The development of brain surgery began around 400 B.C.E. Brain surgery can be defined as: a medical procedure involving the brain and partially, the skull. Brain surgery helped save lives by relieving intracranial pressure, therefore, lengthening lifespans. It could have also been used to treat other head wounds received in battle with other tribes. (Chavez-Rivera and Sanchez)

Brain surgery worked by creating a hole in the skull to treat bleeding within the skull, or pressure within the skull. Evidence also suggests that brain surgery was used to treat chronic headaches. The tools included in the procedure are called tumi. It is a large, curved, metal knife, used for cutting skin. Other obsidian, stone, bronze, and copper tools were used for the bone. The surgeon, before preforming the surgery, possibly sterilized their hands using cocoa leaves. (Guo)

Brain surgery was a very convenient invention. It lengthened lifespans, reduced chronic pain, and was overall very convenient. Because brain surgery helped people live longer, the Inca Empire was strengthened. Warriors could go back into battle, and tradesmen could continue selling their services. People didn't have to worry about serious head injuries because they could be treated somewhat effectively. (Chavez-Rivera and Sanchez)