Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 65 pptx

ab c
d
ef
g
Figure 3. Standard radiography
a Compensated double major curve. b Decompensated thoracic curve. c Risser sign I–II (arrows). d Sagittal profile with
a flat back.
e, f Thoracic and lumbar side bending views. g Silhouette radiograph demonstrating a rib cage deformity.
Idiopathic Scoliosis Chapter 23 633
ab
cd
Figure 4. Radiographic assessments
a Cobb measurement. b Risser sign. c Vertebral rotation according to Nash/Moe: the more rotated the vertebra, the more
the pedicle at the convexity passes towards and beyond the midline and the pedicle at the concavity disappears.
d Verte-
bral rotation according to Perdriolle: the radiograph of the target vertebra is superimposed by a torsionometer. The
intersection of the pedicle at the convexity with the respective line of the torsionometer determines the rotation.
cation of the apophysis of the iliac crest [185]. This apophysis first appears ante-
rosuperiorly of the iliac crest and progresses towards posterior before it fuses
with the iliac spine. According to Risser, the iliac crest is divided into four quar-
ters in the anteroposterior radiograph. If none of the quarters is calcified, Risser
stage is 0; if one quarter is calcified Risser stage is 1 and so on. If the complete
apophysis is fused with the iliac crest, Risser stage is 5.
634 Section Spinal Deformities and Malformations
Two methods are commonly used to assess vertebral rotation on standard ante-
roposterior radiographs:
Nash/Moe method
Perdriolle method
The technique by Nash and Moe determines vertebral rotation according to the
pedicles into five grades [150] (
Fig. 4c). In grade 0 (neutral) both pedicles show a

symmetric distance from the lateral borders of the vertebral bodies. In grade I
and II the pedicle on the convex side translates towards the middle line of the ver-
tebralbodywhereastheoneontheconcavesidebeginstodisappear.IngradeIII
the pedicle of the convex side lies in the midline of the vertebral body and in
grade IV and V it passes the midline towards the concave half of the vertebral
body.Inthesetwogradesthepedicleoftheconcavesideisnolongervisible.
Vertebral rotation
is measured by the method
of Nash and Moe
or Perdriolle
The method of Perdriolle (Fig. 4d)allowstheangleofrotationtobeestimated
by using a specific transparent torsionometer which is laid on the radiograph
[175, 176]. The angle of rotation can then be read off the torsionometer according
to the projection of the pedicle on the convex side.
The rib-vertebral angle (RVA) is construed by a midvertebral vertical line and
a line centered through the rib head. Progression or resolution of infantile idio-
pathic scoliosis may be predicted by the RVA difference. Mehta described this
method which combines the difference of the rib-vertebra angles of the convex
and the concave curve side as the so-called “phase of the rib head” [137]. Two
phasesmaybedistinguished.InPhase1theribheadoftheconvexriboftheapi-
cal vertebra shows no overlap with the apical vertebra. In Phase 2 there is an over-
lap to be found.
Radiographic curve assessments in the lateral view (
Fig. 3d) include the deter-
mination of the following parameters [36]:
thoracic and lumbar profile (angle of kyphosis/lordosis)
sagittalspinalbalance
other abnormalities: spondylolysis/-listhesis
The intraobserver error
in Cobb measurements

ranges between 3° and 10°
For the assessment of the sagittal thoracic profile, the upper endplate of T1 and the
lower endplate of T12 are used to determine the Cobb angle of kyphosis or lordo-
sis, respectively. If T1 is not distinguishable on the radiograph due to overprojec-
tion of the shoulder, the upper endplate of T4 or T5 is usually used. For the assess-
ment of the sagittal lumbar profile, the upper endplates of L1 and S1 are used.
According to inter- and intraobserver reliability studies of the Cobb method in
juvenile and adolescent idiopathic scoliosis, a change of between 5° and 10° [30,
62,94,121,122,180]betweentwomeasurementsisconsideredtobeatruechange
of curvature. In congenital scoliosis, the variability in measurement of the Cobb
angle is largely due to skeletal immaturity and incomplete ossification. However,
it is important always to compare the actual with the baseline radiographs.
Side bending supine images
are necessary to determine
curve rigidity
When a surgical correction of the deformity is considered, additional antero-
posterior supine side-bending views are necessary (
Fig. 3e, f)toassesstherigid-
ity of the curves (i.e., extent of curve correction). The films are taken with the
patient supine on the X-ray table with maximal passive side bending. The rib
hump can be radiologically assessed by a silhouette radiograph taken from pos-
terior with the patient inclined horizontally (
Fig. 3g) [94].
Magnetic Resonance Imaging
The purpose of preoperative MRI is to detect intraspinal pathologies. Possible
pathologies include syringomyelia, Arnold-Chiari malformation, tethered spinal
cord (
Fig. 5a–c) or intraspinal tumors. Several studies have documented the risk
Idiopathic Scoliosis Chapter 23 635
ab c

