Kissing Aneurysms: Radiological and Surgical Difficulties in 30 Operated Cases and a Proposed Classification.

Objective The first aim of this study is to bring up the radiological and surgical difficulties of kissing aneurysms and to present solutions. The second aim is to develop a classification that can help to predict the difficulties encountered during surgery. Methods The records of 817 patients who were operated on for aneurysm were reviewed retrospectively to identify kissing aneurysms. The radiological and clinical databases of these patients were evaluated in detail. Results Kissing aneurysms were detected in 30 patients (3.6%). Radiologically correct diagnosis rate of kissing aneurysms was 80% throughout the series. The most common locations were the anterior communicating artery (12 cases, 40%) and the middle cerebral artery (12 cases, 40.0%). The ruptured aneurysm could not be detected preoperatively in 24% of the patients. Intraoperative rupture occurred in 4 patients (13.3%). Accompanying vascular anomaly/variation was seen in 16 patients (53.3%). As detailed in the text, kissing aneurysms were divided into 3 types according to their position with each other on the parent artery from the surgeon's point of view during surgery: type I (proximal/distal), type II (superior/inferior), and type III (right/left). Conclusions Despite advanced angiographic techniques, even today, kissing aneurysms can be misinterpreted as a single bilobular aneurysm. The ruptured aneurysm may not be detectable preoperatively. These complex aneurysms have a high intraoperative rupture risk. Accompanying vascular anomalies are more common than expected. Clip selection and sequencing are important. Proposed classification helps the surgeon to be aware of intraoperative difficulties that he/she may encounter in advance.