Vibrotactile feedback using exposure variation analysis to reduce musculoskeletal risk in surgical simulation

Work-related musculoskeletal disorders are common in surgery due to sustained non-neutral postures. This study evaluated two wearable vibrotactile feedback methods designed to encourage real-time postural correction: one based on standard Rapid Upper Limb Assessment (RULA) thresholds, and another enhanced with Exposure Variation Analysis (EVA) to account for cumulative posture risk. Thirty participants completed a simulated surgical fine motor task under three conditions: control, RULA-based feedback, and EVA-based feedback. EVA-based feedback reduced time spent in high-risk RULA 5-6 postures by 91.5%, compared to 68.5% with RULA-based feedback when normalised by task duration. EVA-based feedback also required fewer cues on average (4.63 ± 2.13 vs. 10.37 ± 13.92). Both feedback methods significantly reduced mean RULA Category scores without increasing task time or cognitive workload. These findings support EVA-based feedback as a low-disruption, real-time ergonomic intervention that improves posture while minimising alert burden in precision-intensive environments.