Scheuermann’s Kyphosis in Adolescents and Adults
Dr Harry Sunaryo SpOT
In 1920, Scheuermann first described
the entity of structural thoracic
kyphosis that now bears his
name. The clinical condition of
ScheuermannÕs kyphosis has widely
variable presentations that do not
necessarily correlate with the radiographic
findings; evaluation of a
lateral thoracic radiograph is necessary
to establish the diagnosis.
S¿rensen1 defined the radiographic
diagnosis of ScheuermannÕs kyphosis
on the basis of anterior wedging
of 5 degrees or more of at least
three adjacent vertebral bodies.
(This definition is helpful in differentiating
ScheuermannÕs kyphosis
from familial round-back deformity.)
Adolescents with Scheuermann
Õs kyphosis typically present
to medical attention on the urging
of family or teachers who are concerned
about the cosmetic deformity.
Adults who have been living
with the cosmetic deformity for
long periods of time usually seek
medical attention because of increased
pain. Although Scheuermann
Õs kyphosis has been well
described in terms of clinical presentation
and radiographic findings,
the etiology remains largely
unknown, and the indications for
treatment continue to be debated.
Normal Thoracic Kyphosis
Unlike scoliosis, in which any lateral
deviation of the spine in the
coronal plane can be deemed
abnormal, the sagittal alignment of
the thoracic spine displays a range
of normal that is dynamic. Thoracic
kyphosis typically increases
throughout life. Fon et al2 determined
that kyphosis in children
under the age of 10 years averages
20.88 degrees (SD, 7.85) for boys
and 23.87 degrees (SD, 6.67) for
girls; in adolescents up to age 19,
kyphosis averages 25.11 degrees
(SD, 8.16) in boys and 26.00 degrees
(SD, 7.43) in girls. The slightly
greater kyphotic deviation in females
increases after age 40. In
women aged 50 through 59, mean
kyphosis measures 40.71 degrees
(SD, 9.88); in age-matched men, it
is 33.00 degrees (SD, 6.46). While
the values are still debated, the
Scoliosis Research Society has stated
that the accepted range
ScheuermannÕs thoracic kyphosis is a structural deformity classically characterized
by anterior wedging of 5 degrees or more of three adjacent thoracic vertebral
bodies. Secondary radiographic findings of SchmorlÕs nodes, endplate narrowing,
and irregular endplates confirm the diagnosis. The etiology remains
unclear. Adolescents typically present to medical attention because of cosmetic
deformity; adults more commonly present because of increased pain. The indications
for treatment are similar to those for other spinal deformities, namely,
progression of the deformity, pain, neurologic compromise, and cosmesis. The
adolescent with pain associated with ScheuermannÕs kyphosis usually responds
to physical therapy and a short course of anti-inflammatory medications.
Bracing has been shown to be effective in controlling a progressive curve in the
adolescent patient. For the adult who presents with pain, the early mainstays of
treatment are physical therapy, anti-inflammatory medications, and behavioral
modification. In patients, either adolescent or adult, with a progressive deformity,
refractory pain, or neurologic deficit, surgical correction of the deformity
may be indicated. Surgical correction should not exceed 50% of the initial
deformity. Distally, instrumentation should be extended beyond the end vertebral
body to the first lordotic disk to prevent the development of distal junctional
kyphosis.
mal thoracic kyphosis for a growing
adolescent is between 20 and 40
degrees, and that any degree of
kyphosis at the thoracolumbar or
lumbar area of the spine should be
considered abnormal.3
Epidemiology and
Pathogenesis of
Scheuermann’s Kyphosis
In 1964, S¿rensen1 reported a
prevalence of ScheuermannÕs
kyphosis of 0.4% to 8.3%. Of the
five studies that S¿rensen cited,
those by Wassman in 1951 and
Bonne in 1955 reported a prevalence
of 0.4%. While these represented
the larger series, they perhaps
contained inherent bias in
that they included only men who
had been rejected for military service
because of their deformity.
Realizing this potential bias, both
investigators estimated that the
total prevalence of ScheuermannÕs
kyphosis was between 4% and 8%,
which is more in line with the findings
of other investigators. In a
subsequent review of 1,384 cadaveric
specimens, Scoles et al4 reported
a prevalence of 7.4%.
