Evidence of some experimental work and a greater amount of speculation is found in the medical literature on the degree of recovery that may be expected from repair procedures in cases of hydronephrosis. The generally expressed experimental opinion is frankly pessimistic; and, while experimental results cannot be too closely applied to clinical problems, in this case they seemingly correspond. Technical difficulties and complicating infections are factors often held responsible by surgeons for many of their clinical failures, which have been so frequent that there is a pronounced reluctance to attempt the surgical repair of hydronephrotic sacs. The experience of persistent urinary fistulas and the occasional necessity of later nephrectomy is a real discouragement to one conservatively minded, and forms the chief argument of the radical class for an initial nephrectomy. Ureteropyeloplastics, pyeloplications, lateral ureteral anastomoses, ureteropyeloneostomies, nephrocystoneostomies, pyelorenal orthopedic resections, and other plastic repair procedures have fallen into general disfavor.