BASIC AND TRANSLATIONAL UROLOGY

Natural orifice translumenal endoscopic surgery (NOTES) renal cryoablation in a porcine model
Crouzet S, Haber GP, Kamoi K, Berger A, Brethauer S, Gatmaitan P, Gill IS, Kaouk JH
Section of Laparoscopic and Robotic Surgery, Glickman Urological Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA
BJU Int. 2008; 102: 1715-8

• Objective: To present our laboratory experience with natural orifice translumenal endoscopic surgery (NOTES) renal cryoablation.
• Materials and Methods: In two female farm pigs, we performed four procedures of NOTES renal cryoablation. In each pig, NOTES was performed through a transgastric approach and a transvaginal approach for each kidney, respectively. The pig was placed in the flank position and pneumoperitoneum obtained using a transabdominal Veress needle. In the first pig, we started with the left kidney with a transgastric approach: a dual-channel video gastroscope (Olympus, Tokyo, Japan) was used, the stomach wall was punctured using a needle-knife, a guidewire was passed into the abdominal cavity and the access dilated using a controlled radial expansion balloon. The bowel was mobilized medially and the Gerota’s fascia overlying the upper pole was dissected. Under direct endoscopic vision, a cryoablation probe was introduced percutaneously into the anterior upper pole of the kidney. The pig was then flipped to the right flank position and a transvaginal approach was used: the gastroscope was introduced through the posterior fornix of the vagina. For the second pig, we performed initially a transgastric right-side cryoablation then a transvaginal left-side cryoablation as described for the first pig.
• Results: All four procedures were performed successfully, with no intraoperative complications. No additional laparoscopic ports or open conversions were necessary. The vision of the kidney and the ice-ball was adequate for all cases. The mean operative duration was 83 min. Stomach closure was tested watertight, and there were no abdominal or pelvic injuries found at autopsy.
• Conclusions: NOTES can provide adequate minimal surgical dissection for safe and effective percutaneous renal cryoablation under direct videoscopic monitoring at kidney locations otherwise not accessible percutaneously. Both transgastric and transvaginal approaches can be used effectively for renal cryoablation providing a minimally invasive scar-less surgery.
  
  
• Editorial Comment
  This is an interesting bench to bedside research, demonstrating the usefulness of the pig model for research in endourology and videoendoscopy. It has been shown that the pig is the best animal model for translational research in urology, due to its renal similarities with humans, concerning intra-renal anatomy of collecting system, arteries and veins (1-3). Also, abdominal and pelvic cavities in pigs are similar to humans, both in volume and in organ position. So, it is possible to transpose the laboratory research to clinical setting very fast.
  The present paper clearly demonstrated the feasibility of NOTES for videoendoscopic monitoring of percutaneous renal cryoablation both by transgastric and transvaginal approaches.

References
1. Sampaio FJB, Pereira-Sampaio MA, Favorito LA: The pig kidney as an endourological model. Anatomical contribution. J Endourol. 1998; 12: 45-50.
2. Pereira-Sampaio MA, Favorito LA, Sampaio FJB: Pig kidney: anatomical relationships between the intrarenal arteries and the kidney collecting system. Applied study for urological research and surgical training. J Urol. 2004; 172: 2077-81.
3. Bagetti Filho HJ, Pereira-Sampaio MA, Favorito LA, Sampaio FJ: Pig kidney: anatomical relationships between the renal venous arrangement and the kidney collecting system. J Urol. 2008; 179: 1627-30.

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