3D Printing Assisting Complex Heart Surgery
3D Printing is becoming an increasing feature of anatomy research at the UCD School of Medicine and it is no surprise that our surgical colleagues have enthusiastically embraced the technology also. A team of surgeons at the Mater Misericordiae University Hospital, in conjunction with colleagues at UCD Anatomy recently developed a 3D printed, colour-coded heart model to aid them in the preparation and performance of complex heart transplant surgery.
The 41-year-old patient suffered from multiple heart anomalies leading to end stage heart failure including right atrial isomerism, dextrocardia, left inferior and superior vena cava to a single atrium, single ventricle with right ventricular morphology, double outlet right ventricle with transposition of the great vessels and total anomalous pulmonary venous drainage to the superior vena cava.
The surgery/anatomy team included Dr Michelle L. Smith (UCD Anatomy), Mr Lars Nolke (Cardiothoracic Surgery, Mater Misericordiae University Hospital), Dr M.K. O’Reilly (Radiology, Mater Misericordiae University Hospital), and Prof James F. Jones (UCD Anatomy).
This group created a 3D printed colour-coded model to aid visualisation of the aberrant anatomy to enhance surgical planning for transplantation and provide a more informative aid than is possible with 2D images.
Data were obtained using a Somaton Definition AS+ 128 slice scanner to deliver a cardiac gated contrast enhanced Commuted Tomography image at 120kV with automatic mAs modulation. Images were acquired in 0.6mm slices and reconstructed using a Siemens Syngo system. All data were anonymised in keeping with local ethical guidance.
A medical expert proficient in segmentation in conjunction with a Consultant Cardiac Radiologist performed image analysis. Using open source 3D Slicer software, the structures of interest were segmented including the bounding lumen of the heart and vessels.
The generated 3D model was then exported as a stereolithographic (STL) file and further model optimisation was performed using Meshlab and processed using Z Edit Pro for mesh editing and to attribute colours to the structures. The design process took 8 hours with 1 hour for attributing colours. This was then printed using a Z Print 250 binder jetting printer in 6 hours. Post processing involved oven curing to improve model strength before an epoxy infusion system was applied to allow intensive model manipulation without fear of breakage.
The colour-coded patient-specific model was qualitatively verified in conjunction with the CT images by the Consultant Radiologist. The model was utilised immediately preoperatively and was considered very helpful by the surgical team, particularly in the setting of dextrocardia.
This project published in the Proceedings of the Physiological Society showed that colour-coded models of CHDs can be utilised as an adjunct to anatomic study and surgical planning particularly in understanding of complex anatomy.