====== Endoscopic septum pellucidotomy ======

The [[septum pellucidum]] is a bilateral thin membranous structure representing the border between the [[frontal horn]]s of the [[lateral ventricle]]s. Its most examined components are the [[septal vein]]s due to their surgical importance during endoscopic septum [[pellucidotomy]] (ESP), which is a well-accepted method for surgical treatment of [[unilateral hydrocephalus]]. It is widely accepted that the septum pellucidum contains [[nerve fiber]]s as well, but interestingly, no anatomical study has been addressed to its neural components before. The aim of a study of Barany et al. from the Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary.
Department of Neurosurgery, [[Katharinenhospital]],  Friedrich-Alexander University [[Erlangen]], was to identify these elements as well as their relations to the septal veins and to define major [[landmark]]s within the [[ventricular system]] for neurosurgical use.

Nine [[formalin]]-fixed human [[cadaver]]ic [[brain]]s (18 septa pellucida) were involved in this study. A central block containing both septa pellucida was removed and frozen at -30°C for 2 weeks in 7 cases. The [[fiber]]s of the septum pellucidum and the adjacent areas including the venous elements were dissected under magnification by using homemade wooden [[spatula]]s and microsurgical [[instrument]]s. In 2 cases a histological technique was used to validate the findings of the [[dissection]]s. The blocks were sliced, embedded in [[paraffin]], cut in 7-µm-thick slices, and then stained as follows: 1) with [[H&E stain]], 2) with Luxol fast blue combined with cresyl violet, and 3) with [[Luxol fast blue stain]] combined with [[Sirius red]].

The septum pellucidum and the subjacent [[septum verum]] form the medial wall of the [[frontal horn]] of the [[lateral ventricle]]. Both structures contain nerve fibers that were organized in 3 groups: 1) the [[precommissural fiber]]s of the [[fornix]]; 2) the inferior fascicle; and 3) the superior fascicle of the septum pellucidum. The area directly rostral to the postcommissural column of the fornix consisted of macroscopically identifiable gray matter corresponding to the [[septal nuclei]]. The histological examinations validated the findings of the authors' fiber dissections.

The nerve elements of the septum pellucidum as well as the subjacent septum verum were identified with [[fiber dissection]] and verified with histology for the first time. The septal nuclei located just anterior to the fornix and the precommissural fibers of the fornix should be preserved during ESP. Considering the venous anatomy as well as the neural architecture of the septum pellucidum, the fenestration should ideally be placed above the superior edge of the fornix and preferably dorsal to the interventricular foramen
((Barany L, Meszaros C, Ganslandt O, Buchfelder M, Kurucz P. Neural and vascular
architecture of the septum pellucidum: an anatomical study and considerations for
safe endoscopic septum pellucidotomy. J Neurosurg. 2019 Aug 2:1-10. doi:
10.3171/2019.5.JNS19754. [Epub ahead of print] PubMed PMID: 31374555.
)).