Figure. Radiograph of whole spine showing scoliosis.
A 10-year-old girl presents to the office accompanied by her parents with a complaint of upper back asymmetry. She denies any pain or noticeable functional limitations. Her father states that he has a history of scoliosis. On a forward bend test, the patient’s left flank and right rib are prominent. The patient walks with a normal gait and has no motor weakness in the lower extremities. Scoliosis-view radiograph is obtained (Figure) and shows a left coronal Cobb angle of 27° (T9-L3).
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Adolescent idiopathic scoliosis occurs when there is a lateral bend to the spine without an identifiable cause. The condition usually presents in patients aged 10 to 16 years.1 The lateral bend is measured as a Cobb angle, which should be >10° to diagnose scoliosis.1
Scoliosis can occur on either the right or left side based on the direction of the apical convexity. In adolescents, right thoracic curves are most common whereas left thoracic curves are rare. When a left thoracic scoliosis is present, MRI of the entire spine — from the posterior fossa of the skull to the conus medullaris — should be obtained to rule out spinal cord abnormalities as a possible cause. Spinal cord abnormalities may include Chiari malformation, syringomyelia, and/or a tethered cord.2
Another predictor of spinal cord abnormalities causing scoliosis is curve severity, with curves >40° more likely to be associated with an abnormality. Left-sided scoliosis caused by spinal cord abnormalities is more common in boys while right-sided idiopathic scoliosis is more common in girls. Genetics seems to play the largest role in the development of scoliosis; if both parents had idiopathic adolescent scoliosis, their children are 50 times more likely to have it than the general population.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants.
1. Reamy BV, Slakey JB. Adolescent idiopathic scoliosis: review and current concepts. Am Fam Physician. 2001;64(1):111-117.
2. Wu L, Qiu Y, Wang B, Zhu ZZ, Ma WW. The left thoracic curve pattern: a strong predictor for neural axis abnormalities in patients with “idiopathic” scoliosis. Spine (Phila Pa 1976). 2010;35(2):182-185.