As urologists gained experiencein the late 1970s and early 1980s with percutaneous stone removal, it became apparent that the same access techniques could be used for intrarenal surgery for the management of obstructive uropathies including ureteropelvic junction (UPJ) obstruction. Ramsey<sup>13 Ramsey J.W., Miller R.A., Kellett M.J. , e al. Percutaneous pyelolysis: Indications, complications, and results Br J Urol 1984 ;  56 : 586-588

Cliccare qui per andare alla sezione Riferimenti</sup> and Badlani<sup>1 Badlani G.H., Smith A.D. Percutaneous ureteral surgery Semin Urol 1986 ;  4 : 191-197

Cliccare qui per andare alla sezione Riferimenti</sup> and their co-workers reported the first series in the United Kingdom and the United States, respectively. Although the results of these treatments were not as good as those achieved with open surgery, the minimally invasive character of percutaneous access and minimal morbidity had obvious appeal. Antegrade (or percutaneous) endopyelotomy is now a first-choice procedure in patients with UPJ obstruction.