German neuroendoscopy above the skull base.

Endoscopy plays an important part in current minimally invasive neurosurgery. The concepts, indications, and standards of current neuroendoscopy were developed in the beginning of the 1990s by several groups of neurosurgeons. Several factors contributed to its success and acceptance, including technical development, influence of other disciplines, and adaptation to neurosurgical requirements. This historical survey focuses on the period when this technique initially emerged, including the scientific discussions of each group as well as the arguments and reasons that led to present intraventricular neuroendoscopy. Interestingly, despite the almost independent development of neuroendoscopic systems and techniques, the available systems and techniques applied these days grossly correspond. Rigid rod-lens endoscopes are generally accepted as the best option among the various available instrument sets. Nevertheless, frameless as well as frame-based stereotactic endoscopy and flexible steerable endoscopes might have their applications as well.