brain surgery is a technique for guiding the tip of a probe or other delicate
surgical instrument in the brain, through a small burr hole drilled in the
skull and without direct view of the surgical site. Minimizing brain damage
as the probe travels from the skull to the surgical target deep in the brain
requires a straight-lined trajectory that avoids such vital parts of the
brain as the major blood vessels and motor strip. A problem inherent to
stereotactic procedures is that the surgeon cannot view the surgical site.
Therefore. some 3-D localization of the target area is required.
|The Long Beach
Memorial Hospital of Long Beach California initiated an experiment to use a
robot to provide localization to the surgeon by interfacing a CT image of the
patient's brain to the robot's kinematic equations. The procedure consisted
of using a stereotactic frame which is affixed to the patient's head on the
CT scanner couch. Three N-shaped locators on this frame are used to provide a
reference frame to compute the 3-D location of the target image. A robot
bolted to the same CT scanner couch is used to provided the coordinates of
the target relative to the stereotactic frame. The surgeon, based on
observation of CT images, determines the entry point on the skull. The robot
is programmed to align a guide, held by the robot's end-effector, with the
target and the entry point. The surgeon then inserts instruments through the
guide and the entry point, to a depth calculated by the robot.