Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 72 pot

a
b
c
Case Study 1
A 3-year-old boy presented for evaluation and management of a progressive congenital scoliosis. He was diagnosed with
a cardiac murmur at birth and subsequent echocardiogram revealed severe congenital cardiomyopathy and pulmonary
hypertension that eventually required surgical intervention. AP and lateral radiographs (
a, b) of the spine reveal a par-
tially segmented, incarcerated hemivertebra at the thoracolumbar junction. Cobb angle, measured from endplate to
endplate, was 37 degrees at the time of surgery. Physical examination and MRI revealed no other neurologic findings.
The patient underwent an anterior hemiepiphysiodesis and posterior hemiarthrodesis on the convex side of the curve
(
c). Segmental vessels were ligated with surgical clips. The intervertebral disc, and therefore the growth potential on the
concave side of the curve, were left intact. The patient tolerated the procedure well and achieved a solid arthrodesis on
the convexity of the curve. The remaining growth potential produced unilateral growth and progressive correction of
the curve. At latest follow-up (
d, e) the congenital curve had been reduced to 20 degrees over a 5-year period.
Congenital Scoliosis Chapter 25 703
a
b
c
d
e
f
Case Study 2
A 14-year-old male with congenital scoliosis
presented with a 55-degree upper left thoracic
curve. He was otherwise neurologically intact.
There were no other members in his family
with scoliosis. The remaining medical work-up
and MRI was negative for associated cardiac,

genitourinary, or neurologic malformations.
Because of the location of the congenital
anomaly in the high thoracic spine, the patient
developed a fairly dramatic clinical deformity
with an elevated left shoulder (
a, b) and coro-
nal imbalance (
c). As a result, he underwent an
instrumented posterior spinal fusion. Intraope-
ratively, the left convex rod was inserted first
and a compression maneuver performed. The
second concave rod was placed in situ with
minimal distraction. A progressive loss of neuromonitoring signals prompted a Stagnara wake-up test which revealed
that the patient had no voluntary motion of the lower extremities. The patient was placed back under anesthesia and
both rods were loosened returning the curve to its original position. The patient was able to move all four extremities on
the repeat wake-up test. The rods were locked in situ without any correction. Postoperatively, the patient was neurologi-
cally intact and demonstrated a mild improvement in his clinical (
d) and radiographic appearance (e, f). This case empha-
sizes the dangers associated with curve correction in the surgical treatment of the congenital curve.
704 Section Spinal Deformities and Malformations
Spinal Osteotomies
The selective use
of asymmetric spinal
osteotomies can help
correct deformities in
multiple planes, but must
be planned carefully
Most spinal osteotomies are based on a combination of two traditional osteoto-
mies: the Smith-Peterson and the pedicle subtraction osteotomies. Both tech-
niques were originally described for the management of flexion deformities that

occurred in rheumatoid and ankylosing spondylitis patients and have since been
extensively modified [35, 39, 41]. Frequently, as in patients with unsegmented
bars, an asymmetric osteotomy aimed at addressing the specific vertebral anom-
aly should be designed as necessary. A thin-slice or spiral CT scan is essential for
preoperative surgical planning, which can be performed through either a single
posterior approach or a combined approach. The inherent neurologic risks of
such techniques must be well understood before undertaking such a procedure.
Placement of segmental instrumentation for provisional stabilization prior to
completing the osteotomy can help to reduce the risk of uncontrolled translation
of the spine with corresponding neurologic injury.
Hemivertebra Resection
Hemivertebra at the
lumbosacral junction
causing an oblique take-off
maybebesttreated
with hemivertebra resection
This procedure is done either through a posterior approach only (Fig. 4), or
through a sequential or simultaneous anterior and posterior approach [7, 9, 16,
19, 20, 21, 28, 32, 33, 37]. The ultimate surgical approach selected depends on the
location of the hemivertebra, its type, whether it is segmented or not, and famil-
iarity of the surgeon with the technique. These procedures usually provide an
average of 25°–30° of correction, with some correction of the associated kypho-
sis. Perhaps the best indications are a fully segmented hemivertebra located at
the lumbosacral junction associated with an oblique take-off and pelvic obliquity
(
Case Introduction). Recent publications tend to show that hemivertebra resec-
tion is safe even in the thoracic spine; however, they are clearly more dangerous
to perform and should only be carried out by experienced spine surgeons [16].
After hemivertebra excision, the correction can be achieved and maintained
by a variety of methods. Depending on the size of the patient, 4.5-mm AO screws

