A 12 year old girl is referred to the office with a chief complaint of "back looks funny". Her mother noticed the deformity incidentally when her daughter tried on swimsuits at the mall approximately 1 month prior to the visit. The patient did not notice any deformity herself. Previous examinations on annual visits for school did not mention a spinal deformity. Her mother also reports that her child has been growing rapidly for six months, but she has not begun her menses.
PMH is unremarkable.
ROS: She denies back pain, headaches, difficulty urinating or making bowel movements, numbness or tingling in the extremities or weakness. No abnormal skin rashes or birthmarks are appreciated. She denies shortness of breath, palpitations, fatigue or malaise. Frequent bleeding or bruisability is denied. No endocrine abnormalities are reported.
FH: Family history is significant for adolescent-onset scoliosis in a maternal aunt. No treatment was recommended. Pertinent review with the mother regarding family history is negative for short stature syndrome, neurofibromatosis, bone dysplasia, neoplasia, hereditary neuromuscular disease or other syndromes.
Exam: VS are normal. Standing height 152 cm (60 inches), weight 41 kg (90 lbs). Her mother's standing height is 165 cm (65 inches). She is an active and vibrant young girl. Her standing station (erect, feet together) demonstrates a level pelvis and level shoulders. Her gait shows smooth reciprocal heel-toe foot placement. Her forward bending test demonstrates right thoracic rib prominence with rotation of ribs 8 degrees at mid thorax by scoliometer. Her extremities show normal symmetric range of motion of all joints. No leg length discrepancy is present. Pulses are full and equal. Her neurologic exam is intact.
Imaging: Standing posteroanterior radiographs of the thoracolumbar spine are obtained. These images demonstrate an S-shaped curvature across the thoracic and lumbar spine. The larger curve magnitude measures 25 degrees by Cobb angle. Risser stage is 0.
Clinical course: You reassure the family that the condition is not life threatening but recommend follow up in 6 months. Repeat radiographs and examination are planned. The family moves out of state for one year after your initial examination. The patient returns to your office for check up 15 months after your initial visit. She has no back pain or complaint except rib prominence on forward bending. Examination shows her height is 163 cm (64 inches). Rotation on forward bending approaches 12 degrees at the mid-thorax. Neurological examination is normal. Her shoulders and pelvis are level. She began her menses 6 months ago. Radiographs show an increase in her curve magnitude to 32 degrees by Cobb angle. She is now Risser stage 2. Due to her progression by radiographic criteria and relative skeletal immaturity, you recommend a brace to control the curve. The child is compliant with the brace and wears it 23 hours a day for 12 months. No progression of the curvature is noted with brace treatment. At skeletal maturity, she has a well-balanced spinal deformity. Maximal curve magnitude is 28 degrees. She is active in sports and reports no pain.
Idiopathic scoliosis is the most common type of scoliosis. Scoliosis is characterized by lateral curvature of the spine on two-dimensional radiographs. In truth, the deformity is three-dimensional and rotation is a critical component. By definition, the etiology is unknown and the diagnosis can only be made after all other causes of spinal deformity have been excluded. The true prevalence in society is unknown and estimates are dependent on the method of measurement. By radiographic criteria (Cobb angle greater than 10 degrees), the prevalence is approximately 2-3%. For curves greater than 20 degrees, the prevalence drops ten-fold to approximately 0.3%. Females are predominately affected. Boys tend to have smaller curves and are less likely to progress. The female to male ratio is 1.4 to 1 for curves 11 degrees to 20 degrees. The ratio increases to 5:1 for curves greater than 20 degrees.
Idiopathic scoliosis is often divided by age of onset. Infantile curves are noted from birth to 3 years. Juvenile curves are recognized between 4 and 10 years. Adolescent curves are diagnosed after 10 years of age.
