[Intraoperative brain shift in neuronavigation. Causes, clinical significance and solution of the problem]

Intraoperative brain shift is the main cause of inaccurate navigation. This limits the use of both conventional and functional neuronavigation. Causes of brain shift are divided into surgical, pathophysiological and metabolic ones. Brain shift is usually unidirectional and directed towards gravitation. Brain dislocation depends on lesion size and its location. Shift is minimal in patients with tumors <20 ml and skull base neoplasms. Small craniotomy, retractor-free surgery and no ventriculostomy are valuable to reduce brain shift. Brain dislocation increases during surgery that's why marking of eloquent lesions at the beginning of surgery and primary resection near subcortical tracts minimize the risk of damage to conduction pathways. Augmented reality and manual shift of marked objects are the cornerstones of linear correction of brain shift in modern navigation systems. In case of nonlinear brain shift, sonography and intraoperative magnetic resonance imaging can clarify location of surgical target and cerebral structures.