Hybrid transureteral natural orifice translumenal endoscopic nephrectomy: a feasibility study in the porcine model.

BACKGROUND AND PURPOSE: Natural orifice approaches for nephrectomy have included access via the stomach, vagina, bladder, and rectum. The use of the ureter as a natural orifice for natural orifice translumenal endoscopic surgery (NOTES) nephrectomy has not been previously reported. The purpose of this study is to test the feasibility of transureteral laparoscopic NOTES nephrectomy. MATERIALS AND METHODS: Three female farm pigs (29.2-30.8 kg) were placed into the lithotomy position. A cystoscopically placed extra-stiff guidewire was used to place a prototype dilating sheath into the left ureter. After dilation of the ureter and urethra, the sheath was exchanged for a 12-mm bariatric laparoscopic trocar. A 10.5-inch long 10-mm offset operating laparoscope with an internal 5-mm working port was used for the nephrectomy. One 2-mm and one 2/3-mm port were placed transabdominally to facilitate in situ morcellation. The kidney was cut into slices using the bipolar device and extracted via the ureteral port using the housing of a 12-mm bariatric stapling device. RESULTS: All three transureteral nephrectomies were successfully completed. The total mean operative time was 220 minutes (range 113-346 min). Component portions of the procedure were: Ureteral access (mean 21 min), nephrectomy (mean 70 min), and kidney morcellation (mean 103 min). Mean estimated blood loss was 20 mL (range 5-50 mL). There were no intraoperative complications. CONCLUSIONS: This nonsurvival porcine feasibility study demonstrates the successful performance of transureteral nephrectomy. This approach shows promise as a way to decrease the invasiveness of NOTES nephrectomy by using the ureteral orifice as an access site.

Fluoroscopic organ and tissue-specific radiation exposure by sex and body mass index during ureteroscopy.

INTRODUCTION: Although radiation exposure from CT and plain film imaging has been characterized, the radiation received by patients during modern-era fluoroscopy has not been well described. The purposes of this study were to measure absolute organ and tissue-specific radiation doses during ureteroscopy and to determine the influence of body mass index (BMI) and sex on these doses. MATERIALS AND METHODS: Eight cadavers underwent a simulated left ureteroscopy. Using a modern C-arm with automatic exposure control settings, thermoluminescent dosimeters were exposed for a fluoroscopy time of 145 seconds (mean time of clinical ureteroscopies from 2006 to 2008). Total tissue exposures were compared by BMI and between sexes using the Wilcoxon signed ranks test and the Mann-Whitney test with p < 0.05 considered significant. RESULTS: Among all cadavers, radiation doses were significantly lower in all contralateral organs excluding the gonad (p < 0.012). Doses were similar bilaterally in the gonad in cadavers with BMI <30, and in all organs in cadavers with BMI >30 (p > 0.05). There were significantly higher mean bilateral gonadal doses in female cadavers (3.4 mGy left and 1.9 mGy right) compared with male cadavers (0.36 mGy left and 0.39 mGy right). The highest cancer risk increase was seen at the posterior skin equivalent to 104 additional cancers per 100,000 patients. CONCLUSION: Contralateral doses were lower for all organs except the gonad when the BMI was <30. In contrast, when the BMI was >30, there was no difference in radiation dose delivered to the ipsilateral and contralateral organs. Gonadal doses were significantly higher in female cadavers. Modern-era fluoroscopy remains a significant source of radiation exposure and steps should be taken to minimize exposure during ureteroscopy.