Absent superficial abdominal reflexes in children with scoliosis. An early indicator of syringomyelia.

We describe 12 children with idiopathic scoliosis who had a persistent absent superficial abdominal reflex (SAR) on routine neurological examination. MRI showed syringomyelia to be present in ten. The average age at detection of the scoliosis was 4.3 years and at diagnosis of syringomyelia 6.6 years. In all ten children the SAR was consistently absent on the same side as the convexity of the curve. In two it was the only abnormal neurological sign. An absent SAR in patients with scoliosis is an indication for investigation for underlying syringomyelia. In the children with syringomyelia, six had thoracic and four thoracolumbar curves. The clinical features differed in the two groups. Patients with thoracic curves were generally asymptomatic. Their neurological signs were subtle and none had any motor signs. By contrast, patients with thoracolumbar curves had symptoms and neurological signs. Abnormal gait was present in all four patients with thoracolumbar curves. In three this was due to considerable motor weakness. In eight children syringomyelia was associated with a Chiari-I malformation. In seven the syrinx was treated surgically by decompression of the foramen magnum.