Brain Surgery in Bronze Age

Trepanation is a surgical technique in which a hole is drilled into the human skull to treat intracranial diseases. It was quite popular during the 16th and 17th centuries in Europe. Count Philip of Nassau had 27 successive trepanations done in the 17th century. In England, it was a common form of treatment among miners who suffered cranial trauma.
Trepanation has a much older history; it was done during the Bronze Age in Peru and Jericho as well. During those times, it was done to repair skull fracture resulting blows, to remove splinters and blood clots. It was also done on dead people, to obtain skull bones to create necklaces.

At Ikiztepe, a small settlement near the Black Sea occupied from 3200 to 1700 B.C., archaeologist Önder Bilgi of Istanbul University has uncovered five skulls with clean, rectangular incisions that are evidence for trepanation, or basic cranial surgery. The procedure may have been performed to treat hemorrhages, brain cancer, head trauma, or mental illness. Last August Bilgi also unearthed a pair of razor-sharp volcanic glass blades that he believes were used to make the careful cuts.
There is ample evidence that Bronze Age sawbones knew what they doing. Last summer, biological anthropologist Handan üstündag of Anadolu University in Turkey excavated the 4,000-year-old trepanned skull of a man at Kultepe Höyük in central Turkey. üstündag says the surgeon cut a neat 1- by 2-inch incision, and  there are clear signs of recovery in the regrowth of bone tissue at the edges. Judging from the frequency of healed bone in such skulls, anthropologist Yilmaz Erdal of Hacettepe University in Turkey recently proposed that about half of all Bronze Age trepanation patients- and 60 percent of those in Turkey- survived the procedure.[Bronze Age Brain Surgeons]

Trepanation was practiced in Harappa (Lothal, Kalibangan) and the megalithic site of Maski too.

Trepanation is known from the Bronze Age Harappan (ca. 4300 BP) people of the Indus Valley Civilisation. Sarkar (1972) attributed a squarish hole on the right temporal skull of a child of 9-10 years skull found at Lothal, a Harappan site. Roy Chowdhury (1973) also believed that evidence of trepanation was present in Harappan skull No. H 796/B and H 802/B, from Cemetery R37 and possibly in a Kalibangan skull (another Harappan site) in Western India. A megalithic skull (M30) from Maski (Karnataka) in South India also showed evidence of trepanation (Sarkar, 1972): it has two circular holes of 22 mm and 15 mm respectively on the either side of the sagittal suture of the vertex.[Evidence of Surgery in Ancient India:Trepanation at Burzahom (Kashmir) over 4000 years ago]

While the skull of the child found in Lothal is considered the earliest evidence of this type of surgery, a ~4300 year old skull found in Burzahom (10 km north-east of Srinagar)  in Kashmir Valley is definite proof of trepanation. In this particular case, the victim had suffered a blow from a strong wooden stick. She survived the blow as well as the trepanation process.
(Thanks Michel Danino, for the links)
References:

1. The Chicago medical recorder, Volume 35 By Chicago Medical Society
2. God-apes and fossil men: paleoanthropology of South Asia By Kenneth A. R. Kennedy
3. First evidence of brain surgery in Bronze Age Harappa, Current Science, Vol 100, No 11, 10 June 2011