Figure 5. Magnetic resonance imaging
a Standard radiograph showing an atypical left thoracic curve. b MRI of this patient reveals an Arnold-Chiari malforma-
tion Type I (arrows)andasyrinx(arrowheads).
c MRI of the thoracolumbar spine with a tethered cord demonstrated by
a low conus at the level of L4.
of neurological complications in scoliosis correction surgery with concomitant
syringomyelia [91, 159, 160, 167].
There is a broad consensus on performing preoperative MRI of the complete
spine in patients presenting with atypical idiopathic scoliosis, i.e.:
infantile and juvenile onset [61, 119]
painful scoliosis [9, 192]
left convex thoracic curves [9, 231]
neurological abnormalities (e.g., absent abdominal reflexes) [192, 237]
Preoperative MRI
is mandatory in atypical
scoliosis
There is an ongoing controversy in the literature whether to routinely perform pre-
operative MRI in adolescent idiopathic scoliosis [49, 68, 86, 163]. Some authors only
recommend performing MRI in the aforementioned cases [49, 92, 195, 231]. We pre-
fer routine MRI in all patients scheduled for operative scoliosis treatment [68, 86].
Computed Tomography
For severe curves,
CT may be helpful
for surgical planning
Computed tomography is not routinely used in the preoperative assessment of
idiopathic scoliosis. In selected cases, however, preoperative CT scans may be of
value to precisely assess vertebral deformation and rotation. CT may be used to
assess pedicle size and shape before using spinal instrumentation. In juvenile idi-
opathic scoliosis, it may be necessary to assess pedicle size before performing
surgery because the pedicle diameter may be too small for a pedicle screw inser-

tion affording alternative instrumentation methods [71].
636 Section Spinal Deformities and Malformations
Injection Studies
In adult idiopathic scoliosis, injection studies are helpful in identifying the
source of the pain (see Chapter
10 ). Provocative discography may be used to
identify symptomatic disc degeneration. This test is only helpful if the typical
pain can be provoked at the target level without pain provocation at adjacent MR
normal levels [118, 191]. Selective nerve root blocks or facet joint blocks may be
useful in identifying nerve root compromise and symptomatic facet joint arthri-
tis, respectively [73, 118].
Neurophysiologic Evaluation
Neurophysiologic evaluation
is recommended to detect
a subclinical pathology
A thorough neurophysiologic evaluation is necessary in clinically suspicious
patients. In a study on 100 patients with typical right convex idiopathic adoles-
cent curve and normal neurologically, 56% showed alterations in the neurophys-
iologic evaluation of somatosensory evoked potentials (SSEPs) [86]. Preopera-
tive pathologic differences between left and right were found in 17% of the cases
although no clinical signs could be detected. This indicates that by neurophysio-
logic evaluation subclinical pathologies may be detected and that this method
may be used for preoperative screening. It was also found that in uneventful sco-
liosis surgery pre- and postoperative SSEPs were found to be similar and that the
influence of anesthesia on intraoperative SSEPs becomes quite predictable when
using a standardized anesthesia protocol [205].
Treatment
General Considerations
Idiopathic scoliosis does not usually present with severe symptoms (i.e., no pain
or neurological deficits) before adulthood. In this age group, the general objec-

tives of treatment are (
Table 2):
Table 2. General objectives of treatment
arrest progression correct spinal deformity
maintain or restore sagittal and coronal balance maintain or restore sagittal and coronal balance
preserve function of lower lumbar motion segments allow for further growth of the spine (only infantile and
juvenile scoliosis)
When deciding on the most appropriate therapy, the key questions are whether
the individual curve exhibits the potential of progression and with what conse-
quences. The fact that patients with idiopathic scoliosis usually present early in
life and adverse consequences may only occur decades later makes patient selec-
tion a challenge. The knowledge of the natural history is therefore a prerequisite
for a counselling of an appropriate treatment.
Natural History
Infantile Idiopathic Scoliosis
Only few cases of infantile
scoliosis progress rapidly
to severe deformities
Infantile scoliosis was found to usually develop in the first months of life affecting
more males than females (ratio 3:2) [95, 96, 120, 193]. The majority of structural
curves in this age group resolved partly or completely and remained stable there-
after. However, a minority of patients exhibited rapid progression and developed
Idiopathic Scoliosis Chapter 23 637
severe curves when left untreated. Especially girls with right sided curves were
foundtobeatahighriskofdeterioration[215].
A feature that may help to predict progression or resolution of infantile idio-
pathic scoliosis is the RVAD as described by Mehta [137]. In Phase 1,anRVAD
of more than 20° is associated with progression of the curve in 84 % whereas
an RVAD of less than 20° is associated with resolving of the curve in 83%. In
Phase 2, all curves progressed independently of the RVAD [137]. These findings

