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144 Spine Core Knowledge in Orthopaedics
Figure 11–5: Radiographs of a 12-year-old female who had a 53 degree thoracic curve.
She underwent a thoracoscopic anterior spinal fusion and instrumentation from
T5 to T12 with excellent correction of the coronal curve and restoration of
coronal and sagittal balance.
●
Proximal end vertebra
●
Distal fixation most common to the lumbar distal end
vertebra
●
Distal fixation is best performed with pedicle screws
for improved correction and maintenance of curve
correction
Anterior Release or Fusion and
Posterior Instrumentation or Fusion
●
Anterior release required
●
Stiff curves—More than 75 degrees that fail to bend to
less than 50 degrees
●
Skeletally immature
●
Open triradiate cartilage or Risser 0-1
●
Prevent crankshaft
●
Performed open or thoracoscopically in the thoracic spine
●
Advantages of thoracoscopy include smaller incisions,
less postoperative pain, less postoperative pulmonary
problems, and improved cosmesis
●
Disadvantages of thoracoscopy are that it is technically
demanding and more costly because of the use of
disposable items
Aftercare and Follow-up
●
Postoperative antibiotics, diet advancement, and walking
while in the hospital
●
Postoperative bracing is not required when using modern
segmental instrumentation
●
Activities are slowly advanced until patients are
performing full activities between 6 and 12 months
CHAPTER 11
Spinal Scoliotic Deformities 145
Figure 11–5: Cont’d
Outcome of Surgical Treatment
●
Long-term follow-up only available for Harrington
instrumentation
●
Average correction is approximately 50%
●
Distal fusion below L3 results in greater incidence of
low back pain
●
Midterm follow-up of segmental spinal instrumentation
●
Average coronal curve correction is approximately
60% with hook fixation
●
Improved maintenance and correction of sagittal plane
●
Short-term follow-up using segmental pedicle screw
fixation (Suk et al. 2000)
●
Average coronal curve correction is approximately 75%
●
Rare neurologic injury
Complications
●
The reoperation rate for posterior spinal instrumentation
is 5%-19% for all causes (Boxes 11–1 through 11–3)
(Cook et al. 2000).
Adult Scoliosis and Deformity
Introduction
●
Defined as a coronal plane Cobb angle greater than 10
degrees in a patient older than 20 years.
●
The natural history of the curve in the mature patient is
variable.
●
De novo curves of the lumbar spine may progress
rapidly.
●
The rate of curve progression is not constant.
●
Lumbar curves progress more rapidly than thoracic curves.
●
Adult scoliosis more often presents symptoms of
associated back pain, leg pain, or both.
●
Treatment of adult deformity can be more challenging
than that of adolescent deformity because of the following:
●
Greater curve stiffness
●
Presence of degenerative changes
●
Associated medical comorbidities
●
Need for neural element decompression, thus extending
surgical time and removing areas for bony fusion
146 Spine Core Knowledge in Orthopaedics
Figure 11–6: Radiographs of a 13-year-old female with a triple major curve (Lenke 4). She underwent a posterior spinal fusion
and instrumentation from T2 to L3. Proximal hook fixation, apical sublaminar wire fixation, and distal pedicle screw fixation were
used to achieve excellent correction with restoration of coronal and sagittal balance.
●
Osteopenia
●
Sagittal and coronal plane imbalance
●
Difficulty in determining pain generators
●
Frequent need for longer fusions and more common
combined anterior or posterior procedures
Box 11–1:
●
Incidence—5%
●
Treatment—hardware removal
Late Onset Surgical Pain
Classification
●
See Box 11–4.
Pathophysiology and Natural
History
Adult Scoliosis
●
Curve progression is usually not seen if less than 40
degrees.
●
Box 11–2:
●
Incidence—3%
●
Treatment—Compression instrumentation or bone graft
Box 11–3:
●
Incidence—1%-7%
●
Treatment—Hardware removal and short-term antibiotics
Pseudarthrosis
Delayed Infection
Curve progression averages 1 degree per year if greater
than 50 degrees.
●
Risk factors for the progression of lumbar curves include
the following:
●
Large apical rotation
●
Lateral and rotatory listhesis
●
For double curves, the lumbar curve tends to progress
more rapidly than the thoracic curve.
●
There is no difference in pulmonary function among
age-matched, normal patients.
