Unilateral biportal endoscopic (UBE) surgery is a minimally invasive technique increasingly used for lumbar spine pathologies. However, its learning curve is steep, and structured training is required before clinical practice. The aim of this study was to evaluate the educational validity and reliability of a three-dimensional (3D) simulation model for UBE lumbar discectomy according to Messick’s validity framework. This single-center study was performed at (Blinded for review) in October 2025. Ten neurosurgeons participated: six residents (novices) and four experienced UBE surgeons (experts). Each participant performed a simulated lumbar discectomy task using the UpSurgeOn Endoscopic LumbarBox . Technical performance was assessed by a Task-Specific Checklist (TSCL) and a Global Rating Scale (GRS). Face, content, construct, internal structure, and consequence validity were analyzed statistically. Experts achieved significantly higher TSCL (median 18.5 vs. 11) and GRS (30 vs. 17) scores, shorter task time (15 vs. 25 min), and fewer errors (1 vs. 3) compared with novices (p < 0.05). Inter-rater reliability was excellent (ICC = 0.93 for TSCL, 0.87 for GRS), and internal consistency was high (Cronbach’s α ≥ 0.8). Face and content validity scores were strong (median ≥ 8/10). Novices showed a significant improvement in self-efficacy after training (26 to 56.5, p = 0.028) and a clear positive learning curve across three trials. The 3D simulation model demonstrated strong validity and reliability for UBE discectomy training. It successfully differentiated between experience levels and improved participants’ confidence and technical skills. This simulator provides a safe and effective platform for developing UBE competencies during residency prior to real surgical application.
Demirtaş et al. (Sun,) studied this question.