An abnormal lateral curvature of the spine is known as scoliosis. The most common period for scoliosis diagnosis is childhood or early adolescence. In a normal spine, curves occur at one’s cervical, thoracic and lumbar regions (in the “sagittal” plane). The curves of the spine position one’s head over the pelvis. In addition, they work to absorb shock and distribute mechanical stress while one is engaged in movement. Scoliosis is typically defined as spinal curvature in the “coronal”, or frontal, plane. However, while the degree of curvature is measured on one’s coronal plane, scoliosis is a much more complex, 3-D problem, often involving the following planes:
- Coronal plane: a vertical plane, ranging from head to foot and parallel to the shoulders; divides the body into front (anterior) and back (posterior) sections
- Sagittal plane: divides the body into right and left halves
- Axial plane: parallel to the plane of the ground and at right angles to the coronal and sagittal planes
INCIDENCE AND PREVALENCE
2-3% of the population is affected by scoliosis, and six to nine million people in the United States are estimated to have it alone. This condition may develop during infancy or early childhood. However, the primary age of scoliosis onset is 10-15 years old, and it occurs equally among both genders. Women are 8x more likely than men to progress to a curve magnitude which would require treatment. Each year, scoliosis patients take more than 600,000 visits to private physician offices, with about 30,000 children being fitted with a brace and 38,000 patients undergoing spinal fusion surgery.
Scoliosis can be classified by etiology: idiopathic, congenital or neuromuscular.
Idiopathic scoliosis represents about 80% of all scoliosis cases. It is the diagnosis when all other causes are excluded. Of this category, adolescent idiopathic scoliosis presents most commonly, usually being diagnosed during puberty.
Embryological malformation of one or more vertebrae results in congenital scoliosis, a condition that may occur in any location of the spine. The vertebral abnormalities cause one area of the spinal column to lengthen at a slower rate than the rest, creating curvature and other spinal deformities. Additionally, the geometry and location of these vertebral abnormalities determine the rate at which scoliosis progresses as a child grows. As these abnormalities are present at birth, congenital scoliosis is typically detected at a younger age than idiopathic scoliosis.
Neuromuscular scoliosis is scoliosis secondary to neurological or muscular diseases. This form of scoliosis can be associated with spinal muscular atrophy, spinal cord trauma, cerebral palsy, muscular dystrophy, and spina bifida. This type of scoliosis generally progresses more rapidly than idiopathic scoliosis and often requires surgical treatment.
Several signs exist that may indicate the possibility of scoliosis. If one or more of the following signs is noticed, it is recommended that you schedule an appointment with a doctor.
- Uneven shoulders with one or both shoulder blades possibly sticking out
- One’s head not being centered directly above the pelvis
- Raised or unusually high hips (one or both)
- Rib cages are at different heights
- An uneven waist
- The appearance or texture of the skin that overlies the spine changes (dimples, color abnormalities, hairy patches)
- The entire body leaning to one side
About 23% of patients in one study with idiopathic scoliosis presented with back pain at the time of initial diagnosis. 10% of these patients were found to have an underlying associated condition (e.g. spondylolisthesis, herniated disc, syringomyelia, tethered cord, or spinal tumor). If a patient diagnosed with idiopathic scoliosis ends up producing greater than mild back discomfort in a patient, a thorough evaluation for another cause of pain is advised.
Due to changes in the size and shape of the thorax, idiopathic scoliosis may affect one’s pulmonary function. Recent reports on pulmonary function testing in patients with mild to moderate idiopathic scoliosis displayed diminished pulmonary function.
Scoliosis is usually confirmed through x-rays, physical examinations, spinal radiographs, MRIs, or CT (CAT) scans. The curve of one’s spine is measured by the Cobb Method, being diagnosed in terms of severity by the number of degrees. A positive diagnosis of scoliosis is created based on a coronal curvature, which is measured on a posterior-anterior radiograph of an angle greater than 10 degrees. Generally, a spinal curve is considered significant if it is greater than a range of 25 to 30 degrees. Curves exceeding 45 to 50 degrees are considered severe and often require more aggressive treatment.
A standard exam, used by pediatricians and in grade school screenings at times, is known as the Adam's Forward Bend Test. While taking this test, the patient leans forward, keeping his or her feet together and bending at 90 degrees at their waist. From this angle, any asymmetry of the trunk, along with any abnormal spinal curvatures, are easily able to be detected by the examiner. This procedure is a simple initial screening test, which can detect potential problems. However, the Adam's Forward Bend Test cannot determine accurately the specific severity or type of one’s spinal deformity, as radiographic tests are required for to complete a positive and accurate diagnosis.
- Computed tomography scan (CT or CAT scan)
- Magnetic resonance imaging (MRI)
Scoliosis in children is classified by age:
- Infantile (0 to 3 years)
- Juvenile (3 to 10 years)
- Adolescent (age 11 and older, or from onset of puberty until skeletal maturity)
Idiopathic scoliosis makes up the majority of cases that present in patients during their adolescence. Depending on its severity, along with the age of the child, scoliosis is managed by bracing, close observation, and/or surgery.
In children who have congenital scoliosis, there is a known increased incidence of other congenital abnormalities. These congenital abnormalities are most commonly associated with the genitourinary system (20-33%), the spinal cord (20%), and the heart (10-15%). It is critical that evaluation of the genitourinary, neurological, and cardiovascular systems is undertaken when a patient receives a diagnosis of congenital scoliosis.
Scoliosis that occurs or is diagnosed in adulthood is distinctive from childhood scoliosis, since the underlying causes and goals of treatment differ in patients who have already reached skeletal maturity.
