A team of doctors at a medical center in the Romanian city of Cluj announced on Thursday the conclusion of the first partial kidney transplant in the world.

The team led by Dr. Mihai Lucan at the Urology and Renal Transplant Institute in Cluj performed the surgical intervention on a 3-year old boy who received a part of his mother’s kidney. The operation, which lasted 7 hours, is considered a success.

The boy suffered from renal insufficiency.