and fuse if herniated disk
372
What is the recommended treatment for bilateral dislocation with an HNP?
Approach posteriorly
373
What is the treatment of a stable lateral mass fracture? What is the treatment of a unstable lateral mass fracture?
1. Stable: collar; 2. Unstable: surgery
374
What is the usual treatment for a subaxial compression fracture?
Collar
375
Is halo treatment generally effective for the subaxial spine?
No, a halo poorly immobilizes subaxial spine
376
What is the treatment for a subaxial burst fracture with nerve injury and an intact posterior element?
ACDF
377
What is the treatment for a subaxial burst fracture with nerve injury and unstable posterior elements?
Anterior and posterior fusions
378
Where should the anterior pin be placed?
Lateral one-third of brow
379
What structure is at risk if an anterior pin is placed too medially?
Supraorbital nerve
380
When applying a halo to a child, what is the key preoperative imaging study?
CT scan to assess skull thickness
381
When applying a halo to a child, how many pins should be placed?
Eight
382
At what torque?
4 pounds
383
When applying a halo to an adult, how many pins should be placed and at what torque?
4 pins at 8 pounds
384
What is the most common injury mechanism?
Flexion distraction
385
What is the associated visceral injury? What is the treatment to avoid in patients with abdominal injuries?
1. Associated with abdominal injury and ileus; 2. Avoid extension bracing
386
What is the bone scan appearance of sacral insuffciency fracture?
H-shaped uptake
387
A vertical shear pelvic fracture causes tension on which ligaments? What fracture may result?
1. Tension on iliolumbar ligaments; 2. Classic x-ray finding: L5 transverse process fractures (check the pelvis!)
388
What is Grisel's syndrome?
Retropharyngeal bursitis preceding rotatory subluxation
389
Early treatment for Grisel's consists of?
Traction/bracing
390
What is the general classification of rotatory subluxation?
1. I: rotation, no anterior displacement; 2. II: rotation with anterior displacement 3 to 5 mm; 3. III: rotation with anterior displacement >5 mm; 4. IV: rotation with posterior displacement
391
What is the imaging study of choice?
Dynamic CT
392
What is the treatment of traumatic subluxation <1 week in duration?
Soft collar
393
… 1 week to 1 month in duration?
Cervical traction
394
… >1 month in duration?
Fusion
395
What is the treatment for a late presentation?
C1–2 fusion
396
Os odontoideum may appear radio-graphically similar to what condition?
Type II odontoid fracture
397
What are the three surgical indications?
1. Instability >10 mm; 2. SAC <13 mm (SAC = space available for the cord); 3. Neurologic deficit
398
What is the procedure of choice for symptomatic os odontoideum?
Posterior C1–2 fusion
399
Are contact sports permitted with an os odontoideum?
No
400
What injury mechanism is generally responsible?
Hyperextension leading to posterior cord compression
401
What imaging study is necessary for diagnosis of SCIWORA? What percentage of studies will appear normal?
MRI 25%
402
What is the treatment of cervical SCIWORA?
Cervical collar
403
What is a common long-term complication of paraplegia/quadriplegia?
Paralytic scoliosis
404
Where is the apex of normal thoracic kyphosis?
T5 to T8
405
What is the average annual spinal growth rate per segment? What is the approximate total?
0.07 cm per year per segment 1 cm per year total
406
What is the recommended scoliometry threshold for referral for spine surgery evaluation?
7 degrees on Adams forward bend
407
Curve progression best corresponds with which measure?
Peak growth velocity
408
Peak growth velocity generally occurs at which Risser stage? How about menarche?
1. Peak growth velocity at Risser 0; 2. Menarche occurs before Risser 1
409
What are five indications for obtaining an MRI in the adolescent scoliosis patient?
1. Left thoracic curve; 2. Abnormal neurologic exam, especially asymmetric abdominal reflexes; 3. Excess kyphosis (conider neurofibromatosis); 4. Onset <11 years old (think infantile, juvenile); 5. Pain
410
How are stable vertebrae and neutral vertebrae defined?
1. Midsacral line bisects the stable vertebrae; 2. Neutral vertebrae have no rotation and symmetric-appearing pedicles
411
What is the usual sagittal alignment at the apical vertebrae with AIS?
Apical vertebrae usually hypokyphotic
412
What are the six components of the Lenke classification for AIS?
1. Main thoracic; 2. Double thoracic; 3. Double major; 4. Triple major; 5. Thoracolumbar/lumbar; 6. Thoracolumbar/lumbar-main thoracic
413
What is the definition of a structural curve? Why are structural curves clinically significant?
1. Structural curves do not bend out to less than 25 degrees; 2. All structural curves should be incorporated in fusion
414
What three aspects make the progression of neuromuscular scoliosis unique?
1. More rapid; 2. Continues after maturity; 3. Pelvic obliquity
415
In general, at what age should fusion surgery be undertaken for neuromuscular scoliosis?
10 to 12 years
416
If the apex is proximal to T7, what brace is needed?
Milwaukee brace
417
Bracing has been prospectively shown to be effective for which population?
Females with 25- to 35-degree curves
418
An anterior spinal fusion alone may suffice for which curve type?
Thoracolumbar curves
419
What are the two classic advantages of an anterior fusion in this population? Is there an important caveat?
1. Save levels; 2. Improve correction; 3. Caveat: pedicle screws may negate these advantages
420
What are the three general indications for a combined anterior and posterior fusion?
1. Curves >75 degrees; 2. Crankshaft prevention (females <13 years old); 3. Neuromuscular scoliosis
421
Why are some neuromuscular conditions treated with posterior fusion alone?
To avoid compromising already fragile pulmonary function
422
What are three examples of neuromuscular disorders treated with posterior fusion only?
