Effect of Anesthesia Type on Surgical Ergonomics in Patients Undergoing Flexible Ureteroscopy and Retrograde Intrarenal Surgery: A Prospective Observational Study

This is a prospective, single-center, observational study including adult patients undergoing elective flexible ureteroscopy and retrograde intrarenal surgery (RIRS) for kidney stones. Eligible patients will be enrolled consecutively. No intervention regarding the type of anesthesia or surgical technique will be assigned by the study protocol. The anesthesia technique will be selected according to routine clinical practice and the assessment of the anesthesiology team. Patients will subsequently be categorized into two observational groups: those receiving general anesthesia and those receiving spinal anesthesia.

All RIRS procedures will be performed according to standard clinical practice. Surgical steps, including the use of a ureteral access sheath, lithotripsy technique, energy source, and placement of a ureteral stent, will be determined by the treating surgeon and will not be modified for research purposes.

The primary outcome will be surgeon-perceived intraoperative workload assessed using the Surgery Task Load Index (SURG-TLX). The SURG-TLX evaluates six domains: mental demands, physical demands, temporal demands, task complexity, situational stress, and distractions. The questionnaire will be completed by the surgeon within 15-30 minutes after completion of the procedure. Individual domain scores and the overall SURG-TLX score will be recorded.

Secondary outcomes will include operative duration, fluoroscopy time or dose when available, use of a ureteral access sheath, ureteral stent placement, intraoperative complications, postoperative complications, postoperative pain and analgesic requirement, stone-free status, and the need for additional intervention. Preoperative demographic and clinical characteristics, including age, sex, body mass index, ASA classification, comorbidities, stone characteristics, hydronephrosis, and relevant preoperative clinical data, will also be recorded.

The main analysis will compare SURG-TLX scores between the general anesthesia and spinal anesthesia groups. Potential confounding variables related to patient characteristics, stone burden, procedural factors, and operative characteristics will be considered in adjusted analyses.