lumbar subarachnoid ureterostomy, a surgical procedure to drain cerebrospinal fluid through the ureter to the bladder in hydrocephalus, usually in the newborn. A lumbar laminectomy and a left nephrectomy are performed, after which a polyethylene tube is passed from the lumbar subarachnoid space through the paraspinal muscles and into the free ureter. The procedure is performed to correct a communicating type of hydrocephalus.