It is generally considered that
the prevalence of ScheuermannÕs
kyphosis is approximately equal in
males and females. In S¿rensen’s
review,1 58% of the patients were
male, and 42% were female. There
are, however, widely divergent
reports on relative prevalence
between the sexes. Bradford3
reported a female-male ratio of 2:1
for the prevalence of Scheuermann
Õs kyphosis, while Murray et
al5 reported a 2.1-times higher
prevalence in males.
The age of onset of Scheuermann
Õs kyphosis is difficult to
establish. S¿rensen1 described a
ScheuermannÕs prodrome in patients
who have a Òlax, asthenic
posture from the age of approximately
4 to 8 years, and [in whom]
within a few years a real fixed
kyphosis has developed.Ó Radiographic
findings consistent with
ScheuermannÕs kyphosis are not
visible until the age of 12 to 13, corresponding
with the onset of
puberty. Therefore, adolescent
girls typically evidence the radiographic
findings before adolescent
boys.
The pathogenesis of Scheuermann
Õs kyphosis has yet to be elucidated,
although many theories
have been proposed. Scheuermann
Õs initial description included
a hypothesis that avascular necrosis
of the ring apophysis leads to
premature cessation of growth
anteriorly, which results in wedging
of the vertebral body. Schmorl
postulated that herniations of disk
material through the vertebral endplates
(which now bear his name)
lead to a loss of disk height and
anterior wedging of the vertebral
body.6 Subsequent studies disproved
these early theories, but
have not yet established a cause.
An underlying genetic factor has
been suggested. Halal et al7 reported
in 1978 on five families who
demonstrated an autosomal dominant
mode of inheritance with high
penetrance but variable expression.
Skogland et al8 reported on 62 girls
aged 9 to 18 years whose mean
height was 2.5 SDs above average;
18 had thoracic kyphosis greater
than 40 degrees, and 11 had additional
vertebral abnormalities consistent
with ScheuermannÕs disease.
Ascani et al supported a similar
correlation of ScheuermannÕs kyphosis
with height and also demonstrated
increased levels of growth
hormone.6
Although the anatomic and histologic
findings in Scheuermann’s
kyphosis are well established, the
cause-and-effect relationships are
less clear. Gross anatomic findings,
such as a thickened anterior longitudinal
ligament, narrowed vertebral
disks, and wedged vertebral
bodies, are consistent findings.2,9
Histologic abnormalities of the cartilaginous
endplate have also been
described. The ratio of collagen to
proteoglycan in the matrix of the
endplate is below normal in
patients with ScheuermannÕs
kyphosis. The relative decrease in
collagen is postulated to result in
an alteration in the ossification of
the endplate and thus altered vertical
growth of the vertebral body.6
It has also been postulated that
osteoporosis may be an etiologic
factor in the development of
ScheuermannÕs kyphosis. Bradford
et al10 prospectively studied 12
patients with ScheuermannÕs
kyphosis with an extensive osteoporosis
workup and iliac crest
biopsy. While their study did not
demonstrate cause and effect, it did
show that some patients with
ScheuermannÕs kyphosis have a
mild form of osteoporosis, and
dietary analysis demonstrated
some deficiency in calcium intake.
It was hypothesized by the investigators
that the osteoporosis may be
transient, presenting early in the
course of the disease before it
becomes radiographically evident.
Gilsanz et al11 subsequently reported
on 20 adolescent patients with
ScheuermannÕs kyphosis aged 12 to
18. No evidence of osteoporosis
could be demonstrated when compared
with controls as measured
by quantitative computed tomography.
However, this does not necessarily
contradict the theory that
early osteoporosis may be an etiologic
factor.
Mechanical factors have also
been postulated in the development
of ScheuermannÕs kyphosis.
Scheuermann initially noted a high
incidence of kyphosis in industrial
workers. The role of mechanical
factors is also supported in part by
the success of bracing.12 What
remains unclear in the mechanical
theory is whether the histologic
endplate changes predispose to the
development of pathologic kyphosis
or are secondary.
Evaluation
The indications for the treatment of
patients with ScheuermannÕs kyphosis
can be grouped in five general
categories: pain, progression of
deformity, neurologic compromise,
cardiopulmonary compromise, and
cosmesis.
