Oct 4, 2009, 2:39pm

ADOLESCENT IDIOPATHIC SCOLIOSIS-TO OPERATE OR NOT? A debate article

Hans-Rudolf Weiss*1, Shay Bess2, Man Sang Wong3, Vikas Patel4,
Deborah Goodall5 and Evalina Burger*4


Abstract

Introduction

Adolescent idiopathic scoliosis (AIS) is a three-dimensional
spinal deformity with potential adverse long-term
physical and psychological impact on young patients. Surgical
treatment of spinal deformity remains an emotional
decision for both the patients and their parents. Positive
results from non-operative treatment modalities have
been increasingly reported in the peer-reviewed literature.
Thus, the decision-making process for operative vs. non-
operative treatment should be based on the individual
patient's disease characteristics, curve type, risk factors for
progression, and subjective expectations. In the present
paper, two groups of experts in the field for operative and
non-operative treatment of AIS were invited to debate this
important topic from an evidence-based perspective. The
aim of this debate article is to provide a balance between
the available treatment options and help as a guide in the

decision making process for this uncommon, but potentially
disabling disorder in young patients.

Debate: "Pro" surgery

In order to promote an intervention for a specific condition,
it must be demonstrated that; 1) the natural history
of the condition is undesirable, 2) the intervention alters
this natural history in a favorable and reproducible manner,
3) the complications are minimal, and 4) the long
term side-effects of the intervention are not detrimental,
so that the risk-benefit ratio favors the intervention over
the condition's natural history. Scoliosis is a general term
indicating a lateral curvature of the spine due to a variety
of etiologies. Each etiology has a specific natural history
and, consequently, has its own unique treatment goals,
and risk-benefit and treatment efficacy profile. Early studies
that investigated the natural history of untreated scol-

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iosis and complications associated with treatment,
contain study populations of mixed scoliosis etiology,
and, therefore, have provided somewhat tainted conclusions
clouded by heterogeneous study populations [1-4].
The purpose of this argument is to demonstrate that 1)
spinal deformity associated with AIS can increase, 2) specific
risk factors have been identified that reliably predict
curves at risk for progression, 3) the natural history of
untreated, progressive scoliosis is unfavorable and, 4) surgical
treatment of progressive AIS is safe, consistently
achieves the goals of treatment, and favorably alters an
otherwise negative natural history in a measurable fashion
(figures 1, 2, 3).

Identification of patients at risk of progressive spinal
deformity

The Scoliosis Research Society (SRS) definition of AIS is a
structural lateral curvature of the spine that creates a thoracic
and/or lumbar asymmetry on forward bending

(a.k.a. the "Adams forward bend test") combined with a
curve of at least 10° as measured by the Cobb technique
on a standing radiograph of the spine with associated vertebral
rotation. The diagnosis of the curvature must occur
after the age of 10 years, and there is no other established
etiology for the curve [5]. Given this definition, it has
been repeatedly demonstrated that AIS curves can and will
progress. Curve progression is defined as an increase in
curve magnitude of 5–10° on serial radiographs. The primary
factors for AIS curve progression include growth
potential and curve magnitude.
Growth potential

Duval-Beaupere initially reported the correlation between
skeletal growth and curve progression, indicating that
curve progression occurs most rapidly during the adolescent
growth spurt. However this study was confounded by
inclusion of post-polio and AIS patients in the study population
[6]. Subsequent reports that focused exclusively
upon AIS and curve progression have demonstrated that
curve progression is dependent upon the child's remaining
growth, and have identified specific radiographic and
clinical indicators for skeletal maturity and the risk for
curve progression [7,8]. Lonstein and Carlson used the
iliac apophysis ossification (Risser sign) and onset of
menses as indicators for skeletal maturity to correlate
curve magnitude and skeletal maturity with curve progression
in 727 patients with AIS [8,9]. Immature children
(Risser sign 0 or 1) with larger curves (20–29°) at initial
diagnosis demonstrated a 68% risk for curve progression,
whereas mature children (Risser 2–4) with similar curves
at initial presentation had a 23% risk for curve progression.
Conversely, immature children with smaller curves
(5–19°) demonstrated 22% chance for curve progression,
while mature children with smaller curves had only a
1.6% risk for curve progression. Sixty-eight percent of girls

