Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 78 docx

Juvenile Kyphosis Scheuermann’s Disease Dietrich Schlenzka, Vincent Arlet Core Messages ✔Scheuermann’s disease Type I, “classic” Scheu-ermann’s is a thoracic or thoracolumbar hyper-kyph

Juvenile Kyphosis (Scheuermann’s Disease) Dietrich Schlenzka, Vincent Arlet

Core Messages

✔Scheuermann’s disease (Type I, “classic”

Scheu-ermann’s) is a thoracic or thoracolumbar

hyper-kyphosis due to wedged vertebrae developing

during adolescence

✔Atypical Scheuermann’s disease (Type II,

“lum-bar” Scheuermann’s) affects the lumbar spine

and/or the thoracolumbar junction It is a

growth disturbance of the vertebral bodies

without significant wedging causing loss of

lumbar lordosis or mild kyphosis

✔The natural history of the deformity is benign

in the majority of cases

✔Back pain is common but usually mild and

rarely interferes with daily activities or

profes-sional career

✔Lung function is impaired only in very severe

deformities (> 100 degrees)

✔Diagnosis is based on the clinical picture and

typical changes in plain lateral radiographs

✔During growth, brace treatment is

recom-mended in mobile deformities of between

45 and 60 degrees

✔Rare spinal cord compression is the only

abso-lute indication for operation

✔Relative indications for operation are kyphosis

greater than 70 degrees, pain, and cosmetic impairment

✔The results of operative treatment are

satisfac-tory in the majority of cases regarding pain and cosmesis

✔The risk of severe intra- and postoperative

com-plications should be weighed carefully against the benefits

Epidemiology

Scheuermann’s disease is a thoracic or thoracolumbar hyperkyphosis due to wedged vertebrae

Scheuermann’s disease is a thoracic or thoracolumbar hyperkyphosis due to

wedged vertebrae developing during adolescence Ancient presentations of

hyperkyphosis usually depict extreme gibbus formations as seen due to infection

(tuberculosis) or congenital vertebral anomalies Michelangelo’s ceiling fresco in

the Sistine Chapel at the Vatican shows an ignudo with a kyphosis resembling a

thoracolumbar juvenile kyphosis (Fig 1) It was painted in 1511 and is possibly

the earliest pictorial representation of the disease [30] Following Schanz,

Hag-lund named the deformity “Lehrlingskyphose” (apprentice’s kyphosis) as it was

detected mainly in youngsters involved in heavy labor [27, 61] He saw the cause

as muscular insufficiency and mechanical overloading during growth Credit is

due to Holger Werfel Scheuermann from Denmark for first describing it in 1920

as being different from mobile postural kyphosis [62 – 64] He recognized from

radiographs that the wedge vertebrae formation in the thoracic spine was the

underlying reason for the deformity Scheuermann was the first to describe its The incidence of juvenile

kyphosis ranges between

1 % and 8 %, being more common in boys

typical radiographic features and named it “osteochondritis deformans juvenilis

dorsi” The true incidence of juvenile kyphosis is not known It ranges from 1 %

to 8 %, being more common in boys than in girls (ratio 2/1 to 7/1)

a b c d

Case Introduction

A 14-year-old boy was referred by the school doctor The boy was otherwise healthy and played hockey and soccer regu-larly Four years previously, posture changes were detected for the first time The boy had pain in the thoracolumbar area since then during the day and especially after playing sports Sometimes night pain in the back also occurred No radiat-ing pain to the lower extremity was present There were no back problems in the family Clinically, the boy appears to be healthy Height is 153 cm, sitting height 77.5 cm The spine is balanced in the frontal as well as in the sagittal plane Shoul-ders and pelvis are leveled The thoracic kyphosis is pronounced especially in the mid-thoracic area (a) Kyphosis corrects partially during spine extension in the prone position The left scapula is slightly elevated A mild left convex thoracic sco-liosis with 3 degrees of rib hump is present (b) Lumbar lordosis appears normal Lumbar range of motion is free On pal-pation, the spine is free of pain Hamstring tightness of 70 degrees is present bilaterally No neurological abnormalities are found in the lower extremity Abdominal skin reflexes are symmetrical On the standing lateral radiograph, thoracic kyphosis measures 56 degrees, lumbar lordosis 55 degrees (c) There are Scheuermann’s changes in the T6–T10 vertebral bodies On supine extension radiographs, thoracic kyphosis has corrected to 30 degrees The skeletal age is 13.5 years, i.e 6 months behind the chronological age (d) As the kyphosis is mobile, a sufficient amount of growth is left, and the boy seems to be well motivated, brace treatment is initiated (e,f) The correction in the brace is very acceptable The tho-racic kyphosis decreases from 56 to 42 degrees (g) The brace is worn full-time (23 h/day) It may, however, be removed for sports training hours Daily exercises including pectoralis stretching, hamstring stretching, and back and abdominal muscle strengthening are advocated.

