This prospective exploratory study evaluated whether patient positioning influences intrarenal conditions and clinical outcomes during flexible ureteroscopic lithotripsy when a negative-pressure sheath is used. The investigators compared a leg-split-free lateral decubitus position with the conventional lithotomy (supine with legs apart) position. Continuous intrapelvic pressure and temperature monitoring was performed to quantify intraoperative differences that might affect infection risk, renal safety, and stone clearance.
The study was conducted at Peking University People’s Hospital between January 2024 and December 2025. It enrolled patients undergoing unilateral flexible ureteroscopy combined with a negative-pressure aspiration sheath. Participants were allocated into two groups according to the surgical position used: leg-split-free lateral decubitus group (n = 20) and conventional lithotomy group (n = 20). The report describes this as a prospective comparison; no randomization or blinding details were provided in the abstract.
An intelligent flexible ureteroscopy system with both pressure and temperature control was employed to continuously record intrapelvic pressure and intrapelvic temperature during the procedure. The system provided detailed, time-resolved measurements used to calculate the incidence and duration of intrapelvic hypertension episodes and periods of elevated intrapelvic temperature for each case.
Intraoperative analysis focused on the duration of intrapelvic hypertension and the duration of elevated intrapelvic temperature. The leg-split-free lateral decubitus group had a markedly shorter median duration of intrapelvic hypertension compared with the lithotomy group: 25.0 (0.0, 31.8) seconds versus 115.0 (79.8, 176.0) seconds, respectively (P < 0.01). Likewise, the duration of elevated intrapelvic temperature was shorter in the lateral decubitus group: median 3.0 (2.0, 9.8) seconds versus 18.5 (16.0, 24.5) seconds in the lithotomy group (P < 0.01). These findings indicate the lateral decubitus position was associated with shorter cumulative periods of intraoperative intrapelvic pressure elevation and hyperthermia during the procedures performed with the negative-pressure sheath.
Postoperative follow-up included assessment of febrile complications and radiologic evaluation of stone clearance. No patients in the leg-split-free lateral decubitus group developed fever postoperatively; two patients in the lithotomy group experienced fever. This difference did not reach statistical significance (P = 0.15) in the reported analysis. All patients underwent computed tomography at three months to determine stone-free status. The stone-free rate was significantly higher in the leg-split-free lateral decubitus group than in the lithotomy group (P = 0.04).
The two groups were similar at baseline. Reported variables that showed no statistically significant differences included gender, age, stone diameter, stone number, stone location, and the degree of hydronephrosis (all P > 0.05). The study reports group-wise comparisons for intraoperative and postoperative measures with P values provided for the primary reported endpoints.
Within this prospective cohort, positioning the patient in a leg-split-free lateral decubitus position during flexible ureteroscopy with a negative-pressure sheath was associated with shorter durations of intrapelvic hypertension and elevated intrapelvic temperature compared with the conventional lithotomy position. The lateral decubitus group also showed a higher radiologic stone-free rate at three months. Fewer postoperative febrile events occurred in the lateral decubitus group, but the difference did not reach statistical significance in this sample.
These results suggest a potential benefit of the leg-split-free lateral decubitus position in terms of intrarenal physiological parameters and stone clearance when using a negative-pressure sheath. However, the study is described as exploratory and includes a modest total sample size of 40 patients. The abstract does not provide details on randomization, allocation concealment, or other measures that would reduce bias, and it does not report secondary outcomes such as operative time, blood loss, or longer-term complications beyond three months. Such details and external validation are needed before changing routine practice.
The authors conclude that, compared with the lithotomy position, the leg-split-free lateral decubitus position may better maintain lower intrapelvic pressure and temperature during flexible ureteroscopy with a negative-pressure sheath and is associated with a higher stone clearance rate three months postoperatively. They explicitly state that these findings require confirmation in large-sample, multicenter, randomized controlled trials. Conflict of interest disclosure: all authors declared no conflicts of interest.