The first Nobel Prize was awarded for discovery of technology that would go on to revolutionize medical imaging. Since Wilhelm Roentgen’s discovery of the x-ray in 1895, innovation has continued to refine our glimpse into the human body.1 The next century saw the addition of computed tomography (CT), nuclear medicine, ultrasound and magnetic resonance imaging (MRI) to the physician’s tool box.2 These technologies have had an immeasurable impact on screening, diagnosis, image-guided procedures, obstetric care, and preoperative planning. Further advances have made it possible to generate 3-dimensional (3D) constructs from 2-dimensional images. That technology has been applied to other surgical disciplines and gynecologic surgeons have begun investigating the utility of 3D printing in perioperative planning.
How and why of 3D printing
Three-dimensional printing was first introduced in the 1980s, in engineering and manufacturing.3 Prototype generation quickly followed and commercial printers became available by the 1990s. The earliest methods of 3D printing involved subtractive techniques (i.e., chipping away at a solid material to leave the desired product) whereas newer technology allows for additive printing (i.e., sequential deposition of layers of material.) The process of converting a radiographic image to a tangible model is complicated and involves several steps. For 3D printing, CT or MRI scan slices often need to be thinner than usual to optimize the model. Slices too thick will lead to loss of fine details while very thin slices require significant modification. These details necessitate a constant discussion between the clinician, radiologist and engineers. Three-dimensional printers do not recognize the standard mode of medical imaging storage, DICOM (Digital Imaging and Communications in Medicine), and require conversion to a recognizable format, a process known as segmentation. The new format, STL (Standard Tessellation Language), can then be recognized by the printers. Some post-processing can still be performed, such as artifact removal, hollowing lumen, smoothing, etc. with communication between the engineers and medical team. After details, such as material and color are selected, an STL file is then printed, generating the model (Figure 1).
Commercially, with decreasing cost and improving technology, 3D printing continues to gain momentum and a wide array of products have been printed (clothing, weapons, car parts, toys, jewelry). Medical applications include printing of surgical instruments, organ scaffolds, prostheses, and complex organ reconstruction for perioperative purposes. Three-dimensional printing is in use for patient care in all surgical fields as well as dentistry.4-13