Early Onset Scoliosis can be classified as congenital, syndromic, neuromuscular or idiopathic. How are these types defined, and what are the clinical distinctions?
Scoliosis is defined as a three-dimensional deformity of the spine that includes both a more noticeable lateral deviation (Figure 1) and also a rotation of the vertebrae within the lateral curvature.
Early onset scoliosis is defined as scoliosis diagnosed before the age of 10 years old due to any cause.
Scoliosis can be categorized by etiology, as follows: congenital, syndromic, neuromuscular and idiopathic.
Figure 1: a 120 degree thoracic curve from congenital scoliosis. From Postoperative pulmonary complications following posterior spinal instrumentation and fusion for congenital scoliosis https://doi.org/10.1371/journal.pone.0207657
Congenital scoliosis is defined as scoliosis caused by at least one bony anomaly of the spine which is present at birth including failure of vertebral formation, such as hemivertebrae or wedged vertebrae, or failure of separation or segmentation, such as block vertebrae or unilateral bars.
Congenital scoliosis is due to developmental abnormalities formed during embryogenesis at 6 weeks of gestation, at which time the heart and kidneys are also developing. Thus, the presence of congenital scoliosis is a red flag for associated cardiac and renal malformations.
Syndromic scoliosis is defined as scoliosis that appears in conjunction with a recognized pediatric syndrome, such as Marfan’s, Ehlers-Danlos, trisomy 21 (Down Syndrome), Prader-Willi, Retts, neurofibromatosis, Noonan, and osteoporosis imperfecta.
Syndromic scoliosis is typically discovered after the diagnosis of a syndrome. When a child is diagnosed with a syndrome known to be associated with scoliosis, it is important that physicians screen for scoliosis. The natural history of scoliosis associated with the aforementioned syndromes varies, so the spinal curvature they cause progresses at different rates and requires personalized approaches to treatment.
Neuromuscular scoliosis is defined as scoliosis caused by a neurologic disorder, such as muscular dystrophy, cerebral palsy, spina bifida, spinal muscular atrophy, or Freidrich’s ataxia.
The likelihood of developing neuromuscular scoliosis usually depends on the extent of nerve and muscle involvement of the specific disorder. Not all children with a neuromuscular disorder will develop scoliosis, but it is especially common in those who are non-ambulatory and wheelchair-bound.
Neuromuscular scoliosis differs in particular from other types of scoliosis as the deformity is often a long, sweeping curve, typically involving the thoracic spine and the lumbar spine, as well as the pelvis.
Idiopathic scoliosis is defined as scoliosis without known cause; that is, when congenital, syndromic and neuromuscular causes have been excluded. Children with idiopathic scoliosis are considered otherwise healthy. For them and their parents, reassurance is indicated, though the curve must be monitored to ensure that the chest cavity develops adequately (as to allow normal pulmonary function).