inserted into the pedicles with a tension band system can be used, and supra- or
infralaminar hooks with cast or brace treatment are also options [3]. In older
patients a classic pedicle screw rod system is indicated. Depending on the size
and location of the vertebra, anterior instrumentation is also an option [33].
Spinal Column Resection
Spinal column resection
may be the only way
to rebalance the spine
in patients with complex
deformities
In very complex spinal deformities the only way to rebalance the spine may be
through a spinal column resection with shortening of the spinal column. This
was described by Bradford and Tribus, and consists of an anterior approach
where one or several vertebrae are removed after a decorticated osteoperiosteal
flap has been elevated [6]. The involved vertebral bodies are removed down to
thedura,theconvexpediclesareremoved,andasmuchaspossibleoftheconcave
pedicles is removed. The posterior surgery, done in the same sitting or a few days
later, consists of removing the corresponding posterior laminae and the rest of
the concave pedicles. The spinal deformity is then corrected at the same time as
the shortening is carried out. Careful monitoring of the neurologic function is
mandatory during these exceptional procedures [6]. This procedure should be
undertaken by only the most experienced spine surgeons, and only after careful
preoperative planning and discussion with the patient and family.
Congenital Scoliosis Chapter 25 705
ab
cd
Figure 4. Techniques of hemivertebra resection (posterior only)
a During the posterior excision of the hemivertebra, the appropriate level is identified and pedicle screws are inserted
above and below the malformation.
b Next the inferior facets of the hemivertebra and the vertebra above are removed

and a complete laminectomy is performed at the level of the hemivertebra exposing the neural structure.
c Decancella-
tion of the vertebral body of the hemivertebra is performed with a curette. The exiting nerve root is protected during this
stage of the procedure by the medial pedicle wall. Discectomies above and below the hemivertebra are performed. The
hemivertebral excision is completed after removal of the pedicle and the remnant of the vertebral body. This is per-
formed with minimal retraction of the neural elements.
d Compression with the pedicle screw rod system results in
immediate correction of the deformity. Notice that after the hemivertebra is excised, two nerve roots exit through a sin-
gle foramen and should be checked for possible nerve root compression.
706 Section Spinal Deformities and Malformations
Miscellaneous Surgical Techniques
Halo Traction
The use of halo traction should be exceptional in congenital scoliosis, and it may
be dangerous for neurologic function. Its use is formally contraindicated if there
is a rigid acute component of kyphosis associated with the scoliosis. However, in
selected cases it may be a helpful adjunct, especially in order to prepare the
patient for surgery, in cases of severe respiratory compromise, or in between
staged surgery [2, 38, 46].
The Rib Expander
Intheappropriatepatient,
the use of halo traction, the
titanium rib expander, and
the subcutaneous growing
rod are acceptable surgical
options
The rib expander (Fig. 5) – the titanium rib expansion project developed in San
Antonio by Campbell – will allow some spine growth as well as chest and lung
expansionifcarriedoutbeforetheageof8years,torecruitmorepulmonary
alveoli [10]. Its best indications are in cases of congenital scoliosis associated
with fused ribs and/or patients with thoracic insufficiency syndrome and/or

chest hypoplasia.
Subcutaneous Rods
Subcutaneous rods without fusion and subsequent lengthening may play a role in
maintaining the growth of the spine in very young children, but these procedures
do not address the area where the malformation of the spine is. They may be
combined with convex growth arrest [12]. They expose the patient to multiple
lengthening operations and carry a significant risk of complications, mostly
infections or instrument complications.
a
Figure 5. Alternative treatment
options for congenital scoliosis
In carefully selected cases the use of
a the titanium rib expander or
Congenital Scoliosis Chapter 25 707
bc
d
Figure 5. (Cont.)
b–d the subcutaneous growing rod is a reasonable option for the
treatment of congenital anomalies of the spine.
Recapitulation
Epidemiology.
Thetrueincidenceofcongenital
scoliosis is unknown. There do not appear to be any
significant ethnic or geographic differences, al-
though there is a greater female to male ratio
(1.4–2.5 to 1). Most cases are non-hereditary.
Cases with a syndromic association can have a he-
reditary component with a 10% risk to siblings and
subsequent generations.
Pathogenesis. In sporadic cases, the etiology is be-

