A Federation surgeon is a surgery specialist working for the Galactic Federation. They were seen attempting to save Samus Aran's life at Galactic Federation Headquarters in the beginning of Metroid Fusion after she was infected by the X Parasite. Samus had fallen into a coma, crashed her Gunship and was transported on the Biologic Space Laboratories vessel to Headquarters. During the trip, she was given a less than 1% prognosis of survival due to the X's infestation of her Power Suit and body. The surgeons were unable to remove the Power Suit directly as it was so ingrained with Samus's body that they had to surgically remove parts of it. One of the scientists eventually devised a cure: Vaccine "Metroid", a serum prepared from the baby's preserved cell culture. Samus was vaccinated immediately, and the X were quickly destroyed. The surgeons sent the removed pieces of Samus's Power Suit to the Biologic Space Laboratories research station for study. However, the X that had infested these components of the suit still remained, creating the SA-X, an X Parasite clone of Samus that began to wreak havoc on the BSL station.
The surgeons are seen wearing hazmat suits, ostensibly a measure of protection from the X Parasites in Samus's body. The suits are similar to those worn by the BOTTLE SHIP Security Guards.
Fleet Troopers carried out a similar operation performed on Samus many years prior, following the Norion invasion, in which Phazon Enhancement Device functionality was built into her Power Suit to take advantage of the Phazon she began self-generating in her body.