Double major curves
are likely to progress
were supported by Ferreira and James [64]. The appearance of a double curve
was found to be correlated with progression by Ceballos et al. [32]. These curves
must therefore be followed closely.
Juvenile Idiopathic Scoliosis
Spinal growth during the age between 3 and 10 years is rather steady [172].
Regression of the curve may occur [136] but usually curves in this group are char-
acterized by slow to moderate progression [65, 95, 106, 179]. Early onset curves
are at higher risk for severe progression. The reported necessity for surgery
varies between 30% [136, 216] and 56% [65]. Right thoracic and double major
curves are the predominant curve patterns. In approximately 20% of patients in
this age group, scoliosis is associated with an intraspinal abnormality and it is
strongly recommended that curves larger than 20° should be evaluated by MRI
[77, 119].
Adolescent Idiopathic Scoliosis
Several studies postulated that less than 10% of individuals exhibiting curves
larger than 10° require treatment [23, 125, 188, 228]. Several studies have
explored the natural history of progression in idiopathic scoliosis during adoles-
cence. Risk factors for curve progression are:
young age at onset [187]
premenarchal status [25, 125]
physical immaturity (Risser sign, Tanner stages) [185, 211]
larger curves [25, 125, 220]
female gender [25]
Thoracic curves (>50°)
tend to progress even
after skeletal maturity
Progression is influenced by the curve type with double major curves being at
highest progression risk [25, 125]. Larger curves generally have a higher progres-

sion risk than smaller ones [25, 125, 220] and progression is more frequent in
female patients [5, 25, 56, 221, 222]. Curve progression has also been found to
occurafterskeletalmaturity,especiallyinthoraciccurveslargerthan50°[5,179,
222]. Curves that were smaller than 30° at skeletal maturity did not tend to pro-
gress during adulthood.
Health related quality
of life in patients with AIS
is comparable to healthy
controls
Early studies on the natural history of scoliosis included mixed types of scolio-
sis and reported higher mortality rates, more back pain and psychosocial adverse
effectssuchasalowerrateinmarriedwomenorareducedabilitytowork[148,
156]. More recent selective studies on adolescent idiopathic scoliosis did not
show such unsatisfactory outcomes. Collis and Ponsetti [39] found that most of
their 215 investigated patients with non-operated AIS led normal and active lives,
were productive, worked, married and showed similar activities compared to the
normal population. They did not find a higher mortality rate in scoliosis patients.
However, they found back pain to occur more frequently than in the normal pop-
ulation. Similar findings were reported by Weinstein et al. [222]. Danielsson et al.
[43] found that health-related quality of life in patients with adolescent idio-
pathic scoliosis was about the same as in the general population after more than
638 Section Spinal Deformities and Malformations
20 years of follow-up. However, the scoliosis patients exhibited slightly reduced
physical function (SF-36) and more disability (Oswestry Score) compared to
healthy controls.
The prevalence of back pain
and physical disability
seems higher in scoliosis
patients than in healthy
controls

Similar findings were found by Haefeli et al. [79] in a 10- to 60-year follow-up
of conservatively treated patients who exhibited a similar quality of life com-
pared to healthy controls according to the WHOQOL-Bref. assessment. Whereas
Danielsson et al. [43] and Weinstein et al. [220] found no correlation between
Cobb angle and disability or pain, Haefeli et al. [79] detected slightly but signifi-
cantly higher pain levels in patients with curves of more than 45°.
In contrast to the earlier studies mentioned above, Danielsson et al. [42] and
Weinstein [220] did not find differences regarding rates of marriages, childbear-
ing and sexual function in women 22–50 years of age regardless of treatment.
Respiratory and cardiac
failure may occur in large
(>70°) thoracic curves
This data suggests adolescent idiopathic scoliosis to be a rather benign spinal
disorder especially in cases of small to moderate curve sizes. On the other hand,
it has been shown that thoracic curves bigger than 70° exhibit an increased risk
of chronic respiratory or cardiac failure [11].
Non-operative Options
Considering the relatively benign natural history of idiopathic scoliosis, surgical
treatment is reserved for progressive large curves. The vast majority of remain-
ing cases can be treated non-operatively. Conservative measures consist of:
physiotherapy
bracing
electrotherapy
So far, there is no evidence for the efficacy of electrotherapy [117].
Physiotherapy
Physiotherapy does not
arrest curve progression
Non-operative treatment generally consists of observation and physiotherapy in
curves smaller than 25° [123]. A recent review of the effectiveness of physiother-
apy in the treatment of scoliosis has identified 11 studies [151]. The methodolog-

