Robotic Surgical Assistant for Brain Surgery
Stereotactic 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 surgeon must know through what angle and how deep he must insert the probe in order to reach the target. This 3-D localization is usually accomplished by coupling the stereotactic frame with some X-ray device. 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.
One main obstacle to using this robot-assisted technique was the inaccuracy of the hospital's commercial robot, a Puma 200. Only large tumors close to the surface of the skull could be treated, requiring a large entry hole. A robot calibration technique developed by NASA's Jet Propulsion laboratory was used to increase the pointing accuracy of the guide held by the robot, enabling application of the procedure to small tumors which were in the interior portion of the brain. This improvement also decreased the necessary skull drilling hole diameter by 50%. Several successful operations were performed using this procedure at the Long Beach Memorial Hospital in the late 1980's.
Point of Contact:
Samad Hayati
Mail Stop 198-219
Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109
818-354-8273
Samad.A.Hayati@jpl.nasa.gov
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Maintained by: Dave Lavery
Last updated: May 10, 1996