For appropriate evaluation, a
detailed history and physical examination
must be combined with
radiographic evaluation to document
the patientÕs status in each
category.
History and Physical
Examination
The adolescent typically comes
to medical attention for different
reasons than the adult. Adolescents
often present on the urging of
parents, teachers, or friends, primarily
for cosmetic or postural
complaints. Pain is more commonly
the chief complaint of adults.
The issues in the history and physical
examination, however, are similar
for both groups.
If pain exists, its location, exacerbating
features, and severity
should be documented. Typically,
pain is located just distal to the
apex of the deformity in a paraspinal
location. If the pain pattern
is atypical, particularly in an adolescent,
other causes for the pain
must be ruled out. In the adolescent,
when pain or discomfort is reported,
it is most often activityrelated
and presents as either pain
in the typical area associated with
ScheuermannÕs kyphosis or simply
early fatigue. The symptoms are
most commonly relieved immediately
with rest and usually are not
activity-limiting. In adults, pain is
a much more common presenting
complaint. Hyperlordosis distal to
the thoracic deformity and subsequent
degenerative disk and facet
arthropathy predispose adults to
low back pain; the typical pain
over the deformity may coexist or
predominate. S¿rensen1 reported
that pain was the presenting complaint
in over 50% of the 103 patients
in his initial review. Other
authors have noted the occurrence
of pain in 20% to 60% of their
patients.3
ScheuermannÕs disease may also
exist in a variant form (pseudo-
ScheuermannÕs disease), in which
the predominant deformity is at the
thoracolumbar or even the lumbar
region of the spine. Pain is typically
concordant with these variant
locations, and the cosmetic deformities
at these alternate locations
may not be as severe.13
Progression of the deformity is
an additional indication for treatment
of patients with Scheuermann
Õs kyphosis. Careful attention
to the history of the curve is essential.
The deformity may have been
ignored or considered to merely
represent poor posture; this combined
with typical adolescent hesitancy
and self-consciousness may
result in a delay in diagnosis. The
patientÕs perception that the deformity
is increasing and previous
radiographic evaluation can provide
concrete evidence of progression
of the deformity. Similar
issues should be addressed in the
adult, in whom radiographic confirmation
can more often be obtained.
Cord compression secondary to
ScheuermannÕs kyphosis is rare,
but when present may mandate
surgical treatment. The history of
onset of the neurologic compromise
is quite variable, ranging from
acute onset of unilateral radiculopathy
to insidious onset of spastic
paraplegia. The underlying
cause is that the spinal cord is
draped over the apex of the deformity.
A short-segment severe
deformity is generally considered
to be at highest risk, but this is not
fully supported in the literature.
Lonstein et al14 demonstrated an
average kyphosis of 95 degrees in a
mixed population of patients with
neurologic compromise, while
Ryan and Taylor15 showed an average
kyphosis of only 54 degrees in
three patients with ScheuermannÕs
kyphosis. Patients with Scheuermann
Õs kyphosis may also present
with extradural cysts or acute thoracic
disk herniations, which may
be exacerbated by the underlying
deformity and may cause neurologic
compromise.
Cardiopulmonary complaints are
extremely rare on initial presentation
of patients with ScheuermannÕs
kyphosis. S¿rensen1 reported that
chest wall abnormalities had no
negative effect on cardiopulmonary
function. However, Murray et al5
documented restrictive pulmonary
disease in patients with kyphosis
measuring greater than 100 degrees,
with the apex of the curve in the
upper thoracic region.
Cosmetic issues related to the
curve should also be addressed
with the patient. These concerns
should not be underestimated as
the driving force that initially
brings the patient to medical attention.
However, when cosmesis is
an isolated indication for treatment,
particularly surgical intervention,
caution should be exercised.
The physical examination is
important in documenting the findings
of ScheuermannÕs kyphosis
(Fig. 1). Even in adolescents, the
sagittal deformity is fairly rigid on
hyperextension, whereas in the
patient with postural kyphosis, the
deformity is more correctable. Both
types of deformity may be rigid in
Clifford B. Tribus, MD
Vol 6, No 1, January/February 1998 39
the adult. Having the patient bend
forward and viewing the deformity
from the side is the best way to
delineate the kyphosis. Typically,
the cervical spine and the lumbar
spine display increased lordosis,
while the overall sagittal and coronal
balance is well maintained. The
shoulder girdles are often rotated
anteriorly; the combination of this
characteristic with the cervical lordosis
can produce a stooped and
awkward appearance. The arms
and legs will appear relatively long
compared with the shortened
trunk. The lower extremity should
also be evaluated, particularly for
hamstring tightness and underlying
neurologic compromise. On forward
bending, the patient with
ScheuermannÕs kyphosis will have
an ÒA-frameÓ deformity with a
more limited area of involvement
than the patient with familial
round-back deformity.
