Studying spinal feedback loops post tendon transfer surgery using the pincer grasp task: A Neuro-Musculoskeletal...

The aim of the study is to create an in-silico test bed, which allows to replicate clinical scenarios using a virtual wrist model that encompasses both neural and musculoskeletal components along with implants. We used four wrist models: damaged FPL muscle; healthy FPL muscle; tendon-transfer surgery model with FPL latched to BRD muscle; and pulley-based surgery model with an implanted pulley over tendon-transfer model. These models were used for analyzing surgical cases and musculoskeletal biomechanics. This was developed on NEUROiD platform, simulating neural and musculoskeletal systems using NEURON and OpenSim. We simulated pincer grasp across all wrist models and analyzed impact of proprioceptive afferents on force exerted by thumb. The thumb exerted lesser force in presence of afferents. Pulley model exerted higher force on index digit than tendon-transfer model. The pulley system enhances FPL force through altered muscle dynamics and contributed inhibition of BRD muscle. Our model can be used to simulate patient cohorts in clinical trials, where one can design virtual trials to test feasibility, efficacy, and safety of new interventions before conducting real-world trials.