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with non-progressive curves had onset of menses prior to
the initial assessment. More recently, Sanders and coworkers
contributed substantially toward identifying the most
valid and reproducible indicators of skeletal maturity and
correlating skeletal growth with curve progression [10].
The authors evaluated different radiographic measures,
secondary sexual characteristics, and serum markers to
identify the most accurate predictor of skeletal maturity
and the relationship of these markers to the child's peak
height velocity (PHV; the maximal adolescent growth
height velocity) [10]. The Tanner Whitehouse III RUS
scoring system (which uses the radiographic appearance
of the epiphyses of the hand, distal radius, and distal ulna
to generate a skeletal maturity scoring system) was the
most predictive and reliable method to determine the
patient's chronological relationship to PHV. Subsequently,
the authors evaluated scoliotic curve behavior
and reported that progressive curves demonstrated consistent
behavior with reproducible periods of progression,
the most rapid period of progression was termed the curve
acceleration phase (CAP) [11]. Different criteria were then
evaluated to predict the relationship of the child's remaining
growth to the CAP. Again, the Tanner Whitehouse III
RUS scoring system correlated most accurately with the
the child's maturity and the CAP. The authors developed
a simplified version of Tanner Whitehouse III RUS scoring
system, and were able to correlate the appearance of the
hand epiphyses with different stages of skeletal growth
and also these growth stages with the CAP [11]. Sanders et
al. have since developed a predictive model that correlates
hand epiphysis scores with scoliosis progression, and is
able to pair the stages of skeletal maturity with the probability
of scoliosis progression beyond 50° [12]. In their
study, patients at greatest risk for curve progression
beyond 50° were children that presented with curves >
20° and were hand stage 2, and children that were hand
stage 3 with curves > 30°.

Curve magnitude

The size of a scoliotic curve is an independent predictor of
curve progression. Nachemson et al, and Weinstein et al,
correlated curve progression with age and curve magnitude,
demonstrating the importance of age and curve
magnitude when predicting curve progression [13-16].
However, it has been demonstrated that curve magnitude
is an independent predictor of curve progression and that
larger curves can progress after skeletal maturity. Weinstein
et al. and Ascani and colleagues reported that children
with curves < 30° at skeletal maturity did not
demonstrate curve progression into adulthood, while the
majority of curves > 50° progressed at approximately 1°
per year [15-17]. Consequently, patient counseling usually
involves discussions indicating that curves that are <
30° at skeletal maturity are at low risk for progression,

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ABCDEFImages courtesy of Nobumasa Suzuki,
MD
Figure 1
Case example of a 19 year-old old female with a curvature of 56 degrees (preoperative panels, A-C). A surgical
deformity correction was performed. At 6-months follow-up, the patient has a perfect correction of the curve cosmesis and
rib hump (postoperative panels, D-F). The pictures were kindly provided by courtesy of Dr. Nobumasa Suzuki.

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Images courtesy of Larry Lenke,
MD
ABCDEFGH
Figure 2
Case example of a 13 year-old old female with progressive AIS. Clinical photographs show spinal imbalance, and elevated right shoulder (preoperative panels A, G). Adam's forward bend test shows right thoracic prominence correlating with
vertebral rotation and right rib elevation. Radiographs in postero-anterior and lateral views show a proximal thoracic curve of
40°, a main thoracic curve of 74°, and a lumbar curve of 42° (panel C), with normal sagittal parameters (panel D). A posterior
correction with fusion from T4-L2 was performed. Five years postoperatively, radiographs show a 97% correction of the proximal and main thoracic curves with a good maintenance of sagittal balance (panels E, F). Clinical photographs at 5 years show a
restoration of spinal balance (panel B). The Adam's forward bend shows reduction of thoracic rib prominence (panel H). The
pictures were kindly provided by courtesy of Dr. Larry Lenke.

while curves > 50° are at risk for progression into adulthood
[16,18].

Impact of progressive spinal deformity on the quality oflife

The question of untreated AIS causing pain, disability,
and negative impact on quality of life in adulthood has
demonstrated conflicting results. Early studies reported
that untreated scoliosis resulted in increased back pain
and disability, negative socioeconomic effects on work
and marriage, and early mortality compared to controls
[3,4,19,20]. As previously indicated, however, these studies
had mixed etiology of scoliosis, including infantile and
juvenile idiopathic scoliosis. Recent work by Weinstein

and coworkers re-evaluated the amount of disability that
adults with untreated AIS incur. Fifty year follow up of
117 patients with untreated AIS (average curve magnitude
> 75° for thoracic, thoracolumbar, and double major
curve patterns) demonstrated no increase in mortality
rates, disabling back pain, and ability to complete daily
activities compared to age and gender matched controls
[18]. However, acute and chronic back pain, and dissatisfaction
with appearance were more prevalent in patients
with scoliosis, as was shortness of breath in patients with
thoracic curves > 80°. These findings demonstrate that the
prognosis for untreated AIS is not as poor as was originally
reported, however their findings further demonstrate that