Radiologic Evaluation
Routine radiographic studies
obtained for evaluation of the patient
with ScheuermannÕs kyphosis
should include anteroposterior and
lateral radiographs of the entire
spine on long films and a hyperextension
lateral image of the thoracic
spine. The lateral radiograph
should be obtained with the patient
standing with knees and hips fully
extended and arms flexed forward
to 90 degrees. The patient should
be looking straight forward. The
lateral radiograph will document
the typical changes of Scheuermann
Õs kyphosis, such as SchmorlÕs
nodes, disk-space narrowing, irregular
endplates, and vertebral
wedging.
Both the vertebral wedging and
the kyphosis should be measured
by the Cobb technique. For measuring
the kyphosis, the end vertebral
bodies, which are the last vertebral
bodies tilted into the kyphotic
deformity, should be selected. The
angle between the distal endplates
of these end vertebral bodies is the
kyphotic angle. When evaluating
serial radiographs to document true
progression, care should be taken to
ensure that the same end vertebral
bodies are being used. The angle
between the endplates of individual
vertebral bodies can be measured to
assess for vertebral wedging.
Wedging of at least 5 degrees of
three or more successive vertebral
bodies is essential to the diagnosis
of ScheuermannÕs kyphosis.
Variations of ScheuermannÕs
kyphosis do exist, and the diagnosis
of ScheuermannÕs kyphosis may
be expanded to allow for the presence
of a wider spectrum of the
disease. Bradford3 has stated that
the presence of one wedged vertebral
body suffices for the diagnosis
of ScheuermannÕs kyphosis. Patients
who present with irregular
endplate changes, disk-space narrowing,
and SchmorlÕs nodes without
vertebral wedging may have
another variation of ScheuermannÕs
kyphosis, as may patients with
fixed kyphosis but no other typical
radiographic findings.
The lateral radiograph should
also be used to evaluate other associated
conditions, such as hyperlordosis
of the lumbar spine,
spondylolisthesis, and degenerative
changes in the lumbar spine.
The anteroposterior radiograph is
used to assess the coronal balance
of the spine as well as the presence
of scoliosis, which is associated
with ScheuermannÕs kyphosis in
approximately a third of all patients.
To assess the flexibility of the
kyphosis, a lateral radiograph in
hyperextension may be obtained.
The same vertebral endplates used
to assess the standing lateral
kyphosis can be selected for the
hyperextension lateral view.
Radiography is the most helpful
tool in eliminating other elements
in the differential diagnosis and in
making the diagnosis of Scheuermann
Õs kyphosis. In both adolescents
and adults, postural kyphosis
is the most common entity in the
differential diagnosis. Postural
kyphosis is an increase in the thoracic
kyphosis of as much as 60
degrees. Radiographic findings
typical of ScheuermannÕs kyphosis
should not be found. In the adolescent,
the kyphotic angle should
be entirely correctable on hyperextension
radiographs.
Adolescent with kyphotic deformity.
The presence of congenital kyphosis
must be ruled out, particularly
in the adolescent. If an anterior
bar is present, ScheuermannÕs
kyphosis is effectively ruled out. In
the adult, other causes of fixed thoracic
kyphosis also exist: ankylosing
spondylitis, multiple healed
compression fractures, tumor,
infection, tuberculosis, and postlaminectomy
kyphosis. Computed
tomography, magnetic resonance
(MR) imaging, and myelography
may be helpful adjunctive studies
to complete the evaluation of the
kyphotic deformity.
Natural History
The natural history of Scheuermann
Õs kyphosis is difficult to discern.
