Comparison of T-tilt, Trendelenburg, and dorsal lithotomy positions in retrograde intrarenal surgery: surgical, inflammatory, and efficiency outcomes.

OBJECTIVE: To compare perioperative and postoperative outcomes of the T-tilt (TTP) and Trendelenburg (TRP) positions with the traditional dorsal lithotomy position (DLP) during retrograde intrarenal surgery (RIRS). METHODS: The surgical data of patients who underwent RIRS between February 2024 and July 2025 were retrospectively analyzed. A total of 223 patients were included and classified according to surgical position: DLP, TTP, or TRP. Preoperative stone characteristics, postoperative stone-free status, residual stone volume, infection-related parameters, energy consumption index, and operative efficiency index were evaluated. Demographic data, infection parameters measured preoperatively and on postoperative day 1, and stone-free rates (SFR) were compared among the groups. RESULTS: RIRS was performed in the DLP in 74 patients, the TTP in 75 patients, and the TRP in 74 patients. SFR differed significantly between the groups, favoring the TTP. Compared with the other surgical positions, TTP was associated with lower residual stone volume and smaller preoperative-to-postoperative increases in neutrophil-to-lymphocyte ratio and systemic immune-inflammation index. In addition, TTP was associated with more favorable proposed efficiency indices compared with DLP. TTP was associated with significantly higher likelihood of achieving stone-free status compared with DLP (OR = 4.897; p = 0.007) and the TRP (OR = 3.783, p = 0.026). Receiver operating characteristic analysis identified a stone index (STI) cut-off value of 68.71. Within this subgroup, TTP achieved an SFR of 92%, while DLP and TRP achieved SFRs of 50.0% and 64.7%, respectively (p = 0.005). CONCLUSION: TTP was associated with improved outcomes and favorable inflammatory profiles; efficiency indices and STI cut-off remain preliminary and require prospective validation.