Operations Using a Frameless Stereotactic System with a Marker: Technical Note

One of the most critical problems in navigation systems is that of brain shifts during operations. In order to solve this problem, we developed a simple method using a marker placed prior to microsurgery to provide a reference point. We produced a thin probe. After the dural incision, the probe, covered with a silicone tube, was inserted into the target point. Then only the probe was removed, leaving the silicone tube in place. This tube moved together with the brain, which deviated during the operation, and throughout the operation indicated the same point as that which it was pointed at first. This result suggests that this is a simple and useful method to allow navigation systems to accommodate brain shifts during operations.