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Purpose: Ureteroscopy (URS) is related to complications, as fever or postoperative urinary sepsis, due to high intrapelvic pressure (IPP) during the procedure. Micro-ureteroscopy (m-URS) aims to reduce morbidity by miniaturizing the instrument. The objective of this study is to compare IPP and changes in renal haemodynamics, while performing m-URS vs. conventional URS., Methods: A porcine model involving 14 female pigs was used in this experimental study. Two surgeons performed 7 URS (8/9.8 Fr), for 45 min, and 7 m-URS (4.85 Fr), for 60 min, representing a total of 28 procedures in 14 animals. A catheter pressure transducer measured IPP every 5 min. Haemodynamic parameters were evaluated by Doppler ultrasound. The volume of irrigation fluid employed in each procedure was also measured., Results: The range of average pressures was 5.08-14.1 mmHg in the m-URS group and 6.08-20.64 mmHg in the URS (NS). 30 mmHg of IPP were not reached in 90% of renal units examined with m-URS, as compared to 65% of renal units in the URS group. Mean peak diastolic velocity decreased from 15.93 to 15.22 cm/s (NS) in the URS group and from 19.26 to 12.87 cm/s in the m-URS group (p < 0.01). Mean resistive index increased in both groups (p < 0.01). Irrigation fluid volume used was 485 mL in the m-URS group and 1475 mL in the URS group (p < 0.001)., Conclusions: m-URS requires less saline irrigation volumes than the conventional ureteroscopy and increases renal IPP to a lesser extent.

Miniaturization of ureteroscopy materials is intended to decrease tissue damage. However, tissue hypoxia and the gross and microscopic effects on tissue have not been adequately assessed. We compared the gross and microscopic effects of micro-ureteroscopy (m-URS) and conventional ureteroscopy (URS) on the urinary tract. We employed 14 pigs of the Large White race. URS was performed in one of the ureters with an 8/9.8 F ureteroscope, while a 4.85 F m-URS sheath was used in the contralateral ureter. Gross assessment of ureteral wall damage and ureteral orifice damage was performed. For microscopic assessment hematoxylin-eosin staining and immunohistochemistry for detection of tissue hypoxia were conducted. Regarding the macroscopic assessment of ureteral damage, substantial and significant differences were recorded using URS (C = 0.8), but not with m-URS. Microscopic assessment after staining with hematoxylin-eosin revealed greater epithelial desquamation in the URS group (p < 0.05). Pimonidazole staining revealed greater hypoxia in the epithelial cells than in the remainder of the ureteral layers. We conclude that m-URS causes less damage to the ureteral orifice than URS. Histopathological findings show m-URS reduces ureteral epithelial damage compared with conventional ureteroscopy. Both URS and m-URS cause cellular hypoxia.

Purpose: The aim of this study is to assess the effectiveness, safety, and reproducibility of the microureteroscopy (m-URS) in the treatment of distal ureteral stones in women. Materials and Methods: A multicenter, prospective observational study was designed and conducted between March and December 2015. We included women having at least one stone in the distal ureter and being a candidate for surgical treatment using the 4.85F sheath of MicroPerc®. Patients with clinical criteria and/or laboratory analysis indicating sepsis or coagulation alteration were excluded. Results: Thirty-nine women were operated in eight hospitals. The profile of the patients was fairly homogeneous among hospitals. Only differences were found in age, preoperative stent, and the result of the previous urine culture. Immediate stone-free status was achieved in 88.2% and 100% 7 days after the procedure. 97.4% of patients did not present any complication in the postoperative period, with only one case with complication Clavien II. Postureteroscopic Lesion Scale (PULS) in 76.9% of patients did not show any injury, 20.5% had lesions grade 1, and grade 2 lesions 2.6%. As for the reproducibility of m-URS between hospitals, statistical analysis of the results showed differences between all the centers participating in the study. Conclusions: m-URS is an effective, safe, and reproducible technique that minimizes surgical aggression to the ureteral anatomy. Satisfactory and comparable results to ''conventional'' ureteroscopy were obtained in the treatment of distal ureteral stones in women, although clinical trials are needed. The reduction of the ureteral damage may reduce secondary procedures and increase the cost-effectiveness of the procedure. [ABSTRACT FROM AUTHOR]