August 4, 2021

3D printing of medical devices in hospitals, a revolution that turns into a puzzle

By Lilas Pepy

Posted today at 6:30 a.m.

After having modeled the necrotic jaw of the patient according to a scanner, the surgeon creates the cutting guide to be printed (here in blue-green) according to a particular angle and axis.

In the second basement of Henri-Mondor hospital (Val-de-Marne), in a maze of endless corridors lit by icy neon lights, a cool room of a few square meters houses two 3D printers, placed on a shelf . Far from industrial production lines, plastic surgeon Romain Bosc prints tailor-made medical devices (MDs) for his patients, a stone’s throw from a brand new operating theater and the sterilization department.

“Having integrated a manufacturing process within our establishment is a real revolution”, says the doctor. And for good reason: the preparation of MDs is, with some exceptions, carried out by external service providers. In 2018, this activity would have brought in more than a billion dollars in the world.

The disappearance of patents on 3D printers and computer-aided design software in the 2000s prompted Dr. Bosc to embark on the adventure. But, as revolutionary as it is in the medical world, this internalization of 3D printing is a real headache.

Arrived thirty years ago at the hospital, 3D printing is used by odontologists, orthopedic surgeons, maxillofacial and plastic surgeons … “In short, to all those who do tailor-made reconstruction”, summarizes Romain Bosc. “In France, postcancer surgery represents the majority of reconstruction needs”, he continues. The surgeon performs around twenty operations of this type per year using his two printers.

Time saving

In his consultation room on the fifth floor, the specialist explains that on June 4 he will reconstruct the necrotic mandible of a man in his forties from his fibula. Following a tonsil cancer operated on in 2019, the patient underwent radiation therapy which damaged his jaw. Using software using artificial intelligence, Dr. Bosc models the man’s mandible and fibula from a scanner. With his eyes riveted on his computer screen, it will take him two hours to plan his operation virtually: where and how to extract pieces of the fibula to insert them in place of the piece of necrotic mandible that he will remove. “Planning allows me to save two hours on an intervention that already takes nine, that’s considerable! “, he assures.

Read also Surgery: lack of corpses, virtual patients to help themselves

From these files, it extracts cutting guides that it sends to the printer, seven floors below. In a few hours, the print head manufactures, at a temperature of 145 ° C, two acrylonitrile butadiene styrene devices pierced with slits, which the surgeon will position on the mandible and fibula on the day of the operation. This helps to get the saw to the right place. Back in the second basement, in sterile clothes from head to toe, Dr Bosc explains: “The axis, the angle, the length, everything must match for the functional and aesthetic result to be perfect. “ In all, the planning, corrections and printing process will take about ten days, “Against four to five weeks in an industrial”, says the doctor. Gold, “After the assessment and the pre-treatment, we cannot afford to waste a month on tumors of the face which evolve rapidly”, specifies Lydia Brugel, head of the ENT unit at the intercommunal hospital center of Créteil, and collaborator of Doctor Bosc on certain reconstruction operations. Especially since the results of the custom-made cutting guides sent by manufacturers are sometimes obsolete upon receipt: the tumor can grow and errors occur.

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