Publication: Süperior Meduller Velum: Koyun Beyninde Anatomik-Histolojik Çalışma ve İnsan Beyninde Ön Traktografik Çalışma
Abstract
AmAÇ: Süperior medüller velumun anatomi, histolojisi ve lif bağlantılarını çalışmak. yÖNTEm ve GEREÇlER: Önceden formalinle fikse edilerek dondurulmuş 10 adet koyun beyni kullanıldı. Fiber diseksiyon, Marmara Nörolojik Bilimler Enstitüsü Rhoton Anatomi Laboratuvarı'nda yapıldı. Ayrıca 5 gönüllü hastada süperior medüller velumun lif bağlantılarını görmek için traktografi yapıldı. BulGulAR: Ortalama kalınlık ve uzunluk sırasıyla 0,296 mm (aralık 0,09-1 mm) ve 4,25 mm (aralık 3,25-4,5 mm) olarak bulundu. Histolojik olarak süperior medüller velumun 4. ventriküle bakan anterior yüzünde ependimal küboidal hücreler gözlendi. Subependimal tabakada birkaç glial hücreyle birlikte hiposellüler fibriler bölge, dış ince tabakada ise fibroblastlar görüldü. Hiposellüler fibriler bölgenin altında bol miktarda akson ve organize yapılar görülmekle birlikte, nöron spesifik boyalarla sadece birkaç nöron benzeri yapı dışında nöron gözlenmedi. Difüzyon tensör görüntülemede (DTG) sadece birkaç trakt izlendi. soNuÇ: Anatomik olarak belirgin bir trakt ve histolojik olarak nöronal yapı tanımlanamadı. İmmünohistokimyasal olarak sadece nöronbenzeri hücreler ve organize yapılar gözlendi. DTG çalışmasında spinal kord'dan süperior medüller velum'a çıkan birkaç trakt izlenebildi. Bu yapıyı cerrahi yaklaşımlarda trakt ve nöronlara zarar vermeden feda edebiliyoruz diyebilmek için daha çok sayıda insan kadavra, histoloji ve traktografi de içeren ileri araştırmaya ihtiyaç vardır
AIm: To study the anatomy, histology and fiber relations of the superior medullary velum.mATERIAl and mEThods: Ten previously frozen and formalin-fixed sheep brains were used. The fiber dissection was done using the operating microscope at the Rhoton Anatomy Laboratory of Marmara Faculty of Medicine. A tractographic study was conducted on five volunteer patients to see the fiber anatomy of the superior medullary velum. REsulTs: The average thickness and length was found to be 0.296 mm (range 0.09-1 mm) and 4.25 mm (range 3.25-4.5 mm) respectively. Histologically, the superior medullary velum consisted of cuboidal layer of ependymal cells on the anterior surface related to fourth ventricle. The subependymal layer contained hypocellular fibrillary zone with few glial cells, and the outer layer consisted of thin layer of fibroblasts. Under the hypocellular fibrillary zone, abundant axons and organized structures were observed. Tractographically, only a few fibers were identified on diffusion-tensor imaging (DTI). CoNClusIoN: We could not identify a distinct tract anatomically and neuron cells histologically. Neuron-like cells and organized structures were observed on immunohistochemical analysis. Also a few tracts were observed on DTI study as an ascending pathway from spinal tracts to the superior medullary velum. Further studies including human cadaveric, histologic and fiber tractographic investigations are needed to say that it is harmless to divide this anatomical structure
AIm: To study the anatomy, histology and fiber relations of the superior medullary velum.mATERIAl and mEThods: Ten previously frozen and formalin-fixed sheep brains were used. The fiber dissection was done using the operating microscope at the Rhoton Anatomy Laboratory of Marmara Faculty of Medicine. A tractographic study was conducted on five volunteer patients to see the fiber anatomy of the superior medullary velum. REsulTs: The average thickness and length was found to be 0.296 mm (range 0.09-1 mm) and 4.25 mm (range 3.25-4.5 mm) respectively. Histologically, the superior medullary velum consisted of cuboidal layer of ependymal cells on the anterior surface related to fourth ventricle. The subependymal layer contained hypocellular fibrillary zone with few glial cells, and the outer layer consisted of thin layer of fibroblasts. Under the hypocellular fibrillary zone, abundant axons and organized structures were observed. Tractographically, only a few fibers were identified on diffusion-tensor imaging (DTI). CoNClusIoN: We could not identify a distinct tract anatomically and neuron cells histologically. Neuron-like cells and organized structures were observed on immunohistochemical analysis. Also a few tracts were observed on DTI study as an ascending pathway from spinal tracts to the superior medullary velum. Further studies including human cadaveric, histologic and fiber tractographic investigations are needed to say that it is harmless to divide this anatomical structure