Article
Most important venous landmarks for use in subtemporal approaches in skull base surgery
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Authors
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Peter A. Winkler
- Department of Neurosurgery, Christian Doppler Medical Center, Laboratory of Microsurgical Neuroanatomy, Paracelsus Medical University, Salzburg, Austria
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S. Ottavio Tomasi
- Department of Neurosurgery, Christian Doppler Medical Center, Laboratory of Microsurgical Neuroanatomy, Paracelsus Medical University, Salzburg, Austria
| Published: | June 2, 2015 |
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Outline
Text
Objective: The exact knowledge of the course of the inferior anastomotic vein and the related temporobasal veins is of crucial importance for subtemporal procedures in skull base surgery. The inferior anastomotic vein and the superior anastomotic vein appear embryologically after the third fetal month. This late appearance reflects the high variability. The present study offers an exact description of these anatomical patterns.
Method: 30 formalin-fixed brains were examined, measured and provided data from 60 cerebral hemispheres. The distance between the confluence of the vein of Trolard into the superior sagittal sinus (SSS), the central sulcus (CS), and the joining point with the Sylvian veins (SV) were registered. Also the junctions of the vein of Labbé with the SV and the transverse sinus (TVS) were recorded.
Results: The vein of Trolard (existing in 48% right and 38% left) connects the SSS precentrally in 40% (right) and 50% (left). The most anterior vein was found 6 cm (right) and 5 cm (left) frontally from CS, the most posterior was located 4.5 cm (right) and 2.5 cm (left) away from CS. The distance between the temporal pole and the occipital pole at the level of the calcarine sulcus was divided into 10 segments. The mean joining point of the vein of Labbé with TVS is located in the sixth segment away from the temporal pole on both sides. The most anterior point was found in the sixth (right) and fifth (left), the most posterior in the seventh segment on both sides. Four patterns of the major superficial anastomotic veins have already been described by Oka K. et al. These patterns consist of a dominant vein of Trolard, the vein of Labbé as the largest superficial vein, a dominant SV, and the last pattern shows of all three veins equally dominant. In addition to these types in three (10%) of our specimens a not yet described variant with a direct connection of the veins of Trolard and Labbé without joining the SV was found.
Conclusions: The knowledge of the patterns and of the confluence points of these veins to the SSS and the TVS leads to a more detailed preoperative planning applying our results to angiograms or MRI-venograms. Accordingly we propose a new classification of the superficial anastomotic veins as shown in the figure above (type I–V).
