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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6009_Библиотеки_им_академика_М_И_Перельмана.pdf
Scoliosis and Devices Instrumentation
KEY FACTS
TERMINOLOGY
• Spinal fusion surgery recommended when curve
magnitude > 40-45° for adolescent idiopathic scoliosis
• Adult scoliosis presents with lumbar back ± leg pain, L3-L4
rotatory subluxation, L4-L5 tilt, and L5-S1 disc degeneration
on radiographs
IMAGING
• Radiographs
Devices and Instrumentation
○ Main thoracic, thoracolumbar, and lumbar curves should
be assessed for structural characteristics
○ 36" standing anteroposterior & lateral radiographs &
supine side-bending radiographs
○ In adult scoliosis, assess for degenerated changes and
rotatory ± lateral listhesis
• CT
○ Assess integrity of hardware
○ Look for osseous bridging at levels of interbody fusion
and lucency along screw tracks
(Left) Anteroposterior
radiograph shows sigmoid
scoliosis of the thoracic and
lumbar spines st. Fusion is
extended to L5 if there is fixed
tilt or subluxation at L4-L5, or
to the sacrum if L5-S1 central
or foraminal decompression is
needed. (Right)
Anteroposterior radiograph
depicts posterior fusion from
the thoracolumbar junction st
to the sacrum . Extension of
the fusion to the sacrum
increases the incidence of
pseudarthrosis and
reoperation.
• MR
○ Preoperative planning to evaluate for central &/or
foraminal stenosis and disc degeneration
CLINICAL ISSUES
• Adult bones tend to be weaker or osteoporotic, making
instrumentation and fusion more difficult
• Degenerative disc changes, spinal stenosis, and facet
arthropathy can be exacerbated and in turn exacerbate
scoliosis, leading to more rigid spines
• Goals: Prevent progression, restore acceptability of clinical
deformity, reduce curvature, prevent neurologic deficit
○ Resolve pain ± make it more controllable with
medications
○ Fuse spine in as normal anatomical position as possible
80
(Left) AP and lateral
radiographs show fusion from
the thoracic spine st to the L5
level ſt. Fusion is not
terminated next to a severely
degenerated segment.
Proximal extension of the
fusion should not stop distal to
a proximal thoracic curve.
Cross-links improve
torsional stiffness. (Right)
Lateral radiograph shows
posterior fusion st and L3
pedicle subtraction osteotomy
ſt to restore lumbar lordosis.
Lumbar scoliosis results in loss
of lumbar lordosis with
positive sagittal balance.
Scoliosis and Devices Instrumentation
TERMINOLOGY
Abbreviations
• Scoliosis instrumentation (SI)
Synonyms
• Scoliosis surgery, long spinal fusion surgery (> 4 vertebral
segments)
Definitions
• Spinal fusion surgery recommended when curve
magnitude > 40-45° for adolescent idiopathic scoliosis (AIS)
• Adult scoliosis patient presents with lumbar back ± leg pain,
L3-L4 rotatory subluxation, L4-L5 tilt, and L5-S1 disc
degeneration on radiographs
○ Goals: Prevent progression, restore acceptability of
clinical deformity, reduce curvature, correct positive
sagittal malalignment, prevent neurologic deficit and
pain reduction
IMAGING
Radiographic Findings
• Main thoracic, thoracolumbar, and lumbar curves should be
assessed for structural characteristics
○ 36" standing AP & lateral radiographs and supine side-
bending radiographs
○ ± 36" supine lateral or hyperextension lateral radiograph
over bolster
– Supine evaluation is helpful to determine curve
flexibility
is defined by Cobb angle 25° on side-bending
radiographs
○ Overall flexibility is important to note → indicates
expected curve correction
○ Coronal & sagittal balance, including center sacral vertical
line and C7 plumbline
○ Shoulder height, apical vertebral translation of thoracic
and lumbar curves, and relative curve magnitudes
○ In adult scoliosis, assess for degenerated changes and
rotatory &/or lateral listhesis
CT Findings
• Look for osseous bridging at levels of interbody fusion and
