Citation: Minc˘ a, D.I.; Rusu, M.C.; R˘ adoi, P.M.; Hostiuc, S.; Toader, C. A New Classification of the Anatomical Variations of Labbé’s Inferior Anastomotic Vein. Tomography 2022, 8, 2182–2192. https://doi.org/ 10.3390/tomography8050183 Academic Editor: Emilio Quaia Received: 22 July 2022 Accepted: 24 August 2022 Published: 30 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Article A New Classification of the Anatomical Variations of Labbé’s Inferior Anastomotic Vein Drago¸ s Ionu¸t Mincă 1 , Mugurel Constantin Rusu 1, * , Petrinel Mugurel Rădoi 2,3, *, Sorin Hostiuc 4 and Corneliu Toader 2,3 1 Division of Anatomy, Department 1, Faculty of Dental Medicine, “Carol Davila” University of Medicine and Pharmacy, RO-020021 Bucharest, Romania 2 Division of Neurosurgery, Department 6—Clinical Neurosciences, Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, RO-020021 Bucharest, Romania 3 Clinic of Neurosurgery, “Dr. Bagdasar-Arseni” Emergency Clinical Hospital, RO-041915 Bucharest, Romania 4 Department of Legal Medicine and Bioethics, Faculty of Dental Medicine, “Carol Davila” University of Medicine and Pharmacy, RO-020021 Bucharest, Romania * Correspondence: mugurel.rusu@umfcd.ro (M.C.R.); petrinel.radoi@umfcd.ro (P.M.R.) Abstract: (1) Background: The inferior anastomotic vein of Labbé (LV) courses on the temporal lobe, from the sylvian fissure towards the tentorium cerebelli and finishes at the transverse sinus (TS). The importance of the LV topography is related to skull base neurosurgical approaches. Based on the hypothesis of the existence of as yet unidentified anatomical possibilities of the LV, we aimed through this research to document the superficial venous topographic patterns at the lateral and inferior surfaces of the temporal lobe. (2) Methods: A retrospective cohort of 50 computed tomography angiograms (CTAs) of 32 males and 18 females was documented. (3) Results: Absent (type 0) LVs were found in 6% of cases. Anterior (temporal, squamosal–petrosal–mastoid, type 1) LVs were found in 12% of cases. LVs with a posterior, temporoparietal course (type 2) were found to be bilateral in 46% of cases and unilateral in 36% of cases. Type 3 LVs (posterior, parietooccipital) were found to be bilateral in 8% and unilateral in 32% of cases. In 24% of cases, duplicate LVs were found that were either complete or incomplete. A quadruplicate LV was found in a male case. On 78 sides, the LV drained either into a tentorial sinus or into the TS. (4) Conclusions: The anatomy of the vein of Labbé is variable in terms of its course, the number of veins and the modality of drainage; thus, it should determine personalized neurosurgical and interventional approaches. A new classification of the anatomical variations of Labbé’s vein, as detected on the CTAs, is proposed here (types 0–3). Keywords: vein of Labbé; cerebral vein; tentorium cerebelli; tentorial sinus; superficial middle cerebral vein; computed tomography 1. Introduction Temporal lobe venous drainage is important in various neurosurgical procedures and combined skull base approaches [1]. The most important draining vein of the temporal lobe is the inferior anastomotic vein (Labbé’s vein, LV) [1]. During fetal development, the LV, an anastomosis between the middle and inferior cerebral veins, is identifiable at 20 weeks; the superior anastomotic vein (vein of Trolard), which connects the superior and middle cerebral veins, appears after 30 weeks [2]. The superficial middle cerebral vein, or superficial sylvian vein (SV), drains most of the lateral surface of the cerebral hemisphere and follows the lateral (sylvian) fissure to terminate in the cavernous sinus [2]. The superior anastomotic vein (vein of Trolard) passes between the SV and the superior sagittal sinus, thus, connecting it with the cavernous sinus [2]. Commonly, the veins of Trolard and Labbé are alternatively present, thus, dominant. The LV courses the temporal lobe and connects the SV with the transverse sinus (TS) [2]. Currently, the term LV is used to indicate the largest vein in the lateral aspect of the Tomography 2022, 8, 2182–2192. https://doi.org/10.3390/tomography8050183 https://www.mdpi.com/journal/tomography