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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6009_Библиотеки_им_академика_М_И_Перельмана.pdf
Spondylolisthesis
KEY FACTS
TERMINOLOGY
• Anterolisthesis: Anterior displacement of vertebral body
relative to one below
• Retrolisthesis: Posterior displacement of vertebral body
relative to one below
IMAGING
Disorders of Alignment
• Lateral flexion and extension to evaluate for instability
○ Napoleon's hat sign on AP plain film
○ Instability uncommon in degenerative listhesis
– 90% of normal volunteers show 1- to 3-mm
translation on flexion-extension radiographs
• Spondylolysis may be difficult to identify on MR
○ T1-weighted sagittal images critical
○ CT for definitive diagnosis of subtle fracture
PATHOLOGY
• Degenerative (DS)
(Left) Anteroposterior
radiograph shows the
Napoleon's hat sign. The hat is
inverted with the crown ſt
representing the anterior
cortex of the vertebral body
and the brim being the
transverse processes. (Right)
Sagittal T1WI MR shows
postoperative
spondylolisthesis following
lumbar laminectomy st. There
is advanced degenerative
changes of the L4-L5
intervertebral disc space with
anterior subluxation of L4 on
L5. Note the acute superior
endplate compression fracture
of L1 ſt.
○ Degenerative retrolisthesis associated with disc
degeneration
○ Sagittal oriented facets more likely to have DS
• Spondylolysis (isthmic)
○ Bilateral in 80%
• Postsurgical: Loss of posterior element stability
• Dysplastic: Small L5 body leading to pars lysis
• Trauma: Severe to produce vertebral body displacement
• Pathologic: Underlying tumor with instability
CLINICAL ISSUES
• 9.2% overall complication rate for treatment of
spondylolisthesis
○ Complications related to higher grade spondylolisthesis,
DS > isthmic, older age (> 65)
• DS + stenosis treated surgically show greater improvement
in pain and function over 4 years compared to nonsurgical
treatment
150
(Left) Sagittal T2WI MR shows
grade I spondylolisthesis of L4
on L5 ſt with intervertebral
disc degeneration and
associated fatty endplate
change. There is also
degeneration of the
interspinous ligament .
(Right) Sagittal T2WI MR
shows a grade I
spondylolisthesis of L4 on L5
with resultant severe
foraminal stenosis ſt.
Instability
KEY FACTS
Disorders of Alignment
TERMINOLOGY
• Loss of spine motion segment stiffness, when applied force
produces greater displacement than normal, with
pain/deformity
IMAGING
• Deformity, which increases with motion and time
• Various parameters used for degenerative instability by
plain films
○ Dynamic slip > 3 mm in flexion/extension
○ Static slip of ≥ 4.5 mm
○ Angulation > 10-15° suggests need for surgical
intervention
• Flexion/extension plain films best for definition of motion
TOP DIFFERENTIAL DIAGNOSES
• Pseudoarthrosis
• Infection
○ Endplate destruction, disc T2 hyperintensity
• Tumor
○ Enhancing soft tissue mass
• Postoperative
○ Following multilevel laminectomy or facetectomy
PATHOLOGY
• Degenerative instabilities
○ Axial rotational
○ Translational; plain films show spondylolisthesis, traction
spurs, vacuum phenomenon
○ Retrolisthesis; plain films show increased retrolisthesis
with extension
○ Degenerative scoliosis
○ Post laminectomy; resection of 50% of bilateral facets
alters segmental stiffness
○ Post fusion; altered biomechanics
(Left) Lateral radiograph
shows a fracture through the
base of the odontoid ſt,
which shows satisfactory
alignment in the neutral
position. (Right) Lateral
radiograph shows a fracture
through the base of the
odontoid, which displaces
posteriorly with slight
extension ſt. This patient
underwent occiput to C3
fusion.
(Left) Sagittal STIR MR shows
extensive prevertebral edema
in this patient with a type II
odontoid fracture. There is
cord edema and focal cord
hemorrhage seen as slight
hypointensity st. (Right) CT
study 3 months after trauma
shows new instability and
subluxation of C4 on C5 ſt
with a kyphotic deformity and
widening of the posterior
elements . The initial study
showed normal alignment.
