The Chinese medical world is increasingly becoming known for their very open approach to new 3D printed solutions. A diverse list of 3D printed medical innovations has already been used in Chinese hospitals, where the lives of numerous patients have already been saved with the help of 3D printed surgical tools or implants. But these efforts are no longer confined to the third dimension, as surgeons in the Tang Du Hospital in Xi’an have become the first in China to use 4D printed tools during surgery. Using a 4D printed tracheal stent, they successfully operated on the 46-year-old Ms. Wu, who suffered from a life-threatening respiratory obstruction.
The patient in question is a farmer from the Xingping county in the Shaanxi province. She had been taking medication to fight endobronchial tuberculosis for the past two years already, but the condition had gradually worsened over the past six months. Then one night, a few weeks ago, the 46-year-old could no longer cough up sputum, which severely limited her ability to breathe. After an hour of trying, with her face becoming increasingly purple, her family quickly took her to the Tang Du Hospital.
There, it was discovered that the patient’s trachea had softened and was ready to collapse. At one point, the trachea had even narrowed down to just 3 mm. As the hospital’s thoracic surgeon Li Xiao-Fei explained, this was life threatening. A trachea is about 12 cm long, but half of Ms. Wu’s trachea could no longer function. As the surgeon explained, this was a very rare complication and prevented them from inserting a traditional tubular support stent, as this would cause expectoration difficulties and other complications.
To save the patient, the surgeon thus had to act quickly and turned to the latest 4D printing solutions. The surgery itself took place on the morning of March 28. Taking a 4D printed tracheal stent, this tubular support was inserted into the patient’s windpipe to keep it open and enable airflow. It also enabled the surgeons to lift up the softened trachea and suture it into place. This enabled them to open up the airway and make manual breathing possible again. “Now that the airway is opened up, I can breathe and spit normally again. Before the surgery, I could hardly even breathe,” the patient said afterwards.
But what’s so special about a 4D printed stent? 4D printing is one of those terms that pops up every so often. It’s essentially a 3D printed object with specific material properties that allow it to change into another shape without human intervention. An example would be a 3D printed plastic seal that opens or closes when exposed to a certain amount of pressure or water. In this particular medical situation, the surgical team developed a 3D printed stent that is gradually absorbed by the body over a two to three year period, eliminating the need for an invasive second surgery. The model was based on a foreign-made stent, though that was only used for a 1.5 cm lesion – not a 6 cm one. First 3D printing a test model, Li Xiao-Fei subsequently decided to implement a custom-made 4D printed scaffold.
According to the surgeon, this successful operation on Ms. Wu paves the way for a lot of similar procedures. The 4D printed trachea scaffolding, made from absorbable polycaprolactone biomaterials, not only proved to be a successful solution for tracheal stenosis, but it also decreases the stress for the patients involved. As the material is biocompatible, the likelihood of adverse reactions are minimized, while the need for a second surgery is completely eliminated. Li Xiao-Fei therefore went as far as saying that 4D printing could be used to upgrade trachea surgery as a whole in the near future.