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140
120
100
80
60
40
20


Preoperative SRS score Postoperative SRS score (5 year)
Figure 3
Preoperative and 5-year postoperative Scoliosis
Research Society (SRS) score of the patient shown in
figure 2, showing a subjectively improved health-
related quality of life (HRQL).

patients with untreated AIS are unquestionably dissimilar
to matched controls. The authors acknowledge that the
clinical significance of their report is to differentiate the
natural history of AIS from the more negative prognosis
for untreated infantile and juvenile idiopathic scoliosis
patients, rather than demonstrate equality between
patients with and without AIS. A growing body of literature
does indicate that adults with scoliosis demonstrate
greater function limitation, greater daily analgesic use,
and less satisfaction with their appearance compared to
unaffected individuals [19,21-23]. In an attempt to quantify
the amount of disability associated with scoliosis, Berven
et al used established "health-related quality of life"
(HRQL) outcomes measures, including the SRS research
instrument (SRS-22), to evaluate pain and function in
adult patients with and without scoliosis (figure 3). The
SRS research instrument was originally developed to evaluate
surgical outcomes for AIS in children [24-26]. This
instrument has subsequently been validated as the standard
measure for AIS surgical outcomes and disability associated
due to AIS, with validated translations in Chinese,
Japanese, Spanish, and Turkish. The SRS questionnaire
has also demonstrated differences in function, pain, and
self-image between children with and without scoliosis, as
children with AIS demonstrate lower scores than controls
in all domains across cultures [26-35]. In an attempt to
extrapolate these data to adults, Berven and colleagues
demonstrated that the SRS-22 is a reliable instrument for
measuring disability associated with adult spinal deformity,
reporting SRS-22 criteria to be valid in use with the SF36
[21]. The authors reported that adults with scoliosis
scored significantly worse on every SRS-22 and SF-36
domain (including pain, function, self-assessment, and
mental health), compared to controls with no scoliosis.

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These findings have subsequently been supported by Bridwell
et al., validating the SRS-22 as an accurate measure of
function and disability in adults with scoliosis, and that
the SRS-22 demonstrates greater accuracy and consistency
for measuring outcomes for the treatment of adult scoliosis
compared to previous HRQL measures including SF12,
SF-36, and Oswestry Disability Index (ODI) [29].

Surgery for AIS is safe and efficient

The primary surgical goals for treating AIS are to prevent
curve progression, obtain solid arthrodesis, and restore
spinal balance. A plethora of literature has repeatedly
demonstrated that, if established surgical guidelines are
followed, surgical arthrodesis prevents AIS curve progression,
restores spinal balance, and, when permissible, preserves
spinal motion segments via selective fusion of
structural curves and indirect deformity correction of
compensatory curves [36-38]. Using modern surgical
techniques (i.e. segmental spinal fixation, meticulous
posterior element decortication, and bone grafting) solid
arthrodesis is achieved in over 95% of AIS cases [39,40].
Additional goals addressing comesis and self-image concerns
are also addressed, as current surgical techniques
and have demonstrated improved curve correction and
cosmetic outcome compared to early surgical techniques
[40-43].

Reported perioperative complication rates following surgery
for AIS range between 5% and 20%, depending upon
the surgical approach, and differentiation between major
and minor complications [40,42,44,45]. The most recent
SRS morbidity and mortality committee update reported
a 5.7% surgical complication rate in 6334 patients treated
for AIS from 2001–2003 [45]. Recorded complications
included pulmonary, infection, neurological deficit, dural
tear, deep venous thrombosis, and death, but were not
divided into major and minor complications. The incidence
of complications following posterior spinal fusion
was 5.1% whereas the incidence following combined
anteroposterior spinal fusion was 10.2%. Wound complications
were the most common complications for PSF
(1.4%), and pulmonary problems were the most common
for anterior procedures (1.6%). Neurologic complication
rates for anterior, posterior, and combined
procedures were 0.26%, 0.32%, and 1.75%, respectively.
Diab et al, reported 0.69% rate of neurological complications
in 1,301 surgically treated cases of AIS [46]. These
findings were corroborated by a 1.06% rate of neurological
complications following surgery for AIS at a Chinese
hospital over a 7 year period [47]. Carreon and colleagues
prospectively evaluated the prevalence of non-neurologic
complications following surgical treatment of AIS, reporting
a 15.4% prevalence in 702 patients treated from
2002–2004 [44]. The reported prevalence of major complications
including major blood vessel injury, visceral

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injury and deep infection was 0%, 0.28% and 0.71%,
respectively. The majority of compilations (3.7% prevalence)
were labeled "miscellaneous", including transverse
process failures, ileus, lateral femoral cutaneous nerve
dysesthesia, diarrhea, and allergic reactions to medication.
There was no significant association between the
prevalence of a non-neurologic complications and curve
pattern, curve magnitude, surgical approach, number of
spinal levels fused, and type of bone graft used.

