Scoliotic curve patterns in patients with Chiari I malformation and/or syringomyelia

A retrospective radiographic review was performed on 41 patients with scoliosis associated with a Chiari I malformation and/or syringomyelia. To characterize curve patterns and curve features in this population and possibly refine the radiographic indications for magnetic resonance imaging in patients with a normal history and physical examination. A subset of patients with "idiopathic" scoliosis may have an underlying neurologic abnormality. The radiographic indications for magnetic resonance imaging in asymptomatic patients with a normal clinical examination are not well defined. Data were collected from standing posteroanterior and lateral radiographs. The curve pattern and specific curve features were recorded and compared with historic controls. Thoracic kyphosis and total lumbar lordosis were also measured. Fifty-one percent of patients were male. Ten curve patterns were identified, and, based on our criteria, approximately 50% of patients had an "atypical" pattern (left thoracic, double thoracic, triple, long right thoracic). A subset of those with "typical" patterns (right thoracic, right thoracic/left lumbar) had atypical features including a superior or inferior shift of the apex and/or the upper or lower end vertebrae. The mean kyphosis (T3-T12) was 41.8 degrees. Although the decision to obtain magnetic resonance imaging in a patient with scoliosis should be based on both clinical and radiographic criteria, we suggest that a heightened index of suspicion is warranted with certain curve patterns (left thoracic, double thoracic, triple, and a long right thoracic curve with end vertebra caudal to T12), and with a high or low apex and/or end vertebra, especially in males and patients with a normal to hyperkyphotic thoracic spine.