Eastern Aleppo's eight remaining hospitals have hit by at least 23 recorded attacks since the siege began in July, according to Médecins Sans Frontières (MSF).
The two main surgical facilities in the eastern part of the city were damaged five times each, leaving one facility out of service since October 1.
Within the past two weeks, bomb attacks have claimed at least 377 lives, according to the Directorate of Health, which registers casualties confirmed at hospital sites.
Carlos Francisco, MSF’s head of mission in Syria, said: "The situation is unbearable. The few remaining doctors with capability to save lives are also confronting death.
"Only a few days ago, the manager of one of the health centres we support and his whole family, including kids, were killed by a barrel bomb."
Only seven professionals qualified to perform surgeries on war-wounded patients remain in an area with a population of around 250,000, MSF said.
Dr Abu Waseem, the manager of a surgical hospital in the area, commented: "There are a lot of wounded people because the bombs are falling in busy areas – crowded streets, bread queues, or the queues where aid is being distributed."
Pablo Marco, MSF’s operations manager in the Middle East, added: "The Syrian and Russian governments have taken this battle to a new level.
"The whole of eastern Aleppo is being targeted. Hundreds of civilians are being massacred; their lives have turned into hell."