The family history is positive for scoliosis in approximately 30% of cases suggesting that inheritance has some role. Recognition of scoliosis in a family member is not helpful for determining curve magnitude or risk of progression. Inheritance patterns (sex-linked, autosomal dominant or recessive) are debated. Hormonal interactions and growth alterations have been implicated but are also controversial (1). Rapid growth is associated with curve progression, but this does not explain how the deformity initiates. Biomechanical forces must play a role as larger curves and the unbalanced spine tend to progress more than small well-balanced curves. Disorders of the connective tissue and matrix proteins are also suspect. The most viable hypothesis relates to abnormalities of the vestibular and equilibrium systems in the central nervous system. Disorders of equilibrium are probably the most widely supported as the cause of idiopathic scoliosis (2,3).
The diagnosis begins with a complete history. Back pain should be well characterized with respect to severity and duration as the presence of pain may suggest an irritant focus such as infection or tumor (4). Radicular signs, numbness, changes in bowel or bladder habits, tingling in the extremities or perineum imply a neurologic origin. Any history of trauma should be investigated thoroughly. Information regarding skeletal maturity may be helpful to determine the risk of progression and, therefore, one should inquire about menstrual history and sexual development (Tanner staging).
The physical examination begins with inspection from the back. The patient is standing with her/his feet together. Palpation of the tops of the iliac crest will assess pelvic tilt and leg length discrepancy. Screen the spine for midline dimples or cutaneous changes as these findings suggest a defect in the underlying spine. The "Forward Bending Test" is routinely used to screen for spinal deformity. The child is asked to bend forward at the waist with her hands clasped together. The head and arms are allowed to hang dependent in a relaxed manner. Inspection from the rear allows the examiner to sight tangentially down the spine. Attention should be paid for asymmetry of the rib or trunk height. Rotation of the spine is reflected in prominence of the ribs on the convexity of the curve. A Scoliometer (trademark) is an inclinometer used to measure trunk rotation in degrees. Each level of deformity should be measured (thoracic, thoracolumbar, and lumbar).
Objective measurement of spinal deformity begins with a standing posteroanterior (PA) radiograph of the entire thoracolumbar spine. The image is taken on a long cassette (36 in) to include the thoracic and the lumbar spine on one view. PA imaging is used to limit the radiation exposure to the breast and thyroid in an adolescent female. The Cobb angle can be determined by measuring the horizontal (transverse plane) endplate of the most tilted vertebrae at each end of the curve. The angle formed by the perpendicular to these two endplates is measured. True scoliosis is defined as a structural curvature of the spine with a Cobb angle greater than 10 degrees. Curves below 10 degrees should be labeled "minimal spinal curvature" as they represent positional curves and will likely regress spontaneously. For true scoliosis, radiographs are repeated every six months until skeletal maturity. Thereafter, annual rechecks are recommended until stability is confirmed.
Monitoring ossification of the iliac apophysis on radiographs can assess skeletal maturity. Normal ossification begins laterally and progresses medially as the child matures. By dividing the crest into quadrants, five stages of maturation can be assigned according to the system of Risser. Complete ossification requires approximately one year. Risser stages 0 - 2 imply relative immaturity. Risser stages 3 - 5 suggest that spinal growth is nearly complete.
Idiopathic scoliosis is diagnosis of exclusion. Scoliosis can result from congenital, irritative, neuromuscular, degenerative, and traumatic causes.
Congenital scoliosis is the product of the failure of formation or segmentation of spinal elements in prenatal life. Irritative curves are due to infections or neoplasms. Neuromuscular curves develop due to muscle imbalance in children with encephalopathy, spina bifida, or myopathies. Degenerative curves are seen in adulthood and result from biomechanical failure of the arthritic spine. Trauma can result in scoliosis if the injury weakens the integrity of the spine by fracture or dislocation.
Accurate knowledge of the natural history of a disease is mandatory for determining appropriate management of patients. The natural history of spinal curvature in the skeletally immature is different from expectations for curves presenting after spinal growth ceases. The probability of curve progression is the primary consideration when planning treatment (5,6).
