The spine is a column of small bones, or vertebrae
that supports the entire upper body. The column is grouped into
three sections of vertebrae: the cervical vertebrae are the five
spinal bones that support the neck; the thoracic vertebrae are
the twelve spinal bones that connect to the rib cage; and the
lumbar vertebrae are the five lowest and largest bones of the
spinal column. Most of the body's weight and stress falls on the
lumbar vertebrae. Below the lumbar region is the sacrum, a shield-shaped
bony structure that connects with the pelvis at the sacroiliac
joints. At the end of the sacrum are two to four tiny partially
fused vertebrae known as the coccus or "tail bone".
Vertebrae in the spinal column are separated
from each other by small cushions of cartilage known as intervertebral
discs. Inside each disc is a jelly-like substance surrounded by
a fibrous structure. The disc is 80% water, which makes it very
elastic. Each vertebra in the spine has a number of bony projections,
known as processes. The spinal and transverse processes attach
to the muscles in the back and act like little levers, allowing
the spine to twist or bend. The articular processes form the joints
between the vertebrae themselves, meeting together and interlocking.
Each vertebra and its processes surround and protect an arch-shaped
central opening. These arches, aligned to run down the spine,
form the spinal canal, which encloses the spinal cord, the central
trunk of nerves that connects the brain with the rest of the body.
Scoliosis is a three-dimensional curvature
of the spine. It may develop as a single primary curve (resembling
the letter C) or as two curves (a primary and compensating secondary
curve that form an S shape). Scoliosis may occur only in the upper
back (the thoracic area) or lower back (lumbar), but most commonly
it develops in the area between the thoracic and lumbar area Scoliosis
is often categorized as structural or nonstructural. In structural
scoliosis, the spine not only curves from side to side, but the
vertebrae also rotate, twisting the spine. As it twists, one side
of the rib cage is pushed outward so that the spaces between the
ribs widen and the shoulder blade protrudes (producing the rib-cage
deformity, or hump); the other half of the rib cage is twisted
inward, compressing the ribs. A nonstructural curve does not twist
but is a simple side-to-side curve. Other abnormalities of the
spine that may occur alone or in combination with scoliosis include
kyphosis, an exaggerated backward rounding of the spine, the so-called
hunchback. Hyperlordosis is an exaggerated forward curving of
the lower spine, also called swayback.
Scoliosis is usually painless. Often the curvature
itself may be too subtle to be noticed by even observant parents.
Some may notice abnormal posture in their growing child that includes
a tilted head, protruding shoulder blade, and one hip or shoulder
that is higher than the other, causing an uneven hem or shirt
line. The child may lean more to one side than another. With more
advanced scoliosis, fatigue may occur after prolonged sitting
or standing. Curves caused by muscle spasms or growths on the
spine can sometimes cause pain. Nearly always, however, there
are no symptoms for mild scoliosis, and the condition is usually
detected by the pediatrician or during a school screening test.
Causes
In 80% of patients, the cause of scoliosis
is unknown. Such cases are called idiopathic scoliosis, and they
account for about 65% of the structural forms of scoliosis. Most
cases of idiopathic scoliosis have a genetic basis, but researchers
have still not identified the gene or genes responsible for them.
Some experts are looking at inherited imbalances in perception
or coordination that may relate to asymmetrical growth in the
spine of some children with scoliosis. Other researchers are investigating
a possible defective gene responsible for production of fibrillin,
an important component of connective tissue, which makes up bones
and muscles. One study showed a higher incidence of abnormally
high arches in the feet in people with idiopathic scoliosis, suggesting
that altered balance may be a factor in certain cases.
Investigators are also looking at enzymes
known as matrix metalloproteinase, which is involved in repair
and remodeling of collagen, the critical structural protein found
in muscles and bones. In high levels, however, the enzymes can
cause abnormalities in components in the spinal discs, contributing
to disc degeneration. Some researchers have found high levels
of the enzymes in the discs of patients with scoliosis, which
suggests that the enzymes may contribute to curve progression.
Birth defects are known to cause scoliosis,
including spina bifida or myelomeningocele (a hernia of the central
nervous system that can also cause hydrocephalus). Scoliosis may
also be a result of muscle paralysis or deterioration from diseases
such as muscular dystrophy, polio, or cerebral palsy. Other diseases
that can cause scoliosis are Marfan's syndrome, rheumatoid arthritis,
and osteogenesis imperfecta. Injury to the spinal cord may also
cause scoliosis.
Nonstructural scoliosis is sometimes caused
by poor posture, differences in leg length, and muscle spasms.
Tumors, growths or small abnormalities on the spinal column may
play a larger role than previously thought in the causes of scoliosis
in small children. Back surgery, known as laminectomy, for removal
of benign tumors increases the risk for spinal deformity.
