Inverse engineering of medical devices made of bioresorbable polymers

The degradation of medical devices made of bioresorbable polymers such as fixation devices in orthopaedic surgeries and scaffolds for tissue engineering can take from months to years. The trial and error approach of device development is therefore problematic and mathematical modelling of the biodegradation can help to accelerate the device development. This paper presents an inverse scheme to obtain the material parameters in a biodegradation model developed by Pan and his co-workers from existing experimental data of bioresorbable devices. The parameters can then be used to predict the degradation rate of new devices made of the same polymer. Firstly, the previously developed model is briefly outlined. Secondly, a finite element scheme and a time integration algorithm are developed for the direct analysis using the biodegradation model. Thirdly, an inverse analysis scheme is presented in combination with the direct analysis. Finally, several case studies of existing degradation data are presented to demonstrate the effectiveness of the inverse engineering approach.