151
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SECTION 5
Trauma
Vertebral Column, Discs
Fracture Classication 154
Atlantooccipital Dislocation
Ligamentous Injury
Occipital Condyle Fracture
Jeerson C1 Fracture
Atlantoaxial Rotatory Fixation 166
Odontoid C2 Fracture
Burst C2 Fracture
Hangman’s C2 Fracture
Apophyseal Ring Fracture
Cervical Hyperexion Injury 173
Cervical Hyperextension Injury
Cervical Burst Fracture
Traumatic Disc Herniation
Thoracic and Lumbar Burst Fracture
Fracture Dislocation 178
Chance Fracture
Anterior Compression Fracture
Sacral Insuciency Fracture
160
162
163
164
168
170
171
172
174
175
176
177
179
180
181
Cord, Dura, and Vessels
Posttraumatic Syrinx 182
Presyrinx Edema
Spinal Cord Contusion-Hematoma
Idiopathic Spinal Cord Herniation
Traumatic Epidural Hematoma
Traumatic Subdural Hematoma 187
183
184
185
186
Fracture Classification
CraniocervicalJunction
Occipital condyle fractures are classified into 3 types.
Trauma
• Type I = comminuted fractures due to axial loading;
stable if contralateral side is intact
• Type II = occipital condyle fracture with skull base
fractures; most of these are stable
• Type III = avulsion fracture due to tensile force on alar
ligaments; may show occipitocervical instability
Recent data (Maserati 2009) suggests that initial evaluation
should be primarily concerned with identification of
craniocervical malalignment. Fusion or halo used in patients
with initial scans show fracture and malalignment with rigid
cervical collar with delayed imaging follow-up for all others.
Atlantooccipital Disassociation (Dislocation)/C0-C1
Distraction Injury
Complete (disassociation) or partial (subluxation) ligamentous
disruption between occiput and C1, which can occur in 1 of 3
directions: (1) Anterior superior displacement of cranium
relative to spine most common; (2) pure distraction injury with
superior displacement of cranium; or (3) posterior dislocation
of cranium which is least common.
Numerous measurement techniques have been used to
assess craniovertebral junction trauma, many of which were
1st defined in the plain film era. Many of these measurements
have been superseded by the direct soft tissue visualization
afforded by CT and MR. There is reasonable literature support
for use of the following measurements.
Basion-dental interval (BDI) isabnormal if > 10 mm on
sagittal CT.
Summed condylar displacement(sum of the bilateral
distances between midpoint of occipital condyle and C1
condylar fossa) is abnormal if > 4.2 mm.
Single side condylar distance measurement of > 2 mm is also
considered abnormal in adults. The 2-mm upper limit of C0-C1
spacing also applies to children up to 18 years of age.
Other measurements such as the Powers ratio and Lee lines
do not have sufficient sensitivity and specificity to recommend
their use. The Harris "rule of 12" for the BDI and basion-axial
interval are for plain film use only and so are very limited given
the use of CT for acute trauma evaluation.
C1 Fractures
• Anterior arch = vertical or transverse with avulsion from
longus colli
• Anterior arch bilateral fractures with posterior
atlantoaxial dislocation = plow fracture
• Lateral mass = stable if lateral ring intact; rare
• Posterior arch = common
• Jefferson = combined lateral mass displacement relative
to C2 of 6.9 mm indicates disruption of transverse
ligament and potential for instability
Atlantoaxial Instability
• Nonphysiologic motion between C1-C2
• Wide variety of causes
• → transverse ligament rupture (most common)
• → odontoid fracture
• → unstable Jefferson fracture
• → fracture of lateral mass of C1 or C2
• → unilateral alar ligament rupture
• → alar and tectorial membrane rupture
Classification of Atlantoaxial Rotatory Fixation(Fielding
1977)
• Type I = rotation about dens without anterior translation
[no increase in atlantodental interval (ADI)]
• Type II = rotation about 1 lateral mass with anterior
translation of 3-5 mm (ADI) (transverse ligament injury)
• Type III = rotation about lateral mass with anterior
translation > 5 mm (transverse and alar ligament injury)
• Type IV = posterior dislocation of C1 behind dens (rare,
usually fatal)
Odontoid
• Type I = avulsion at tip of odontoid
• Type II = transverse fracture of dens above C2 body
• Type III = fracture involving superior portion of C2 body
C2 Ring Fractures(Effendi 1981)
• Type I = bilateral pars fractures with < 3-mm anterior
subluxation (stable)
• Type II = displacement of pars fracture + anterior
translation of C2 with discoligamentous injury
• Type III = pars fractures with C2-C3 facet dislocations
C2 Body Fractures(Fujimura 1996)
• Type I = extension teardrop fracture of anterior inferior
endplate of C2
• Type II = horizontal shear fracture through body (more
caudal than type III odontoid fracture)
• Type III = C2 body burst fracture
• Type IV = unstable sagittal cleavage fractures
CervicalFracture Classification
Hyperflexion
• Simple compression fracture