Risk Factors for Scoliosis
Mild curvature occurs about equally in girls
and boys, but serious scoliosis is ten times more prevalent in
girls. Scoliosis nearly always occurs during the growth spurt
right before and during adolescence, although it occasionally
presents as a birth defect. Some degree of spinal curvature occurs
in 10% of the population
Emotional and Social Impacts
The financial and emotional costs of scoliosis
can be considerable. The emotional impact of scoliosis, particularly
on young girls or boys during their most vulnerable years, should
not be underestimated. Young people who need to wear a brace or
whose scoliosis has progressed to an obvious deformity endure
social isolation and low self-esteem. They often have significant
behavioral problems without strong family and professional support.
Modern bracing, which is concealed under clothing, may help reduce
the social and emotional difficulties related to treatments for
scoliosis. Patients and their families should discuss all options
fully with their physicians and, if possible, talk to patients
who have had these therapies.
Screening
Screening programs for scoliosis, which began
in the 1940s, are now mandatory in middle or high schools in many
states. The American Academy of Orthopaedic Surgeons recommends
that girls be screened twice, at ages 10 and 12, and that boys
be screened once at 13 or 14. Older teenagers may need to have
repeat screening tests.
The screening test most often used in schools
and in the offices of pediatricians or primary care physicians
is called the forward bend test, in which the child bends forward
dangling the arms, with the feet together and knees straight.
The curve of structural scoliosis is more apparent when bending
over, and the examiner may observe an imbalanced rib cage, with
one side being higher than the other, or other deformities. The
forward-bend test is not sensitive to abnormalities that occur
in the lower back, which is a very common site for scoliosis.
For other tests, a patient is usually requested
to walk on the toes, then the heels, and then is asked to jump
up and down on one foot. Such activities indicate leg strength
and balance. The physician will also check for tight tendons in
the back of the leg. The physician will also check for neurologic
impairment by testing reflexes, nerve sensation, and muscle function.
Treatment
Treatment for scoliosis has undergone major
changes over the past decade and a number of options are available.
The general rule of thumb for treating scoliosis is to monitor
the condition if the curve is less than 20 degrees and to consider
treating curves greater than 25 degrees or those that progress
by 10 degrees while being monitored. Whether scoliosis is treated
immediately or simply monitored depends on many factors, including
the age, gender, and general health of the patient, and the severity
and location of the curvature.
Braces may be recommended for moderate
curves of 24 to 40 degrees, a brace is often used to prevent further
curvature. A full torso brace called the Milwaukee brace was standard
treatment until a decade ago and is still used. The device uses
a wide flat bar in front and two smaller ones in back that attach
to a ring around the neck that has rests for the chin and back
of the head. The brace is periodically adjusted for growth. The
brace needs to be worn 23 hours a day with relief only during
bathing and exercise. Newer, molded braces, called a Boston brace,
come up to beneath the underarms and can be fitted to be worn
close to the skin so that they don't show under clothes. Patients
are still urged to wear these braces 20 hours a day; although
wearing them for 16 hours a day may still be beneficial, the risk
for curve progression is significantly higher when patients wear
braces for less time..
A team approach, with several health professionals
involved, is usually beneficial and often necessary to support
the patient through the bracing process. An orthopedic surgeon
interprets the x-rays, assesses the potential progression of the
scoliosis, and plans the treatment with the patient and family.
If a brace is used, an orthotist measures and fits the patient
with the device. A physical therapist plans the exercise program
best suited for the patient. A nurse may also be involved to coordinate
the treatment plans and provide physical and emotional support.
Electrostimulation has been used in
some cases of mild scoliosis. Electrodes are placed on the skin
along the convex (rounded) side of the spine at bedtime; they
send small jolts of electricity for five seconds every 30 seconds
to stimulate muscles while the patient is sleeping. Although the
procedure is painless, it causes the shoulder to jerk, and patients
have complained about sleeplessness and irritability.
Surgery is almost always recommended
for anyone whose curve exceeds 50 degrees and for growing children
whose curve has gone beyond 40 degrees. For children whose scoliosis
is due to inborn abnormalities, the younger they are when surgery
is performed, the better their chances for success. It should
also be performed as early as possible for children with multiple
physical handicaps; older children who have surgery tend to experience
improved well being from the changes in their appearance, even
if they have no actual improved physical functioning.
The goals of scoliosis surgery are to straighten
the spine as much and as safely as possible, to balance the torso
and pelvic areas, and to maintain correction. These goals are
accomplished by fusing (joining together) the vertebrae along
the curve and supporting these fused bones with instrumentation
-- steel rod, hooks, and other devices attached to the spine.
A number of variations on scoliosis surgery exist, using different
instruments and procedures.
If you are a Munson Healthcare patient and have a compliment,
concern, or complaint, please contact one of our Patient
Liaisons.
