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.
ASA physical status I-III
Presence of renal calculi indicated for PNL
Pregnancy
Uncontrolled coagulopathy
Previous renal surgery
Severe cardiac, pulmonary, or neurological disease
Parallel
Prone Position Percutaneous Nephrolithotomy
Procedure/SurgeryPatients in this arm will undergo percutaneous nephrolithotomy (PNL) in the prone position. The procedure begins with ureteral catheter placement in lithotomy position, followed by prone positioning for renal access under C-arm fluoroscopic guidance. Stone fragmentation will be performed using pneumatic or ultrasonic lithotripters, and nephrostomy placement will be completed according to standard protocol.
Supine Position Percutaneous Nephrolithotomy (Galdakao-modified Valdivia)
Procedure/SurgeryPatients in this arm will undergo percutaneous nephrolithotomy (PNL) in the Galdakao-modified Valdivia supine position. Following general anesthesia, the ipsilateral side will be elevated 20-30°, with the ipsilateral leg extended and the contralateral leg abducted. Ureteral catheter placement will be followed by renal access under C-arm fluoroscopy. Stone fragmentation and removal will be performed using the same standardized lithotripsy and irrigation protocols as in the prone group.
Change in Hemodynamic Parameters (Intraoperative)
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
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 Diastolic Blood Pressure (Intraoperative)
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)
Mean arterial pressure (mmHg) will be recorded at predefined time points (preoperative baseline, intraoperative intervals, and immediate postoperative period) to assess intraoperative hemodynamic stability.
Operative Time
Total time from initial skin incision to completion of stone removal will be recorded for each group.
Anesthesia Duration
Total anesthesia time will be measured to assess any differences related to patient positioning.
Intraoperative Blood Loss
Estimated blood loss will be calculated and recorded; intraoperative transfusion requirements will also be noted.
Complication Rate
Complications will be identified and classified according to the Clavien-Dindo classification system.
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