lucency along screw tracks
• Assess integrity of instrumentation
• May be helpful in delineating congenital osseous
abnormalities (such as hemivertebrae or fused vertebrae)
• 3D reformations may be helpful for preoperative planning
and postoperative evaluation
MR Findings
• Preoperative planning to evaluate for central &/or
foraminal stenosis and disc degeneration
DIFFERENTIAL DIAGNOSIS
Plates and Screws
• Instrumentation in fusion surgery used to stabilize bony
elements
Devices and Instrumentation
Flat Back Syndrome
• Loss of lumbar lordosis after lumbar or scoliosis distraction
instrumentation, vertebral fracture, ankylosing spondylitis,
degenerative disease
CLINICAL ISSUES
Natural History & Prognosis
• Complications
○ Surgical: Severe blood loss, UTI, pancreatitis, obstructive
bowel dysfunction due to bowel immobilization,
neurological damage
– Retroperitoneal approach: Abdominal visceral, great
vessel, and superior hypogastric nerve plexus injury
– Transthoracic approach: Injury to great vessels,
pulmonary complications, chylothorax, and post-
thoracotomy pain syndrome
○ Migration of graft, implant breakage
○ Penetration of implants into canal or dorsally into
cutaneous tissues
○ Compression of nerve roots by implant components
• Pseudoarthrosis
○ Can occur years after surgery
○ Most likely to occur at thoracolumbar junction
○ Reported in 15-27% of cases
• Irreversible loss of normal active range of movement of
spinal column, including nonfused segments
• Strain on unfused skeletal framework
○ Postsurgical degenerative changes within 2 years
○ Higher degree of correction results in higher rate of
degenerative osteoarthritis
• Curvature progression: Crank shaft phenomenon described
in children: Spinal growth causes rotation around fusion
• Pain at iliac graft site, rib resection site
• Infections reported in 5-10% of patients at 11-45 months
after surgery
• Venous thromboembolism (pulmonary embolism and deep
vein thrombosis)
Treatment
• Goal of surgery in adult scoliosis
○ Resolve pain ± make it more controllable with
medications
○ Fuse spine in as normal anatomical position as possible
○ Biggest operative decision is to determine proximal and
distal extent of instrumentation and fusion
– Operative levels include fusion of Cobb angle, typically
L3 or L4, and extending to L5 when there is lateral or
rotatory listhesis present
– Restoration of sagittal balance reported to be primary
parameter associated with outcome
• SI recommended when magnitude of curvature exceeds
40-45° in AIS
○ Approaches: Posterior instrumentation & fusion alone,
anterior instrumentation & fusion alone, & anterior
release (to restore spinal flexibility) combined with
posterior fusion, posterior only
○ Fusion often extended to sacrum if
– L5-S1 spondylolisthesis, or prior laminectomy
– L5-S1 stenosis
– Severe L5-S1 disc degeneration
81
Pumps and Catheters
KEY FACTS
TERMINOLOGY
• Intrathecal baclofen (ITB)
• Intraspinal drug delivery (IDD)
• Malfunction or malposition of pump or catheter delivery
system
PATHOLOGY
• ITB used for treatment of spasticity
○ Typically used in children with severe quadriplegic
Devices and Instrumentation
pattern cerebral palsy
• IDD system therapy widely utilized in patients with
intractable, nonmalignant, and malignant pain
○ Epidural analgesia trial may be conducted to document
efficacy prior to implantation of permanent intrathecal
drug delivery pump
CLINICAL ISSUES
• ITB rate of complications varies widely, range: 8-30%
(Left) This is a syringopleural
shunt failure due to formation
of a pseudocyst at the
catheter site in the chest.
Initial T2W MR study after
placement of the shunt shows
postoperative change ſt with
a small epidural fluid
collection in the midthoracic
spine and syrinx in the upper
thoracic cord . (Right)
Sagittal T1WI MR in the same
patient 1 year later now
shows marked expansion of
the syrinx throughout the
thoracic cord ſt.