It is generally agreed that
patients with mild deformities may
have few clinical sequelae. Those
patients who come to medical
attention typically do so because of
concern about deformity, pain,
cosmesis, or (rarely) neurologic
symptoms. Back pain and fatigue
in the adolescent may improve
with skeletal maturity. Back pain
in the adult patient with Scheuermann
Õs kyphosis is typically secondary
to spondylosis associated
with the deformity and is quite
often refractory to nonoperative
care. Paajaanen et al16 reported
that 55% of the disks in young
adults with ScheuermannÕs kyphosis
were abnormal on MR imaging.
This rate was five times that in
asymptomatic controls.
Murray et al5 reported on the
natural history and long-term follow-
up of ScheuermannÕs kyphosis
in 1993. They followed up 67
patients who had a mean kyphotic
angle of 71 degrees for an average
of 32 years and compared them
with age-matched controls. Patients
with ScheuermannÕs kyphosis
rated their back pain as more
intense and localized in the thoracic
spine. They had less demanding
jobs on average and less
extension of the thoracic spine
compared with controls. However,
both groups were similar in
terms of the level of education, the
number of days absent from work,
social limitations, use of medications
for back pain, and level of
recreational activities. The patients
in their series also reported
little preoccupation with physical
appearance. In regard to pulmonary
function, those patients
with kyphotic curves greater than
100 degrees had a higher incidence
of restrictive lung disease.
Other authors have encountered
more ominous results. Bradford17
reported the incidence of severe
pain over the thoracic spine in 50%
of his patients, with an increased
incidence of pain when the kyphosis
was centered over the upper
lumbar spine. Similarly, Lowe18
reported severe deformity and
back pain as common sequelae in
adults with untreated adolescent
ScheuermannÕs kyphosis.
In summary, there is a wide
variation in the natural history in
patients with ScheuermannÕs kyphosis.
There appears to be a subset
of patients with refractory
symptoms that warrant the
increased risk associated with
more aggressive treatments, such
as bracing and surgical management.
Treatment
Treatment for patients with symptomatic
ScheuermannÕs kyphosis
ranges from observation to anterior
and posterior reconstructive surgery.
The recommended treatment
should be tailored to the individual
patient on the basis of the severity
of the curve and its consequent
symptoms.
Anti-inflammatory Medications
Anti-inflammatory medications
can be a useful short-term adjunct
to nonoperative care of the adolescent.
They may also be considered
for longer-term use for the adult
patient with low back pain associated
with spondylosis.
Exercise
The use of exerciseÑspecifically,
extension or postural exercisesÑ
has never been demonstrated to
improve or halt progression of
fixed ScheuermannÕs kyphosis.
However, a thoracic extension program
combined with an aerobic
exercise program may improve
physical conditioning and ameliorate
associated pain. In the adult
patient with lumbar spondylosis,
spinal stabilization or even an
aggressive flexion program may be
added to the regimen to help manage
low back pain.
Brace Treatment
Brace treatment of Scheuermann
Õs kyphosis is typically reserved
for the adolescent patient
with growth remaining and thus
potential for correction of the
kyphosis. The indications for instituting
brace treatment vary. Sachs
et al12 used 45 degrees as a threshold
for initiating treatment.
The brace can be a Milwaukeestyle
brace, with a neck ring and
anterior and posterior uprights connecting
to a pelvic girdle. The
occiput should be padded off of the
neck ring, and there should be pads
in the posterior uprights overlying
the apex of the kyphosis. Accessory
pads can be added over the apex of
the scoliotic deformity, should one
coexist. The rods are straightened
and the pads are adjusted as correction
is obtained. Other styles of
braces are also available.
When a patient is fitted with a
customized Milwaukee brace, a lateral
radiograph is obtained to conClifford
firm proper fit of the brace as well
as the degree of correction. The
patient should then return to the
clinic in 3 to 4 weeks to again ensure
proper brace fitting. Lateral
radiographs should be obtained at
4- to 6-month intervals thereafter.
During bracing, physical therapy
may be initiated, including pelvictilt
exercises to reduce lumbar lordosis
as well as a thoracic extension
program. The brace should be
sequentially adjusted to maximize
correction.
After correction has been stabilized
and maximized and as skeletal
maturity approaches, a weaning
process from the brace can begin.
Lateral radiographs should be
obtained during the weaning
process, and any early loss of correction
should be addressed by
slowing the weaning process.
