The severity of scoliosis and need for treatment is usually determined by two factors:
- The extent of the spinal curvature. (Scoliosis is diagnosed when the curve measures 11 degrees or more.)
- The angle of the trunk rotation (ATR).
Both are measured in degrees. These two factors are usually related. For example, a person with a spinal curve of 20 degrees will usually have a trunk rotation (ATR) of 5 degrees. These two measurements, in fact, used to be the cutoff for recommending treatment. However, it is now well known that the great majority of 20-degree curves do not get worse. Patients do not usually need medical attention until the curve reaches 30 degrees and the ATR is seven degrees.
Adams Forward Bend Test. The screening test used most often in schools and in the offices of pediatricians and primary care physicians is called the Adams forward bend test.
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. In a child with scoliosis, the examiner may observe an imbalanced rib cage, with one side being higher than the other, or other deformities.
|The forward bend test is a test used most often in schools and doctor's offices to screen for scoliosis. During the test, the child bends forward with the feet together and knees straight while dangling the arms. Any imbalances in the rib cage or other deformities along the back could be a sign of scoliosis.
The forward bend test, however, is not sensitive to abnormalities in the lower back, a very common site for scoliosis. Because the test misses about 15% of scoliosis cases, many experts do not recommend it as the sole method for screening for scoliosis.
Other Physical Tests.
- The 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 leg length and look for tight tendons in the back of the leg, which may cause an uneven leg length or other back problems.
- The physician will also check for neurologic impairment by testing reflexes, nerve sensation, and muscle function.
Identifying the Curvature
Proper diagnosis is important. A misjudgment can lead to unnecessary x-rays and stressful treatments in children not actually at risk for progression. Unfortunately, although measurements of curves and rotation are useful, no test exists yet to determine whether a curve will progress.
Inclinometer (Scoliometer). An inclinometer, also known as a Scoliometer, measures distortions of the torso. The procedure is as follows:
- The patient bends over, arms dangling and palms pressed together, until a curve can be observed in the upper back (thoracic area).
- The Scoliometer is placed on the back and measures the apex (the highest point) of the upper back curve.
- The patient continues bending until the curve can be seen in the lower back (lumbar area). The apex of this curve is also measured.
- Measurements are repeated twice, with the patient returning to a standing position between repetitions.
- If results show a deformity, x-rays probably need to be performed to determine the extent.
Some experts believe the Scoliometer would make a useful device for widespread screening. Scoliometers, however, indicate rib cage distortions in more than half of children who turn out to have very minor or no sideways curves. They are therefore not accurate enough to guide treatment.
Currently, x-rays are the most cost efficient method for diagnosing scoliosis. Experts hope that accurate, noninvasive diagnostic techniques will eventually be developed to replace some of the x-rays used to monitor the progression of scoliosis. To date, some under investigation appear to be fairly accurate for detecting scoliosis in the upper back (the thoracic region), but not scoliosis in the lower back (the lumbar region).
X-Rays. If screening indicates scoliosis, the child may be sent to a specialist who takes an initial x-ray and monitors the child every few months using repeated x-rays. X-rays are essential for an accurate diagnosis of scoliosis in that they:
- Reveal the degree and severity of scoliosis.
- Identify any other spinal abnormalities, including kyphosis (hunchback) and hyperlordosis (swayback).
- Help the physician determine whether or not skeletal growth has reached maturity.
- X-rays taken when patients are bending forward can also help differentiate between structural and nonstructural scoliosis. Structural curves persist when a person bends over, and nonstructural curves tend to disappear. (It should be noted that muscle spasms or spinal growths may sometimes cause nonstructural scoliosis that shows a curve on bending.)
- In children and young adolescents who have mild curves and in older adolescents who have more severe curvatures but whose growth has stopped or slowed down, x-rays should be performed every few months in order to detect increasing severity. Young people who are diagnosed with scoliosis should be sure to keep their x-rays indefinitely in case they develop back problems later in adulthood and need to be re-examined.
Protective Measures for Frequent X-Rays
Because frequent x-rays may be required for young children with scoliosis, parents should be sure that x-ray technicians take all necessary protective methods. Experts are concerned about the long-term effects of radiation on sensitive young organs, particularly about a possible increase in the risk for cancer. Studies have reported an increased risk for cancer in women and men who, because of scoliosis, had been exposed to diagnostic x-rays in their childhood and adolescence.
X-ray techniques have become safer in recent years, and the hazards may be reduced with simple measures:
- X-ray beams should be directed through the patient from back to front, rather than the reverse.
- Filters for the x-ray tube are available that absorb some of the beam.
- Fast film should be used, which can reduce exposure by two to six times.
- Lead aprons or shields should always be worn over parts of the body that are not being x-rayed.