Most adults with scoliosis can be divided into the following categories:
- Adult scoliosis patients who received surgical treatment as an adolescent
- Adults who failed to receive treatment when they were younger
- Adults affected by degenerative scoliosis
In one 20-year study, about 40% of adult scoliosis patients experienced a progression in their condition. Of those, 10% of these patients showed a very significant progression, and the other 30% of them experienced a very mild progression (generally of less than one degree of progression per year).
Degenerative scoliosis occurs most frequently in the lumbar spine (lower back), more commonly affecting people of ages 65+. This condition is often accompanied by spinal stenosis (the narrowing of the spinal canal), which pinches one’s spinal nerves, making it difficult for them to normally function. Back pain associated with degenerative scoliosis typically begins gradually, being linked with activity. The curvature of the spine in this form of scoliosis is usually relatively minor, so surgery may only be advised if conservative methods do not alleviate pain associated with the condition.
When a patient receives a confirmed scoliosis diagnosis, there are several issues to assess that can help determine treatment options:
- Spinal maturity: is a patient's spine still changing and growing?
- Extent and degree of curvature: how severe is the curve? How does it affect the patient's lifestyle?
- Location of curve: according to some experts, thoracic curves are more likely to progress than curves located in different regions of the spine
- Possibility of curve progression: patients who possess large spinal curves prior to their adolescent growth spurts are more likely to experience curve progression.
After these variables are assessed, a doctor may recommended the following treatments:
In many children who have scoliosis, the spinal curve is mild enough to not require treatment. Nevertheless, if the doctor is worried that the curve may be increasing, he or she may choose to examine the child every four to six months throughout adolescence.
In adults who have scoliosis, X-rays are typically recommended once every five years, unless one’s symptoms are getting progressively worse.
Braces are only effective in patients that have not yet reached skeletal maturity. If the child is still growing and his or her curve is between 25-40 degrees, a brace may be recommended to prevent their curve from progressing further. There have been improvements in brace design, with newer models fitting underneath the arm, rather than around the neck. Several different types of braces are available to patients. Some disagreement exists among experts as to which type of brace is most effective. However, large studies indicate that braces, when used with full compliance, successfully stop curve progression in about 80% of children with scoliosis. For optimal effectiveness, the brace should be checked regularly to assure a proper fit and may need to be worn 16-23 hours every day until growth stops.
In children, the two primary goals of surgery are to stop the curve from progressing during adulthood and to diminish spinal deformity. Most experts would recommend surgery only when the spinal curve present is greater than 40 degrees and there are signs of progression exist. This surgery can be done through the front (an anterior approach) or through the back (a posterior approach). The approach taken depends on the particular case.
Certain adults treated as children may require revision surgery. In particular, this may be useful if these adults were treated 20-30 years ago, before major advances in spinal surgery procedures had been implemented. In those times, it was common for doctors to fuse a long segment of the spine. When multiple vertebral segments are fused together, the remaining mobile segments assume much more of the stress and the load associated with movements. Adjacent segment disease is the process of degenerative changes occurring over time in the mobile segments above and below the spinal fusion. This condition can result in painful arthritis of the facet joints, discs, and ligaments.
Generally, surgery in adults can be recommended if the curve is greater than 50 degrees, when the patient has sustained nerve damage to their legs, and/or is experiencing bowel or bladder symptoms. Adults who have degenerative scoliosis and spinal stenosis may require decompression surgery with spinal fusion, along with a surgical approach from an anterior and posterior approach.
A variety of factors may lead to increased surgical-related risks in older adults who have degenerative scoliosis. These factors include being overweight, advanced age, being a smoker, and the presence of other health/medical problems. In general, both surgery and recovery time are expected to be longer in older adults with scoliosis.
Posterior approach: The most frequently performed surgery in adolescent idiopathic scoliosis patients involves posterior spinal fusion, along with bone grafting and instrumentation. This surgery is performed through an approach from the back, while the patient lies on his or her stomach. During this surgery, the spine is straightened with rigid rods, followed by spinal fusion. A spinal fusion surgery involves adding a bone graft to the curved area of one’s spine, forging a solid union between two+ vertebrae. The metal rods, when attached to the spine, ensure that the backbone remains straight as the spinal fusion surgery occurs.
This procedure usually takes several hours in children, but will generally take longer in older adults. With recent advances in technology, most people with idiopathic scoliosis are released within a week of surgery and do not require post-surgical bracing. Most patients are able to return to school or work within 2-4 weeks post-surgery. Patients are also able to resume all pre-surgical activities within four to six months.
Anterior approach: The patient lies on his or her side during this surgery from an anterior approach. Incisions are made to the patient’s side, deflating the lung and removing a rib to reach the spine. Video-assisted thoracoscopic (VAT) surgery offers enhanced visualization of the spine, allowing a less invasive surgery than an open procedure to be carried out. This anterior spinal approach is associated with numerous potential advantages: improved spine mobilization, better deformity correction, quicker patient rehabilitation, and fusion of fewer segments. The potential disadvantages of this surgery include the fact that numerous patients require post-surgery bracing for several months. Additionally, this approach has a higher risk of morbidity, even though VAT has helped to reduce the latter.
Decompressive laminectomy: The laminae (roof) of the vertebrae are removed to create more space for the nerves. A spinal fusion either with or without spinal instrumentation is usually recommended if both spinal stenosis and scoliosis are present. A variety of devices (i.e. rods and screws) can be used to enhance fusion and support unstable areas of the spine.
Minimally invasive surgery (MIS) : At times, fusion may be performed via smaller incisions through MIS. The use of advanced fluoroscopy (X-ray imaging during surgery) and endoscopy (camera technology) has improved the accuracy of incisions and hardware placement, minimizing tissue trauma while enabling a MIS approach. It is important to keep in mind that not all cases can be treated in this manner and a number of factors contribute to the surgical method used.