Comparison of clinical outcomes of TVT and TOT procedures and the role of the methylene blue test in detecting bladder perforation

Aim: Stress urinary incontinence is commonly treated with mid-urethral sling procedures such as tension-free vaginal tape (TVT) and transobturator tape (TOT). Cystoscopy is widely used to detect intraoperative bladder injury during retropubic sling placement, yet access and routine use vary between centers. We compared perioperative outcomes of TVT and TOT and and described the pragmatic role of an intravesical methylene blue leak test as an intraoperative screening maneuver in settings where immediate cystoscopy is not available.

Materials and Methods: This retrospective two-center cohort included 131 women who underwent TVT (n=62) or TOT (n=69) between 2020 and 2025. Demographics, operative time, hemoglobin change, postoperative CRP, post-void residual urine, and complications were analyzed. Intraoperative bladder integrity assessment (cystoscopy and/or methylene blue leak test) followed center-based protocols and equipment availability, and postoperative cystoscopy practices were recorded.

Results: Demographic and perioperative parameters were similar between groups. Operative time, hemoglobin change, CRP levels, and residual urine showed no significant differences (p>0.05). Complication rates were 6.5% in the TVT group and 1.4% in the TOT group (p=0.25). One intraoperative bladder perforation occurred during TVT and was identified by dye leakage at the incision site during the methylene blue leak test; this event was documented in a supplementary video. Intraoperative and postoperative evaluation practices differed between centers and procedures.

Conclusion: TVT and TOT showed comparable short-term perioperative outcomes with low complication rates. In a single video-documented TVT case, an intravesical methylene blue leak test allowed immediate recognition of bladder perforation at the incision site. Although cystoscopy remains the reference standard this single illustrative observation suggests that the methylene blue leak test may provide a practical intraoperative warning sign when cystoscopy is unavailable. The diagnostic performance of this approach cannot be determined from this cohort and requires prospective evaluation.