1. Muscular dystrophy; 2. Spinal muscular atrophy; 3. Werdnig-Hoffmann
423
What should the distal extent of fusion ideally be in the adolescent idiopathic population?
L3 or above
424
What are the two risk factors for neurologic injury?
1. Excessive correction; 2. Sublaminar wires
425
What is the ideal pedicle screw depth?
80% of vertebral body depth
426
In what percentage of patients do pseudarthroses develop?
0.02
427
How is an asymptomatic pseudarthrosis treated?
Observation
428
If symptomatic?
Revision with compression instrumentation
429
What graft type increases pseudarthrosis risk in adult scoliosis patients?
Freeze-dried allograft
430
In general, what are the two surgical options for flatback correction?
1. Posterior closing wedge osteotomy (at L2 or below); 2. Anterior release and fusion
431
Untreated AIS patients are more likely to suffer from which two conditions as adults?
1. Dyspnea ; 2. Back pain
432
What are treated AIS patients more likely than the general population to suffer from?
Back pain
433
Has the magnitude of Cobb angle correction ever been associated with patient satisfaction?
No
434
What is the preferred tool for evaluation of patient postoperative satisfaction?
SRS-22 has been validated as an outcome measure
435
What age group is affected by infantile idiopathic scoliosis?
<3 years of age
436
What gender is most commonly affected?
Male
437
With which two musculoskeletal conditions is infantile scoliosis associated?
1. Plagiocephaly (fat skull); 2. Congenital defects; 3. Congenital defects
438
What percentage of patients have associated spinal cord disease?
0.2
439
What is the most common curve pattern?
Left thoracic curve
440
What is the difference between phase I and phase II? What is the clinical significance?
1. Phase I: no rib/vertebral overlap; 2. Phase II: rib/vertebral overlap is present; 3. All phase II curves progress
441
For phase I curves, what two conditions indicate that spontaneous resolution is likely?
1. Curve <20 degrees
442
Where should the RVAD be measured?
Curve convexity
443
What does surgical treatment entail?
Combined anterior and posterior fusion
444
Under which two conditions may a preoperative brace be of benefit?
1. To delay surgery until greater maturity; 2. If RVAD is increasing
445
What is the treatment if RVAD >20 degrees and if it progresses?
1. If RVAD >20 degrees, then brace; 2. If progresses, then operate
446
What age group is affected by juvenile idiopathic scoliosis?
3 to 10 years old
447
What is the most common curve type?
Right thoracic
448
How does the risk of progression compare with the risk of AIS?
Increased
449
What are the two general treatment options?
1. Growing rods (unfused); 2. Combined anterior/posterior spinal fusion
450
With congenital scoliosis, the defect occurs at how many weeks of gestation?
4 to 6 weeks
451
Patients must also be evaluated for which two conditions? Why?
1. Renal anomalies (abdominal ultrasound); 2. Heart disease; 3. Because these systems develop at same point in gestation
452
What are the two components of the general classification of congenital scoliosis?
1. I: failure of segmentation (bar); 2. II: failure of formation (hemivertebra)
453
Which type has the best prognosis? Which has the worst?
1. Best: block vertebrae (bilateral failure of segmentation); 2. Worst: unilateral unsegmented bar with contralateral fully segmented hemivertebra
454
What is the treatment for unilateral unsegmented bar with contralateral fully segmented hemivertebra?
Fuse at presentation with combined anterior/posterior procedure
455
What is the treatment for other types of congenital scoliosis?
Await progression
456
What is the classic form of treatment? What is the notable exception?
1. Classically, posterior spinal fusion in situ; 2. Exception: combined anterior/posterior fusion if significant crankshaft risk
457
What are the two other surgical options and their associated criteria?
1. Hemivertebra excision (curve >40 degrees; especially L4, L5); 2. Anterior/posterior hemiepiphysiodesis (curve >40 degrees)
458
Which type has the worst prognosis? Why?
1. Failure of formation (type I); 2. Because it is most likely to result in paraplegia
459
What is the surgical procedure of choice?
Posterior spinal fusion (because crankshaft is desirable)
460
An anterior approach should also be considered with curves of which magnitude?
>55 degrees
461
What is the definition of diastematomyelia?
Longitudinal cleft in cord
462
With what condition is diastematomyelia associated?
Cord tethering
463
What is a key radiographic feature suggestive of diastematomyelia?
Intrapedicular widening
464
What is the treatment if asymptomatic?
Observation
465
How can sacral agenesis be differentiated from myelomeningocele?
Protective sensation present, but motor function still absent
466
What is the classic physical exam finding?
Dimpling of buttocks
467
What is the characteristic gait pattern of these patients?
Trendelenburg
468
What are the two treatment options?
Amputation Spinal-pelvic fusion
469
What are the two diagnostic criteria?
1. >45 degrees thoracic kyphosis; 2. >5 degrees anterior wedging of three sequential vertebrae
470
Scheuermann's may be associated with what three spinal conditions?
1. Spondylolysis; 2. Scoliosis; 3. Schmorl's nodes
471
Which gender is most commonly affected?
Male
472
What are the two indications for bracing?
1. Kyphosis <75 degrees; 2. Skeletally immature patient
473
What are the three criteria for surgical intervention?
1. Skeletally mature patient; 2. Kyphosis >75 degrees; 3. Does not correct to <55 degrees (relatively inflexible curve)
474
What is the surgical procedure of choice?
Posterior spinal fusion with or without anterior release and fusion
475
What levels should be included in the fusion? What are the proximal and distal extents?
1. T2 proximally; 2. One level beyond lordosis distally
476
What are the two common complications of operative treatment?
1. SMA syndrome; 2. Junctional kyphosis