CHAPTER 11
Spinal Scoliotic Deformities 147
Figure 11–6: Cont’d
●
Back pain incidence is similar; however, the severity is
worse and more recurrent when compared with controls.
●
The reasons for presenting symptoms to the physician
could be as follows:
●
Pain at the location of the curve
●
Progression of the curve
De Novo Scoliosis
●
Prevalence is approximately 6%.
●
The average age at which symptoms are presented is the
sixth and seventh decade of life.
Box 11–4:
Adult scoliosis
●
Previous AIS
●
Without degenerative changes—Usually younger than 40 years
●
With degenerative changes—Usually older than 40 years
●
De novo scoliosis (adult onset scoliosis)
●
Develops secondary to degenerative changes of the lumbar
spine
●
Usually in elderly patients
Adult Scoliosis and Deformity
Classification
●
The average curve progression is approximately 3.3
degrees per year.
●
A greater number of males are affected than in adult
scoliosis (females are still more common in both).
●
The reason for presenting symptoms is pain caused by
one, or combinations, of the following:
●
Neurogenic claudication
●
Radicular symptoms
●
Back pain—Not usually the main complaint
Diagnostic Tools
Plain Radiographs
●
Indications—All patients should have initial PA and
lateral long-cassette radiographs.
●
Long-cassette radiographs—PA and lateral
radiographs should include the cervical spine down to
the pelvis.
●
Supine right-sided and left-sided bend films should be
used to assess flexibility (especially when determining
whether anterior surgery is necessary).They also are
helpful when choosing fusion levels.
148 Spine Core Knowledge in Orthopaedics
●
Traction films are useful in assessing flexibility and
choosing fusion levels.
●
Ferguson view—An x-ray beam directed 30 degrees
cephalad and focused on the lumbosacral junction
provides an excellent view of the lumbosacral junction.
Assessment Parameters
Posteroanterior–Anterior Radiograph
●
Cobb measurement of all curves (upper thoracic,
thoracic, lumbar, and lumbosacral fractional curves)
●
Coronal imbalance—Measured as a trunk shift from the
CSVL or a deviation of a C7 plumb from the CSVL
(most important in adult deformity)
●
Rotatory listhesis or subluxation
●
Disk height and wedging
●
Osteophyte formation noted of the vertebral bodies and
facet joints
Lateral Radiograph
●
Cobb measurement—Thoracic kyphosis (T5 to T12) and
lumbar lordosis (L1 to L5)—Loss of lumbar lordosis is
usually seen.
●
Sagittal balance—The C7 plumb line should fall on the
posterior aspect of the L5-S1 disk level.
●
Disk space height
●
Osteopenia of the vertebral bodies
●
Degree of degeneration the facet joints
Computed Tomography and
Computed Tomography Myelography
●
Indications—CT largely has been replaced by MRI, so
indications today are as follows:
●
Inability to get MRI ( presence of certain
ferromagnetic implants or claustrophobia)
●
Assessment of central and lateral recess stenosis and
presence of disk herniations in the setting of previous
spine surgery
●
Best for assessment of the integrity of a spinal fusion
●
May be better for patients with large curves to assess
canal stenosis
●
Advantages—Still an accurate method of evaluating bone
density and anatomy (osteophyte and facet arthropathy),
canal and foraminal stenosis, and bony fusion
●
Disadvantages—Radiation exposure and its invasive nature
Magnetic Resonance Imaging
●
Technique
●
Usually T1- and T2-weighted axial and sagittal images
●
May add gadolinium in the face of previous surgery
●
Indications—Assessment of central and lateral recess
stenosis, presence of disk herniation, and morphology and
degree of degeneration of the intervertebral disks when
planning fusion levels
●
Advantages—No radiation exposure and excellent
visualization of osseous and soft tissue structures
●
Disadvantages—Artifact and distortion in the presence of
metal implants and claustrophobia for some patients
Nonoperative Treatment
●
Aerobic conditioning
●
Strengthening
●
Stretching
●
Nonsteroidal anti-inflammatory medications
●
With associated lumbar radiculopathy or neurogenic
claudication, nerve blocks or epidural steroid injections
may be helpful.
●
For lumbar curves, a lumbar corset may be beneficial in
improving pain control.
Operative Treatment of Adult
Scoliosis
●
See Box 11–5.
