In a previous post we saw how new technologies aim at printing human body parts by means of 3D printers. Recently, an amazing result has been achieved by some Doctors at the University of Michigan: they managed to print in 3D a tracheal splint for a 20-month-old patient in order to restore his bronchus functionality. This website offers the description of the surgical operation they performed, step by step.
Abstract – Tracheobronchomalacia in newborns, which manifests with dynamic airway collapse and respiratory insufficiency, is difficult to treat. In an infant with tracheobronchomalacia, we implanted a customized, bioresorbable tracheal splint, created with a computer-aided design based on a computed tomographic image of the patient’s airway and fabricated with the use of laser-based three-dimensional printing, to treat this life-threatening condition.
Description – At birth at 35 weeks’ gestation, the patient did not have respiratory distress and otherwise appeared to be in normal health. At 6 weeks of age, he had chest-wall retractions and difficulty feeding. By 2 months of age, his symptoms progressed and he required endotracheal intubation to sustain ventilation. The workup revealed the following:
- an anomalous origin and malposition of the pulmonary arteries, with crisscross anatomy;
- right pulmonary-artery hypoplasia;
- compression of the left mainstem bronchus between an abnormally leftward-coursing ascending aorta and an anteriorly displaced descending aorta;
- air trapping;
- postobstructive pneumonia.
Despite placement of a tracheostomy tube, mechanical ventilation, and sedation, ventilation that was sufficient to prevent recurring cardiopulmonary arrests could not be maintained.
We reasoned that the localized tracheobronchomalacia was the cause of this physiological abnormality and made a custom-designed and custom-fabricated resorbable airway splint. Our bellowed topology design, similar to the hose of a vacuum cleaner, provides resistance against collapse while simultaneously allowing flexion, extension, and expansion with growth. The splint was manufactured from polycaprolactone with the use of a three-dimensional printer.
The institutional review board of the University of Michigan consulted with the Food and Drug Administration and approved the use of the device under the emergency-use exemption, and written informed consent was provided by the patient’s parents. After transposition of the right pulmonary artery and failed aortopexy, sutures were placed around the circumference of the malacic left bronchus and tied through interstices of the splint, and the bronchus was expanded. Subsequent bronchoscopy revealed normal patency of the bronchus without dynamic collapse and normal ventilatory variation in the size of the left lung. The partial pressure of carbon dioxide in venous blood decreased from 88 to 48 mm Hg. Seven days after placement of the airway splint, weaning from mechanical ventilation was initiated, and 21 days after the procedure, ventilator support was discontinued entirely and the child was discharged home with the tracheostomy in place. One year after surgery, imaging and endoscopy showed a patent left mainstem bronchus . No unforeseen problems related to the splint have arisen. Full resorption of the splint was estimated to occur in 3 years.
This case shows that high-resolution imaging, computer-aided design, and biomaterial three-dimensional printing together can facilitate the creation of implantable devices for conditions that are anatomically specific for a given patient.