Autograft harvest site pain is often reported as a common
complication and source of morbidity following spinal
arthrodesis, however a separate bone graft harvest might
not be necessary when treating AIS. Betz et al. reported
equivalent arthrodesis rates for allograft vs. no graft in a
prospective, randomized study that evaluated grafting
techniques and fusion rates following posterior spinal
fusion for AIS [39]. The authors reported a 1.3% pseudarthrosis
rate, minimum 2 year follow up, among 76 AIS
patients. Patients randomized to no graft demonstrated
no pseudarthrosis compared to one patient randomized
with allograft, who developed a non-union.

Finally, in order to advocate for surgical treatment of AIS,
it must be demonstrated that the consequences of surgical
treatment in adolescence are not detrimental in adulthood.
Long term studies from Canada and Sweden have
indicated that adult patients treated with spinal fusion as
adolescents report reduced function and greater frequency
of back pain compared to controls [48,49]. However, the
reported severity of reported back pain was mild and daily
back pain was uncommon. Additionally, it is difficult to
ascertain if these limitations were due to surgical treatment
of scoliosis or due to scoliosis itself, as it has been
reported that patients treated surgically for AIS indicate
greater function and less pain than patients treated non-
operatively, however function and pain levels continue to
remain inferior to controls without scoliosis [22]. As indicated
above, adolescents treated surgically for AIS demonstrate
significant improvement in HRQL measures
compared to preoperative scores, including improvement
in all SRS questionnaire preoperative domains at 2 year
follow-up, and report high treatment satisfaction levels
[26]. Of note, Upasani et al reported that AIS patients
demonstrated significantly increased back pain 5 at year
follow-up compared to 2 postoperative values [50]. The
etiology of this increase in pain was not determined, nor
was the clinical significance of the increase in pain,
namely if it reached a so-called "minimally clinical important
difference". Even so, pain scores at 5 year follow up
were still lower than preoperative values, and patients
continued to reported high treatment satisfaction and
high self-image, independent of the pain scores.

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Discussion

Surgical treatment of spinal deformity remains and emotional
decision for both the patients and their parents. In
our modern society, the affected child's parents have to
assume the responsibility for making a decision that could
influence their child's life forever. It is therefore necessary
to define the roles for each treatment option and to define
the expected long-term outcomes for each treatment
modality. Many adults are now presenting for scoliosis
surgery who still remember their childhood years spent in
casts and turnbuckle braces. The advancement of general
medicines are keeping these patients alive and they are in
chronic pain and disabled. They have been able to live a
relatively productive life and are now faced with the late
effects of untreated scoliosis, quite bitter that they were
denied the surgical option by their parents when they
were young. It is hard to balance this argument when
faced with a young teenager as it is impossible for us to see
what future development might bring in term of revolutionizing
the disease. It is agreed from both view points
that the disease warrants treatment. We therefore suggest
that surgical and non surgical treatment option each has
their rightful place and that the decision for treatment
should be based on the curve type and the risk factories for
progression, keeping in mind the end result as well as the
expected long-term outcomes (figures 2, 3).

Debate: "Contra" surgery

Signs and symptoms of scoliosis cannot be changed by
spinal fusion surgery

Spinal fusion surgery, which is recommended when the
magnitude of curvature exceeds 40–45 degrees, has been
used as a treatment for nearly a century [51-53]. The aims
and goals of surgery have varied widely. The early belief
was that spinal fusion could be used to leave the patient
with a mild residual deformity but this is not the case as
one third of patients lost all postoperative correction
within one to ten years post surgery [54]. Expectations
have been revised to the more modest goals of preventing
progression, restoring 'acceptability,' and reducing curvature.
In spinal fusion, the vertebrae are accessed by posterior,
anterior, or thoracoscopic incision. The main
principle of these surgical techniques is to use the spine as
a structural scaffold, cementing the parts onto this via a
bone paste, giving it an overall straighter shape. [53,5557].
These surgical methods are based on the assumption
that this will heal well and remain sturdy for patient's
lifespan. Metal rods, screws, wires etc. have been used to
reinforce the stability of the spinal fusion [56-61] and the
choice of instrumentation is based upon the preferences
of the surgeon [62-66]. Failure of spinal fusion requires
re-operation to restore curvature correction [62].