○ Baclofen complications relate to withdrawal and
overdose
○ Infection rates: 8-10%
○ Hardware-related complications from 5-20%
○ Majority of complications requiring reoperation involve
the catheter
• IDD systems
○ Granuloma formation at catheter tip relatively common
○ Effects include loss of analgesia or new/progressive
neurologic symptoms
DIAGNOSTIC CHECKLIST
• Malfunction must be evaluated from pump level to distal
aspect of catheter
○ CT abdomen following baclofen side port contrast
injection extending cephalad beyond intradural catheter
tip
82
(Left) AP chest film in the
same patient shows a
loculated pleural collection at
the site of the coiled shunt
catheter . (Right) This is a
syringopleural shunt failure
with expansion of the
extensive cord syrinx due to
formation of a pseudocyst at
the catheter site in the chest.
Axial T1 MR in the same
patient shows the large
thoracic cord syrinx ſt and a
large fluid collection in the left
chest at the site of catheter
placement .
Pumps and Catheters
TERMINOLOGY
Abbreviations
• Intrathecal baclofen (ITB)
• Intraspinal drug delivery (IDD)
Definitions
• Malfunction or malposition of pump or catheter delivery
system
Devices and Instrumentation
– Multiple agents, including morphine, may cause
formation
□ Dose escalation and increased dosage increase risk
of formation
– Effects include loss of analgesia or new/progressive
neurologic symptoms
• Other signs/symptoms
○ Pump malfunction may present with spinal/abdominal
fluid collection/effusion
IMAGING
General Features
• Best diagnostic clue
○ Abnormal contrast accumulation after pump side port
injection
• Location
○ Anywhere along course of pump and catheter
DIFFERENTIAL DIAGNOSIS
Intrathecal or Epidural Catheter Granuloma
• May mimic epidural neoplasm or abscess
PATHOLOGY
General Features
• Etiology
○ ITB used for treatment of spasticity
– Decrease level of spasticity to improve range of
motion, facilitate movement, reduce contractures,
and improve quality of life
– Typically used in children with severe quadriplegic
pattern cerebral palsy
○ IDD system therapy widely utilized in patients with
intractable, nonmalignant, and malignant pain
– Epidural or intrathecal
– Epidural analgesia trial may be conducted to
document efficacy prior to implantation of permanent
intrathecal drug delivery pump
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ ITB rate of complications varies widely, range: 8-30%
○ Related to (a) baclofen, (b) infection, (c) hardware
○ Baclofen complications relate to withdrawal and
overdose
○ Infection rates: 8-10%
– Common reason for infection is skin breakdown or
dehiscence over pump
– Subfascial implantation provides greater soft tissue
coverage over pump
○ Hardware-related complications from 5-20%
– Majority of complications requiring reoperation
involve catheter
– CSF leak from site of catheter penetration of dura
– Catheter fracture or disconnection
– Low rate of pump failure
○ IDD systems
– Granuloma formation at catheter tip relatively
common
DIAGNOSTIC CHECKLIST
Consider
• Malfunction must be evaluated from pump level to distal
aspect of catheter
○ CT abdomen following baclofen side port contrast
injection extending cephalad beyond intradural catheter
tip
SELECTED REFERENCES
1. Haranhalli N et al: Intrathecal baclofen therapy: complication avoidance and
management. Childs Nerv Syst. 27(3):421-7, 2011
2. Lawson EF et al: Current developments in intraspinal agents for cancer and
noncancer pain. Curr Pain Headache Rep. 14(1):8-16, 2010
3. Maugans TA: Intracranial migration of a fractured intrathecal catheter from a
baclofen pump system: case report and analysis of possible causes.
