Introduction: Endoscopic combined intrarenal surgery (ECIRS) using retrograde fURS and PCNL was developed as a single-step treatment for removal of renal calculi. Both prone split-leg (PSL) and Mod-V (MV) position are available for ECIRS, but there is no data regarding their differing benefits and disadvantages. To investigate the ideal position for ECIRS, this study examined (1) the characteristics of surgical results and (2) the changes in renal anatomy by using computed tomography (CT) for the different positions
Methods: (1) The subjects were 89 of 112 patients who underwent ECIRS registered in the SMART Study Group from January 2014 and May 2015 (PSL: MV = 49:40). Surgical data including intraoperative renal pelvic pressure were compared between two groups. (2) Contrast-enhanced CT images in the PSL and MV positions were analysed for each patient. The distance from the skin to the kidney and the tilt of the major renal axes (anterior, lateral) were measured.
Results: (1) The renal punctures in the PSL position were predominantly executed through the inferior calyces (79.5%), whereas those in the MV position were through the middle calyces (72.5%). Intraoperative renal pelvic pressure was significantly higher in the PSL than MV position. The stone clearance rate (81.5%:85.0%) did not significantly differ between the positions. Five (10%) patients in the PSL position group and 2 (5%) patients in the MV position group showed a fever of >38°C after the surgery, and this difference between the groups was significant. (2) The results of CT images showed that the distance to the kidney was significantly shorter and the tilt of the major renal axis was significantly greater in the anterior direction (21.7°:9.6°; p < 0.01) and significantly lesser in the lateral direction (21.5°:32.7°; p = 0.03) in the PR position than the corresponding values in the MV position.
Conclusions: We consider that the MV position is better for puncture of the middle calyces but not the lower calyces, because the lower kidney may be displaced medially and ventrally in the MV position due to gravity. Additionally, because the extent of increase in the renal pelvic pressure is lesser in the MV position, thereby posing a low risk of post-surgical fever. Flexibility in alteration of the positions depending on the stone position, body type, and infection status will lead to an ideal treatment. Source of