Scoliosis Déformations

Adolescent idiopathic scoliosis

Scoliosis in patients between 10 and 18 years of age is termed adolescent scoliosis. By far the most common type of scoliosis is one in which the cause is not known. It 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. Despite this, we currently have accurate methods to determine the risk for curve progression of scoliosis and good methods of treatment.

Causes

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. A genetic screening test, called the ScoliScore™ is available as an adjunct to clinical and x-ray information to determine risk of progression in Adolescent Idiopathic Scoliosis. It is currently used in Caucasian (North American, European, Eastern European, Middle Eastern) patients between the ages of 9 and 13 years with a mild scoliotic curve (less than 25 degrees). The stated goal of the test is to determine the risk that the curve will increase to 40 degrees or more. Thus far independent verification of the test has not been done.

Symptoms

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 often 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 adolescences 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.

Treatment

Treatment of adolescent idiopathic scoliosis falls into three main categories: observation, bracing and surgery. The treatment recommended is based on the risk of curve progression. In general, AIS curves progress during the rapid growth period of the patient. While most curves slow their progression significantly at the time of skeletal maturity, some, especially curves greater than 60o, continue to progress during adulthood. Since scoliosis gets larger during rapid growth, the potential for growth is evaluated taking into consideration the patient's age, the status of whether females have had their first menstrual period, as well as radiographic parameters. In general, girls grow until 14 years of age, while boys grow until 18 years of age. Girls grow very rapidly until their first menstrual period, and then their growth generally slows down. Women continue to grow until approximately 2 years after their first menstrual period.

Figure 1: "Risser Grading System - as the iliac apophysis (growth area) moves fromoutside to inside, the child is approaching skeletal maturity.

Radiographs of the spine, pelvis, and hand/wrist are also used to determine growth. The Risser grading system (Figure 1) is often used to determine a child's skeletal maturity (how much growth is left) on the pelvis, which correlates with how much spine growth is left. The Risser grading system rates a child's' skeletal maturity on a scale of 0 to 5. Patients who are Risser 0 and 1 are growing rapidly, while patients who are 4 and 5 have stopped growing. Generally patients who are being treated in a scoliosis clinic will have their height measured at each visit to help determine growth potential.

Non-Operative Treatments

Observation

Observation is generally for patients whose curves are less than 25-30º who are still growing, or for curves less than 45º in patients who have completed their growth. Scoliosis surgeons often wish to observe the scoliosis every few years after patients complete their growth to make sure it does not progress into adulthood.

Alternative Treatment

Alternative treatments to prevent curve progression or prevent further curve progression such as chiropractic medicine, physical therapy, yoga, etc. have not demonstrated any scientific value in the treatment of scoliosis. However, these and other methods can be utilized if they provide some physical benefit to the patient such as core strengthening, symptom relief, etc. These should not, however, be utilized to formally treat the curvature in hopes of improving the scoliosis.

Bracing

Bracing is recommended for patients with curves that measure between 25o and 40o during their growth phase. The goal is to prevent the curve from getting bigger. This is accomplished by correcting the curve while the patient is in the brace so that the curve does not progress with time. Growth plates on the vertebrae are more likely to grow symmetrically if they have equal pressure over their surface as the child grows. Straighter spines equalize pressure better than curved spines. Once the brace is discontinued, the goal is to maintain the curve at the magnitude present when the brace was started. Even if slight curve progression occurs despite wearing the brace, surgical treatment is not necessary as long as the curve remains below 45o at the end of growth. There are several types of braces available but all of them work in the same fashion. All braces are worn under the clothes and cannot be seen by others. Bracing is most effective when it is worn more than 20-22 hours per day. Your physician will often recommend removing the brace for bathing and sports.     When bracing treatment is started, radiographs are usually performed with the brace on to ensure that the brace is effective in achieving some correction of the curve(s) . Future X-rays can be taken either in the brace or out of the brace depending on the preference of the physician.

Surgical Treatment

Surgical treatment is recommended for patients whose curves are greater than 40o while still growing, or are continuing to progress greater than 40o when growth stopped. The goal of surgical treatment is two-fold: first, to prevent curve progression and secondly to obtain some curve correction. Surgical treatment today utilizes metal implants that are attached to the spine, and then connected to a single rod or two rods. Implants are used to correct the spine and hold the spine in the corrected position until the instrumented segments fuse as one bone. The surgery can be performed from the back of the spine (posterior approach) (Figure 2 and 3) through a straight incision along the midline of the back or through the front of the spine (anterior approach) (Figure 4). Although there are advantages and disadvantages to both approaches, the posterior approach is utilized most often in the treatment of AIS and can be utilized for all curve types. The anterior approach is an option when a single thoracic curve or a single lumbar curve is being treated. Many factors go into the decision as to the surgical approach and your doctor will review the options and choose the best approach for you. Following surgical treatment, no external bracing or casts are used. The hospital stay is generally between 3 and 6 days. The patient can perform regular daily activities and generally returns to school in 3-4 weeks. Depending on the activities of the patient, full participation is allowed between 3 and 6 months after surgery. Most children will not need pain medications 10-14 days after surgery.

Figure 2: A) Front X-rays of a patient with adolescent idiopathic scoliosis in her thoracic spine. B) Post-surgical correction through a posterior approach using two rods and pedicle screws.

Figure 3: A) Front X-rays of a patient with adolescent idiopathic scoliosis in her thoracic and lumbar spine. B) Post-operative xrays showing instrumentation placed via a posterior approach

Figure 4: A) Front X-rays of a patient with adolescent idiopathic scoliosis in her thoracic and lumbar spine. B) Post-operative xrays showing instrumentation placed via an anterior (side) approach.