Neurosurgery. 66(2):319-22, 2010
4. Myers J et al: Intraspinal techniques for pain management in cancer patients:
a systematic review. Support Care Cancer. 18(2):137-49, 2010
5. Stetkarova I et al: Procedure- and device-related complications of intrathecal
baclofen administration for management of adult muscle hypertonia: a
review. Neurorehabil Neural Repair. 24(7):609-19, 2010
6. Fukuhara T et al: Tangled catheter as a rare cause of baclofen pump
malfunction. Surg Neurol. 72(1):80-2; discussion 82, 2009
7. van Rijn MA et al: Intrathecal baclofen for dystonia of complex regional pain
syndrome. Pain. 143(1-2):41-7, 2009
8. Borowski A et al: Baclofen pump implantation and spinal fusion in children:
techniques and complications. Spine (Phila Pa 1976). 33(18):1995-2000,
2008
9. Caird MS et al: Outcomes of posterior spinal fusion and instrumentation in
patients with continuous intrathecal baclofen infusion pumps. Spine (Phila
Pa 1976). 33(4):E94-9, 2008
10. Ruan X et al: Edema caused by continuous epidural hydromorphone
infusion: a case report and review of the literature. J Opioid Manag. 4(4):2559, 2008
11. Kallweit U et al: Successful treatment of methicillin-resistant Staphylococcus
aureus meningitis using linezolid without removal of intrathecal infusion
pump. Case report. J Neurosurg. 107(3):651-3, 2007
12. Markman JD et al: Interventional approaches to pain management. Med Clin
North Am. 91(2):271-86, 2007
13. Motta F et al: The use of intrathecal baclofen pump implants in children and
adolescents: safety and complications in 200 consecutive cases. J Neurosurg.
107(1 Suppl):32-5, 2007
14. Narouze SN et al: Erosion of the inferior epigastric artery: a rare complication
of intrathecal drug delivery systems. Pain Med. 8(5):468-70, 2007
15. Vender JR et al: Identification and management of intrathecal baclofen
pump complications: a comparison of pediatric and adult patients. J
Neurosurg. 104(1 Suppl):9-15, 2006
16. Amar AP et al: Percutaneous spinal interventions. Neurosurg Clin N Am.
16(3):561-8, vii, 2005
17. Hassenbusch SJ et al: Polyanalgesic Consensus Conference 2003: an update
on the management of pain by intraspinal drug delivery-- report of an expert
panel. J Pain Symptom Manage. 27(6):540-63, 2004
18. Gooch JL et al: Complications of intrathecal baclofen pumps in children.
Pediatr Neurosurg. 39(1):1-6, 2003
19. McMillan MR et al: Catheter-associated masses in patients receiving
intrathecal analgesic therapy. Anesth Analg. 96(1):186-90, table of contents,
2003
83
SECTION 3
Congenital and Genetic Disorders
Bony Variations
C2-C3 Fusion 86
C1 Assimilation
Ponticulus Posticus
Ossiculum Terminale
Paracondylar Process
Condylus Tertius 91
Posterior Arch Rachischisis
Split Atlas
87
88
89
90
92
93
Diagnoses
Odontoid Hypoplasia/Aplasia 94
C1 Dysmorphism/Hypoplastic Arch
Chiari 1
Complex Chiari
Chiari 2
Chiari 3 99
Myelomeningocele
Lipomyelomeningocele
Lipoma
Dorsal Dermal Sinus
Simple Coccygeal Dimple 104
Dermoid Cysts
Epidermoid Cysts
Tethered Spinal Cord
Segmental Spinal Dysgenesis
Caudal Regression Syndrome 109
Terminal Myelocystocele
Anterior Sacral Meningocele
Occult Intrasacral Meningocele
Sacrococcygeal Teratoma
Klippel-Feil Spectrum 114
Failure of Vertebral Formation
95
96
97
98
100
101
102
103
105
106
107
108
110
111
112
113
115
Vertebral Segmentation Failure 116
Diastematomyelia
Neurenteric Cyst
Os Odontoideum
Lateral Meningocele
117
118
119
120
Genetic
Neurobromatosis Type 1 122
Neurobromatosis Type 2
Down Syndrome
Mucopolysaccharidoses
Achondroplasia
Osteogenesis Imperfecta 133
Spondyloepiphyseal Dysplasia
126
130
131
132
134
C2-C3 Fusion
KEY FACTS
TERMINOLOGY
• Congenital C2-C3 vertebral segmentation failure
IMAGING
• Rudimentary C2-C3 intervertebral disc space with narrow
"waist"
○ C2-C3 disc space smaller than normal disc spaces in
remainder of cervical spine
○ ± facet fusion
• Chiari 1 malformation may be present
• Spinal cord compression, syringomyelia unusual
Congenital and Genetic Disorders
TOP DIFFERENTIAL DIAGNOSES
• Juvenile inflammatory arthritis
• Surgical fusion
• Chronic sequelae of discitis
PATHOLOGY
• Congenital cervical fusion
(Left) Sagittal T1WI MR of the
craniovertebral junction
demonstrates the
characteristic rudimentary C2C3 disc space ſt with normal
vertebral body marrow and
intervertebral disc signal. The
fused C2 and C3 spinous
processes are relatively
inapparent on MR. (Right)
Sagittal bone CT of the
craniovertebral junction
depicts incomplete vertebral
segmentation at C2-C3 ſt,
with characteristic
rudimentary intervertebral
disc space (narrow "waist")
and fusion of the spinous
processes .