Figure 1 Michelangelo’s Ignudo

This painting (1511) exhibits a

Scheuer-mann’s kyphosis at the thoracolumbar

junction.

Pathogenesis

The exact causes are unknown

The exact etiology of Scheuermann’s kyphosis is unknown Genetic, hormonal,

and mechanical factors have been discussed An autosomal dominant pattern of

inheritance has been described [21, 28] Scheuermann considered it a growth

disturbance in the vertebral epiphysis resembling Calv´e-Perthes disease He

therefore named it osteochondritis deformans juvenilis dorsi [64] Aufdermaur

reported a developmental error in collagen aggregation leading to a disturbance

of the enchondral ossification of the vertebral endplates [3] Ippolito and Ponsetti

detected a mosaic-like pattern of alterations in the growth cartilage and vertebral

endplates The collagen fibers in the matrix are thinner and their number is

diminished The proteoglycan content of the matrix is increased The growth

process is slowed down or even absent in the altered areas The process should be

interpreted as an “absence of growth” rather than a destruction [2] In the

nor-mal areas growth is accelerated This causes wedge-shaped deformation of

verte-brae and an increase in kyphosis [2, 32, 33] For biomechanical reasons,

increased kyphosis causes increased pressure to the vertebral bodies which the

pathologic bone cannot withstand This creates a vicious circle of increased

wedging and increased kyphosis leading to increased load on the vertebral

bod-ies There are no data available on the rate of progression after cessation of

growth

Juvenile kyphosis has

a genetic background and develops due to an ossification disturbance

of the vertebral bodies

The sources of pain are not very well defined Pain symptoms in the adolescent

can arise from the posture changes The musculature is insufficient to counteract

the increasing kyphosis during the growth spurt This causes fatigue in the

para-vertebral muscles Pain in the neck region and in the lumbar spine is caused by

compensatory hyperlordosis above or below the primary deformity It develops

when the degree of the primary deformity exceeds the capacity of the adjacent

segments to adapt to it In the adult patient, disc degeneration and facet joint

osteoarthritis may be the reason for pain in the kyphotic vertebral segment as

well as in the segments above and below

Normal Sagittal Profile

The sagittal profile develops

during growth and changes

throughout adult life

Classic Scheuermann’s disease is a thoracic or thoracolumbar hyperkyphosis,

which implies that kyphosis deviates from the normal sagittal curvature of the spine Therefore, a thorough knowledge of the normal sagittal profile is required

for the understanding of this clinical entity The sagittal profile of the spine in

humans varies greatly between individuals It is not established at birth but develops and changes during life [5, 46, 68, 69, 72, 75]

The sagittal profile of the

spine is largely variable

There is no scientifically based definition of the degree of normal sagittal spi-nal curvatures At birth, the whole spine is kyphotic from the occiput to the coc-cyx As the child starts in the upright position, first lumbar lordosis develops and later thoracic kyphosis It is only when the child becomes a young adult that the definitive sagittal curves are acquired Confusingly, different methods for mea-surement of the sagittal curvatures of the spine are used in the literature Mea-sured from the back surface using spinal pantography, at the age of 14 years tho-racic kyphosis in healthy children ranges from 7 to 57 degrees (mean 29 degrees)

in girls and from 6 to 69 degrees (mean 30 degrees) in boys, being between 20 and

