In this procedure, which they named the “precision operation,” the brain was approached from the lateral surface of the skull rather than from the top […]. “[B]urr” holes were drilled on both sides of the cranium at points designated by distances in millimeters from “landmarks” on the skull. A 6-inch cannula, the tubing from a heavy-gauge hypodermic needle, was inserted through one hole and aimed toward the hole on the opposite side of the head. The cannula was inserted about 2.5 inches into the brain and, if no fluid oozed out […] it was lowered to the bony […] ridge at the base of the skull. The cannula was then withdrawn, and a blunt spatula—much like a calibrated butter knife—was inserted about 2 inches into the track left by the cannula. Care had to be taken to avoid damaging major arteries located near the midline of the brain. After the spatula was inserted, its handle was swung upward so that the blade could be drawn along the base of the skull, and a cut was made as far to the side as possible. The spatula was then withdrawn, and the site was rinsed. That was only the first of four quadrants to be cut […] .

         —Elliot S. Valenstein, Great and Desperate Cures, 1986