Occult intraspinal anomalies in congenital scoliosis.

Thirty consecutive patients with congenital spinal deformity underwent magnetic resonance imaging (MRI) to determine the incidence of occult intraspinal anomaly. These congenital spinal deformities included 29 cases of congenital scoliosis and one case of congenital kyphosis. Physical examination findings and plain radiographs were reviewed in an attempt to correlate these findings with subsequent intraspinal pathology. Nine patients had intraspinal anomalies identified on MRI consisting of five with tethered cord, four with syringomyelia, three with lipoma, and one with diastematomyelia. One patient required surgery for diastematomyelia; another underwent release of his tethered cord. Only one patient, with diastematomyelia associated with a syrinx and bifocal tethering, had his anomaly suggested by physical examination and plain radiographs. Two other patients had findings on plain radiographs previously associated with high prevalence of occult intraspinal anomalies; one patient with congenital kyphosis had a tethered cord, and one patient with a unilateral hemivertebrae associated with a contralateral bar had a tethered cord. Two of nine patients with occult intraspinal anomalies required surgery for their anomaly. In patients with a congenital spinal deformity, we found nine (30%) of 30 to have an associated anomaly within the spinal canal. Only three of these nine had plain radiographs and physical examination findings suggestive of their subsequent MRI findings. Given the poor correlation between findings on physical examination, plain radiographs, and subsequent occult intraspinal anomalies on MRI, we believe that MRI is helpful in evaluating patients with congenital spinal anomalies.