○ Secondary to failure of normal cervical somite
segmentation (3rd → 8th weeks)
• C2-C3 fusion (type II Klippel-Feil spectrum) → autosomal
dominant with variable penetrance
CLINICAL ISSUES
• Usually asymptomatic
○ Identified incidentally during spinal imaging for other
reasons
• Predisposition for accelerated degenerative changes below
fused level
DIAGNOSTIC CHECKLIST
• C2-C3 segmentation failure is usually incidental finding
discovered while imaging for other reasons
• Less often it is associated with multiple vertebral
segmentation anomalies (Klippel-Feil spectrum)
86
(Left) Coronal bone CT shows
congenital fusion of C2-C3
with a small and rudimentary
disc margin ſt. Note the
normal-sized discs at the lower
levels. There is also
assimilation of C1 into the
occiput . (Right) Coronal
bone CT of the craniovertebral
junction in a child shows
asymmetric, incomplete C2-C3
segmentation ſt that results
in mild upper cervical
curvature convex to the right.
The atlantooccipital and
atlantoaxial articulations are
normal.
C1 Assimilation
KEY FACTS
Congenital and Genetic Disorders
TERMINOLOGY
• Synonyms: Atlantooccipital assimilation, atlantal
assimilation, "occipitalization"
• Nonresegmentation of proatlas sclerotome → failure of C1
to correctly segment from occipital bone
IMAGING
• Partial or complete atlas assimilation into occipital bone
○ ± C1 ring hypoplasia → canal stenosis
○ ± posterior C2 arch hypertrophy → canal stenosis
• ± posterior fossa, spinal cord anomalies
TOP DIFFERENTIAL DIAGNOSES
• Juvenile idiopathic arthritis
• Craniovertebral junction surgical fusion
PATHOLOGY
• Inappropriate PAX1 repression (humans) probably
contributory, not sole mechanism
• Associated anomalies include
○ Atlantoaxial instability (up to 60%)
○ C2/3 segmentation failure
○ Klippel-Feil syndrome
○ Basilar invagination
○ Chiari 1 malformation
CLINICAL ISSUES
• May remain asymptomatic throughout life
• Symptomatic patients report neck pain, stiffness,
myelopathy
○ Neurological deficits usually begin in 3rd-4th decade,
worsen with age
DIAGNOSTIC CHECKLIST
• Clinical symptoms related to presence of atlantoaxial
instability, cervical stenosis, and severity of associated
anomalies
(Left) Coronal bone CT
confirms segmentation failure
of the occipital condyles ſt
and C1 lateral masses
(zone 2 assimilation).
Formation of the proatlas is
asymmetric, producing a mild
head tilt to the right. (Right)
Sagittal bone CT obtained in
the midline shows normal
alignment of clivus and
odontoid tip. The anterior C1
ring is in normal position,
but the posterior C1 ring st is
fused to the foramen magnum
opisthion (zone 3
assimilation).
(Left) Sagittal midline bone CT
shows no posterior C1 arch
due to C1 assimilation to
occiput. The odontoid is
upwardly placed (basilar
invagination) ſt, and the
atlantodental interval is
widened . There is a
rudimentary disc at C2-C3 st.
(Right) Sagittal T1WI MR
shows basilar invagination
with mass effect on the
cervicomedullary junction ſt.
There is a Chiari 1
malformation and cervical
cord syrinx st as well as
widening of the atlantodental
interval .
