Microsurgical Anatomy of Periventricular White Matter from the Endoventricular Perspective

Understanding the spatial disposition of fiber bundles is a requisite for efficient operative planning in cerebral surgery, respecting the most eloquent structures even when not seen by the naked eye. In this study, we used fiber dissection to show critical relationships between the lateral ventricles and white matter fasciculi.

Twenty cerebral hemispheres obtained from body donation were used to study the lateral ventricles, white matter tracts, and their anatomic relationships. We used a variant of the method described by Ludwig and Klingler for fiber dissection, from inside the ventricular cavity after removing the ependyma.

After removing the ventricular ependyma, adjacent structures were exposed. Corpus callosum fibers form the roof of the lateral ventricle, as well as the anterior wall and floor of the frontal horn. The tapetum, optic radiations, and association fasciculi dominate in the atrium and occipital horn, with distinct fiber orientation patterns. The medial wall of the occipital horn is marked by the presence of the major forceps fibers underneath the bulb of the corpus callosum. The temporal horn walls are characterized by multiple elements, including the hippocampus medially, tapetum fibers laterally and posteriorly, and key neighboring bundles, such as the optic radiations superiorly and the inferior longitudinal fasciculus inferiorly.

Fiber dissection through ependyma removal is an effective method for studying anatomic relationships with adjacent white matter bundles, important for developing a precise anatomic mental picture necessary for effective and safe brain surgery.