Hemodynamic Effects of Surgical Position in Prone vs. Supine Percutaneous Nephrolithotomy

Not Applicable

Recruiting

• Conditions: Percutaneous Nephrolithotomy (PCNL); Surgical Positioning; Prone Position; Supine Position; Hemodynamic Stability; Nephrolithiasis

• Registration Number: NCT07138872
• Lead Sponsor: Gaziosmanpasa Research and Education Hospital

Brief Summary

This prospective, randomized controlled study evaluates the hemodynamic effects of prone and supine positions during percutaneous nephrolithotomy (PNL) for large kidney stones. Surgical position may influence intraoperative and postoperative hemodynamic stability. Prone positioning can increase intrathoracic pressure and reduce venous return, whereas supine positioning may provide greater hemodynamic stability. A total of 84 patients will be randomized to undergo PNL in prone or supine positions. Primary outcomes include changes in hemodynamic parameters during surgery. Results may guide surgical position selection, especially in patients with potential hemodynamic risk.

Detailed Description

Percutaneous nephrolithotomy (PNL) is a widely used minimally invasive surgical technique for the treatment of large and complex renal calculi. Traditionally, PNL has been performed in the prone position; however, the supine position has gained popularity in recent years due to potential anesthetic and surgical advantages. Surgical positioning can significantly influence cardiovascular and respiratory function, potentially leading to intraoperative and postoperative hemodynamic fluctuations.

Previous literature suggests that the prone position may increase intrathoracic pressure and impair venous return, potentially compromising hemodynamic stability, while the supine position may provide a more stable cardiovascular profile. However, existing data are limited, and results remain inconclusive, particularly in direct comparative studies.

This prospective, randomized controlled clinical trial aims to compare the effects of prone and supine positions during PNL on patients' intraoperative and postoperative hemodynamic parameters. The study will enroll 84 patients aged 18-80 years with American Society of Anesthesiologists (ASA) physical status I-III undergoing elective PNL. Patients will be randomly assigned to either the prone (n=42) or supine (n=42) position.

Inclusion criteria include patients with renal calculi suitable for PNL and meeting the study's eligibility requirements. Exclusion criteria include pregnancy, uncontrolled coagulopathy, previous renal surgery, severe cardiac, pulmonary, or neurological disease, preoperative urinary tract infection, surgery duration outside 60-120 minutes, and multiple access tracts.

Preoperative evaluation will include demographic data, stone characteristics, and relevant laboratory and imaging findings. Intraoperative data will include systolic and diastolic blood pressure, heart rate, arterial blood gas analysis, operative time, anesthesia duration, access details, irrigation volume, and any transfusion or complications. Postoperative parameters will include nephrostomy duration, length of hospital stay, and presence of residual stones as assessed by postoperative CT scan.

Surgical techniques will be standardized for both positions. Prone PNL will involve initial lithotomy positioning for ureteral catheter placement followed by prone positioning for renal access under fluoroscopic guidance. Supine PNL will be performed in the Galdakao-modified Valdivia position with similar access and fragmentation protocols.

The primary outcome is the difference in intraoperative and postoperative hemodynamic stability between positions. Secondary outcomes include complication rates, residual stone rates, and hospital stay duration.

This study aims to provide high-quality evidence to guide surgeons and anesthesiologists in selecting the optimal patient position for PNL, particularly in individuals with higher hemodynamic risk.

Study Timeline

• Study Start: 2025-06-01
• Status Verified: 2025-08
• Study First Submitted: 2025-08-09
• Study First Submitted QC: 2025-08-16
• Last Update Submitted: 2025-08-16
• Study First Posted: 2025-08-24
• Last Update Posted: 2025-08-24
• Primary Completion: 2025-12-30
• Study Completion: 2025-12-30

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 84

Inclusion Criteria

• ASA physical status I-III
• Presence of renal calculi indicated for PNL

Exclusion Criteria

• Pregnancy
• Uncontrolled coagulopathy
• Previous renal surgery
• Severe cardiac, pulmonary, or neurological disease
• Preoperative urinary tract infection (non-sterile urine culture)
• Surgery duration <60 minutes or >120 minutes
• Preoperative blood transfusion
• Multiple access tracts