Algorithm for Operative Treatment of
Adult Scoliosis
Approach
●
Based on curve type, magnitude, flexibility, and sagittal
balance
Curve Type
●
Thoracic curves
●
Posterior approach more commonly used
●
Only the thoracic curve is fused, leaving distal lumbar
motion
●
Thoracolumbar curves
●
Anterior (more common) or posterior approach
●
Double major curves
●
Posterior approach to include both curves
●
Indications to include an anterior (combined) fusion
●
Large stiff curves
●
Kyphosis (use structural anterior grafts)
Box 11–5:
●
Documented curve progression
●
Increased coronal imbalance, sagittal imbalance, or both
●
Symptoms unresponsive to nonoperative treatment
●
Relative indications
●
Pulmonary symptoms (rare)
●
Back pain—Not an indication alone for surgical intervention
●
Leg pain (with lumbar curves) because of objective nerve root
compression
Indications for Operative Treatment
of Adult Scoliosis
CHAPTER 11
Spinal Scoliotic Deformities 149
●
Rotatory subluxation or listhesis
●
Fusion to L5 or S1
●
Performance of anterior and posterior surgery on the
same day is dependent on the medical condition of
the patient and the duration and clinical status of the
patient at the completion of the initial stage of
surgery
Fusion Levels
●
Similar to AIS especially for the younger adult (younger
than 40 years)
●
End-instrumented vertebra should be neutral (no
rotation) and stable (bisected by the center sacral line)
●
For a patient older than 40 years with degenerative
changes
●
Assessment of the distal lumbar disk levels below L3
with MRI is recommended to ensure that fusion does
not require inclusion of these levels because of the
presence of advanced degeneration
●
Levels of decompression for spinal stenosis are included
in the fusion levels
Operative Treatment of De Novo
●
Anterior surgery assists in creating lumbar lordosis
●
Anterior structural grafting assists fusion and creates a
ligamentotaxis effect
●
Anterior surgery (structural support) of L4-L5 and
L5-S1 increases fusion success, maintains or improves
sagittal fusion success, and maintains or improves
sagittal alignment when fusing to the sacrum
Internal Fixation
●
Segmental internal fixation is always recommended
●
Pedicle screw fixation
●
Improved three-dimensional correction when
compared with hooks
●
Always used in the lumbar spine
●
Can be used in the thoracic spine safely when the
morphology of the thoracic pedicle is of adequate size
●
Sacropelvic fixation
●
Many implants available
●
Galveston, iliac screws, intrasacral rods, and S2 screws
provide fixation to “backup” S1 screws
Treatment of Fixed Sagittal
Imbalance
(Degenerative) Scoliosis
●
See Boxes 11–6 through 11–9.
●
Anterior surgery accomplishes the following:
●
Anterior release improves correction and fusion rates
Box 11–6:
●
Progressive deformity
●
Spinal imbalance
●
Neurogenic claudication unresponsive to conservative treatment
Box 11–7:
●
Mild scoliosis coronal curve less than 10 degrees
●
No instability, lateral listhesis, or rotatory subluxation
Box 11–8:
●
Scoliosis >30 degrees
●
Sagittal imbalance, coronal imbalance, or both
Indications for Operative Treatment
of De Novo (Degenerative) Scoliosis
Decompression Only
Decompression, ASF and PSF, or
Instrumentation
Indications for Treatment
●
Fixed kyphosis with pain
●
Significant sagittal imbalance—C7 plumb line falling
anterior to the L5-S1 disk
Smith-Petersen Osteotomies
●
Multiple osteotomies done posteriorly (may also need
anterior surgery; see Fig. 11–7)
●
Closes the posterior column and opens the anterior and
middle columns (often requiring structural graft)
Before
Area of
bony resection
After
Box 11–9:
●
Scoliosis >30 degrees
●
Fixed coronal imbalance
Decompression, PSF, or Vertebral
Column Resection
Figure 11–7: Smith-Petersen osteotomy. Correction is achieved
by closing the posterior column (location of the osteotomy) and
opening the anterior column. (Reprinted from Bridwell 2003.)
150 Spine Core Knowledge in Orthopaedics
●
Indications for posterior surgery only
●
Young patient
●
Fusing short of sacrum with mild or moderate
correction needed in the setting of normal disks
●
Indications for anterior and posterior surgery—Narrow
disks that may not compensate for a significant correction
of sagittal imbalance in a patient requiring greater than
30 degrees of correction
Pedicle Subtraction Osteotomy
●
Technically more challenging (Fig. 11–8) (Bridwell et al.