Progression of spinal deformity is known to be associated with growth (7). Therefore, determination of skeletal maturity is often helpful in predicting risk of progression. The onset of puberty is associated with a rapid increase in spinal growth velocity. Menarche occurs after the peak velocity has been reached (8). For girls, the end of spinal growth corresponds to Risser stage 4. For boys, spinal growth can occur after Risser stage 4 and is less well defined. The risk of curve progression is higher for a child in Risser stage 0 - 2 compared to a child in Risser stage 3 - 5.
Larger curves at presentation are at higher risk of progression. The probability of progression greater than 10 degrees by Cobb angle is 67% for curves 40 -50 degrees. The corresponding probability for curves 20 -30 degrees is 30% (7). Thus, for young patients with scoliosis, the major factors determining risk of progression are skeletal maturity, curve magnitude, and curve type. Optimal interval of follow-up is determined by the ability to detect a real difference in the curve magnitude by Cobb angles. A widely accepted estimate of error in measurements of Cobb angles is approximately 5 degrees (9). During the peak velocity of spinal growth, the curvature may progress by 1 to 2 degrees per month. Therefore, rechecks should be scheduled every six months to allow sufficient time for a true change in the curvature to be detectable (greater than 5 degree error). More frequent follow up should be scheduled if rapid curve progression is noted.
Most patients with an established diagnosis of idiopathic scoliosis do not require treatment. For minor curves (less than 25 degrees) or the mature patient, examination and radiographs are repeated twice a year to monitor the curve. If the risk of progression is high due to curve magnitude and skeletal maturity, a brace is often recommended. The goal of bracing is to prevent progression. In fact, the brace does not attempt to correct or to improve the magnitude of the curvature with any lasting effect. Correction in the brace should be greater than 50% to achieve its goal. Bracing is used in a carefully selected patient to achieve a curvature under 30 degrees at skeletal maturity. The effect of the brace is dose-dependent. Therefore, the current recommendation is for the brace to be worn 23 hours a day for optimal results. Compliance can be a problem even with appropriate counseling (10-12). Physical therapy regimens and electrical stimulation have not been shown to affect the natural history of adolescent idiopathic scoliosis (12).
Surgical indications are based on many factors including the curve type, skeletal maturity, and curve magnitude. Documented progression on radiographs or parameters that suggest a high risk of progression must also be noted. In general terms, the immature patient who presents with a curve beyond the limits of effective bracing (greater than 40 - 50 degrees) or who has demonstrated significant progression despite effective bracing is a candidate for fusion. Standard techniques have evolved considerably over the last fifteen years. Instrumentation uses a combination of rods, hooks, and screws to correct the spine over individual segments. The ability to straighten the spine and maintain that correction until effective fusion occurs is tremendous. Depending on the specific characteristics of the patient, different approaches can be used. The standard posterior spinal fusion requires a long fusion construct. Anterior approaches allow a shorter construct and maintenance of flexibility by saving spinal segments. Thorascopic and laparoscopic techniques are being developed to allow microinvasive approaches to instrument and fuse the scoliotic spine (13).
Overall, the prognosis is favorable (14,15). Progression in adulthood is generally much slower than in adolescence. Curves less than 30 degrees at maturity are unlikely to progress. However, curves greater than 50 degrees have a 68% chance of progression. For curves between 50 and 75 degrees, the curves will progress by 1 degree per year. Therefore, surgical stabilization of the spine is recommended for curves greater than 50 degrees at skeletal maturity (5,6).
Mild to moderate idiopathic scoliosis in adulthood has no negative effect on pregnancy or delivery method. Generally, normal pulmonary function is found in patients with scoliosis. Restrictive pulmonary function does not occur until the curve reaches 100 degrees (16). No increased risk of mortality is found for adults with adolescent-onset idiopathic scoliosis (17). In most studies, the incidence of back pain does not differ significantly from the general population (4). Patients frequently note cosmetic concerns related to scoliosis. Severe psychological reactions to scoliosis are uncommon.
