LAUSR

The microsurgical management of posterior communicating artery (PCoA) aneurysms can be modified depending on their localization, with respect to the tentorial edge consisting of the anterior petroclinoid ligament (APCL). However, the imaging of APCL has been impractical to date. In this study, we evaluated a simple method for assessing the relationship between PCoA aneurysms and APCL, using three-dimensional computed tomographic angiography (3D-CTA). We retrospectively reviewed all surgically treated cases of PCoA aneurysms via the pterional approach in our institute from May 2013 to August 2018. To predict the localization of the aneurysms, three anatomical lines were drawn on non-subtracted volumetric 3D-CTA as follows: 1. the apex of the anterior clinoid process to the posterior border of the trigeminal depression of the petrosal bone (AACP-PBTD); 2. AACP to the superior edge of the arcuate eminence (AACP-SEAE); 3. the base of the ACP to the superior edge of the arcuate eminence (BACP-SEAE). The relative location of each line to the PCoA aneurysms was compared with actual intraoperative findings. Fifty-six aneurysms were included. The sensitivity, specificity, and positive and negative predictive values of the superior localization of the aneurysm of the AACP-TDPB line were 93.8%, 40.0%, 38.5%, and 94.1%, respectively. Those of the AACP-SEAE line were 93.8%, 42.5%, 39.5, and 94.4%, respectively. In contrast, those of the BACP-SEAE line were 93.8%, 97.5%, 93.8%, and 97.5%, respectively. The BACP-SEAE line is a simple and practical landmark in predicting APCL.