40 degrees in more than two-thirds of children [46] In a mixed population with

an age range from 4.6 to 29.8 (mean 12.8) years, Bernhart et al found thoracic kyphosis ranging from 9 to 53 (mean 36) degrees measured from standing lateral

Normal kyphosis is in the

range of 10° to 60°

radiographs between the top of T3 and the bottom of T12 They proposed a nor-mal range from 20 to 50 degrees [5] In healthy adults, Stagnara et al measured from standing radiographs thoracic kyphosis from 7 to 63 (mean 37) degrees between the top of T4 and the bottom of the intermediate vertebra (mainly L1, T12, or L2), with the majority being between 30 and 50 degrees [69] They did not find, however, any hint that those individuals outside the 30 – 50 degree range were functionally inferior Vaz et al reported a global thoracic kyphosis ranging from 25 to 72 (mean 47) degrees [73] Boulay et al [9] used true Cobb angle mea-surements, i.e they measured thoracic kyphosis from the upper endplate of the most tilted vertebra cranially to the lower endplate of the most tilted vertebra caudally In 149 healthy adults, they found a range from 33.2 to 83.5 (mean

53.8) degrees The Scoliosis Research Society proposes to regard 10–40 degrees

as the range for normal kyphosis between the upper endplate of T5 and the lower endplate of T12 [51] Thoracic kyphosis increases in the elderly due to degenera-tive changes

Thoracic kyphosis is more

prominent in males

There are significant differences between the genders Thoracic kyphosis is

more prominent in males There is a steady increase from adolescence to

adult-hood In females, thoracic kyphosis increases during the adolescent growth spurt but decreases during the descending phase of peak growth, i.e until young adult-hood Thoracic hyperkyphosis (& 45 degrees) is equally prevalent in both gen-ders at the age of 14 years, but more prevalent in males (9.6 %) than in females at the age of 22 years [57] Left-handedness was identified as a risk factor for tho-racic hyperkyphosis but no significant correlation between hyperkyphosis and low-back pain during adolescence could be established [47, 48]

There is no scientifically based definition of the threshold for “normal” kyphosis So-called normal ranges in the literature are derived from cohort mea-surements using statistical methods These figures, however, should not be used

as such for deciding what is pathologic in the individual Thoracic kyphosis should always be judged in view of the balance of the entire spine, not as an iso-lated part of it The thoracolumbar junction from T10 to L2 is slightly kyphotic

[5] The upper thoracolumbar junction (T10–T12) varies from 3 degrees of lor-dosis to 20 degrees of kyphosis (mean 5.5 degrees of kyphosis) The lower thora-columbar junction (T12–L2) ranges from 23 degrees of lordosis to 13 degrees

Lumbar lordosis is more pronounced in females

of kyphosis (mean 3 degrees of kyphosis) The segment T12–L1 is on average in

1 degree of kyphosis [5] Lumbar lordosis is normally somewhat greater than

thoracic kyphosis On average, lumbar lordosis is more pronounced in females

It is relatively constant during growth from adolescence to young adulthood [57]

In girls, lumbar lordosis measured from the back surface using the spinal

panto-graph ranges from 18 to 55 (mean 33.4) degrees at the age of 14 years and from 18

to 72 (mean 37.8) degrees at the age of 22 years In boys, the corresponding

fig-ures are 15 – 56 (mean 33) degrees and 11 – 58 (mean 34.6) degrees [57]

Accord-ing to Bernhart and Bridwell, the range of lumbar lordosis measured from

stand-ing radiographs between the bottom of T12 and the bottom of L5 is 14 – 69 (mean