ical quality of the retrieved studies was found to be very poor. Therefore, the lit-
erature fails to provide solid evidence that physical exercises influence the natu-
ral history. Nevertheless, physiotherapy is a helpful adjunct to reduce symptoms
related to muscle imbalance and to improve or preserve back function [224, 225].
The limitations of physiotherapy with regard to curve progression have to be
clearly communicated to the patient and their parents prior to treatment.
Patients having physiotherapy remain under surveillance with regard to curve
progression.
Casts and Bracing
Infantile and Juvenile Idiopathic Scoliosis
Progression risk is high
in early onset scoliosis
In early onset (<6 years), scoliosis therapy is dominated by the progression risk.
Curves that are expected to resolve may be simply observed every 4–6 months.
Active treatment should be initiated at a progression of 10°. Patients whose
curvesresolveshouldbefolloweduntilmaturitytoruleoutanyprogressiondur-
ing the growth spurt [2]. In resolving curves plaster-bed treatment showed no
advantage over physiotherapy with regard to the time of resolution or functional
outcome after 25 years [48]. When progression is documented treatment should
be started. Initial therapy consists of serial molded body casts that have to be
Idiopathic Scoliosis Chapter 23 639
changed every 6–12 weeks until maximum correction is achieved. Then, full-
time bracing is started for at least 2 years and until there is no further progression
to be observed [2]. Prognosis is good if total correction is achieved before the
prepubertal growth spurt [138]. If no full correction may be achieved, progres-
sion may occur, possibly necessitating surgery.
Adolescent Idiopathic Scoliosis
The choice of therapy
depends on the severity of
the curve and the potential

for progression
In adolescent idiopathic scoliosis with curves between 25° and 40° in a skeletally
immature (<Risser 3) patient, bracing is indicated [123]. However, it must be
borne in mind that the primary goal is to prevent curve progression through
bracing (
Fig. 6). The treatment is considered successful if the initial curve size at
treatment entry can be preserved at the end of bracing. Often an improvement
occurs during therapy but is lost after brace cessation [31, 139, 227]. In the pres-
ence of a true thoracic lordosis (>5° to 10°), bracing may be impossible as any
positioning of the thoracic pad will increase thoracic lordosis and thus make cor-
rection impossible. The possible psychological distress of a long-term therapy
such as bracing and the efficacy of the treatment must carefully be considered
[63, 135, 157, 165, 219].
There is limited evidence for
the effectiveness of bracing
The effectiveness of conservative treatment modalities has been the subject of
several studies [117]. The only study that found a significant difference in favor
of bracing compared to observation and overnight electrical stimulation was
presented by Nachemson and Peterson for curves ranging from 25° to 35° in
female patients [149]. In the same study, no difference was found between brac-
ing and physiotherapy. Other studies found no significant differences for bracing
versus natural history [158]. A recent survey among members of the Scoliosis
Research Society and of the Pediatric Orthopaedic Society of North America
revealed a high degree of variability with regard to the opinion of the effective-
ness of brace treatment [52]. Based on the current literature, there seems to exist
only limited evidence for the effectiveness of bracing.
a
b
cd
Figure 6. Thoracolumbar brace

a, b Thoracolumbar brace. c, d Patients should wear the
brace for a minimum of 23 h daily to achieve a treatment
effect.
640 Section Spinal Deformities and Malformations
Operative Treatment
The risks and benefits of surgery must be carefully weighed against the natural
history when the scoliosis is left untreated. Intensive counselling of the patients
and their parents is necessary to explain the pros and cons of the intervention,
risks and potential outcome. The indications for surgery for idiopathic scoliosis
depend on:
risk for progression
skeletal maturity
curve type
curve magnitude
cosmetic appearance
failure of conservative treatment
Intraoperative neuromonito-
ring is the standard of care
Surgeryhastobewellplannedinadvanceandrequiresadedicatedteamtaking
care of children and adolescents. Intraoperative neuromonitoring has become
the standard of care to control spinal cord function during correcting surgery
[67, 131, 168, 173] (see Chapters
12 , 15 ). The use of intraoperative somatosen-
sory evoked potential (SSEP) recording has been found to reduce the incidence of
postoperative neurological deficits [161, 166]. Combined monitoring of motor
and somatosensory potentials has even been found to be superior compared to
single mode monitoring by increased sensitivity [174].
Indications for Surgery
Indications for surgery are somewhat different for the specific age group and are
discussed under each type of scoliosis accordingly.

