Introduction“Navigation in surgery” spans a broad area, which, depending on the clinical challenge, can have different meanings. Over the past decade, navigation in surgery has evolved beyond imaging modalities and bulky systems into the rich networking of the cloud or devices that are pocket-sized.DiscussionThis article will review various aspects of navigation in the operating room and beyond. This includes a short history of navigation, the evolution of surgical navigation, as well as technical aspects and clinical benefits with examples from neurosurgery, spinal surgery, and orthopedics.ConclusionWith improved computer technology and a trend towards advanced information processing within hospitals, navigation is quickly becoming an integral part in the surgical routine of clinicians.

BACKGROUND: Intraoperative knowledge about extent of resection (EOR) and correlation with eloquent neuronal and vascular structures is important in skull base tumor surgery, especially when complete removal is not feasible and a combination with radiosurgery/radiotherapy is planned. Currently, ultrasound, computed tomography or magnetic resonance imaging (iMRI) are modalities to assess EOR during surgery. Their use, however, is restricted by limited availability and costs, interruption of workflow, and data interpretation. Purpose of this prospective single-institutional study was to objectify EOR online without the need for additional