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Change in Hemodynamic Parameters (Intraoperative)	From induction of anesthesia to the end of surgery (approximately 60-120 minutes)	Systolic blood pressure (mmHg) will be recorded at predefined time points (preoperative baseline, intraoperative intervals, and immediate postoperative period) to assess intraoperative hemodynamic stability.
Change in Arterial Blood pH	Preoperative, intraoperative, postoperative day 1	Arterial pH will be measured at predefined time points (preoperative, intraoperative, postoperative day 1) to evaluate metabolic changes between prone and supine groups.
Change in Oxygen Saturation	Preoperative, intraoperative, postoperative day 1	Arterial oxygen saturation (%) will be measured at predefined time points (preoperative, intraoperative, postoperative day 1) to evaluate respiratory status.
Change in Diastolic Blood Pressure (Intraoperative)	From induction of anesthesia to the end of surgery (approximately 60-120 minutes	Diastolic blood pressure (mmHg) will be recorded at predefined time points (preoperative baseline, intraoperative intervals, and immediate postoperative period) to assess intraoperative hemodynamic stability.
Change in Mean Arterial Pressure (Intraoperative)	From induction of anesthesia to the end of surgery (approximately 60-120 minutes)	Mean arterial pressure (mmHg) will be recorded at predefined time points (preoperative baseline, intraoperative intervals, and immediate postoperative period) to assess intraoperative hemodynamic stability.
Change in Heart Rate (Intraoperative)	From induction of anesthesia to the end of surgery (approximately 60-120 minutes)	Heart rate (beats per minute) will be recorded at predefined time points (preoperative baseline, intraoperative intervals, and immediate postoperative period) to assess intraoperative hemodynamic stability.
Change in Arterial pO₂	Preoperative, intraoperative, postoperative day 1	Arterial oxygen partial pressure (mmHg) will be measured at predefined time points (preoperative, intraoperative, postoperative day 1) to evaluate respiratory function.
Change in Arterial HCO₃-	Preoperative, intraoperative, postoperative day 1	Arterial bicarbonate (mmol/L) will be measured at predefined time points (preoperative, intraoperative, postoperative day 1) to evaluate metabolic changes.
Change in Arterial pCO₂	Preoperative, intraoperative, postoperative day 1	Arterial carbon dioxide partial pressure (mmHg) will be measured at predefined time points (preoperative, intraoperative, postoperative day 1) to evaluate respiratory changes.

Secondary Outcome Measures

Name	Time	Method
Complication Rate	From intraoperative period through hospital stay and up to 30 days postoperatively.	Complications will be identified and classified according to the Clavien-Dindo classification system.
Residual Stone Rate	At postoperative 1 month, assessed by CT scan.	Presence of residual stones larger than 4 mm will be recorded; stones ≤4 mm will be considered clinically insignificant.
Length of Hospital Stay	From hospital admission until discharge (typically 2-10 days).	The total number of days of hospitalization will be compared between groups.
Nephrostomy Tube Duration	From postoperative day 0 (day of surgery) until nephrostomy tube removal, typically within 7-14 days.	The duration (in days) that the nephrostomy tube remains in place will be recorded for each patient.
Operative Time	From initial skin incision until completion of stone removal (approximately 30-180 minutes).	Total time from initial skin incision to completion of stone removal will be recorded for each group.
Anesthesia Duration	From induction of anesthesia until termination of anesthesia and awakening of the patient (approximately 60-240 minutes).	Total anesthesia time will be measured to assess any differences related to patient positioning.
Intraoperative Blood Loss	Intraoperative period (from skin incision to completion of surgery, approximately 30-180 minutes).	Estimated blood loss will be calculated and recorded; intraoperative transfusion requirements will also be noted.

Trial Locations

Locations (1)

Gaziosmanpaşa Training and Research Hospital; 🇹🇷 Istanbul, Turkey