gms | German Medical Science

Background: An intimate knowledge of the so called first order anastomotic veins of the supratentorial cerebral drainage is of crucial importance for exact planning of microneurosurgical procedure, for implantation of grid electrodes in epilepsy surgery and for decompressive craniectomies. Although the existence of the first order inferior anastomotic vein was published by Labbé in 1879 and of the first order superior anastomotic vein by Trolard in 1893 an exhausted and subtle description and classification of these venous trunks and their relation to the Sylvian group of veins is still lacking so far. The present study was carried out in the research laboratory for microsurgical neuroanatomy in order to close this gap.

Materials and methods: 42 cerebral hemispheres were carefully dissected and meticulously described with special regards to presence of the above described, so defined first order anastomotic veins. The caliber were measured and the branches and ramifications of the different main trunks of the three most important first order anastomotic veins were visualized. Special interest was paid to anatomical collateralization and patterns of drainage from the different supratentorial cerebral venous drainage-territories. The investigations were performed under operating microscope and with the use of a digital ruler. The documentation was carried out photographically and by drawings.

Results: The following types of venous drainage-patterns were defined and related to the following classification type I - V:

Type I: 21%: Dominant vein of Trolard

Type II: 17%: Dominant vein of Labbé

Typ III: 43%: Dominant Sylvian vein

Type IV: 17%: Equally dominant vein of Labbé and vein of Trolard with collateralization to the Sylvian veins

Type V: 2%: Direct collateralization between dominant veins of Labbé and Trolard without connection to the Sylvian veins.

Conclusion: The presented study visualizes for the first time an overview about the first order anastomotic veins of the supratentrorial cerebral veins, their dominance and their patterns of collateralization. Also their finest ramifications and branches with their relations to the cortical relief was described. The latter informatiopn is of crucial importance to overcome the phenomenon of brain shifting using neuronavigation with preoperatively provided data. Additionally to the existing scarse literature five types I - V of venous drainage-patterns were described. This classification is applicable for clinical use like exact planning of microneurosurgical procedures and for decompressive craniectomies.