lieved to be an insult to the fetus during the 4th–
6th week of gestation. As a result, up to 60 % of pa-
tients with congenital scoliosis may have malfor-
mations in other organ systems.
Classification. The congenital anomalies are classi-
fied as either failure of formation, failure of seg-
mentation,ormixed. Examples of failure of forma-
tion are hemivertebra and wedge vertebra, while
unilateral unsegmented bars and block vertebra
are examples of failure of segmentation. In addi-
tion, hemivertebra is further classified as fully, par-
tially, or non-segmented and as incarcerated or
non-incarcerated. In general, a non-incarcerated
fully segmental hemivertebra has a worse progno-
sis for progression compared to an incarcerated
non-segmented vertebra.
Clinical presentation. Often the diagnosis of the
spinal deformity is made at the time of the prenatal
ultrasound examination or is discovered incidental-
ly. Otherwise, the child will be referred for the eval-
uation of a spinal deformity.
Physical findings. Examination should include the
skin and spine, but one should also look for any foot
or leg asymmetry, craniofacial malformations, Klip-
pel-Feil web neck, and cardiac and urinary malfor-
708 Section Spinal Deformities and Malformations
mations. A thorough neurologic examination is
required.
Diagnostic work-up. The best X-rays are usually ones
taken at birth. Several Cobb angles should be calcu-

lated, one within the deformity and one over the
whole curve. The same landmarks should be used
during subsequent measurements. A 10-degree
increase in the Cobb angle is considered as progres-
sion. Occasionally, although the Cobb angle does not
change, the clinical deformity may worsen requiring
early surgical intervention. When further detail is
needed, cone down views and CT reconstructions
can provide additional detail. MRI evaluation of the
spinal column is mandatory. Furthermore an ultra-
sound examination of the genitourinary and cardiac
system should be performed as indicated.
Non-operative treatment. Observation may be
considered for non-progressive balanced curves.
Bracing in most instances is ineffective in congeni-
tal scoliosis.
Natural history and progression. The rate of pro-
gression in congenital scoliosis is directly related
to: (1) the potential for asymmetric growth and (2)
the location of the vertebral anomaly. Depending
on the location, early surgical intervention may be
required to address congenital curves that result in
significant shoulder, pelvic, or trunk imbalance.
Operative treatment. The goal is to achieve a solid
fusion and prevent further progression, to achieve
as straight a spine as possible at the end of growth.
Prophylactic surgical procedures refer predomi-
nantly to in situ fusions and hemiepiphysiodesis.
The general principle is to balance the growth by
slowing or stopping the convex side growth while

allowing the remaining concave growth potential
to catch up. Posterior spine fusion without instru-
mentation and correction with a cast is an option
in young children, but exposes the spine to the
crankshaft phenomenon. Posterior spine fusion
with instrumentation is indicated in older patients.
Anterior and posterior spine fusion with instru-
mentation can achieve a significant correction;
however, neurologic complications are a concern.
The use of spinal cord monitoring and/or a wake-
up test is strongly recommended. In selected cases
an osteotomy with subsequent corrective instru-
mentation is an option; however, the inherent neu-
rologic risks of such techniques must be well
understood before undertaking such a procedure.
Hemivertebra resection is done either through a
posterior approach only or through a sequential or
simultaneous anterior and posterior approach, and
provide an average of 25°–30° of correction. Fully
segmented hemivertebra at the lumbosacral junc-
tion may be the best indication for resection. In
very complex deformities the only way to rebal-
ance the spine may be through a spinal column
resection. In the appropriate patient, the use of
halo traction, the titanium rib expander,andthe
subcutaneous growing rod are acceptable surgi-
cal options.
Key Articles
Wynne-Davies R (1975) Congenital vertebral anomalies: etiology and relationship to
spina bifida cystica. J Med Genet 12:280 – 88