• Anterior subluxation = posterior ligament disruption
• Bilateral interfacetal dislocation = unstable
• Flexion teardrop fracture = unstable
• Clay shoveler's fracture: Avulsion of spinous process of
C7-T1
Hyperflexion and Rotation
• Unilateral facet dislocation (locked facet)
• May have associated facet fracture
• Radiograph shows forward displacement of vertebra <
1/2 AP diameter of cervical vertebral body
Hyperextension and Rotation
• Pillar fracture
Vertical Compression
• Jefferson fracture = fractures of both anterior and
posterior rings with 2, 3, or 4 parts with radial
displacement
• Burst fracture = middle column involvement with bony
retropulsion
Hyperextension
• Hyperextension dislocation
• C1 anterior arch avulsion fracture = longus colli insertion
around anterior tubercle of C1
• Extension teardrop fracture of C2
• C1 posterior arch fracture = compressed between
occiput and C2 spinous process
• Lamina fracture = between articular mass and spinous
process
• Hangman's fracture = bilateral pars fractures of C2
• Hyperextension fracture: Dislocation = bilateral facet
fracture ± dislocation
154
Fracture Classification
Lateral Flexion
• Uncinate process fracture
Subaxial Cervical Spine Injury Classification(Vaccaro 2007)
• 3 major components including morphology of spinal
column disruption, integrity of discoligamentous
complex, and neurologic status
• Within each component, subgroups are graded from
least to most severe
Thoracolumbar Fracture Classification
Holdsworth 2 Column Model(1963)
• Superseded by Denis classification
• Anterior column = anterior longitudinal ligament (ALL),
vertebral body, disc, posterior longitudinal ligament
(PLL)
• Posterior column = skeletal and ligamentous structures
posterior to PLL
Denis 3 Column Model(1983)
• Anterior = ALL, anulus, anterior vertebral body
• Middle = posterior wall of vertebral body, anulus, PLL
• Posterior = facets, posterior elements, posterior
ligaments
• 3 column model also relevant to lower cervical injuries
Denis Subclassification of Burst Fracture(1984)
• Denis type A
• Axial load force; anterior and middle columns involved,
unstable
• Upper and lower endplates involved
• Denis types B and C
• Flexion and axial load, anterior and middle columns,
possibly unstable
• B upper endplate involved (most common)
• C lower endplate involved
• Denis type D
• Axial load and rotation, all columns, unstable
• Atlas modification of D injuries (1986)
• D1 burst lateral translation, D2 burst sagittal translation
• Denistype E
• Lateral compression, all columns, possibly unstable
Magerl AO Pathomorphologic System(1994)
• A, B, C types reflecting common injury patterns
• Each type has 3 groups, each with 3 subgroups (3-3-3
scheme)
• Type A vertebral compression fractures due to axial
loading without soft tissue disruption in transverse plane
(66%)
• Type B distraction of anterior and posterior elements
with soft tissue disruption in axial plane (14.5%)
• Type C with axial torque forces giving anterior and
posterior element disruption with rotation (19%)
• Severity progresses through types A to C as well as
within types, groups, and subdivisions
• Stable type A1 most common (wedge fracture)
• A3 corresponds to burst fracture of Denis classification
• Unstable = A3.2, A3.3, B, C types
McCormack "Load-Sharing" Classification(1994)
• Specifically designed to evaluate need for anterior
column reconstruction following pedicle screw
stabilization
• Also useful as more generic guide to magnitude of
comminution and biomechanical instability
• Comminution graded
• → amount of vertebral of body damage
• → fragment of spread at fracture site
• → degree of corrected kyphosis
Thoracolumbar Injury Classification and Severity Score
(TLICS)(Vaccaro 2006)
• 3 components give final numeric score that directs
treatment
• Injury mechanism, integrity of posterior ligamentous
complex, and neurologic status
Unstable Fractures
Cervical
• Atlantoaxial dissociation
• Atlantooccipital dislocation
• Occipital condyle fracture with malalignment
• Jefferson fracture where combined offset of C1 lateral
masses > 7 mm or > 7 mm separation of fracture
fragments
• Hangman II, III
• Odontoid types I, II
• Subaxial anterior subluxation of > 3.5 mm
• Hyperflexion fracture dislocation
• Hyperflexion teardrop
• Hyperextension fracture dislocation
• Burst
Selected References
1. Pizones J et al: Prospective analysis of magnetic resonance imaging accuracy
in diagnosing traumatic injuries of the posterior ligamentous complex of the
thoracolumbar spine. Spine (Phila Pa 1976). 38(9):745-51, 2013
2. Walters BC et al: Guidelines for the management of acute cervical spine and
spinal cord injuries: 2013 update. Neurosurgery. 60 Suppl 1:82-91, 2013
3. Vaccaro AR et al: The subaxial cervical spine injury classification system: a
novel approach to recognize the importance of morphology, neurology, and
integrity of the disco-ligamentous complex. Spine (Phila Pa 1976).