A range of 20° to 60° is regarded as normal lordosis

44) degrees They propose a normal range of from 20 to 60 degrees [5] Stagnara

et al reported a range for lumbar lordosis of from 32 to 84 degrees The higher

values may be explained by the fact that these authors measured the lumbar

lor-dosis from the upper border of the intermediate vertebra down to the upper

end-plate of S1 [69] Bouley et al [9] reported in adults a lordosis ranging from 44.8

to 87.2 (mean 36.4) degrees measured according to Cobb between the most tilted

vertebrae Vaz et al measured in adults a global lumbar lordosis ranging from 26

to 76 (mean 46.5) degrees [73] The Scoliosis Research Society proposes to regard

40 – 60 degrees as a normal range of lumbar lordosis for the adult measured

between the upper endplate of T12 and the upper endplate of S1 [51] Lumbar

lor-dosis decreases in the elderly due to degenerative changes

The threshold for “normal”

thoracic kyphosis is not defined

According to Stagnara et al., every person has her or his “unique spinal

physi-ognomy” [69] Average values are only indicative not normative [5, 69] There is

no indication that persons with a degree of thoracic kyphosis not fitting into the

postulated “normal range” are handicapped in any respect

Sagittal balance is of the utmost importance for an ergonomic upright

pos-ture The spine is sagittally balanced if a plumb line dropped from the odontoid

process crosses the thoracolumbar junction and through the posterior edge of S1

For practical purposes on radiographs, the plumb line is often drawn from the

center of the vertebral body C7 [51] (Fig 2a–c) Normal sagittal balance is

essen-tial for the ability of the individual to stand in the upright position with minimal

effort Abnormal sagittal balance will be observed when the spinal column

can-not compensate to keep the gravity line between the femoral heads and the

sacrum Spinal imbalance is positive when the gravity line falls in front of the

femoral heads It is negative when the gravity line falls posterior to the sacrum

Normal sagittal spinal bal-ance is the prerequisite for

an economic upright pos-ture in the standing position

This is important to consider A negative sagittal balance may be observed in

neuromuscular conditions with weak hip extensors A positive sagittal balance

may be observed in patients with developmental delay, loss of lumbar lordosis

(flat back), or rigid kyphotic lumbar spine Most Scheuermann patients fall into

the category of negative sagittal balance [31, 40, 41]

When judging the importance of a thoracic hyperkyphosis, one not only has to

take into account the absolute measure of the deformity in degrees, but one must

also assess it in relation to the location of the apex of the kyphosis The lower the

apex of the hyperkyphosis the greater its impact on spinal balance and on the

adjacent spinal segments below (compensatory lumbar hyperlordosis) For

instance, a thoracolumbar kyphotic deformity of 20 degrees between T10 and L3

has a much higher impact on the sagittal balance than a thoracic hyperkyphosis

of 55 degrees between T2 and T12, which may be clinically unimportant

The concept of pelvic incidence has recently been introduced by Duval

Beau-pere [36] Pelvic incidence is defined as the angle between the perpendicular to

the top of S1 and the line joining the middle of S1 to the femoral heads (Fig 3) It

was found that the pelvic incidence was the only morphometric character that is

constant throughout life A strong correlation between the pelvic incidence and

the lumbar lordosis has been defined Pelvic incidence regulates the sagittal

Figure 2 Sagittal balance

a The spine is sagittally balanced when the plumb line

from C7 touches the posterior edge of S1.bSpinal

imbal-ance is positive when the line falls in front of this point.cIt

is negative when the plumb line falls behind this point.

Figure 3 Pelvic incidence (PI)

a = midpoint of the sacral endplate, 0 = center of the

femo-ral head.

Figure 2 Sagittal balance

alignment of the spine and pelvis [9, 36, 73] As a rule of thumb, lumbar lordosis

is approximately 10 degrees greater than the pelvic incidence in normal

individu-als However, no study has focused yet on any possible relationship between

pel-vic incidence and Scheuermann’s kyphosis

Definition and Classification

According to Sörensen [65], the diagnostic criteria are wedging of more than

5 degrees in three consecutive vertebrae with typical endplate irregularities on a

lateral radiograph A widely accepted definition is based on Bradford [11]:

