Hopf N J
Department of Neurosurgery, Johannes Gutenberg-University, Mainz, Germany.
Minim Invasive Neurosurg. 1999 Mar;42(1):27-31. doi: 10.1055/s-2008-1053364.
Endoscopically "working around the corner" is presently restricted to the use of flexible endoscopes or an endoscope-assisted microneurosurgical (EAM) technique. In order to overcome the limitations of these solutions, endoscopic equipment and techniques were developed for "working around the corner" with rigid endoscopes. A steering insert with a 5 French working channel is capable of steering instruments around the corner by actively bending the guiding track and consecutively the instrument. A special fixation device enables strict axial rotation of the endoscope in the operating field. Endoscopic procedures "around the corner", including aqueductal stenting, pellucidotomy, third ventriculostomy and biopsy were performed in human cadavers. Special features of the used pediatric neuroendoscope system, i.e., reliable fixation, axial rotation, and controlled steering of instruments, increase the safety and reduce the surgical traumatization in selected cases, such as obstructive hydrocephalus due to a mass lesion in the posterior third ventricle, since endoscopic third ventriculostomy and biopsy can be performed through the same burr hole trephination. Limitations of this technique are given by the size of the foramen of Monro and the height of the third ventricle as well as by the bending angle of the instruments (40-50 degrees).
目前，内镜下“转角操作”仅限于使用软性内镜或内镜辅助显微神经外科（EAM）技术。为了克服这些解决方案的局限性，人们开发了用于硬性内镜“转角操作”的内镜设备和技术。一种带有5 French工作通道的转向插入件能够通过主动弯曲引导轨道进而使器械弯曲，从而实现器械的转角操作。一种特殊的固定装置可使内镜在手术区域进行严格的轴向旋转。在人体尸体上进行了包括导水管支架置入术、透明隔造瘘术、第三脑室造瘘术和活检在内的“转角”内镜手术。所使用的小儿神经内镜系统的特殊功能，即可靠的固定、轴向旋转和器械的可控转向，提高了安全性，并在某些特定病例中减少了手术创伤，例如由于第三脑室后部占位性病变导致的梗阻性脑积水，因为内镜下第三脑室造瘘术和活检可通过同一个骨孔环钻进行。该技术的局限性在于孟氏孔的大小、第三脑室的高度以及器械的弯曲角度（40 - 50度）。
