It has been well known that when there exists some functional disturbance in one side of the kidney or nephrectomy is applied, the kidney of the other side undergoes compensatory hypertrophy Attempts to know, however, the intensity of this hypertrophy by simple clinical measure have not been active
This author investigated, on X-ray picture, the significance of the measurement of renal area in relation to the duration, intensity or completion of the compensatory renal hypertrophy.
First of all, on normal X-ray picture of the kidney, mersurements were made on the long axis, width, the area of kidney, calix, the angle formed by the renal axis and the median line, width/longaxis · 100, and also their difference between right and left.
Then, this author demonstrated the presence of significant correlation with 99% confidence between the height and renal long axis, Pignet-Vervaeck's body index and renal area as well as between the chest and the maximun renal width. The reason why correlations were investigated was because the in vivo morphological changes of the kidney might better be understood in this manner rather than the simple discussions of the size of kidney on X-ray films.
In addition, measuments were made on the area, long axis and the width of the residual kidney on the 10th, 20th, 30th, 3 months, 6 months, 12 months and 2 years after nephrectomy in order to know the respective rate of hypertrophy. Hypertrophy was found to advance rapidly for about 20 days after operation and thereafter it was found to diminish gradually following the elapse of time. By the end of 6-12 months, the area showed an increase of 12-16% and it appeared that the compersatory hypertrodhy was completed.
Lastly, an investigation was made on the adequacy of employing the determination of renal area as the basis for the discussion of renal hypertrophy. As the result of this investigation, it was found that the rate of hypertrophy determined by the calculation of the renal area was virtually in agreement with that determined by the calculation of the renal volume, and the curve drawn by this rate of hypertrophy showed parallel relationship, though slightly lower, with the curve of hypertrophy determined by body index, height and the circumference of the chest demonstrating the possession of sufficient value for clinical application.
Namely, the determination of the area of healthy side kidney can tell the presence or absence or intensity of compensatory hypertrophy and also it supplies inf orrnations to know the state of functional disturbance on the diseased kidney, or when the patient undergoes nephrectomy, it helps the observation of the convalescence of the residual kidney as well as the patient himself.