1. How is idiopathic scoliosis defined clinically and radiographically?
2. Who is more commonly affected - males or females?
3. As a diagnosis of exclusion, what other causes of scoliosis must be eliminated?
4. What physical findings are present in patients with scoliosis?
5. In the forward bending test, what physical finding suggests scoliosis?
6. What are the primary considerations when planning treatment?
7. What three forms of treatment are valid?
8. What is the long term prognosis for a patient with scoliosis in adulthood?
1. Upadhyay SS, et al. Disproportionate body growth in girls with adolescent idiopathic scoliosis. A longitudinal study. Spine 1991;16(8 Suppl):S343-S347.
2. Byl NN, Gray JM. Complex balance reactions in different sensory conditions: adolescents with and without idiopathic scoliosis. J Orthop Res 1993;11(2):215-227.
3. Brinker MR, et al. Neurologic testing with somatosensory evoked potentials in idiopathic scoliosis. Spine 1992;17(3):277-279.
4. Ramirez N, Johnston CE, Browne RH. The prevalence of back pain in children who have idiopathic scoliosis. J Bone Joint Surg Am 1997;79(3)364-368.
5. Weinstein SL, Ponseti IV. Curve progression in idiopathic scoliosis. J Bone Joint Surg 1981;65A:447-455.
6. Weinstein SL, Zavala DC, Ponseti IV. Idiopathic scoliosis: long-term follow-up and prognosis in untreated patients. J Bone Joint Surg Am 1981;63(5):702-712.
7. Lonstein JE, Carlson JM. The prediction of curve progression in untreated idiopathic scoliosis during growth. J Bone Joint Surg Am 1984;66(7):1061-1071.
8. Dimeglio A. Growth in pediatric orthopaedics. J Pediat Orthop 2001;21(4):549-555.
9. Morrissy RT, Goldsmith GS, Hall EC, Kehl D, Cowie GH. Measurement of the Cobb angle on radiographs of patients who have scoliosis: Evaluation of intrinsic error. J Bone Joint Surg Am 1990;72(3):320-327.
10. Fernandez-Feliberti R, et al. Effectiveness of TLSO bracing in the conservative treatment of idiopathic scoliosis. J Pediatr Orthop 1995;15(2):176-181.
11. Nachemson AL, Peterson LE. Effectiveness of treatment with a brace in girls who have adolescent idiopathic scoliosis. A prospective, controlled study based on data from the Brace Study of the Scoliosis Research Society. J Bone Joint Surg Am 1995;77(6):815-822.
12. Rowe DE, et al. A meta-analysis of the efficacy of non-operative treatments for idiopathic scoliosis [see comments]. J Bone Joint Surg Am 1997;79(5):664-674.
13. Bridwell KH. Surgical treatment of adolescent idiopathic scoliosis: the basics and the controversies. Spine 1994;19(9):1095-1100.
14. Cordover AM., et al. Natural history of adolescent thoracolumbar and lumbar idiopathic scoliosis into adulthood. J Spinal Disord 1997;10(3):193-196.
15. Montgomery F, Willner S. The natural history of idiopathic scoliosis. Incidence of treatment in 15 cohorts of children born between 1963 and 1977. Spine 1997;22(7):772-774.
16. Pehrsson K, Bake B, Larsson S, Nachemson A. Lung function in adult idiopathic scoliosis. Thorax 1991;46:474-478.
17. Pehrsson K, Larsson S, Oden A. Long term followup of patients with idiopathic scoliosis: A study of mortality, causes of death, and symptoms. Spine 1992;17:1091-1096.
Answers to questions
1. Clinical - side-to-side (sagittal) curvature of the spine. Radiographic - curvature of the spine whose curvature is greater than or equal to 10 degrees.
2. Females are affected more commonly than males.
3. Congenital, neuromuscular, traumatic, infectious, neoplastic, inflammatory, syndromic and degenerative causes.
4. Side-to-side curvature of the spine, rib hump, shoulder elevation, chest wall deformity, prominence of the scapula on one side.
5. Asymmetry of the rib hump
6. Risk of progression - skeletal maturity and magnitude of curvature.
7. Observation, brace, and surgery
8. Curvature less than 30 degrees - asymptomatic, non-progressive. Curvature greater than 50 degrees - progression in adulthood (1-2 degrees/year).