Bracing can be expected to provide
up to 50% correction of the deformity
while the brace is in place,
with a gradual loss of correction
over time. Sachs et al12 demonstrated
that of 120 patients followed
up for more than 5 years
after discontinuation of the brace,
69% still had improvement of 3
degrees or more from the initial
radiograph. Montgomery and Erwin19
demonstrated similar findings
in 21 patients treated with the
Milwaukee brace. The initial 21-
degree improvement while in the
brace had decreased to only 6
degrees at latest follow-up. However,
Sachs et al found that when
the presenting kyphosis was 74
degrees or more, brace treatment
failed in almost one third of cases,
necessitating surgical correction.
The role of bracing in the skeletally
mature patient with Scheuermann
Õs kyphosis is less clear. Bradford
et al20 reported in 1974 that
skeletal maturity is not necessarily
a contraindication to Milwaukeebrace
treatment and that partial
correction of the kyphosis could
sometimes be obtained. However,
bracing in the adult is often poorly
tolerated; perhaps its best niche is
in the patient with severe refractory
pain due to the kyphosis or lumbar
spondylosis who is nevertheless
not a surgical candidate.
Surgical Treatment
The operative indications for
patients with ScheuermannÕs kyphosis
are similar to those for
patients with other types of deformities:
progression of the deformity,
pain associated with the deformity,
neurologic compromise, and
cosmesis. An adolescent with
ScheuermannÕs kyphosis with a
curve of 75 degrees or more despite
appropriate bracing may be an
operative candidate. An adult with
ScheuermannÕs kyphosis may become
a surgical candidate when
severe refractory pain develops
secondary to the deformity, which
is generally of at least 60 degrees.
Neurologic compromise can also
become a surgical indication in
both adolescents and adults. The
perceived cosmetic benefit of
surgery cannot be underestimated
in dealing with either adult or adolescent
patients.
The goal of operative treatment
of ScheuermannÕs kyphosis is to
safely obtain a solid arthrodesis
throughout the length of the
kyphosis with correction of the
kyphotic deformity. This can be
obtained with a posterior-only
approach, an anterior-only approach,
or a combined anteriorposterior
approach .
The anterior-only approach, as described
by Kostuik,21 is an anteriorinterbody
fusion and anterior instrumentation
with a Harrington
distraction system augmented by
postoperative bracing. While the
authorÕs results in 36 patients were
good, with reduction of the mean
preoperative deformity of 75.5
degrees to an average of 60 degrees
at follow-up, the anterior instrumented
approach is not as widely
used for managing ScheuermannÕs
kyphosis.
The posterior-only approach has
both advantages and limitations. It
offers decreased blood loss and
surgical time and avoids the risks
associated with a thoracotomy.
Reported disadvantages include a
higher rate of pseudarthrosis and
less correction. The posterior-only
approach remains the recommended
approach for patients with a
flexible deformity that corrects on
hyperextension to less than 50
degrees.22 For more severe deformities,
its use may be extended
with the addition of segmental fixation
and posterior facetectomy.
The anterior-posterior procedure
is reserved for patients with more
rigid deformities (typically 75
degrees or more) that do not correct
to less than 50 degrees on a hyperextension
lateral view. Recently, the
combined procedure has been more
commonly performed at one operative
sitting; however, some authors
still advocate a staged anteriorposterior
procedure. The anterior
approach may be performed either
open or thoracoscopically. The
anterior approach is typically performed
on the right to avoid the
great vessels. If a concomitant coronal
deformity is present, the approach
should be directed at the
convexity of the deformity. If a leftsided
approach is planned, preoperative
MR imaging is recommended
to assess the location of the great
vessels, which, if located posteriorly,
can obstruct a safe approach to
the thoracic spine.
The open approach is facilitated
by resecting a rib, which is later
used in performing the arthrodesis.
The rib level resected is that corresponding
to the most cephalad level
of the planned arthrodesis. Care
should be taken when planning this
approach, however. Radiographs
should be reviewed preoperatively
to evaluate the angle of the thoracic
ribs to the thoracic spine and thereby
to identify which rib should be
resected to facilitate the exposure.
An anterior release and interbody
fusion is performed on all levels
that are wedged or have a narrowed
disk space. A full anterior
release is performed, including
removal of the entire disk back to
the posterior longitudinal ligament
as well as resection of the anterior
longitudinal ligament.
