Surgical retractor stability is crucial for precision and safety. This study quantifies kinematic performance of manual, collaborative, and robotic retractor holding using 6-DOF tracking at 80 Hz during ex-vivo porcine liver retraction. Robotic assistance reduced position deviation from 133 mm (manual) to 0.74 mm (99.4%), tremor intensity by 99.6%, and path length from 9.3 m to 0.17 m (98%). Effect sizes ranged from d=1.03 to d=2.64. Collaborative mode achieved intermediate stability (50% deviation reduction, 93% path reduction) while preserving adjustment capability. Results establish objective metrics for retraction quality assessment and demonstrate that passive robotic assistance achieves submillimeter precision while addressing personnel shortages in open surgery.
Zehny et al. (2025) studied this question.