“…The convexity of the papilla neutralises the high hydrostatic pressure wave and thus prevents intrarenal reflux. As repeatedly demonstrated, intrarenal reflux is the cause of pyelonephritic scarring, be it by the high pressure of sterile urine or, in the case of infected urine, by massive intratubular invasion of micro-organisms (Rose et al, 1975;Bourne et al, 1976). This explains why reflux, without urinary tract infection, can lead to renal failure (Salvatierra et al, 1973;Bakshandeh et al, 1976).…”