Isaac Cruz showcasing his new prosthetic hand. The device was created using 3D printing technology and custom-designed to fit Isaac’s upper arm. Photo: Pedro F. Frisneda/El Diario
NYC Health + Hospitals/Jacobi has created a prosthetic arm and hand using 3D printing for its youngest patient yet. Born without forearms or hands, three-year-old Isaac Cruz is adjusting well to his new limb, which he has nicknamed “Mano” (“hand,” in Spanish).
The development of Isaac’s arms was halted in utero because of congenital amniotic bands. Cesar Colasante, MD, a burn surgery fellow in the Plastic Surgery Department, measured Isaac for the device using both traditional measuring tape and photogrammetry scanners. He used the measurements to custom-design a prosthetic device using CAD/CAM software. He imported Isaac’s scan and modeled the parts in contact with the boy to be a perfect fit. “This is probably the first one like this made for such a young patient,” said Dr. Colasante. (Dr. Colasante’s work is supervised by Ralph Liebling, MD, Chief of Plastic and Reconstructive Surgery at NYC Health + Hospitals/Jacobi, who is Isaac’s attending physician.)
Because reimbursement models for 3D-printed prosthetics aren’t yet established, Dr. Colasante paid out of his own pocket for the needed supplies on two versions of the prosthetic: wires, elastics, screws, a harness, and a spool of poly-lactic acid—a raw material for 3D printing. Assisted by Andrew Peredo, MD, another burn surgery fellow, he worked on the designs and construction nights and weekends. “The printer used to be in the call room, but the residents weren’t happy that I had prints going at night, since it can be loud,” Dr. Colasante said. “That’s why our printer has since been moved to the Occupational Therapy gym.”
Once the overall construction was completed on the latest version, several sessions were required to fit the device and adjust it for Isaac. The system was created to allow Isaac to close the “hand” by using one arm to position the prosthetic and the other to pull a trigger to grab things.
An earlier version required that Isaac bring his shoulders forward–thereby pulling a wire that extends from shoulder to shoulder in the harness he wears on his back—to grab things. But the elastic bands on this prosthetic provided more resistance than practical for the three-year-old. Moreover, Isaac was instinctively trying to activate the grip using his other arm—even though the earlier device didn’t work that way—so Dr. Colasante redesigned the prosthetic to work the way the boy instinctively wanted it to work.
Weeks after receiving the new device, Isaac’s father, Alan Cruz, says his son has adjusted well to the prosthetic arm, noting that he is thrilled to show his friends how colorful the device is. He’s now using the device to play with his toy cars.
“The more he uses the arm, the better,” explains Dr. Colasante. “With patients like Isaac, the issue is that it takes forever to get a prosthesis, or they never get it at all. They get used to not having the limbs and fully compensate with other body parts. While that is great for independence—for example, learning how to feed themselves with their feet—they have a hard time adjusting to a prosthesis later because their brain is then wired to not having arms. And using the feet for everything creates tremendous strain on the spine.”
The doctor guesses Isaac will outgrow this prosthesis in six months to a year, but since Isaac is a pioneer, how many times this device can be recalibrated before a new device is needed is unknown.
“Dr. Colasante really helped Isaac with creating this device,” said Mr. Cruz. “He’s a great person, and this arm has helped Isaac a great deal with his everyday tasks.”
“For his other arm, I am creating a myoelectric prosthetic that senses muscle contractions and sends a signal to a computer board that drives a motor to close the hand,” adds Dr. Colasante.
NYC Health + Hospitals/Jacobi began pioneering 3D printing two years ago. Dr. Colasante wrote the original grant proposal to secure a 3D printer and has been pairing patients with these low-cost yet highly durable devices. Approximately 20 patients at NYC Health + Hospitals/Jacobi have received 3D printed prosthetics.