What specific evidence is there to support scoliosis surgery?
The signs and symptoms of scoliosis obviously can-

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not be changed by scoliosis surgery and long-term
beneficial effects have not been reported yet [67,68] and,
in addition to this, there are no studies presenting the
long-term risks [67]. Moreover, no report of the long-term
surgical outcome (balance, rate of fusion, rib hump correction,
cosmetic correction, pain, and patient satisfaction)
is available for any study series. Further prospective
studies including these parameters will be required to
determine the real benefit of such procedures for the
patient [67].

No evidence for surgery in prospective controlled trials

There are in fact prospective controlled studies comparing
the outcome of patients with AIS treated conservatively
with a series of patients treated surgically [48,69-73]. Nevertheless
no study is available comparing surgery to the
natural history prospectively [74-76]. The Gothenburg's
papers do not offer any evidence that the long-term outcome
of surgery is superior to the long-term outcome of
patients treated conservatively [48,69-73]. The studies
relating to HRQL/SRS-22 questionnaires do not demonstrate
differences between the two groups of patients [70],
pain and function do not differ [48,73], nor does degeneration
[71], sexual function [72] or restrictive ventilation
disorder [69]. As early as 1973, Paul Harrington envisioned
in the future a common database or registry of all
Scoliosis Research Society (SRS) members' patient's treatment
results [51]. Unfortunately the SRS failed to follow
this vision until recently. Instead of achieving long-term
evidence for surgical treatment on a higher level and
addressing the problems after surgery to attempt to
improve patient safety, the surgical community is presenting
large numbers of papers describing HRQL after surgery
and related research [26,77-81].

The problem with such studies is that they lack validity as
they do not investigate the actual signs of scoliosis or the
post-surgery symptoms of the patient [82]. Those studies
containing psychological questionnaires may be compromised
by the dissonance effect [74-76,82,83]. This implies
that all situations which include important decisions to be
made. Cognitive dissonance occurs most often in the situations
where an individual must choose between two
incompatible beliefs or actions and there is a tendency for
individuals to seek consistency among their cognitions.
Unable to face an inconsistency, such as being dissatisfied
with a surgical procedure, an individual will often change
an attitude or action. Surgery is impossible to reverse, but
subjective beliefs and public attitude can be altered more
easily. The clinical significance of this is that a patient dissatisfied
with surgical treatment may not necessarily
admit this publicly, as the findings of the following studies:


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"Slim objective favorable outcomes correlate with high post-surgical patient satisfaction, while a considerable share of patients
with whom a highly favorable outcome has been attained
express relatively low post-surgical patient satisfaction. This
paradoxical trend may be well understood when applying Cognitive Dissonance Theory. The whole pattern of results point
again at highly complex and powerful psychological processes,
some of them seemingly irrational" [82].

"Patient satisfaction is subjective. It does not reflect the benefits
of surgery with respect to the future preservation of pulmonary
function in thoracic curves nor the prevention of osteoarthritis
in lumbar curves" [84].

"Radiographic and physical measures of deformity do not correlate well with patients' and parents' perceptions of appearance.
Patients and parents do not strongly agree on the cosmetic outcome of AIS surgery" [85].

From searching all of the studies based on questionnaires
within this review, no evidence can be derived that supports
the assumption that patients have experienced benefits
from undergoing surgery, as none were able to rule
out the cognitive effect of dissonance. Without being able
to rule out such effects on the post-operative experience
these outcomes do not appear to be valid for the group of
scoliosis patients treated surgically [74-76].

Complications of spinal fusion surgery

In principal, all kinds of complications may occur in all
scoliosis aetiologies [67]. However, in the otherwise
healthy subjects with AIS the incidence of major complications
may not be as high as in neuromuscular disorders
[67,86]. Risks of spinal fusion include those occurring in
any major surgery such as severe blood loss; urinary infections
due to catheterization; pancreatitis; and obstructive
bowel dysfunction due to immobilisation during and
after surgery [67,86]. The frequency of specific complications,
including death is unknown. This is due to problems
in reporting such as; mandatory reporting,
definitions, interpretation of complications and variations
within compliance [67]. Information is based on
voluntary reporting by clinicians. Other risks of scoliosis
surgery, as listed in recent reviews [67,86] are summarised
below:

Death and neurological damage

The incidence of death as a complication of spine surgery,
for otherwise healthy patients is reported to be less than
1%. In one survey only one child out of 352 patients died
of peritonitis and in a group of 447 patients, 2 deaths
occurred due to pulmonary complications. The life
expectancy of patients with complex neuromuscular condition
was significantly reduced by spinal surgery.
Another study involving adults with a less than 60% vital

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capacity measure, 20% had died within 1 year post surgery.
In a survey further highlighting these complications,
21% were contributed to be secondary to spinal fusion
surgery [86].

