3-D Printed Splints Shore Up Weakened Airways

Custom three-dimensional (3-D) airway splints are being printed to improve breathing in infants suffering from tracheobronchomalacia (TBM), reports a new study.

Researchers at the University of Michigan (Ann Arbor, USA) successfully applied 3-D printing technology to produce a personalized medical implant for treatment of TBM, a condition that involves excessive collapse of the airways during respiration that can lead to cardiopulmonary arrest. The patient-specific 3-D-printed external airway splints were created from a CT scan of the trachea/bronchus, integrating an image-based computer model with laser-based 3-D printing using polycaprolactone, and were designed to accommodate airway growth, while preventing external compression.

The splints were designed as hollow, porous tubes that could be stitched over the affected airways, forming a scaffold that helped support the weakened structures; they undergo bioresorption over a predetermined time period of around three years. The splints were implanted in three infants with severe TBM; in a recent study, the researchers reported that all infants no longer exhibited life-threatening symptoms and demonstrated resolution of both pulmonary and extrapulmonary complications of their TBM. The study was published on April 29, 2015, in Science Translational Medicine.

“This is the first 3-D printed implant specifically designed to change shape over time to allow for a child's growth before finally reabsorbing as the disease is cured,” study coauthor Associate Professor of Pediatric Otolaryngology Glenn Green, MD. “This process has broad application for medical manufacturing of patient-specific 3-D-printed devices that adjust to tissue growth through designed mechanical and degradation behaviors over time.”

TBM is an uncommon disease of the central airways resulting from softening or damage of the cartilaginous structures of the airway walls in the trachea and bronchi. Since cartilage contributes to the stiffness and structure of the central airway and bronchi, its loss can result in a collapse of the central airway when breathing out during forced expiration. There are two forms of TBM; a congenital form that typically develops during infancy or early childhood, and an acquired form that is usually seen in adults, especially smokers.

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