32(21):2365-74, 2007
4. Vaccaro AR et al: Reliability of a novel classification system for
thoracolumbar injuries: the Thoracolumbar Injury Severity Score. Spine (Phila
Pa 1976). 31(11 Suppl):S62-9; discussion S104, 2006
5. Vaccaro AR et al: A new classification of thoracolumbar injuries: the
importance of injury morphology, the integrity of the posterior ligamentous
complex, and neurologic status. Spine (Phila Pa 1976). 30(20):2325-33, 2005
6. Leone A et al: Occipital condylar fractures: a review. Radiology. 216(3):63544, 2000
7. Oner FC et al: MRI findings of thoracolumbar spine fractures: a
categorisation based on MRI examinations of 100 fractures. Skeletal Radiol.
28(8):433-43, 1999
8. Brandser EA et al: Thoracic and lumbar spine trauma. Radiol Clin North Am.
35(3):533-57, 1997
9. Vollmer DG et al: Classification and acute management of thoracolumbar
fractures. Neurosurg Clin N Am. 8(4):499-507, 1997
10. Dickman CA et al: Injuries involving the transverse atlantal ligament:
classification and treatment guidelines based upon experience with 39
injuries. Neurosurgery. 38(1):44-50, 1996
11. Fujimura Y et al: Classification and treatment of axis body fractures. J Orthop
Trauma. 10(8):536-40, 1996
12. Noble ER et al: The forgotten condyle: the appearance, morphology, and
classification of occipital condyle fractures. AJNR Am J Neuroradiol.
17(3):507-13, 1996
13. Benzel EC et al: Fractures of the C-2 vertebral body. J Neurosurg. 81(2):20612, 1994
14. Magerl F et al: A comprehensive classification of thoracic and lumbar injuries.
Eur Spine J. 3(4):184-201, 1994
15. McCormack T et al: The load sharing classification of spine fractures. Spine
(Phila Pa 1976). 19(15):1741-4, 1994
16. Atlas SW et al: The radiographic characterization of burst fractures of the
spine. AJR Am J Roentgenol. 147(3):575-82, 1986
17. Denis F: The three column spine and its significance in the classification of
acute thoracolumbar spinal injuries. Spine (Phila Pa 1976). 8(8):817-31, 1983
Trauma
155
Fracture Classification
Subaxial Cervical Spine Injury Classification
Trauma
Morphology
Discoligamentous Complex
Neuro Status
Surgical vs. nonsurgical is determined by the total score: 1-3 nonoperative treatment, ≥ 5 operative treatment recommended. (Vaccaro 2007.)
Description Points
No abnormality 0
Compression 1
Burst + 1 = 2
Distraction (perched facet, hyperextension) 3
Rotation/translation (facet dislocation, unstable teardrop) 4
Intact 0
Indeterminate (MR signal abnormality only, isolated
interspinous widening)
Disrupted 2
Intact 0
Root injury 1
Complete cord injury 2
Incomplete cord injury (most urgent situation so higher value
than complete injury
Continuous cord compression in setting of neuro deficit
(modifier)
1
3
+ 1
Thoracolumbar Injury Severity Score
Description Qualifier Points
Injury Mechanism
Compression
Simple 1
Lateral angulation >15° 1
Burst 1
Transitional/rotational 3
Distraction 4
Posterior Ligamentous Complex
Intact 0
Suspected/indeterminate for disruption 2
Injured 3
Neuro Status
Nerve root involvement 2
Cord, conus involvement (incomplete) 3
Cauda equina involvement 3
Cord, conus involvement (complete) 2
The score is a total of 3 components. A score ≤ 3 suggests nonoperative treatment, while a score of 4 is indeterminate. A score ≥ 5 suggests operative
treatment. For injury mechanism, the worst level is used, and the injury is additive. An example is distraction injury with burst without angulation is 1
(simple compression) + 1 (burst) + 4 (distraction) = 6 points. (Vaccaro 2006.)
