Scoliosis is a side-to-side curvature of the spine.
When viewed from the rear, the spine usually appears perfectly straight. Scoliosis is a lateral (side-to-side) curve in the spine, usually combined with arotation of the vertebrae. (The lateral curvature of scoliosis should not beconfused with the normal set of front-to-back spinal curves visible from theside.) While a small degree of lateral curvature does not cause any medicalproblems, larger curves can cause postural imbalance and lead to muscle fatigue and pain. More severe scoliosis can interfere with breathing and lead to arthritis of the spine (spondylosis).
Approximately 10% of all adolescents have some degree of scoliosis, though fewer than 1% have curves which require medical attention beyond monitoring. Scoliosis is found in both boys and girls, but a girl's spinal curve is much more likely to progress than a boy's. Girls require scoliosis treatment about five times as often. The reason for these differences is not known.
Four out of five cases of scoliosis are idiopathic, meaning the causeis unknown. While idiopathic scoliosis tends to run in families, no responsible genes had been identified as of 1997. Children with idiopathic scoliosis appear to be otherwise entirely healthy, and have not had any bone or joint disease early in life. Scoliosis is not caused by poor posture, diet, or carrying a heavy bookbag exclusively on one shoulder.
Idiopathic scoliosis is further classified according to age of onset:
- Infantile. Curvature appears before age three. This type is quite rare in theUnited States, but is more common in Europe.
- Juvenile. Curvature appears between ages 3 and 10. This type may be equivalent to the adolescent type, except for the age of onset.
- Adolescent. Curvature appears betweenages of 10 and 13, near the beginning of puberty. This is the most common type of idiopathic scoliosis.
- Adult. Curvature begins after physical maturation is completed.
Causes are known for three other types of scoliosis:
- Congenital scoliosis is due to congenital birth defects in the spine, often associated with other organ defects.
- Neuromuscular scoliosis is due to loss of controlof the nerves or muscles which support the spine. The most common causes of this type of scoliosis are cerebral palsy and muscular dystrophy.
- Degenerative scoliosis may be caused by degeneration of the discs which separatethe vertebrae or arthritis in the joints that link them.
Scoliosis causes a noticeable asymmetry in the torso when viewed from the front or back. The first sign of scoliosis is often seen when a child is wearinga bathing suit or underwear. A child may appear to be standing with one shoulder higher than the other, or to have a tilt in the waistline. One shoulderblade may appear more prominent than the other due to rotation. In girls, onebreast may appear higher than the other, or larger if rotation pushes that side forward.
Curve progression is greatest near the adolescent growth spurt. Scoliosis that begins early on is more likely to progress significantly than scoliosis that begins later in puberty.
More than 30 states have screening programs in schools for adolescent scoliosis, usually conducted by trained school nurses or gym teachers.
Treatment decisions for scoliosis are based on the degree of curvature, the likelihood of significant progression, and the presence of pain, if any.
Curves less than 20 degrees are not usually treated, except by regular follow-up for children who are still growing. Watchful waiting is usually all thatis required in adolescents with curves of 20-30 degrees, or adults with curves up to 40 degrees or slightly more, as long as there is no pain.
For children or adolescents whose curves progress to 30 degrees, and who havea year or more of growth left, bracing may be required. Bracing cannot correct curvature, but may be effective in halting or slowing progression. Bracingis rarely used in adults, except where pain is significant and surgery is not an option, as in some elderly patients.
Surgery for idiopathic scoliosis is usually recommended if:
- The curvehas progressed despite bracing
- The curve is greater than 40-50 degrees before growth has stopped in an adolescent
- The curve is greater than 50 degrees and continues to increase in an adult
- There is significant pain.
Orthopedic surgery for neuromuscular scoliosis is often done earlier. The goals of surgery are to correct the deformity as much as possible, to prevent further deformity, and to eliminate pain as much as possible. Surgery can usually correct 40-50% of the curve, and sometimes as much as 80%. Surgery cannotalways completely remove pain.
The surgical procedure for scoliosis is called spinal fusion, becausethe goal is to straighten the spine as much as possible, and then to fuse thevertebrae together to prevent further curvature. To achieve fusion, the involved vertebra are first exposed, and then scraped to promote regrowth. Bone chips are usually used to splint together the vertebrae to increase the likelihood of fusion. To maintain the proper spinal posture before fusion occurs, metal rods are inserted alongside the spine, and are attached to the vertebraeby hooks, screws, or wires. Fusion of the spine makes it rigid and resistantto further curvature. The metal rods are no longer needed once fusion is complete, but are rarely removed unless their presence leads to complications.
Spinal fusion leaves the involved portion of the spine permanently stiff andinflexible. While this leads to some loss of normal motion, most functional activities are not strongly affected, unless the very lowest portion of the spine (the lumbar region) is fused. Normal mobility, exercise, and even contactsports are usually all possible after spinal fusion. Full recovery takes approximately six months.
Although important for general health and strength, exercise has not been shown to prevent or slow the development of scoliosis. It may help to relieve pain from scoliosis by helping to maintain range of motion. Good nutrition is also important for general health, but no specific dietary regimen has been shown to control scoliosis development. In particular, dietary calcium levels do not influence scoliosis progression. Most cases of mild adolescent idiopathic scoliosis need no treatment and do not progress.