Neuroendoscopic trans-third ventricle approach for lesions of the ventral brainstem surface

Due to the establishment in recent years of neuroendoscopic third ventriculostomy (ETV), it has become possible during ETV to observe the ventral brainstem surface--particularly the prepontine cistern--in a minimally invasive manner via the third ventricular base with a neuroendoscope. As an adaptation of that technique in this study, we investigated a neuroendoscopic trans-third ventricle approach (ETTVA), which accesses lesions of the ventral brainstem surface with a neuroendoscope inserted via the stoma of the third ventricular floor. Our study included 6 cases, including one case each of neurenteric cyst, chordoma, pontine glioma (astrocytoma), ecchordosis physaliphora, endodermal cyst, and cystic schwannoma. Surgical operations performed by ETTVA included 3 cases of tumor resection, 2 cases of tumor biopsy, and 1 case of cyst puncture and aspiration. There were no complications accompanying ETTVA. Out of the 6 cases, only 1 required additional surgical treatment following ETTVA surgery. In the other 5 cases, no additional surgical procedures were performed. This study showed that ETTVA allowed access to the prepontine cistern quickly and in a minimally invasive manner. In selected cases, ETTVA can offer a new approach to these lesions.