Finite element analysis of degradation of biodegradable medical devices

Abstract

Introduction This paper presents a set of case studies for calculating the degradation rates of medical devices made of biodegradable polymers using the finite element method. Case StudyFirstly, a set of experimental data in the literature showing size effect of the degradation was analysed; it was shown that the finite element model is able to fit the experimental data fairly well. Then four different devices were analysed to demonstrate the applications of finite element analysis in device design. These include (a) a simple cube to demonstrate the three dimensional effect of device degradation, (b) a typical scaffold for tissue engineering, (c) a fixation screw for orthopaedic surgery and (d) a coronary stent. ConclusionThe analysis shows how the design details can affect the degradation rate of the various implants/devices.

A bioinspired 3D shape olibanum‐collagen‐gelatin scaffolds with tunable porous microstructure for efficient neural tissue regeneration

“…Consequently, the compliance between biodegradation rate and regeneration need to be controlled. 64 The sudden degradation of both types of scaffolds after 1 week can be adduced to the high capacity of interaction with water molecules. Similar studies reported that freeze-cast scaffolds maintained their stability more than the prepared constructs with other techniques when the same materials were used.…”

“…Based on another report, the larger pores such as resultant pores in the synthesized OCG1 samples terminated to heterogeneous biodegradation. 64 The sudden degradation of both types of scaffolds after 1 week can be adduced to the high capacity of interaction with water molecules. However, the observed steady gradient after first week may be due to lamellar-type pores and its influence on high mechanical strength.…”

Detection of degradation in polyester implants by analysing mode shapes of structure vibration

“…Pan and co-workers (Pan, 2014) developed a mathematical model for the degradation of bioresorbable polymers. Han and Pan (Han and Pan, 2013) presented a series of case studies of using a commercial finite element package, COMSOL Multiphysics, to obtain the molecular weight distributions in degrading implants. Here their model is used to obtain the distributions of molecular weight in the plate shown in Fig.…”

“…1. Details of the degradation model can be found in (Pan, 2014) and (Han and Pan, 2013). Table 1 provided the model parameters which are used in the calculation for molecular weight distributions using COMSOL Multiphysics.…”

“…Table 1 provided the model parameters which are used in the calculation for molecular weight distributions using COMSOL Multiphysics. These parameters were taken from the model used by Han and Pan (Han and Pan, 2013) for fitting the degradation data of a PLA/PGA copolymer obtained by Grizzi et al It should be emphasised that the data used in the numerical examples here are only loosely based on the mentioned polymers. Use of slightly different values of these data, such as different molecular weight of a polymer unit, do not affect the conclusions of this numerical study.…”