87
Ponticulus Posticus
KEY FACTS
TERMINOLOGY
• Latin: "Little posterior bridge"
• Synonyms: Arcuate foramen, sagittale foramen, canalis
vertebralis, retroarticular canal, retroarticular/retrocondylar
vertebral artery ring, upper retroarticular foramen, and
atlantal posterior foramen
IMAGING
• Osseous roof along superior C1 arch covers C1 vertebral
artery foramen
○ Vertebral artery passes through osseous tunnel
• May be partial or complete
Congenital and Genetic Disorders
• Unilateral or bilateral
TOP DIFFERENTIAL DIAGNOSES
• Broad C1 posterior arch
○ Mistaking ponticulus posticus for broad posterior C1 arch
→ vertebral artery injury during C1 lateral mass screw
placement
(Left) Lateral radiograph of
the upper cervical spine
demonstrates a partial
osseous roof ſt over the C1
vertebral artery foramen,
characteristic of ponticulus
posticus (incomplete variant).
(Right) Lateral radiograph of
the upper cervical spine
reveals a complete osseous
roof over the C1 vertebral
artery foramen, typical of
classic ponticulus posticus
(complete variant).
PATHOLOGY
• Postulated to arise from ossification of lateral segment of
posterior atlantooccipital ligament or joint capsule
• Morphologically normal bone
CLINICAL ISSUES
• Most common: Asymptomatic
• Other symptoms
○ Vertebrobasilar ischemia or infarction
○ Vertigo
○ Headache
○ Neck pain
DIAGNOSTIC CHECKLIST
• Vertebral arteries predisposed to surgical injury during
lateral mass screw placement
• Multiplanar bone CT with 3D reformats best demonstrate
ponticulus posticus
88
(Left) Sagittal CTA depicts a
complete C1 arch with a
robust osseous covering
(complete ponticulus posticus)
over the vertebral artery
along the superior aspect
of the C1 arch. (Right)
Anteroposterior view of a CTA
3D reformat shows a
dominant left vertebral artery
and smaller (nondominant)
right vertebral artery . Both
are covered by a complete
osseous bridge along the
superior aspect of the C1 arch.
Ossiculum Terminale
KEY FACTS
Congenital and Genetic Disorders
TERMINOLOGY
• Synonym: Ossiculum terminale persistens
• Persistence of unfused odontoid tip ossification center into
adulthood
IMAGING
• Separate ossicle with intact cortical margin positioned
above normal-sized odontoid process in adolescent or adult
○ May be dystopic or orthotopic
• Soft tissue pannus suggests atlantoaxial instability
• Myelomalacia, brainstem compression in rare cases
TOP DIFFERENTIAL DIAGNOSES
• Os odontoideum
• Type I or II odontoid fracture
• Normal unfused odontoid tip synchondrosis
• Degenerative remodeling of odontoid process
PATHOLOGY
• Terminal ossicle normally appears by age 3, fuses with
odontoid body by age 12
• Terminal ossicle located above transverse ligament
○ Atlantoaxial instability less common than with os
odontoideum
○ Unstable ossiculum terminale usually dystopic
CLINICAL ISSUES
• Usually asymptomatic
• Uncommonly, neck pain or myelopathy related to CVJ
instability
DIAGNOSTIC CHECKLIST
• Consider ossiculum terminale in patients > 12 years with
persistent terminal ossicle at odontoid tip
• Evaluate for atlantoaxial instability if dystopic ossicle,
excessive soft tissue pannus, or trisomy 21 patient
(Left) Sagittal bone CT
demonstrates a small
ossiculum terminale ſt
located adjacent to the
odontoid tip. The ossicle is in
orthotopic position, and CVJ
alignment is normal. (Right)
Coronal bone CT confirms
orthotopic placement of a
small orthotopic ossiculum
terminale ſt. Note that there
is minimal flattening of the
odontoid tip adjacent to the
ossicle, supporting
classification as a persistent
terminal odontoid ossicle.
(Left) Sagittal bone CT reveals
a small dystopic ossiculum
terminale ſt positioned
between the odontoid tip and
clivus. The odontoid tip has
remodeled. (Right) Sagittal
bone CT shows subluxation of
the anterior C1 ring
relative to the nearly normalsized odontoid process st.
There is a large dystopic
ossiculum terminale ſt.
Although debatable, the
nearly normal size of the
odontoid process favors
classification as an ossiculum
terminale rather than os
odontoideum.
89