The pig kidney as an endourologic model: Anatomic contribution

We present detailed anatomic findings on collecting system anatomy and renal morphometry in the pig and compare these findings with previous findings in humans. We studied three-dimensional polyester resin corrosion endocasts of the pelviocaliceal system obtained from 100 kidneys (50 pigs). Eighty kidneys were evaluated morphometrically, considering length, cranial pole width, caudal pole width, thickness, and weight. The pig collecting system was classified into two major groups (A and B). Group A (40%) was composed of kidneys in which the mid-zone is drained by calices dependent on the cranial or the caudal caliceal group or both. Group B (60%) kidneys have the mid-zone drained by calices independent of the polar groups, Group B includes two subtypes (B-I and B-II). The pig collecting system showed only angles smaller than 90 degrees between the caudal (lower) infundibulum and the renal pelvis. Renal morphometric measurements revealed the following means: length 11.8 cm, cranial pole width 5.64 cm, caudal pole width 5.35 cm, thickness 2.76 cm, and weight 98 g. As in human kidneys, one may group the pig collecting system into two groups. Nevertheless, in pigs, we did not find a subdivision of Group A. The incidence of collecting systems in Groups A and B and the subtypes of Group B in pigs are different from those in humans. Also different from humans, in pigs, we found only angles smaller than 90 degrees between the caudal (lower) infundibulum and the renal pelvis. Except for the length, the means of the other morphometric measurements of the pig kidney are smaller than those of humans. From an anatomic standpoint, despite the differences pointed out, we conclude that the pig kidney is a good animal model for endourologic research and training.