Long-term effect of Boston brace treatment on renal function in patients with idiopathic scoliosis.

The long-term effects of Boston brace treatment on renal function were studied in 20 patients with idiopathic scoliosis. Renal function was tested by clearances of inulin and para-aminohippurate sodium (PAH) when the brace was first applied as well as after four and 12 months of brace treatment. Each function test was performed without and with the brace. The glomerular filtration rate decreased when the brace was first applied, was unchanged after four months, and increased after 12 months. Renal plasma flow decreased when the brace was first applied but was unchanged after four and 12 months. Urinary sodium excretion decreased to values lower than those of control subjects when the brace was first applied, but an adaptive increase was noted after four and 12 months of brace treatment. The acute effects of brace application were observed even after four and 12 months of treatment; an increase in urinary sodium excretion was found when the brace was removed.