Scoliosis is derived from the ancient Greek word “skolios” which means curved or crooked. It is the most common spinal disorder of children and adolescents. Scoliosis is a three-dimensional deformity, better described as a lordo-scoliosis. This deformity is characterized by deviation in the coronal, sagittal & horizontal plane of the spine. The deformity in the coronal plane results in lateral curvature of the spine, while in the sagittal plane results in decreased thoracic kyphosis, and the deformity in the axial plane results in vertebral rotation.
Prevalence of ScoliosisAdolescent idiopathic scoliosis has an overall prevalence of 0.47–5.2 % in the current literature. The female to male ratio ranges from 1.5:1 to 3:1 and increases substantially with age. In particular, the prevalence of curves with higher Cobb angles is substantially higher in girls than in boys: The female to male ratio rises from 1.4:1 in curves from 10 to 20 and up to 7.2:1 in curves more than 40.
Types of Scoliosis DeformityTwo broad types of deformity are defined: Postural and Structural. Postural scoliosis is due to some conditions outside the spine such as a short leg or a pelvic tilt. Structural scoliosis is due to a non-correctable deformity of the affected spinal segment.
The two major groups of structural scoliosis are idiopathic and non-idiopathic scoliosis. Idiopathic scoliosis is the diagnosis of exclusion. Non-idiopathic scoliosis is further classified into the following subgroups: congenital scoliosis, neuromuscular scoliosis, and mesenchymal scoliosis.
Idiopathic scoliosis is classified into the following subgroups based on age: infantile scoliosis (up to 3 years), juvenile scoliosis (4–10 years), adolescent scoliosis (11–18 years), and adult scoliosis (above 18 years).
Idiopathic scoliosis has been further sub-classified based on the magnitude of deformity. Curves more than 10 degrees and less than 25 degrees are considered mild. Similarly, the curves between 25 and 50 degrees are classified as moderate while the curves greater than 50 degrees are termed severe.
Etiology and Risk FactorsAbout 80% of cases are idiopathic with an unknown cause. The other varieties are congenital or acquired. The causes of acquired scoliosis are bony anomalies, nerve abnormalities, muscle dystrophies, and a miscellaneous group of connective-tissue disorders.
Clinical Features of ScoliosisThe major clinical features are:
- Lower back pain and back stiffness
- Curved posture
- Difficulty sitting or standing or walking due to loss of leg muscle coordination
- Leaning towards one side
- Nerve damage, causing weakness, numbness, and pain in legs and feet
- Protruding rib
- Reduction in height due to a curved spine
- Shortness of breath and fatigue, caused by an upper spine curve
- Stiffness of spine
Diagnosing ScoliosisThe diagnostic feature of fixed scoliosis is that forward bending makes the curve more obvious. The doctor will have to assess the spinal mobility and the effect of lateral bending on the curve. An examination is done to see if there is some flexibility in the curve. Neurological examination is also very important. General examination should be done to find out any cardiopulmonary compromise due to scoliosis.
The spine may also exhibit a "C" or "S" curve. Some symptoms in children may display as:
- Shoulders are different heights
- One hip sticking out
- Arms not hanging down straight
- Ribs are pushed out
Additional symptoms in adults may include:
- Difficulty walking
- Shortness of breath
- Numbness or pain in the legs
- Loss of height
Besides clinical examination, radiological evaluation is also very important. The x-ray is the first investigation of choice. It is routinely used to confirm, quantify & monitor the progression of the deformity.
Additionally, a CT scan, MRI, bone scan & ultrasound may be needed. Pulmonary function tests and other biochemical tests may be ordered based on the etiology and extent of damage resulted due to scoliosis.
If you or your child is experiencing back pain or other symptoms of scoliosis you should contact your doctor.
Treatment for ScoliosisThe most important aspect of treatment is early detection and angle of deformity. If the spinal curvature is less than 20 degrees only observation is needed. But if the curve is more than 20 degrees further treatment is required.
Spinal curves between 20 to 40 degrees can be treated by a Milwaukee brace which has to be worn 23 hours per day for at least two years. And, if the curve is more than 40 degrees surgical correction and fusion are needed. Surgery is indicated if there is progression at any age, history of an increasing hump or increasing recommendation, or signs of any neurological deficit or any unacceptable cosmetic deformity.
The objectives of surgical treatment are:
- To halt the progression of the deformity
- To straighten the curve
- To join the entire primary curve by bone grafting
The surgery is done basically for curve correction, stabilization, and fusion. For curve correction, anterior/posterior release or resection can be done. This helps to reduce the rigidity of the spine. For stabilization of the spine, instrumentation is done. There are special techniques that include endoscopy, osteotomy, use of pedicle screws, multi-segmental fixation, hemilaminectomy, fusion and stabilization by Herington rods, shaving and in situ fusion, etc. Bone grafts are used for the fusion of the spine. Spinal fusion and instrumentation surgery is useful, especially for adolescent patients.
Ongoing Scoliosis Clinical Trials and PossibilitiesNew studies have shown good outcomes with vertebral body tethering (VBT) surgeries. It is an innovative and less-invasive surgical procedure than conventional spinal fusion surgeries. However, it should only be considered as an alternative to scoliosis fusion surgery in cases with a high risk for scoliosis curve progression.
Advanced surgical techniques such as robotically-guided spinal implant insertions are also under clinical trials. It offers better performance in spinal surgery than free-hand surgeries. Studies have shown that it increases placement accuracy and reduces neurologic risks.
Complications of Surgery
- Neurological compromise: The incidence of permanent paralysis is less than 1%.
- Spinal de-compensation is due to over-correction, but it can be avoided by careful preoperative planning.
- Pseudoarthrosis may be seen in about 2% of cases and may require further operation and grafting.
- Implant failure results as rarely the hooks may cut out and rods may break.
Clinical trials are being conducted using three-dimensionally integrated exercises for self-correction and stabilization.
Active bodysuits are being researched for adults with degenerative scoliosis that are not candidates for surgery.
Another clinical trial is evaluating the use of the Green Sun Dynamic brace for patients with adolescent idiopathic scoliosis.
PrognosisThe younger the child and the higher the curve the worse the prognosis. Female patients with scoliosis and double curves are more likely to progress.
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