Symptoms of neurological damage post-surgery include;
partial or total paraplegia, quadriplegia, or peripheral
nerve deficit. Neurological deficits can result from vascular,
metabolic, or mechanical complications of spine surgery.
Published cases include migration of bone graft into
the spinal canal; breakage of implants; penetration of
instrumentation into the spinal canal and compression of
the nerve roots by components of implants [86].

Loss of normal spinal function

In every case of spinal surgery there is an irreversible loss
of the normal active range of movement in the spinal column,
including the non-fused segments. When compared
with control subjects, the ability of surgical patients to
side flex was reduced by 20–60%. This loss of spinal
mobility has gained little attention in the literature especially
in relation to the detrimental effects upon patient's
health, function, and quality of life. Winter and colleagues

[87] argued that 'it has long been a clinical observation by surgeons who manage scoliosis that patients seem to function well
and be relatively unaware of spinal stiffness, even after many
motion segments have been fused.' No data in support of this
observation has been provided [67]. In fact, it has been
shown that pain increases as flexibility is reduced in nonsurgical
cases [88].
Strain on adjacent, non-fused vertebrae

The post-surgical rigid spine causes strain on the un-fused
parts of the skeletal framework. More commonly reported
are post surgical degenerative changes, which occur in
young adults and older adults, sometimes within 2 years
post-surgery. A higher degree of correction results in a
higher rate of degenerative osteoarthritis, and the high
stress on the rigid spine can cause serious injuries [86].

Post-surgical pain

Pain is the primary indication for re-operation [67,86].
The mechanism for increased neck and back pain after
surgery is not well understood. Bridwell [53] suggests that
late-developing pain could be a complication of surgery,
or an effect of aging, or 'perhaps a focus on the disability associated with spinal deformity and surgical treatment'. Among
190 patients, 19% required re-operation within 2 to 8
years after surgery. For 27 patients who sought treatment
59% felt their pain had been reduced, but 41% did not
feel a reduction in their pain levels, and a further 26%
were very unhappy with the outcome [86]. Among 34
patients with significant post surgical pain, 56% reported
reduced pain after additional surgery, while 44% did not;
within the same study, 2 patients who did not have pain

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before surgery reported pain in follow-up [86]. Pain at the
iliac graft site, first noted in 1979, has now been formally
published; of 87 patients, 24% complained of pain at the
graft site, with 15% reporting severity sufficient to interfere
with daily activities. As reported by the authors such
problems with iliac crest grafting have been severely
neglected in literature, especially problems associated
with rib-resection [67,86].

Infection and inflammatory processes

Infections from surgery may manifest months or years
later and has been detected more than 8 years after surgery,
with 5 to10% of patients developing deep infections
at 11–45 months after surgery and in some cases leave the
spinal cord exposed to injury. Infections become more
common, perhaps due to larger instrumentation used or
perhaps due to the increasing prevalence of multi-drug
resistant bacteria in hospital settings. Inflammatory
responses to metallic instrumentation can occur independently
or in conjunction with infections. In most
cases, additional surgery to remove instrumentation and
to treat the wound is required [67,86]. Infection also may
be transmitted through blood transfusions needed to
replace the large amounts of blood lost during invasive
procedures and a similar risk occurs with the use of allograft.
Some have reported to be infected with HIV following
this type of surgery. In a survey of spine surgeons, 41%
of those using allograft reported having concerns about
the risk of disease transmission and 88% of those make it
a policy to inform parents [67,86].

Curvature progression

Some curvatures continue to progress after spinal fusion
due to broken rods or other failure of instrumentation.
Renshaw [56] has said that, "One would expect that if the
patient lives long enough, rod breakage will be a virtual certainty." Furthermore, discomfort may occur when any
pressure is placed against the back; this is especially problematical
with newer bulky instrumentation implanted in
thin patients [53]. Pseudarthrosis or failure of the bone
graft, which constitutes the spinal fusion, can occur years
after surgery and can be difficult to diagnose. Among 74
patients treated surgically between 1961 and 1976, pseudarthrosis
occurred in 27% of patients within a few years
of surgery. For adult patients, 15% had failure of fusion
and/or instrumentation requiring additional surgery. Curvatures
may continue to progress in young children
despite a rigid fusion, due to a 'crankshaft phenomenon' in
which spinal growth causes rotation around the fusion
[67,86].

