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Journal of Peking University (Health Sciences) ›› 2026, Vol. 58 ›› Issue (4): 748-753. doi: 10.19723/j.issn.1671-167X.2026.04.010

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Effect of leg-split-free lateral decubitus position and lithotomy position on renal pelvic pressure and clinical outcomes during flexible ureteroscopic lithotripsy

Shicong LAI, Huanrui WANG, Runfeng NI, Haopu HU, Chenlong WANG, Tao XU, Hao HU*()   

  1. Department of Urology, Peking University People' s Hospital; The Institute of Applied Lithotripsy Technology, Peking University People' s Hospital, Beijing 100044, China
  • Received:2026-02-28 Online:2026-08-18 Published:2026-05-19
  • Contact: Hao HU

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Abstract:

Objective: To compare intrarenal pelvic pressure profiles and clinical outcomes between the leg-split-free lateral decubitus position and the conventional lithotomy position during flexible ureteroscopy with a negative-pressure aspiration sheath. Methods: A prospective study was conducted at Peking University People' s Hospital among patients undergoing unilateral flexible ureteroscopy with a negative-pressure aspiration sheath from January 2024 to December 2025. Participants were allocated into two groups according to surgical positioning: Leg-split-free lateral decubitus group and conventional lithotomy group. An intelligent, pressure- and temperature-controlled flexible ureteroscopy system was employed to continuously monitor intrapelvic pressure and temperature throughout the procedure. The incidence, duration, and clinical implications of intrapelvic hypertension were compared between the two groups. Results: A total of 40 patients were enrolled, 20 in each group. No statistically significant differences were observed between the groups in baseline characteristics, including gender, age, stone diameter, stone number, stone location, or degree of hydronephrosis (all P>0.05). Intraoperative analysis revealed that the duration of intrapelvic hypertension was significantly shorter in the leg-split-free lateral decubitus group than in the lithotomy group [25.0 (0.0, 31.8) s vs. 115.0 (79.8, 176.0) s, P < 0.01]; similarly, the duration of elevated intrapelvic temperature was also significantly reduced [3.0 (2.0, 9.8) s vs. 18.5(16.0, 24.5) s, P < 0.01]. Postoperative follow-up showed no cases of fever in the leg-split-free lateral decubitus group, whereas two patients in the lithotomy group developed fever; however, this difference in febrile complication rate did not reach statistical significance (P=0.15). All the patients underwent computed tomography three months postoperatively to assess stone-free status. The results indicated that the stone-free rate in the leg-split-free lateral decubitus position group was significantly higher than that in the lithotomy position group (P=0.04). Conclusion: This prospective exploratory study suggests that compared with the lithotomy position, the leg-free lateral decubitus position may be more conducive to maintaining lower intrapelvic pressure and temperature during the operation and is associated with a higher stone clearance rate postoperatively. However, these findings still need to be verified by large-sample, multi-center, randomized controlled trials.

Key words: Upper urinary tract stones, Negative-pressure sheath, Patient position, Intrarenal hypertension, Clinical outcomes

CLC Number: 

  • R699.2

Table 1

Baseline characteristics of the leg-split-free lateral decubitus position group and the lithotomy position group"

Items Total (n=40) Lateral decubitus group (n=20) Lithotomy group (n=20) P value
Age/years, $\bar x \pm s$ 57.4±11.9 57.3±11.1 57.6±13.0 0.938
BMI/(kg/m2), $\bar x \pm s$ 25.2±3.2 25.4±2.5 25.1±3.8 0.802
Gender, n (%) >0.999
  Male 20 (50) 10 (50) 10 (50)
  Female 20 (50) 10 (50) 10 (50)
Stone lateral, n (%) 0.580
  Left 24 (60.0) 13 (65.0) 11 (55.0)
  Right 16 (40.0) 7 (35.0) 9 (45.0)
Stone location, n (%) 0.190
  Ureter 12 (30.0) 4 (20.0) 8 (40.0)
  Renal 20 (50.0) 10 (50.0) 10 (50.0)
  Both 8 (20.0) 6 (30.0) 2 (10.0)
Stone diameter /cm, $\bar x \pm s$ 1.5±0.7 1.5±0.7 1.4±0.7 0.830
Stone number, n (%) 0.530
  Solitary 20 (50.0) 11 (55.0) 9 (45.0)
  Multiple 20 (50.0) 9 (45.0) 11 (55.0)
Urine culture, n (%) >0.999
  Negative 36 (90.0) 18 (90.0) 18 (90.0)
  Positive 4 (10.0) 2 (10.0) 2 (10.0)
Hydronephrosis, n (%) 0.470
  None 10 (25.0) 4 (20.0) 6 (30.0)
  Yes 30 (75.0) 16 (80.0) 14 (70.0)

Table 2

Perioperative data, stone clearance rate, and complication rates between the leg-split-free lateral decubitus position group and the lithotomy position group"

Items Total (n=40) Lateral Decubitus group (n=20) Lithotomy group (n=20) P value
Operation time/min, M (P25，P75) 80.5 (60.0, 117.5) 87.5 (62.3, 115.0) 77.5 (47.8, 117.5) 0.51
High IPP time/s, M (P25，P75) 38.5 (24.5, 116.0) 25 (0, 31.8) 115.0 (79.8, 176.0) < 0.01
High temperature time/s, M (P25，P75) 15.0 (3.0, 19.0) 3 (2.0, 9.8) 18.5 (16.0, 24.5) < 0.01
Residual stones, n (%) 0.04
  No 33 (82.50) 19 (95.0) 14 (70.0)
  Yes 7 (17.5) 1 (5.0) 6 (30.0)
2 h-WBC (×109/L), $\bar x \pm s$ 6.96±2.45 6.87±2.49 7.06±2.48 0.80
2 h-PCT/(μg/L), $\bar x \pm s$ 0.04±0.04 0.04±0.04 0.04±0.04 0.56
Fever, n (%) 0.15
  No 38 (95.0) 20 (100.0) 18 (90.0)
  Yes 2 (5.0) 0 (0.0) 2 (10.0)
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