Disruptive medicine: 3-D printing revolution

“Disruptive medicine: 3-D printing revolution” reports on an important new technology well worth surgeons’ attention. The basic process reported is a simple, but in many ways, revolutionary approach to manufacturing or assembly. 3-D printing is an additive manufacturing process, exactly the opposite from the usual subtractive process. As an example, a block of steel might be milled, drilled and machined into an engine block in a series of processes to remove material from the original piece of steel, a subtractive process.

3-D printing is an additive manufacturing process whereby materials (metal, plastic, other) are layered together to make a complex three-dimensional solid object. Working from a CAD file, material is laid down in successive layers until the entire object is created. Each layer deposited can be imagined as a thinly sliced horizontal cross-section of the eventual object. As such, 3-D printing is really a stack of 2-D prints. The technique was invented by Charles Hull in 1986 and is revolutionizing prototyping and, in some cases, manufacturing. Applications have included prototyping, metal casting, architectural design and building, and in 3-D design and visualization: this application is well-demonstrated in the medical application of pulmonary artery reconstruction outlined in this article. In this case, complex anatomy can be easily visualized on a solid full-scale model of the pulmonary vasculature, and treatment plans more easily formulated and even modeled.

An extensive, thoughtful discussion of medical 3-D printing can be found in the November 24, 2014 The New Yorker article entitled “Print Thyself: How 3-D printing is revolutionizing medicine.” Other medical applications described include 3-D reconstruction in complex craniofacial repairs, modeling of abnormalities in the tracheobronchial tree to design surgical strategies to manage airway stenosis, and in reconstructive modeling for complex traumatic injuries in bone and soft tissue.

Beyond such applications, concepts have evolved to areas of 3-D printing using mixtures of cells and matrix as an approach to the engineering and additive assembly of complex tissues, and even organs. Thus, functional organs might someday be produced; a massive step beyond simple prototyping.
As in many areas of science and technology, the field moves quickly. The March 20, 2015 issue of Science published a report on “Continuous liquid interface production (CLIP) of 3D objects.” This true 3-D printing process is up to 100 times faster than current technologies and is compatible with producing objects from soft elastic materials, ceramics and biologics! More to come…

Thomas M. Krummel, MD, FACS, is the Emile Holman Professor and Chair, Department of Surgery at Stanford University and the Co-Director, Biodesign Innovation Program at Stanford. He is also a member of the Board of Directors of the Fogarty Institute for Innovation.