Adolescent Idiopathic Scoliosis
Scoliosis in patients between 8 and 18 years of age is termed adolescent scoliosis and can be due to many causes. By far the most common type of scoliosis in the adolescent period is one in which the cause is not known and is called idiopathic or adolescent idiopathic scoliosis (AIS). Although significant ongoing research continues in this area, including the genetic basis for AIS, there are no identifiable causes for this condition today.
There are significant efforts being made toward identifying the cause of AIS, but to date there are no well accepted causes for this particular type of scoliosis. The vast majority of patients are otherwise healthy and have no previous medical history. There are many theories about the cause of AIS including hormonal imbalance, asymmetric growth, and muscle imbalance. Approximately 30% of AIS patients have some family history of scoliosis, and therefore there seems to be a genetic connection. Many Scoliosis Research Society members are working to identify the genes that cause AIS, and this knowledge continues to expand at a rapid pace. Most likely, there will be many genes associated with scoliosis and each may be helpful in detecting scoliosis and determining the risk for progression of the curve.
Adolescent idiopathic scoliosis generally does not result in pain or neurologic symptoms. The curve of the spine does not put pressure on organs, including the lung or heart, and symptoms such as shortness of breath are not seen with AIS. When scoliosis begins in adolescence, patients may have some back pain, typically in the low back area. Although it is often associated with scoliosis, it is generally felt that the curvature does not result in pain. Low back pain is not uncommon in adolescents in general. Many teens experience back pain due to participating in a large number of activities without having good core abdominal and back strength, as well as flexibility of the hamstrings.
Adolescent idiopathic scoliosis generally does not result in pain or neurologic problems. If these symptoms occur, further evaluation and testing may be necessary to include an MRI, CAT scan or Bone scan.
There are many visible symptoms associated with adolescent idiopathic scoliosis. Depending on the curve pattern and the size or magnitude of the curve, scoliosis may be barely seen or it may have significant visible symptoms. One of the most common is shoulder height asymmetry, in which one shoulder appears higher than the other (see figure 1). A shift of the body to the right or the left can occur especially when there is an single curve in the thoracic (chest-part) or the lumbar (lower back) of the spine without a second curve to help balance the patient. This is often seen as some waistline asymmetry in which one hip appears to be higher than the other and may result in one leg appearing taller than the other (see figure 2). A prominence on the back or a rib hump secondary to the rotational aspect of the scoliosis is the most visible sign of scoliosis (see figure 3).
Patients with AIS generally have a normal appearance when viewed from the side. In general, there are no neurologic abnormalities such as weakness or changes in a patients feeling in the upper or lower extremities (see figure 4).
Juvenile Idiopathic Scoliosis
Figure 1: Side-view MRI showing syrinx (abnormal collection of fluid within the spinal cord) in a 7-year-old boy with a 30o neuromuscular scoliosis.
Juvenile idiopathic scoliosis is classically defined as scoliosis that is first diagnosed between the ages of 4 and 10. This category comprises about 10% to 15% of all idiopathic scoliosis in children. At the younger end of the spectrum, boys are affected slightly more than girls and the curve is often left-sided. Towards the upper end of the age spectrum, the condition is more like adolescent idiopathic scoliosis, with a predominance of girls and right-sided curves.
Types of Adult Scoliosis
In addition to the two types of adult scoliosis discussed in this section—Adult Idiopathic Scoliosis and Adult Degenerative Scoliosis—types of scoliosis that develops early in life or that results from a separate syndrome also effect adults.
Adult idiopathic scoliosis is, in essence, a continuation of adolescent idiopathic scoliosis. Sometimes a spine curvature of an idiopathic (cause not known) nature that began during teenage years may progress during adult life. Curves may increase in size 0.5° to 2° per year. Adolescent curves less than 30° are unlikely to progress significantly into adulthood, while those over 50° are likely to get bigger, which is why adult scoliosis specialists should monitor the curves over time.
Occurs in the thoracic (upper) and lumbar (lower) spine, with the same basic appearance as that in teenagers, such as shoulder asymmetry, a rib hump, or a prominence of the lower back on the side of the curvature. Curves can worsen in the older patient due to disc degeneration and/or sagittal imbalance. Additionally, arthritis commonly affects joints of the spine and leads to the formation of bone spurs.
Adults with idiopathic scoliosis have more symptoms than teens because of degeneration in discs and joints leading to narrowing of the openings for the spinal sac and nerves (spinal stenosis). Some patients may lean forward to try and open up space for their nerves. Others may lean forward because of loss of their natural curve (lordosis, sway back) in their lumbar spine (low back). The imbalance causes the patients to compensate by bending their hips and knees to try and maintain an upright posture. Adult patients may have a variety of symptoms, which can lead to gradual loss of function:
- Low back pain and stiffness are the two most common symptoms
- Numbness, cramping, and shooting pain in the legs due to pinched nerves
- Fatigue which results from strain on the muscles of the lower back and legs