4D printed orbital stent for the treatment of enophthalmic invagination.

Currently, the implants used for enophthalmic invagination have the disadvantages of precise filling difficulty, weak filling ability, large surgical wounds, and lack of CT development. Here, a CT-developable orbital stent was manufactured via 4D printing of a shape memory polyurethane composite for enophthalmos treatment. The composite was endowed with good CT development properties via incorporation of gold nanoparticles and nano-hydroxyapatite. Based on the bionic idea and CT reconstruction technique, a 4D printed orbital stent with a bionic honeycomb pore structure and an outer contour matching the orbital coloboma was designed to support the orbital tissue more accurately and stably. CT images of rabbits before and after the 4D printed orbital stent implantation showed better volume-filling capacity compared with the two types of the commercial orbital implants. The three-month follow-up showed the good postoperative result, which demonstrated the excellent performance of the composite in the precise minimally invasive treatment of enophthalmos compared with traditional orbital implants.