Table 4.

Limitations and challenges of 3D printing for medical applications.

3D Printing Applications	Challenges and Limitations	References
Pre-surgical planning and simulation (cardiac disease and tumours)	Limited choices of printing material to simulate the required tissue properties (both radiological and mechanical properties). Limitations in multi-colour and multi-material 3D printing to delineate tumour from the normal tissue. Time-consuming post-processing of the printed model (to remove the support structures of the model).	[26,31,33,37,50,52,72,78,82]
Simulation of interventional cardiac/radiological procedures	Limited choices of printing material to simulate the required tissue properties (radiological properties). The smaller printing size of the 3D printer has limited the ability to print the model in a whole piece. The model will need to be printed in smaller pieces and joined together, thus increasing the post-processing time.	[33,34,53,54,55,61,64,66,67,85,86]
Medical education	Limitations in multi-colour and multi-material 3D printing to delineate different tissues in the model. Limited choices of printing material to produce a realistic 3D model with mechanical properties similar to human tissues.	[49,52,88]
Patient/family education/communication	The FDM and DLP 3D printers are limited by lower printing speed and smaller printing size. This has limited the application of 3D-printed models for patient/family education as the printing involves higher human resources and longer duration.	[88,104]

FDM—fused deposition modelling, DLP—digital light processing.