Importance of the temporal venous drainage to the petrosal approaches of the skull base

Abstract

Objectives: The temporal venous drainage is essential to the favorable prognosis of the patients whose require subtemporal and petrosal approaches to the skull base. To obtain adequate exposure of the middle and posterior fossae the tentorial split is an important step. The aim of this paper is discuss the anatomical aspects of the venous patterns of the temporal lobe stressing the relevant correlations with the petrosal and tentorial approaches. Methods: The authors review the anatomic, surgical and radiological aspects of the temporal venous drainage with special concerning about the preservation of the temporal lobe integrity during the transtentorial and petrosal approaches. Results: The vein of Labbè is the most important vein of the lateral group of veins and it is present in almost 100% of the cases. The inferior system of veins is composed by three different groups of veins in the anterior, medial and posterior portions of the temporal lobe. The anteroinferior veins can be present in 70% of the temporal lobes, the medial-inferior veins in 40% and the posteroinferior in 90% of the cases. The anteroinferior and the posteroinferior groups of veins drain in an independent pattern of the lateral group in more than 10% of the cases. Conclusions: Despite of the preservation of the vein of Labbè during the transtentorial and petrosal approaches, temporal infarction has been observed as a complication of such approaches. The patterns of the venous drainage at the inferior temporal surface should be observed carefully in order to avoid temporal infarction. Angiographic preoperative studies are crucial to evaluate such venous anatomy. The correct positioning of the tentorial incisions according with the temporal venous anatomy and the intermittent gentle temporal retraction are the technical aspects, which permit the better final results.