Editorial Comment on: “Pressurized-Bag Irrigation Versus Hand-Operated Irrigation Pumps During Ureteroscopic Laser Lithotripsy: Comparison of Infectious Complications” by Farag et al.

Irrigation flow is key in optimizing the endoscopic view during ureteroscopic procedures. Maintenance of adequate flow relies on increasing the pressure gradient of the irrigation through the endoscope's working channel and the collecting system. Consequently, elevation of the renal pelvic pressure (RPP) may be further complicated by urosepsis. ¹ In their study, Farag and colleagues investigated whether the type of irrigation system utilized during ureteroscopic procedures adversely affected the postoperative outcomes. ² They found that compared with pressure- or gravity-driven irrigation, the use of manual pump irrigation operated by the surgeon or surgical assistant was associated with significantly higher rate of meeting systemic inflammatory response syndrome (SIRS) criteria (1% vs 7%, OR 2.37) and emergency room presentations (12% vs 28%, OR 3.73).

The rise in RPP above the physiologic range leading to pyelovenous and pyelolymphatic backflow may, in turn, result in systemic absorption of pathogens and endotoxins. ¹ Accordingly, the increase in infectious complications in the manual irrigation group was attributed to the higher RPP compared with that attained by pressurized irrigation. The authors identified manual pump irrigation as the only significant predictor of SIRS on multivariate analysis. However, regardless of the irrigation system that is utilized, preoperative bacteriuria is an imperative predisposing factor for urosepsis after ureteroscopy and cannot be overlooked. Indeed, patients with a positive preoperative urine culture are at an increased risk for urosepsis after ureteroscopy, despite appropriate antibiotic prophylaxis. ³ Furthermore, positive intraoperative stone culture has been shown to be associated with higher rates of infectious complications after ureteroscopy, and may serve as a more reliable predictor of urosepsis than preoperative urine culture alone. ⁴ Therefore, the presence of urine and stone bacteria is a potential confounding variable that may affect the internal validity of the study. To that end, a follow-up prospective randomized trial that helps delineate the relationship between the type of irrigation system and infectious complications after ureteroscopy, while controlling for preoperative urine culture and stone culture, would be of great interest as that would further support a change in practice patterns.