Hybrid polymer chain discretisation for efficient and accurate implementation of hydrolytic chain scission models

Bioresorbable polymer implants offer clinical advantages over traditional bio-inert devices, but their development is complicated by geometry-dependent degradation behaviour. Computational modelling can accelerate implant development, yet mechanistic frameworks such as the Discrete Chain Scission (DCS) model are limited by high computational cost. Consequently, efficient implementation strategies are needed to enable the application of mechanistic degradation models to realistic three-dimensional (3D) implant geometries. We propose a hybrid polymer chain discretisation strategy that reduces computational cost while preserving mechanistic fidelity maintaining accurate implementation of the underlying degradation model. Simulations of random and chain-end scission demonstrate that hybrid discretisation maintains accurate predictions of molecular weight evolution and mass loss, as compared to the full model, while reducing computational cost. Sensitivity analysis confirmed robustness across discretisation thresholds. The proposed implementation strategy was applied to a proof-of-concept case study using experimental in vitro degradation data of P4MC, demonstrating its ability to capture all behaviours represented by the underlying DCS model, including experimentally observed molecular weight evolution and mass loss. This novel hybrid DCS approach implementation enables scalable degradation simulations, representing a key step toward applying mechanistic modelling to realistic 3D implant geometries.