The surgeon has two options for
performing the interbody fusion
technique. Structural rib graft may
be placed in each disk space, providing
support to the anterior column.
Alternatively, a trough can be
created in the lateral aspect of the
vertebral bodies, which is subsequently
filled with morseled bone.
This creates a column of graft that
will not dislodge during posterior
manipulation. The posterior procedure
can then be performed under
the same anesthetic or can be staged.
If the procedure is staged, the
patient can be mobilized out of bed
during the interim to prevent complications
associated with long-term
bed rest. Use of the Harrington
compression system for the posterior
instrumentation is well documented
in the literature. However,
segmental posterior systems (e.g.,
Cotrel-Dubousset, Texas Scottish-
Rite Hospital, and Isola) have
evolved to provide improved correction,
often obviating the need for
postoperative bracing or casting.
Posterior correction of the kyphotic
deformity can be performed
by one of two instrumentation
techniques: the compression technique
and the leverage technique.
The compression technique is a
four-rod construct in which two
upper rods are connected to two
distal rods by domino devices.
Compression is then applied over
the apex of the deformity through
the domino devices. This has the
net effect of shortening the posterior
column and reducing the kyphotic
deformity.
The leverage technique is performed
by using two long posterior
rods with the planned correction
prebent into the rods. The rods are
attached either proximally or distally
by a claw technique. Additional
segmental hooks are then
progressively attached to the rod as
they are levered toward the spine,
thus reducing the deformity. This
technique has the advantage of
decreased hardware bulk over the
apex of the deformity.
Regardless of which technique is
employed, the compression technique
or the leverage technique,
Fig. 2 Anteroposterior (A)
and lateral (B) radiographs of
a 26-year-old man who presented
with a painful thoracic
deformity measuring 88
degrees from T2 to L1. Note
that the L1-2 disk is the first
lordotic disk (arrow). C,
Hyperextension lateral view
shows correction of the deformity
to 62 degrees. Planned
correction was an anterior
release and posterior instrumentation
to L1. Anteroposterior
(D) and lateral (E)
films obtained 1 year after an
anterior release and interbody
fusion, followed by a
posterior instrumented fusion
under the same anesthetic.
Thoracic kyphosis measured
48 degrees from T2 to
L1.
A B
D E
C
88°
48°
62°
great care should be taking in
choosing fusion levels. The sagittal
balance should be assessed preoperatively
by dropping a plumb line
from the C7 vertebral body and
measuring the distance from the
sacral promontory to the plumb
line. If the plumb line falls anterior
to the promontory, the balance is
positive. Sagittal balance is often
negative in patients with severe
ScheuermannÕs kyphosis and is
typically exacerbated by surgical
correction of the kyphosis.
Overcorrection may lead to worsening
of sagittal balance and an
increased incidence of proximal
kyphosis. Proximally, the fusion
should be extended to the end vertebra
(i.e., the most cephalad vertebral
body that remains angulated into
the concavity of the deformity).
Distally, the instrumentation should
be extended beyond the end vertebral
body to the first lordotic disk
beyond the transitional zone. The
overall correction should not exceed
50% of the initial deformity or less
than 40 degrees. Adherence to these
guidelines, which were proposed by
Lowe and Kasten,23 should reduce
the risk for proximal and distal junctional
kyphosis.
Summary
ScheuermannÕs thoracic kyphosis is
a structural deformity classically
characterized by anterior wedging
of at least 5 degrees of three adjacent
thoracic vertebral bodies.
Adolescents typically present to
medical attention with concerns
about cosmetic deformity; adults
more commonly present because of
increased pain. Progression of the
deformity, pain, neurologic compromise,
and cosmesis are the issues
that typically dictate treatment
options. In the adolescent, pain
associated with a kyphotic deformity
will usually respond to physical
therapy and anti-inflammatory
medications; a progressive curve
may be responsive to bracing. In
the adolescent or adult patient with
a progressive deformity, refractory
pain, or neurologic deficit, surgical
correction of the deformity may be
indicated. Surgical approaches
include a posterior-only approach
and a combined anterior-posterior
approach. Meticulous attention to
surgical technique is mandatory;
avoiding overcorrection and junctional
kyphosis by the appropriate
selection of fusion levels is of particular
importance.
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