156
Fracture Classification
Trauma
(Left) Sagittal graphic shows a
normal basion-dental interval
(BDI) (red line) and basionposterior axial line interval
(BAI) (yellow line). BAI is the
distance from the basion to
posterior axial line (black line).
BDI is abnormal if > 10 mm on
sagittal CT. BAI is abnormal if
> 12 mm on plain films. (Right)
Sagittal NECT of a trauma
patient with atlantooccipital
dislocation shows abnormal
distance between basion &
dens (yellow) & abnormal
separation of basion from
posterior axial line (orange).
Posterior axial reference line is
white.
(Left) Parasagittal NECT in a
patient with atlantooccipital
dislocation shows widening of
both C0-C1 and C1-C2
articulations ſt. Summed
condylar displacement (sum of
the bilateral distances
between midpoint of occipital
condyle and C1 condylar fossa)
is abnormal if > 4.2 mm.
(Right) Sagittal STIR MR shows
abnormally widened and
hyperintense C0-C1 and C1-C2
articulations st. This patient
underwent occiput to C3
posterior fusion for
atlantooccipital and
atlantoaxial dislocation.
(Left) Axial NECT shows
multiple fracture sites
involving the C1 ring ſt
without canal compromise.
(Right) Axial NECT shows
fractures involving both
anterior and posterior rings of
C1 ſt and an additional
avulsion fracture off of the
mesial C1 ring at the level of
attachment of transverse
ligament .
157
Trauma
(Left) Coronal graphic of the
C2 vertebra shows the
schematic for the location of
types I, II, and III odontoid
fractures. (Right) Coronal
NECT shows an oblique type III
fracture extending across the
base of odontoid and the
upper body of C2 ſt with
fragmentation of the left
lateral mass of C2.
(Left) Sagittal NECT shows a
C2 pars fracture without
significant offset, angulation,
or distraction. (Right) Axial
bone CT shows a typical case
of traumatic C2 pars fractures
in a classic hangman
configuration. This patient
demonstrates the mildest
class of injury (type I) using the
Levine and Edwards
modification of the Effendi
classification system and
would be considered a stable
fracture.
Fracture Classification
158
(Left) Sagittal graphic shows
an unstable cervical
hyperflexion injury involving
anterior ſt and posterior
longitudinal ligaments , a
disc, and interspinous
ligaments with epidural
hemorrhage and cord
compression. (Right) Lateral
radiograph shows C4-C5
flexion facet dislocation with
bilateral "jumped" facets.
There is disruption of all 3
columns by this injury.
Fracture Classification
Trauma
(Left) Sagittal NECT of
transverse extension fracture
in a patient with ankylosing
spondylitis (AS) shows a
horizontal fracture line
extending through the C5
body into the base of the
spinous process with posterior
displacement of the superior
aspect of the fracture,
indicating hyperextension
mechanism. Note typical
anterior ossification of AS.
(Right) Sagittal NECT shows
complete dislocation of the
upper cervical spine at the C5C6 level. There is over 100%
listhesis of the C5 body
relative to C6.
(Left) Lateral radiograph
shows a hyperflexion injury
with bilateral locked facets, a
widened disc space, anterior
subluxation of C6 on C7 of
50%, and a widened spinous
process distance. (Right) Axial
bone CT shows unilateral left
facet dislocation ſt. There is
reversed relationship of the
facets with the inferior
articular facet of C6 lying
anterior to the superior
articular facet of C7 (back-toback apposition).
(Left) Sagittal graphic of the
thoracolumbar junction shows
compression (wedge) fractures
involving primarily the
anterior column with normal
middle and posterior columns.
(Right) Sagittal graphic shows
a Chance (seat belt) fracture
of the thoracolumbar junction
extending in the horizontal
plane through the body and
posterior elements (3-column
involvement).
159