Decompensation and increased sagittal deformity

Beginning with Harrington's rods, surgeons have experimented
with instrumentation of increasing complexity
and bulk to hold spinal fusions in place. Each new instru-

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mentation has brought with it new problems. One of the
ongoing problems is decompensation or the development
of new deformities involving changes in sagittal contours
and coronal balance of the body as a result of surgery.
Reducing the lateral curvature in thoracic scoliosis can
exacerbate the sagittal deformity and cause flattening of
the cervical, thoracic and or lumbar spine beyond that
cause the deformity itself. Development of 'flat back' is a
painful condition with potentially devastating complications
such as disability. In response to such discoveries,
focus is shifting towards the sagittal contours and coronal
balance of the spine [53,67,86].

Increased torso deformity

Despite the application of force to straighten and de-
rotate the spine during surgery, the rib hump can deteriorate
after surgery. Even when rib hump magnitude
improves postoperatively, much of the correction can be
lost and in many patients appears worse than before the
surgery (figure 4, panels A-E). In response, surgeons
increasingly use costoplasty to assure an improved
appearance, by excising the ribs that comprise the prominence.
This procedure can in actual fact cause a progres-

ABCDEFGHI
sive scoliosis [52] and the destabilising effects of rib
removal can also result in a disabling condition called
'flail chest' in which the normal function of the rib cage is
permanently compromised. Rib resection excises a substantial
part of the functional components of the chest but
the effects on chest expansion have not been documented.
However, this procedure has been shown to reduce the
volume of the chest cage and to substantially impair pulmonary
function [67,86].

Other long-term complications

The complexity of spinal surgery is reflected in the diversity
of complications that may result months or years
later. Given the time delay and difficulty in diagnosis, it is
likely that only a minority of such events are recognised as
surgical complications and when investigated are then
recognised as being related to the surgery [67,86].

Salvage surgery

Due to such complications outlined above more re-operation
is necessary, sometimes referred to as 'reconstructive',
're-corrective,' 'revision,' or 'salvage' surgery. Even
stable fusions may fail in response to sudden force, as in

Figure 4
Selected case examples of patients who underwent spinal fusion surgery for curvatures between 50 and 60
degrees (upper panels, A-D). As shown in the examples in the lower panels (F-I), a ribhump may remain visible despite surgical correction. The patient in panel E was operated for a curve of 32 degrees thoracic and 28 degrees lumbar and had a progression of the thoracic curve to more than 50 degrees after operation. As all of the patients on this picture are still young, a
further clinical (and radiological) deterioration may be expected.

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Patient Safety in Surgery 2008, 2:25

automobile accidents. Some authors suggest that patients
and their parents should be advised that it may take more
than one operation [67]. Documented cases of having 5
or more salvage surgeries, as in one study, 22% of patients
needed a total of 28 additional operations and of 110
adolescent patients, 21% required implant removal [89].
Complication rates vary; failure of fusion has been found
in more than 50% of treated patients [67] and among 25
adult patients, 40% required salvage surgery. Even when a
solid fusion has been obtained by the time of re-operation,
removal of instrumentation 'may lead to spinal collapse and further surgery' [67,86].

Discussion

From the patient's perspective, the preferred plan of action
would likely be based upon avoiding unnecessary risk i.e.
avoiding surgery, or to keep it as the final option, once all
conservative measures have failed. Under this premise,
every effort should be undertaken to improve non-operative
treatments for AIS, the most common form of scoliosis,
which is regarded to be relatively benign [18]. In view
of the fact that there is no evidence that health related
signs and symptoms of a scoliosis can be changed by spinal
fusion in the long-term [67,74-76], a clear medical
indication cannot be derived from most scoliosis conditions
[74-76]. In the light of an actual publication on adolescent
idiopathic scoliosis with a prospective design [44],
showing the short-term risks of scoliosis surgery to be
more than 3 times higher than previously expected from
retrospective reviews, the matter of surgical indications at
present should be investigated more closely in order to
improve the safety for patients, however, as has been
shown [86], still today there are more open questions,
than answers regarding the outcome of spinal fusion surgery
for AIS patients.

