Micro-ureteroscopy vs. ureteroscopy: effects of miniaturization on renal vascularization and intrapelvic pressure
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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.
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.
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).
m-URS requires less saline irrigation volumes than the conventional ureteroscopy and increases renal IPP to a lesser extent.
KeywordsUreteroscopy Urolithiasis Ureteral stones Miniaturization Model, animal Minimally invasive surgical procedures
Systemic inflammatory response syndrome
Retrograde intrarenal surgery
Millimeter of mercury
Body mass index
Peak systolic velocity
Peak diastolic velocity
Mean arterial flow
Wilcoxon signed-rank test
European Association of Urology
JPC-R: project development, data collection, and manuscript writing. JAG-L: project development, data collection, and manuscript writing. FS: project development, data collection, and manuscript writing. EM-M: data collection. PC-P: data analysis. JEC-C: data collection. AG-S: manuscript writing. JR-M: manuscript writing.
Compliance with ethical standards
Conflict of interest
Authors received research funds from a public research institute (ISABIAL-FISABIO) and from Presurgy SL.
The experimental protocol received approval from the Ethics Committee on Animal Experimentation of the Jesús Usón Minimally Invasive Surgery Center (Cáceres), Spain.
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