Infantile and Juvenile Idiopathic Scoliosis
In these young patients, surgery is preserved for those curves that are severe and
progressing despite conservative treatment. Lungs, thorax and spine are still
incompletely developed and usually prohibit multisegmental spinal fusion in
Spinal instrumentation
without fusion is the surgi-
cal treatment of choice for
infantile and juvenile curves
patients younger than 5–6 years. Spinal instrumentation without fusion may be
indicated in large progressive curves allowing the spine still to grow.Different
systems are in use but all have a high risk of complications that may necessitate
several revision operations [66, 105, 183]. If the curve deteriorates despite instru-
mentation, definitive fusion of the spine should be considered. In this age group,
the surgical treatment of scoliosis is usually difficult, prone to complications and
requires multiple surgeries.
Adolescent Idiopathic Scoliosis
Progressive adolescent
curves (>40 –50°) are con-
sidered surgical candidates
Progressive curves (>40–50°) in skeletally immature patients (Risser Grade 3 or
less) are usually considered candidates for surgery. It should be taken into
account that large curves may progress even after skeletal maturity [5, 179, 222].
Cosmetic aspects may also play a role in the indication of surgery, especially in
the presence of a substantial rib hump or shoulder asymmetry [81].
Adult Idiopathic Scoliosis
Indications for surgery in adult idiopathic scoliosis depend on the predominant
problem [1, 15], i.e.
Idiopathic Scoliosis Chapter 23 641
back and/or leg pain
radiculopathy

claudication symptoms
curve progression
spinal imbalance
The surgical indication in
adult curves is determined
by the secondary
degeneration
A thorough diagnostic work-up must be done to reveal the specific problem and
potential pain sources. In cases of adult scoliosis with predominant degenerative
alterations, similar principles apply as for de novo scoliosis (see Chapter
26 ).
Accordingly, selective decompression of neural structures and/or spinal fusion
with or without deformity correction is indicated [16].
General Principles
Approach
The choice of the surgical approach, i.e., posterior, anterior or combined anterior
and posterior, depends on:
curvetypeandsize
curve rigidity
skeletal maturity
spinal instrumentation
surgical skills
Posterior Approach
The posterior approach addresses the deformity by fixing rods to the posterior
structures of the spine, i.e., the pedicles, the transverse processes, or the laminae
(
Fig. 7). This approach necessitates detachment of the posterior paraspinal mus-
cles. Only little is known about the extent of muscle detachment in scoliosis sur-
gery but it does not seem to interfere significantly with the spinal muscle func-
tion after 3–6 months [53]. Harrington introduced the first instrumentation for

posterior scoliosis correction in the 1960s [85]. In general, long term outcome in
terms of quality of life, disability and patient satisfaction were found to be quite
satisfactory after the Harrington operation [38, 74, 154, 169, 170].
In the 1970s, Luque introduced segmental spinal fixation using sublaminar
wires [132].
The so-called third generation instrumentations were introduced in the
1980s. These modern implant systems allowed for a segmental instrumentation
by the use of contourable rods that are fixed to the spine by lamina hooks, pedicle
hooks, transverse process hooks, and pedicle screws. The instrumentation sys-
tems of Cotrel Dubousset [40], the Texas Scottish Rite Hospital (TSRH) and the
ISOLA were the most frequently used implants at that time which allowed for
more correction and preservation of lower lumbar motion segments compared
to the Harrington system [114]. Despite the advances of the third generation
Correction of vertebral
rotation remains a challenge
instrumentations, correction of vertebral rotation is limited even with the use of
pediclescrews.Inyoungpatientswithalargegrowthpotentialthereisariskof
continuing anterior growth of the spine despite a solid posterior fusion, which
leads to the so-called crankshaft phenomenon (see below).
Anterior Approach
Anterior scoliosis correction
allows for a better derota-
tion and shorter fusion
Dwyer introduced the anterior approach for scoliosis correction in 1969 [57].
Ten years later, Zielke first introduced the concept of anterior derotation spon-
dylodesisusingvertebralbodyscrewsconnectedbyarod[238].Hereportedon
642 Section Spinal Deformities and Malformations