In consideration of the questions generated by research
[67,74-76,86], the lack of measurable medical benefit
[67,90] and the high amount of short and long-term risks
of the surgical procedures applied, the decision to have
surgery does not rely on any valid evidence to support it.
The informed patient perhaps should make the final decision
after being provided with all the objective facts available.
There is evidence on physical therapy to be found

[91] justifying a grade A recommendation while conservative
management [75] to be a grade B recommendation
and spinal fusion surgery is considered as only a grade C
recommendation [67,74-76,90]. Some spine surgeons
still do not acknowledge the role of conservative management
although evidence exists [92], reasons for this are
perhaps based in an underlying conflict [93]. Today's
"best practice" bracing technology enables to provide significant
clinical and radiological improvements (figures 5,
6) [94,95], which clinically are comparable to what is
achievable by applying spinal fusion surgery (figure 5,
http://www.pssjournal.com/content/2/1/25


Figure 5
A young female patient with initially 56 degrees thoracic curve at the age of 15 years, treated with a
Chêneau brace and scoliosis intensive rehabilitation
(SIR) at the age of 20 (right panel), currently with 47
degrees and a clinical appearance comparable to the
postoperative appearance shown in figure 4.

compared to figure 4). The current development of scoliosis
braces seems to have a less negative impact on quality
of life than braces of previous standards [96] using less
physically restrictive material but meeting the same in-
brace correction effects (Figure 6) [95]. Physical therapy
due to present evidence has to be regarded to be effective
in preventing curvature progression in smaller curves
[75,91]. Therefore, spinal fusion surgery seems not to be
indicated medically, while in bigger curvatures the
patients themselves should understand the complications
and decide whether their deformity is having too much of
a negative psychological impact to resort to such invasive
treatment. Spinal fusion surgery for AIS patients should be
performed only after describing all the adverse effects the
operation might have [67,86] to enable the patient to
weigh the risks against the benefits in the long term [67].
Conservative management involves very different skills
from surgery, which may sway surgical opinions towards
a negative perspective on this subject [92]. However, anyone
claiming to be a specialist in the treatment of scoliosis
should advise patients according to evidence based practice
and should offer a high quality conservative management
to the patients.

Conclusion

"Pro" surgery

AIS is a relatively uncommon condition, occurring in
approximately 2–3% of children. The number of children
that require treatment for AIS, is even smaller, approximately
0.1–0.3%, and those that receive surgical treat-

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Figure 6
Case example of an 11 year-old girl with 38 degrees curvature, Tanner II, corrected to 19 degrees after two
years of brace treatment (2005–2007), followed by part-time bracing. Clinically, the patient has improved significantly. Current braces work with much less material than conventional braces, thus providing more comfort to the patients.

ment is smaller still27. However, progressive AIS is not a
benign condition and should not be observed. Children
with progressive AIS report lower self-image and worse
HRQL scores than controls with no scoliosis. These low
scores translate into further disability and dissatisfaction
into adulthood. Although recent studies have indicated
that the prognosis for untreated AIS in adults is not as dire
as was originally thought, adult patients with untreated
scoliosis demonstrate greater disability and lower HRQL
scores compared to controls and those treated surgically.
When progressive AIS has been identified, surgical intervention
reliably stops curve progression and restores spinal
balance, with minimal perioperative complications.
Postoperatively, children surgically treated for AIS consistently
demonstrate improved HRQL scores, including
improved function, improved self-image and decreased
pain from preoperative values. These findings support surgical
treatment for progressive AIS, as non-operative
measures will only allow the condition to worsen.

"Contra" surgery

Health-related signs and symptoms of idiopathic scoliosis
cannot be changed by surgery. Long-term beneficial
effects of spinal fusion are not yet revealed and the long-
term risks of surgery for scoliosis simply are not known.
HRQL scores cannot be regarded as being valid considering
the dissonance effect. Therefore the indication for spinal
fusion surgery is for cosmetic reasons, only. When
recognizing, that todays standard of conservative treat


ment can in fact lead to the same cosmetic effects as spinal
fusion surgery, the latter treatment is rarely needed in
patients with AIS.

Competing interests

H–RW is currently applying for a patent relating to the
Chêneau light™ off the shelf bracing system, which is
demonstrated in figure 6. Additionally, he is a consultant
for Koob-Scolitech. EB is a consultant for Synthes, Aesculap,
and Pioneer spine implants. She furthermore declares
research agreements with DePuy and Showa-Ika, and has
received speakers' fees from DePuy. SB, MSW, VP, and DG
did not declare any competing interests related to this
paper.