Proportional analysis of pig kidney arterial segments: differences from the human kidney

To present a systematic study and a proportional analysis of the arterial segments of the pig kidney.

Sixty-one three-dimensional endocasts of the arterial segments of pig kidneys were studied. Each segment was injected with a resin of a different color. Cavalieri's principle was used to calculate the volume of each renal segment, and these results were compared with the results from the point-counting planimetry method used on photographs of pig-kidney surfaces.

Two to five renal segments were observed. Division into two segments, a cranial and a caudal, was the most common (42.62%). The renal volume ranged from 101 to 173 cm(3) (mean 130.85 cm(3)). The cranial segment was present in 39 of the 57 casts (68.42%). It presented the greatest median value of proportional area (50.00%) and also the greatest maximum value of proportional area, accounting for as much as 74.04% of the total kidney area. The ventral segment, which was found in 20 of the 57 casts (35.09%), presented the lowest median value of proportional area (13.87%) and showed the most variation in area (coefficient of variation 72.89%). There was no significant statistical difference between the segmental areas as evaluated by Cavalieri's principle and by the point-counting planimetry method.

The distribution and size of the renal-arterial segments in pigs are not similar to those of the human kidneys. Therefore, this information must be taken into account by practitioners of urologic training or ablation using pigs as the animal model, as the structure of the porcine arterial segments cannot be transposed to humans.