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Conditions
Kyphosis |
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Kyphosis is the name given to the normal curvature of
the human, thoracic spine (looking at the spine from front to back, this curvature is
concave). If, for some reason however, the curve becomes abnormally pronounced, the
condition is referred to as hyperkyphosis – commonly known as dowager’s
hump, or simply kyphosis.
Why does this happen?
From a lateral, or sideways, view the human spine isn’t straight – the curves
are designed to position the head over the pelvis, and distribute mechanical stress during
movement. The natural, kyphotic curve of the thoracic spine (T1 – T12) can be clearly
seen: |
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In some cases, the exact cause of the condition is
poorly understood; however, it is relatively easy to classify the type of kyphosis
that a patient has:
- Postural
- Congenital (present at birth)
- Neuromuscular
- Scheuermann’s
- Degenerative
Note: other forms of the condition exist, but aren’t covered here.
Postural kyphosis is caused by slouching and other forms of bad posture, which tend to
stretch the spinal ligaments – this increases the natural curvature of the spine. It
usually develops during adolescence, and is generally more common in girls than boys.
The remaining forms of kyphosis are structural – that is, caused by an underlying,
structural problem which may affect the vertebrae, inter-vertebral discs, ligaments and/or
muscles.
Congenital kyphosis is present at birth, and is often very severe – it is caused by
physical defects in the spine, including abnormal (or misshapen) vertebrae that fail to
separate. Neuromuscular kyphosis is typically found in children with primary,
neuromuscular conditions, including cerebral palsy; spinal bifida; and muscular dystrophy.
Neither form is particularly common.
Scheuermann’s disease is named after the Danish radiologist who first described the
condition in 1921. It occurs when the vertebrae in the upper spine begin to grow
abnormally (due to a condition called osteochondrosis) – the back of each vertebra
grows more quickly than the front, leading to a wedge-shaped bone. As a result, the
patient displays a pronounced curve in the upper spine (the apex of which is normally
around thoracic vertebrae T7 – T9). Scheuermann’s kyphosis usually develops
during adolescence, while the spine is still growing.
In the elderly, degenerative changes in the spine can lead to dowager’s hump. For
example, an osteoporotic fracture may cause one of the vertebrae to collapse, resulting in
a loss of height of some 15-20% – if the collapse is even, the normal curvature of
the spine will be maintained. However, if the collapse is uneven (as it often is),
a wedge-shaped vertebra is produced. If this happens in the thoracic spine, and the
vertebrae slopes from back-to-front (or posterior to anterior), the normal, kyphotic
curvature will be increased. Degenerative kyphosis can also be caused by: thinning of the
inter-vertebral discs; weak muscles; and weak ligaments. |
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How is it diagnosed?
In visual terms, kyphosis is fairly easy to diagnose (a pronounced, dowager’s hump is
often very noticeable). In strict, medical terms however, the curvature of the thoracic
spine is defined by an angle referred to as the Cobb angle. Normal thoracic curves display
an angle of somewhere between 30° and 40° (the mean is 34°); as a result, kyphosis is
formally diagnosed for curves > 40°.
Distinguishing between structural and postural kyphosis is also relatively easy – if
the increased curvature disappears when the patient lies down, the condition is postural;
if not, it’s almost certainly structural.
Scheuermann’s kyphosis is defined by three (or more) consecutive vertebrae that
display wedging angles in excess of 5°; for this reason, Scheuermann’s disease is
usually confirmed by the use of X-ray. Note: some patients with the condition also display
a mild scoliosis (30%); that is, an
additional, lateral (or side-to-side) curvature of the spine. |
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What are the consequences for back pain?
The extent and severity of pain is largely dependent on the type of kyphosis.
In cases of prolonged, postural kyphosis, pain will almost certainly develop. Having
reviewed the literature, the question of whether pain accompanies Scheuermann’s
kyphosis isn’t very clear – some note that pain is uncommon, whereas others
report an incidence of 50%.
Degenerative kyphosis is often painful – but the extent, and severity, of the pain
usually depends on the underlying condition; for example, osteoporotic kyphosis is
generally very painful, but this is mostly due to underlying fractures. |
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What are the risk factors?
The cause of Scheuermann’s kyphosis is largely unknown – genetics may be
one possible cause, although stress injuries and osteopenia (general bone thinning) have
also been implicated. The primary risk factors of degenerative kyphosis tend to mirror
those of the underlying condition(s); for example, overweight, post-menopausal women tend
to be most at risk from osteoporotic kyphosis.
Postural kyphosis is, of course, the result of bad posture; however, as we grow older,
posture (whether good or bad) often becomes entrenched – ageing is therefore a
secondary risk factor. |
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Can it be treated?
The postural form of the condition is, perhaps, the easiest to treat – the patient
simply needs to correct their posture
and, over time, the curve will disappear. If prolonged, the treatment of bad posture
becomes more difficult – certain muscles may need to be stretched (for example, the
pectorals: minor and major), whereas others may need to be strengthened (for example, the
trapezius and rhomboid muscles); the spine should also be decompressed, using the backrack™.
Kyphotic degeneration is difficult to treat, but it can be prevented. For example, osteoporosis can be avoided, typically by
good diet; weight bearing exercise; decompression of the spine (backrack); and, where
appropriate, hormone replacement therapy (HRT).
The treatment of Scheuermann’s disease depends on a number of factors, including the
age of the patient; the severity of the curve; the presence (or absence) of back pain; and
secondary complications (for example, kyphosis tends to squash the rib cage and, as a
result, can interfere with the heart and lungs).
If a patient is young, has a mild curve, no back pain, and normal pulmonary (lung)
function, then continued observation by a doctor is usually prescribed. A regular
examination is usually performed, combined with radiographs, or X-rays.
Patients are often advised to:
- Strengthen their back (the paraspinal and deep, abdominal muscles).
- Stretch their hamstrings – this prevents them from pulling on the spine.
- Improve their lung function by taking regular, cardiovascular exercise.
This may prevent, or reduce, additional kyphosis. In moderate-to-severe cases
(and where the patient has more than 12 months of growth left) the kyphosis can be
partially treated by wearing a brace – this will improve the curve, during growth, by
restoring height to the front of the vertebral body. Bracing is no longer effective when
the spine stops growing.
In very severe cases (typically, where the vertebral wedging > 10°, and the overall
curve > 65°), and where the patient is either mature, or the condition unresponsive to
bracing, surgery is often performed to
correct the curve. The actual procedure involves a long, posterior fusion, assisted by a series of rods and screws (referred to as the
Cotrel-Dubousset system). A post-operative cast, or brace, is typically worn for 6-9
months.
Potential complications include one, or multiple, pseudoarthroses (manufactured joints
that often degenerate over time); fusion failure, or non-union; instrument failure;
infection; pulmonary complications; loss of correction; and neurological deficits
(including sensory and motor symptoms).
Please note: the backrack is an
effective treatment for Scheuermann’s kyphosis. However, for patients under the age
of 16 (who are still growing), we recommend that you consult us before making a purchase
– you may be too small to use the rack effectively. |
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