2003)
●
Closes the posterior and middle columns and hinges on
the anterior column
●
Should be done at L1 or distal (below the conus
medullaris)
●
Advantages over Smith-Petersen osteotomy
●
Done through the posterior approach alone, gains
more than 30 degrees of correction, and does not
lengthen the anterior column
●
Greater potential for healing without stretch on aorta
or viscera
●
Disadvantages—Technically difficult, increased blood loss,
and greater potential for neurologic injury
●
Pseudarthrosis
●
The most common complication
●
Incidence—5% to 25%
●
Risk factors—Revision surgery, use of allograft bone,
and use of nonsegmental hardware
●
Infection
●
Incidence—0.5% to 8%
●
Risk factors—No perioperative antibiotics,
poor nutrition (use total parenteral nutrition
in staged surgery), poor soft tissue handling,
and posterior surgery more common than anterior
surgery
●
Neurologic compromise
●
Incidence—Less than 1% to 5%
●
Risk factors—Combined anterior and posterior
surgery, revision surgery, or osteotomy surgery
●
Pulmonary embolism
●
Incidence—1% to 20%
●
Spinal decompensation
●
Risk factors—Improper selection of fusion levels and
possibility of error on longer fusions; ideally stop at
neutral and stable vertebra
Neuromuscular Scoliosis
Results and Complications
following Adult Spine Deformity
Surgery
●
Pain (Ahlert et al. 1995, Grubb et al. 1994, Schwab et al.
2003)
●
A balanced patient with solid fusion usually has
improvement in the severity of pain
●
The frequency of pain usually continues
Before
Area of
bony resection
Figure 11–8: Three-column pedicle subtraction osteotomy.
The osteotomy closes all three columns of the spine.
(Reprinted from Bridwell 2003.)
After
Introduction
●
Scoliosis is common in patients with neuromuscular
diseases.
●
Larger curves cause difficulties with sitting or ambulation.
●
Bracing generally does not affect the natural history of
scoliosis in these patients.
●
Progressive severe curves require operative treatment.
●
The goals and treatment methods for neuromuscular
scoliosis are slightly different than those for idiopathic
curves.
●
Longer fusions, often to the pelvis
●
Fusions often for smaller curves
●
Complication rates high
Classification
●
See Box 11–10.
Anatomy and Pathophysiology
(of the more Common Diagnoses)
Cerebral Palsy (Fig. 11–9)
●
Nonprogressive encephalopathy with varying degrees of
severity
●
Damage to the brain occurs prenatal, perinatal, or
postnatal
●
Prenatal—Infections or toxins (drugs or alcohol)
●
Perinatal—Anoxic brain injury
Box 11–10:
Neuromuscular Scoliosis
Classification
Neuropathic
1. Upper motor neuron
●
Cerebral palsy
●
Spinocerebellar degeneration
●
Friedrich’s ataxia
●
Charcot-Marie-Tooth disease
●
Roussy-Lévy disease
●
Syringomyelia
●
Spinal cord tumor
●
Spinal cord trauma
2. Lower motor neuron
●
Poliomyelitis
●
Traumatic
●
Spinal muscular atrophy
●
Werdnig-Hoffmann
●
Kugelberg-Welander
●
Letterer-Siwe
●
Myelomeningocele
3. Dysautonomia (Riley-Day syndrome)
Myopathic
1. Arthrogryposis
2. Muscular dystrophy
●
Duchenne’s
●
Limb-girdle
●
Fascioscapulohumeral
3. Fiber-type disproportion
4. Congenital hypotonia
5. Myotonia dystrophica
●
Postnatal—Meningitis, near drowning, trauma, or child
abuse
●
Classifications
●
Muscle tone—Spastic, hypotonic, dystonic, athetosis,
or ataxic
●
Geographic—Hemiplegic, diplegic, or quadriplegic
●
Spine affected by abnormal tone and imbalance of the
paraspinal muscles
●
Spinal deformity more common in nonambulatory,
quadriplegic, and spastic patients
Myelomeningocele
●
Birth defect characterized by exposure of the meninges
and dysplasia of the underlying neural elements, resulting
in bowel, bladder, motor, and sensory paralysis distal to
the malformation
●
Incidence—1 in 1000 live births in the United States;
50% caused by dietary folate deficiency
●
Clinically—Wide spectrum depending on the level of the
lesion
●
Thoracic level—Sitter
●
Upper lumbar—Household or community ambulator
with assistive devices
CHAPTER 11
●
Lower lumbar—Community ambulator with ankle
Spinal Scoliotic Deformities 151
foot orthoses (AFOs)
●
Sacral—Community ambulator with or without
AFOs
●
Beware of the 15% incidence of latex allergy, which leads
to anaphylaxis and subsequent death
Spinal Deformity
●
Common and complex
●
Causes of spine deformity
●
Congenital anomalies leading to scoliosis and
kyphosis
●
Muscle imbalance
●
Hydrocephalus
●
Tethered cord
Duchenne’s Muscular Dystrophy
●
This is an X-linked recessive disorder.