Magnetic Resonance Imaging. Magnetic resonance imaging (MRI) is an advanced imaging procedure that does not use radiation, as x-rays do. It is expensive, however, and not generally used for an initial diagnosis. MRI can, nevertheless, identify spinal cord and brain stem abnormalities, which some studies indicate may be more prevalent than previously believed in children with idiopathic scoliosis. It also may be particularly useful before surgery for detecting defects that could lead to potential complications.
||Click the icon to see an image of a MRI scan.
Determining the Extent of the Curve
There are various methods for determining and classifying the extent of the curve.
Cobb Method. The degree of the curve is nearly always calculated using a technique known as the Cobb method.
- On an x-ray of the spine, the examiner draws two lines: One line extends out and up from the edge of the top vertebrae of the curve. The second line extends out and down from the bottom vertebrae.
- A perpendicular line is then drawn between the two lines.
- The intersecting angle is measured to determine the degree of curvature.
The Cobb method is limited because it cannot fully determine the flexibility or the three-dimensional aspect of the spine. It is not as effective, then, in defining spinal rotation or kyphosis. It also tends to over-estimate the curve. Other diagnostic tools are needed then to make a more accurate diagnosis.
Classifying the Curve.Classification of the curve allows the physician to identify patterns that can help determine treatments, particularly specific surgical techniques. The following are examples:
- King Classification. The King classification classifies scoliotic curves as one of five patterns, which can help determine surgical treatments. It has limitations, however, and is not very useful for advanced surgical techniques.
- Lenke Classification. Lenke classification takes more features of the curve into consideration and is proving to be more reliable. This includes six curve patterns plus addition factors that modify each of these curves.
Three-Dimensional Modeling Techniques. Advanced computer modeling techniques are able to create three dimensional images using x-rays or other two-dimensional images. They allow physicians to observe the spinal distortions and eventually could reduce the number of x-rays currently needed to monitor scoliosis and help surgeons determine optimal surgical procedures.
Determining the End of Growth
Even if the curve is accurately calculated, it still remains difficult to predict whether the scoliosis will progress. One way of predicting whether or not the curvature will progress is knowing when the child will stop growing:
- If the child has years to grow, then the spine has more time to progress.
- If the child will stop growing within a year, then progression should be very slight. (It should be noted, however, that some progression continues in nearly 70% of curves even after the spine has matured.)
- Knowing the child's age is, of course, the first step in estimating the end of growth. In addition, other methods have been developed to help predict the end of the growth stage.
One method is called the Risser sign, which grades the amount of bone in the area at the top of the hipbone. A low grade indicates that the skeleton still has considerable growth; a high grade means that the child has nearly stopped growing and the curve is unlikely to progress much further. The Risser scale differs between genders, and in boys, a high grade does not always signify the end of progression.
To Screen or Not to Screen for Scoliosis
Screening programs for scoliosis, which began in the 1940s, are now mandatory in middle or high schools in many states, but there is considerable debate over whether screening should be routine.
Arguments Against Routine Screening
US Preventive Services Task Force does not recommend routine screening to detect adolescent scoliosis for the following reasons:
- Screening tests are not accurate and depend too much on the skill of the examiner.
- Schools often refer children with minor curves who are not at any risk for a progressive or serious condition to physicians, and such over-referrals add considerably to the costs of the health system. In one major 1999 study, 94% of the children referred to a physician by the school did not require treatment. (Over 2,000 children were screened in order to find only five children who did need treatment.)
- Patients with scoliosis have no greater danger for significant lung problems than the general population until their curves reach 60 to 100 degrees, making early screening unnecessary.
- At the time of the Task Force, studies were also showing no benefits from the early treatments, specifically braces.
Experts against screening argue, then, that such programs result in early treatments that either will not prevent curve progression and surgery or are unnecessary in the first place since curvatures often do not progress at all.
Arguments for Routine Screening
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. The American Academy of Pediatrics recommends, however, scoliosis screening at ages 10, 12, 14, and 16 years. (In one study, over 40% of high school sophomores with newly diagnosed scoliosis had shown no signs of the disorder in earlier screening tests.) Other experts make the following arguments for universal screening:
- Universal screening is useful for producing information on scoliosis that may eventually lead to knowledge of its cause and ways to prevent it.
- Braces have been proven to be effective since the task force's recommendation and early treatment can be important.
- Without screening, the chances are slim that children with scoliosis will be diagnosed at an early stage if they can only rely on examinations by a family physician or pediatrician. Such physicians often do not even look at backs and, if they do, they tend to use only the forward bend test, which is not accurate.
In any case, some experts argue that widespread screening would be cost effective if schools had reasonable guidelines to use for determining which children should see a physician for further testing. The following are some suggested guidelines for determining the need for a physician referral:
- Children should be sent to a physician only if they have a 30-degree curve. (A 20-degree curve with a 5-degree trunk rotation has been the criteria for recommending treatment, although up to 80% of 20-degree curves do not get worse.)
- Children with curves between 20 and 30 degrees would be screened every six months.
Such guidelines would detect about 95% of all genuinely serious cases while referring only 3% of all children tested, thereby cutting costs without jeopardizing children.