INVESTIGATIVE UROLOGY

Proportional analysis of pig kidney arterial segments: differences from the human kidney
Pereira-Sampaio M, Favorito LA, Henry R, Sampaio FJ
Department of Morphology, Fluminense Federal University, Niteroi, Brazil
J Endourol. 2007; 21: 784-8

• Purpose: To present a systematic study and a proportional analysis of the arterial segments of the pig kidney.
• Materials and Methods: 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.
• Results: 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.
• Conclusions: 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.
  
  
• Editorial Comment
  The pig has been used as the favorite animal model for training and experimental research in urology, including many studies on laparoscopic total and partial nephrectomy, hemostasis techniques and more recently, ablative technologies, including radio frequency ablation and cryoablation. Therefore, a comprehensive knowledge on the proportional areas of the arterial segments would be important for evaluating the extension of experimental lesions in pigs. The aim of this study was to provide an analysis of the pig kidney segmentation and an analysis of the proportional area of each segment as measured on polyester resin endocasts of the kidney arterial vasculature.
  The results demonstrated that the arterial segmental pattern in pigs are not similar to those of the human kidneys, and therefore, the experimental findings concerning renal ablative techniques using the pig must not be completely translated to clinical setting in humans.

Dr. Francisco J.B. Sampaio
Full-Professor and Chair, Urogenital Research Unit
State University of Rio de Janeiro
Rio de Janeiro, RJ, Brazil
E-mail: sampaio@urogenitalresearch.org