●
Encoding for dystrophin protein is abnormal, leading to
complete absence.
●
Becker muscular dystrophy has a decreased amount of
dystrophin.
●
The dystrophy is characterized by progressive weakness in
boys who begin walking late (18 months) and eventually
lose ambulatory ability by 12 years.
●
The life span is shortened to less than 25 years because of
pulmonary compromise.
●
Histology includes muscle necrosis and fibrofatty muscle
infiltration.
●
Spinal deformity develops because of muscle imbalance
and only appears following the loss of ambulatory
status.
●
Beware of the occurrence of malignant hyperthermia
with anesthesia.
Spinal Muscular Atrophy
●
This progressive muscular weakness is caused by a loss of
anterior horn cells of the spinal cord.
●
Type I (Werdnig-Hoffmann disease)
●
Severe weakness in the neonatal period and death by
2 years from respiratory failure
●
Type II
●
Normal development until 5-6 months then failure to
stand or walk
●
Spinal deformity is universal and can be rapidly
progressive
●
Type III
●
Onset before 3 years and progressive loss of
ambulatory ability by 15 years
●
Spinal deformity is common
●
Type IIIb (Kugelberg-Welander syndrome)
●
Onset after 3 years
●
Weakness is often mild (foot drop) with limited
endurance
152 Spine Core Knowledge in Orthopaedics
Diagnostic Tools
Radiographs
●
Standard PA and lateral radiographs—Assess curve
severity (Cobb method) and the rate of progression
●
Supine bending radiographs—Determine flexibility
Imaging Studies
●
Specific imaging studies are diagnosis dependent.
●
Myelomeningocele—MRI is used to identify tethered
cord, syringomyelia, Chiari malformations, and
hydrocephalus.
Laboratory Examination
●
Laboratory examination is important to assess nutritional
status.
Cerebral Palsy
●
Good nutritional status is denoted by the following:
●
Albumin >35 g/L
●
Total lymphocyte count >1500 cells/mm
3
●
Gastrostomy feedings are often necessary to improve
nutritional status.
Duchenne’s Muscular Dystrophy
●
Pulmonary function tests ensure the following:
●
Forced vital capacity greater than 30%-40% of
predicted capacity
●
Cardiology referral for echocardiography of heart
contractility
Nonoperative Treatment
Bracing
●
The natural history of neuromuscular scoliosis is not
affected by bracing.
●
Thoracolumbosacral orthosis may be used in the
skeletally immature child with cerebral palsy,
myelomeningocele, and spinal muscular atrophy with
a supple spine deformity to buy time prior to surgical
treatment.
Figure 11–9: Scoliosis in a patient with cerebral palsy.
Modification of Seating Systems
●
Significant improvements in sitting balance can be
achieved with wheelchair modifications for the
patient who is nonambulatory or partially
ambulatory.
●
It is difficult to achieve better sitting in stiff curves.
Operative Treatment
●
In general, neuromuscular curves require longer fusions
than idiopathic curves.
●
For nonambulatory patients, fusion usually extends from
T2 to the sacrum.
●
Fixation
●
Traditionally segmental Luque wires have been used.
●
Hooks, screws are more often used today.
●
Pelvic fixation has many variations (Figs. 11–10 and
11–11,Table 11–3).
Cerebral Palsy
●
Indications
●
Ambulatory patients—Curves greater than 50 degrees
CHAPTER 11
Spinal Scoliotic Deformities 153
Figure 11–10: Galveston method of pelvic fixation with
sublaminar Luque wires.
Figure 11–9 Cont’d:
Figure 11–11: Dunn-McCarthy method of pelvic fixation.
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