) irregular vertebral endplates

) narrowing of the intervertebral disc space

) one or more vertebrae wedged 5 degrees or more

) an increase of normal kyphosis beyond 40 degrees

Both Sörensen’s and Bradford’s definitions do have their shortcomings since they

are arbitrary Sörensen’s criteria exclude deformities with less than three

deformed vertebrae Bradford’s 40 degrees of thoracic kyphosis as the borderline

between normal and pathologic has its origin in an unpublished X-ray study by

Boseker, who found a range of 25 – 42 degrees in 121 normal children [8, 10] This

is extremely low in comparison to the ranges for thoracic kyphosis in healthy

individuals reported later by other investigators (see above) Besides, it cannot be

generalized for the different regions of the spine In the authors’ opinion, the

diagnosis should be based mainly on the typical pathologic vertebral and disc

changes Bearing in mind the immense variability of the sagittal profile in healthy

persons, it seems inappropriate to base the diagnosis on a certain amount of

(hyper-)kyphosis measured in degrees (Table 1) (Fig 4a):

Table 1 Diagnostic criteria for juvenile kyphosis (Type I)

) wedging of more than 5 degrees in one or more vertebrae in the

thoracic or thoracolumbar region

) disc space narrowing ) endplate irregularities ) increased thoracic or thoracolumbar kyphosis

Schmorl’s nodes are not pathognomonic

Schmorl’s nodes are often associated with juvenile kyphosis but are not a

patho-gnomonic sign

The classification of Scheuermann’s disease concerning its localization in the

spine is inconsistent in the literature In the classic sense, it is a deformity of the

thoracic spine Lindemann reported in 1933 four cases with affection of the

lum-bar spine and called the condition the “lumlum-bar form of adolescent kyphosis”

[37] Lumbar Scheuermann’s disease as a separate entity was described in more

detail by Edgren and Vaino [19] Out of 900 radiographs of Scheuermann’s

patients, they found 30 cases with distinct radiographic features in the lumbar

spine During the growth period (initial stage), they recognized a typical local

defect in the spongiosa in the ventral part of the endplates of one or several

verte-bral bodies (Fig 4c) After the end of growth (final stage), the contours of the

ver-tebral endplates were uneven Schmorl’s nodes and disc prolapses dislocating the

border of the vertebra were seen Intervertebral disc spaces were narrowed A

slight angular kyphosis was present, and the sagittal diameter of the vertebral

bodies was increased Clinically, the patients showed flattening of the lumbar

lor-dosis or a slight kyphosis, stiffness, and tenderness of the lumbar spine No root

symptoms were seen They coined the term “osteochondrosis juvenilis

lumba-lis” (atypical juvenile kyphosis) ( Table 2).

a b c

Figure 4 Types of juvenile kyphosis

aStanding lateral radiographs of juvenile kyphosis Type I changes in the thoracic spine in an 18-year-old male andb tho-racolumbar area in a 52-year-old male Scheuermann’s Type II changes from L1 to L4 in an 18-year-old female gymnast The thoracolumbar junction is slightly kyphotic.cNote the decrease in thoracic kyphosis.

Table 2 Diagnostic criteria for juvenile kyphosis (Type II, “lumbar”)

) endplate irregularities in one or several vertebral bodies of the lumbar

or thoracolumbar area

) apophyseal separation ) increased sagittal diameter of vertebral bodies ) loss of lumbar lordosis or slight kyphosis ) disc space narrowing ) Schmorl’s node

Blumenthal et al defined cases with involvement from T10 to L4 as lumbar

juve-nile kyphosis They proposed three different types:

) I: “classic” juvenile kyphosis (three or more consecutive vertebrae each wedged over 5 degrees)

) IIa: “atypical” juvenile kyphosis (endplate irregularities, anterior Schmorl’s nodes, disc space narrowing)

) IIb: acute traumatic intraosseous disc herniation (after acute vertical com-pression injury) [7]

Wenger proposes a distinction between Type I (thoracic, with wedging), being

the most common form, and Type II (thoracolumbar, lumbar), developing at a

slightly later age and being more commonly painful A mechanical overloading is

thought to be its basis Murray et al., in their natural history study, divided the

patients according to the apex level of the kyphosis into “cephalad” (apex at T1–

T8) and “caudad” (apex at T9–T12) [44]

