[Compensatory hypertrophy of the healthy kidney as an important prerequisite for nephrectomy of the small kidney].

In children with hypertension and unilateral small kidney blood pressure may be normalized by nephrectomy of the small kidney; but hypertension may persist, if the contralateral kidney is not normal. Nephrectomy of the small kidney therefore should only be performed, if integrity of the contralateral kidney is certain. The best indicator about integrity in our experience is the ability of the contralateral kidney to develop compensatory hypertrophy. Compensatory hypertrophy is easy to determine, one or two urograms with clearly visible outlines are needed. If compensatory hypertrophy cannot be proven, nephrectomy of the small kidney is contraindicated. Case reports illustrate the importance of the determination of compensatory hypertrophy of the contralateral kidney for making such decisions.