The induction of urologic malformations. Understanding the relationship of renal ectopia and congenital scoliosis.

The normally straight caudal trunk of the 3-day-old chick embryo was surgically deflected, constricted, or pierced using fine steel instruments. The delayed effects of these injuries were evaluated anatomically by performing microdissections of the genitourinary systems of the chicks surviving these operations. Eighty-six of 181 survivors of 347 operations showed malformations. Renal ectopia appeared with scoliosis 10 times more often than it appeared by itself (P less than 0.01). Eighty-six chicks survived 102 control operations; only two had a urinary anomaly (P less than 0.01). The paring of renal ectopia with scoliosis may be attributable to an isolated spinal defect that precludes complete renal ascent, an injury to the anlages of both the spine and kidney, or a genetic abnormality that affects both anlages.