The confusion arising from these different classifications seems to be mainly

due to the fact that localization and pathoanatomical picture are mingled

Typi-cal wedging (classiTypi-cal juvenile kyphosis, Type I) occurs usually in the thoracic

spine but it may also cross the thoracolumbar junction and reach into the upper

lumbar spine (Fig 4b) Endplate impressions, disc narrowing, and increased

sag-ittal diameter of the vertebral bodies without significant wedging (lumbar

“atypical” juvenile kyphosis, Type II), as described by Edgren and Vainio, seem

to occur only in the lumbar spine up to the thoracolumbar junction (Table 2)

Severe wedging does not develop in the lordotic lumbar spine

Possibly both types are expressions of the same pathology Severe wedging does

not develop in the primarily lordotic lumbar spine due to the fact that the loading

conditions are different from those in the primarily kyphotic thoracic spine [37]

Type II Scheuermann’s disease is commonly attributed to mechanical

overload-ing [23, 40, 74] However, in the reports of Edgren and Vainio as well as

Blumen-thal et al., the majority of patients had not been involved in heavy physical

activ-ity [7, 19] Obviously, there is an idiopathic form due to an “intrinsic” factor and

a secondary form caused by mechanical overloading and endplate damage as

seen in certain sports disciplines (weight lifting, gymnastics, motocross)

For the purposes of clear communication, we propose to define the condition

primarily according to the vertebral changes as Type I or Type II, respectively If

deemed necessary, one can then add the vertebral level(s) for specification

Clinical Presentation

History

In the initial phase of the disease posture changes are not visible yet but back pain

may be present

The cardinal symptoms of juvenile kyphosis are:

) back pain

) cosmetic disturbance

Back pain is activity dependent

Usually, juvenile kyphosis is detected first by caretakers or the school nurse or

doctor (Case Introduction) when a visible deformity has already developed

Dur-ing adolescence, pain in the region of the kyphosis may occur durDur-ing exercise or

prolonged sitting In later adulthood, secondary cervical and lumbar

hyperlor-dosis may cause pain symptoms also in the cervical and/or lumbar region

Seg-mental thoracic pain or lower extremity root pain has not been described Back

pain symptoms occur mainly during the day and under loading They are more

common in Type II as compared to Type I [7, 19, 23, 40, 74] Murray et al found

in Type I that pain interfered significantly more with life if the kyphosis was more

Back pain is related

to curve size and location

severe and the apex more cephalad (T1–T8) But job activity level and pain

intensity were not dependent on the level of the apex of the kyphosis [44].

Patients with Type II Scheuermann’s disease are prone to develop lumbar spinal

stenosis [70] As these patients often have a genetic predisposition, one should

focus on the existence of a family history of a deformity Previous fractures,

infections and neurological disorders should be ruled out

b

c

Figure 5 Clinical appearance of juvenile kyphosis

a Normal harmonic kyphosis of the spine in flexion. b,cA 16-year-old female with a thoracic hyperkyphosis of

88 degrees, apex T8.d,eA 20-year-old male with a low thoracic hyperkyphosis of 79 degrees, apex T10.fA 19-year-old male with Scheuermann’s Type II; the upper lumbar spine is slightly kyphotic.

Physical Findings

Rigid thoracic hyperkyphosis is the

cardinal physical finding

When an adolescent patient presents with a thoracic or thoracolumbar

hyperky-phosis, the diagnosis can be suspected at first glance The hyperkyphosis is fre-quently accompanied by compensatory hyperlordosis of the cervical and/or

lumbar spine (Fig 5) The spine is balanced in the coronal plane but usually in a negative balance in the sagittal plane The clinical examination aims to assess the

rigidity of the curve Asking the patient to lift the head and extend the spine in

the prone position best assesses this aspect Mild secondary scoliosis with mini-mal or no rotation may be present The muscles in the region of the kyphosis or

in hyperlordotic areas above (shoulder-neck region) or below (low back) the

main deformity may be painful on palpation Hamstring tightness is common.

Neurology should be assessed carefully Pathologic neurological findings, how-ever, are very rare

Distinguish juvenile

kyphosis from idiopathic

roundback

Usually it is easy to distinguish Scheuermann’s kyphosis (Type I) from idio-pathic roundback In the latter, the hyperkyphosis is harmonic also in flexion.

Moreover, it corrects well in extension