Tentorial Venous Anatomy: Cadaveric and Radiographic Study with Discussion of Origin and Surgical Significance

Abstract Background Described variations of tentorial venous anatomy impact surgical sectioning of the tentorium in skull base approaches; however, described configurations do not consistently explain post-operative complications. To understand the outcomes of two clinical cases we studied the tentorial venous anatomy of two cadavers. Methods The venous anatomy of the tentorium isolated in two un-injected fresh cadaver head specimens with preserved bridging veins was observed by transillumination before and after methylene blue injection of the dural sinuses and tentorial veins. Our findings in cadavers were applied to explain the clinical and radiologic (MRI and CTV) findings in the 2 cases presented. Results A consistent trans-tentorial venous system, arising from transverse and straight sinuses, communicating with supra- and infratentorial bridging veins was seen in the cadaver and patient radiography (MRI and CTV). Our first patient had a cerebellar venous infarct from compromise of the venous drainage from the adjacent brain after ligation of a temporal lobe bridging vein to the tentorium. Our second patient suffered no clinical effects from bilateral transverse sinus occlusion due to drainage through the accessory venous system within the tentorium. Conclusion Herein, we elaborate upon trans-tentorial venous anatomy. These veins, previously reported to obliterate in completed development of the tentorium, remain patent with consistent observed configuration. The same trans-tentorial venous system was observed in both cases and provided insight to their outcomes. These findings emphasize the importance of the trans-tentorial venous system physiologically and in surgical approaches.