[The reno-calyceal index. Radiological evaluation of pyelocalyceal distensions in children].

The ratio length of one kidney width of the lower calyx, measured pre and post-operatively, is proposed as an objective index to assess the result of pyeloplasty in surgical treatment of hydronephrosis. Statistical approach on a series of 25 children with unilateral hydronephrosis and normal contralateral kidney has demonstrated the reliability of this index to determine the evaluation of the dilatation in the post-operative period. An increase of the ratio was present in all cases in which the result of surgery, as far as distension was concerned, was satisfactory.