Posterior urethral valves, unilateral reflux and renal dysplasia: a syndrome.

Infants with posterior urethral valves and persistent unilateral reflux after valve resection often have an associated nonfunctioning, dysplastic kidney. Spurious function of the unit with reflux may be apparent on the delayed films of the excretory urogram. Misinterpretation of the initial radiographic studies performed without coincident bladder drainage results in the missed diagnosis of this syndrome and misguided surgical management. Of 82 patients with urethral valves 17 (21 per cent) had persistent unilateral reflux. A renal scan was useful in determining nonfunction in 11 (65 per cent) of those patients with persistent unilateral reflux and 1 with bilateral reflux. The functionless kidney was on the left side in 11 of 12 cases (92 per cent). Early nephroureterectomy is advocated to improve voiding dynamics. The prognosis is generally excellent. The embryogenesis of the syndrome is discussed as it relates to the "bud theory" of renal dysplasia and posterior urethral valves.