A structured learning curve for visuomotor recalibration and surgical performance during transition from two-dimensional to three-dimensional laparoscopic radical cystectomy.

BACKGROUND

Three-dimensional (3D) laparoscopy offers stereoscopic depth perception, but moving from conventional two-dimensional (2D) systems calls for a period of visuomotor adaptation. How this learning curve unfolds in complex oncological procedures like laparoscopic radical cystectomy (LRC) has not been well characterized.

METHODS

This single-surgeon retrospective cohort study included 140 consecutive patients who underwent LRC by an experienced surgeon (>300 prior 2D procedures). Cases were divided chronologically into one 2D group (the last 50 2D cases) and three consecutive 3D groups (3D-1 to 3D-3, 30 cases each). The primary endpoint was pelvic-phase operative time- the vision-dependent part of dissection. Secondary outcomes included estimated blood loss (EBL), lymph node yield, positive margin rate, major complications (Clavien-Dindo ≥II), and surgeon-rated stereoscopic comfort and hand-eye coordination (visual analogue scales).

RESULTS

Baseline characteristics were similar across groups. Change-point analysis identified a single significant transition point at case 31 (95% CI: 28-34). Pelvic-phase time in 3D-1 group (median 198 min) was comparable to the 2D reference (185 min, P> 0.05), marking an adaptation phase. After that, time fell sharply to 155 min in 3D-2 group and 152 min in 3D-3 group (both P< 0.001 vs. groups 2D and 3D-1). EBL dropped from 450 mL (3D-1) to 250 mL (3D-3) (P < 0.05). Lymph node yield, positive margin rates, and major complications remained stable. Subjective comfort and coordination scores improved steadily across the 3D groups (both P < 0.001) and correlated negatively with pelvic-phase time (rs  = -0.68, P < 0.001).

CONCLUSIONS

Transitioning from 2D to 3D LRC involves a distinct learning curve of about 30 cases. Once visuomotor recalibration is achieved, operative efficiency and intraoperative safety improve substantially without compromising pathological quality. These findings offer an evidence-based framework for structured training and technology adoption in complex pelvic oncology.