In a study of 337 patients with congenital spinal anomalies, the author found that an iso-
lated hemivertebra or similar localizing defect was sporadic with no risk to subsequent
siblings or offspring. Patients with multiple anomalies, however, carry a 5–10% risk to
subsequent siblings.
McMaster MJ, Ohtsuka K (1982) The natural history of congenital scoliosis. A study of
two hundred and fifty-one patients. J Bone Joint Surg Am 64(8):1128
This paper provides a review of over 200 patients who were observed past the age of 10
without treatment. They found that final severity depended on the type of vertebral
anomaly, the location of the anomaly, and the age of the patient at diagnosis.
Bradford DS, Heithoff KB, Cohen M (1991) Intraspinal abnormalities and congenital
spine deformities: a radiographic and MRI study. J Pediatr Orthop 11:36 –41
Forty-two patients with congenital spinal deformity were studied by MRI. Sixteen
patients (38%) had an associated intraspinal abnormality. The authors recommend MRI
in patients with congenital spinal deformities undergoing spinal stabilization.
Congenital Scoliosis Chapter 25 709
Key Articles
Roaf R (1963) The treatment of progressive scoliosis by unilateral growth arrest. J Bone
Joint Surg Br 45:637
One of the earliest descriptions of the use of convex growth arrest for addressing congeni-
tal scoliosis. Convex growth arrest is achieved by anterior and posterior convex fusions
resultingincontinuedconcavegrowthwithpotentialcurvecorrection.
Bradford DS, Tribus CB (1997) Vertebral column resection for the treatment of rig id
coronal decompensation. Spine 22:1590 –9
Twenty-four patients with rigid coronal decompensation underwent anterior-posterior
vertebral column resection, spinal shortening, with posterior spinal instrumentation and
fusion. Average correction of coronal and sagittal plane deformity was 82 % and 87%
respectively. Although the complication rate was nearly 60% (14 patients), all patients
ratedtheirresultsaseithergoodorexcellent.
Lazar RD, Hall JE (1999) Simultaneous anterior and posterior hemivertebra excision.
Clin Orthop Rel Res 364:76 –84

Eleven patients underwent simultaneous anterior and posterior resection of a congenital
hemivertebra with deformity correction using posterior instrumentation. Preoperative
curves measuring an average of 47 degrees corrected to an average of 14 degrees at
28monthsfollow-up.Therewasonetransientlegweaknesswhichresolved.Nolongterm
complications were noted.
References
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Congenital Scoliosis Chapter 25 711
26
Degenerative Scoliosis
Max Aebi
Core Messages
✔
The average age of patients with degenerative
scoliosis is in the sixties
✔
Degenerative scoliosis is a form of adult scolio-
sis ( =scoliosis after bony maturity)
✔
Degenerative scoliosis can be distinguished
into primary (de novo) degenerative scoliosis
and secondary degenerative idiopathic scolio-
sis (primary curve or compensatory curves)

✔
Degenerative scoliosis can progress with time
✔
The cardinal symptoms are back pain, claudica-
tion symptoms, neurological deficit and curve
progression
✔
Cosmesis does not play an important role
✔
Patients with back pain in degenerative scoliosis
need to be individually evaluated for surgery
✔
Clinical signs and symptoms as well as comor-
bidities determine the extent of surgery
✔
The primary goal of the treatment is not curve
correction but the control of back pain and
claudication symptoms
✔
A decompression at the apex of the curve
needs to be stabilized and fixed in order to pre-
vent curve progression
✔
The loss of lordosis is often the main reason for
back pain, and sagittal realignment is crucial
✔
The fixation of the lumbosacral junction in the
stabilization of a deformed lumbar spine
remains controversial
Epidemiology

Degenerative scoliosis can be differentiated into two major groups, i.e., primary
degenerative scoliosis or de novo scoliosis (after skeletal maturity) and second-
ary degeneration of adult idiopathic scoliosis or scoliosis of other etiology [1, 7].
Slow progression
of degenerative scoliosis
is common
The prevalence of scoliosis in patients older than 50 years is about 6%, includ-
ing patients with secondary degeneration of adult idiopathic scoliosis as well as
patients with degenerative or de novo scoliosis [6, 7, 14, 17], and the average age
of those seeking medical care with degenerative scoliosis is in the sixties. There
is a potential for curve progression with an average of 3.3° a year (
Case Introduc-
tion
). Degenerative scoliosis, which occurs on the basis of idiopathic scoliosis of
less than 30°, usually does not tend to progress; however, curves greater than 50°
have a tendency to progress an average of 1–2° a year.
Nevertheless, for primary degenerative scoliosis, there is no scientific evi-
dence which really documents the full complexity and extent of the natural his-
tory. For instance, degenerative scoliosis occurs more frequently in male
patients than adult idiopathic scoliosis, which is more frequent in females. There
are several aggravating factors in patients with degenerative scoliosis, mostly
duetotheadvancedageofpatients,whohaveseveralcomorbiditiessuchasdia-
betes, heart disease, pulmonary disease, and osteoporosis, factors which play a
significant role in the assessment and decision-making for treatment [3, 8, 11,
18, 25].
Spinal Deformities and Malformations Section 713