We've seen the miracles that 3D printing has brought to the medical field, from custom hip implants to "magic arms" for a young girl, but a large proportion of 3D printing medical interventions are happening in animals. See 5 animals helped by 3D printing.
The technology works so well in these cases because it's fully customizable to the exact injury, and species, at hand. The latest example is a sea turtle that was injured after being hit by a boat propellor off the coast of Turkey. It's beak was shattered and the turtle was found floating almost lifeless in the sea.
It was brought to Dalyan Iztuzu Pamukkale University (PAU), Sea Turtle Research, Rescue and Rehabilitation Center where it was given medical attention and fed by hand. It was on its way to recovery, but without any way to survive in the wild without a working jaw. That's where Turkey’s medical 3D printing company, BTech, stepped in.
The company had plenty of experience creating custom 3D printed implants for human patients, but this would be its first animal recipient. The company performed CT scans on the turtle and converted the scans into 3D models. Working with veterinarians and surgeons, the BTech team designed a replica of the turtle's beak that recreated its powerful upper and lower jaws and their specific movements.
The beak was then 3D printed in medical-grade titanium and airmailed to the surgical team. The turtle had to undergo a long and tedious surgery, but it was a success. The world has seen its first 3D printed turtle jaw implant.
The turtle is still recovering from surgery and receiving antibiotics, but he's doing so well his caretakers plan to release him back into the wild once he has fully healed.
Below is a video about the sea turtle's operation. It's in Turkish, but a commenter on the page transcribed it into English, although the images tell the story just as well.