Innovative approaches to large lower calyceal stones (10-20mm): evaluating modified T-tilt position and lower calyx hydrodilatation techniques in flexible ureteroscopy versus hydrodilatation alone: prospective randomized controlled study.

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Managing lower calyceal stones poses significant challenges. Flexible ureteroscopy and laser lithotripsy (FURSL) are standard techniques for treating large stones (10-20mm). This study evaluates the role of the T-tilt position (45-degree Trendelenburg with a 45-degree lateral tilt against the side of the stone) and hydrodilatation of the lower calyx with 50cc saline injection as needed in optimizing stone-free rates and safety during FURSL for lower calyceal stones. Following ethical approval, a prospective randomized study with 197 patients was conducted. 13 patients were excluded (9 with renal anomalies or prior surgeries affecting anatomy, and four who refused participation). The remaining 184 were randomized into Group A (92 patients in T-tilt with hydrodilatation) and Group B (92 patients with hydrodilatation in lithotomy position). Randomization was achieved with computer-generated numbers stored in sealed envelopes. All patients had 10-20mm stones and underwent FURSL using a 7.5 FR flexible ureteroscope and 200-micron Wolf laser fiber. Follow-up CT KUB was performed at 1 and 3months, assessing stone-free status (no residual stones or residual < 3mm) and the need for auxiliary procedures. Both groups were statistically analyzed for age, sex, BMI, stone size, Hounsfield units (HU), infundibular dimensions, access sheath use, complications (fever, sepsis, hematuria) and hospital stay. No significant differences were found between the two groups in these variables. However, operative time was significantly longer in Group A than in Group B (P value = 0.018). The need for auxiliary procedures was significantly lower in Group A than in Group B (P value = 0.001), and the success rate was significantly higher in Group A than in Group B (P value = 0.001). The T-tilt position and hydrodilatation significantly optimize outcomes and enhance stone-free rates for large lower calyceal stones (10-20mm). This position improves intraoperative vision and facilitates access to the lower calyx, facilitating the clearance of stone fragments.