Objects: To characterize the anatomical features of the ventricular regions in patients with myeloschisis and related to successful performance of endoscopic third ventriculostomy (ETV).
Methods: Radiological and endoscopic findings of 21 myeloschisis patients were retrospectively reviewed. Radiological features that could interfere with endoscopic procedures were (1) a huge massa intermedia (12/19), (2) sloping of the third ventricular floor (3/10), (3) narrow anteroposterior length of the third ventricular floor (2/10), and (4) narrow prepontine cistern (8/21). Endoscopic findings were (a) a narrow foramen of Monro (0/3), (b) hypertrophy of the anterior commissure (1/3), (c) sloping of the third ventricle floor (1/3), (d) a huge massa intermedia (3/3), and (e) opaque third ventricular floor (3/3). These endoscopic findings did not interfere with endoscopic procedures by using the Oi-HandyPro neuroendoscope without the above-mentioned radiological features 3 or 4.
Conclusion: Narrow anteroposterior length of the third ventricular floor and narrow prepontine cistern are not infrequently observed. Preoperative evaluation and intraoperative inspection of these findings are very important in successful performance of ETV.