Pediatric Spinal Deformity: Idiopathic Scoliosis
By Laurence E. Mermelstein, M.D. aka Dr. M."

Spinal deformity is the most frequent problem that will cause a child and his family to seek out spinal evaluation. The diagnosis of a spinal deformity can cause a great deal of distress within a family, mostly due to a lack of knowledge regarding the problem. In the vast majority of cases, these deformities can be managed non-operatively and only require careful observation. This article will highlight the latest medical information regarding the most common pediatric spinal deformity, Idiopathic Scoliosis.

DEFNITION
Scoliosis is defined as a lateral curvature of the spine, most readily noticed when looking at the child from the back (or front). This is frequently manifested as a shoulder or pelvic asymmetry or an overall imbalance of the trunk to the left or right.

ETIOLOGY
There are several known different etiologies of scoliosis, the most common of which is termed idiopathic, a technical term for unspecified or unknown cause. Other less common causes are congenital (secondary to vertebral anomalies that develop in utero) paralytic (secondary to muscle weakness) or neuromuscular in origin (e.g. Cerebral Palsy, Spina Bifida, Muscular Dystrophy).

Various theories regarding the etiology of idiopathic scoliosis have been put forth, but none have been completely validated. Inheritance has a definite role in predisposing a child to developing scoliosis, but a discrete gene or mode of inheritance has not been established. Hormonal imbalance, abnormal tissue structure, subtle neurologic imbalances and/or abnormal reflexes have all been considered as etiologic factors, with no one reason being entirely responsible.

PREVALENCE
Scoliosis is most frequently quantified by a measurement of a curve in degrees. A true structural curve is usually defined as being greater than or equal to 10 degrees. Using this cut-off, the prevalence of scoliosis has been established as approximately 25 out of 1 000 population. For curves measuring greater or equal to 10 degrees, the female to male ratio is approximately 2 to 1. However, for curves of a magnitude requiring some form of treatment (bracing, surgery), the ratio is much closer to 1 0 to 1 with females being much more common than males. The reason for this difference in sex incidence is unclear.

EVALUATION
Children and adolescents usually present to the doctor after a positive screening examination. The wide spread school screening of pre-adolescents in New York State has been very successful at discovering scoliosis in individuals while the curve is mild and early intervention is possible. This is crucial because scoliosis in adolescents is generally asymptomatic.

Detection of a painful scoliosis is usually related to an underlying painful process which must be thoroughly evaluated (fractures, tumors, infections, neurologic problems, etc.). A child's general medical history is an integral part of the initial evaluation to rule out other types of scoliosis other than the truly idiopathic.

Idiopathic scoliosis is usually a slowly progressive problem with curvatures increasing approximately 15 to 20 degrees over the course of a year at the most rapid. Curves that progress clinically faster than this over the course of 3 to 4 months are usually associated with abnormalities of the brain or spinal cord.

Progression in idiopathic scoliosis is directly related to the child's skeletal age which is often different from the child's chronologic age. Basically, the more rapidly a child's spine is growing, the higher the likelihood that any given curvature will progress. Likewise, if a child has finished growing (i.e. skeletally mature), the chances that a given curve will progress is very small assuming that the curve is of the small to moderate size. Skeletal age can be assessed with the knowledge of a girl's age at the onset of menarche, assessment of the pelvic growth plates ("Risser's sign") or special hand radiographs which assess "bone age". One "rule of thumb" is that a girl will usually finish growing approximately 1.5 to 2 years after the onset of menses. The difference between a child and her parent's height is another way to assess a child's growth potential.

A physical examination is an integral part of the initial assessment. Leg lengths must be assessed as a possible cause for pelvic imbalance. When the child is evaluated from behind with the back flexed, rotational and lateral curvatures are highlighted and more easily quantified. A careful neurologic examination including leg strength and reflexes is performed to look for subtle signs of a neuro-muscular disorder.

For clinically apparent curves, radiographic assessment is the best way to document curve size and progression. The initial radiographs should include a long back-to-front picture of the entire spine (PA-posteroanterior radiograph) as well as a side view (lateral). Curve magnitude is measured in degrees (called Cobb angles). In many curves, the degree of roundback (or flatback) seen on the lateral view is just as important.

Page 2 - Treatment and Follow-up