The Art of Cerebral Revascularization: An Illustrative Case Series of Bypass Techniques for Complex Intracranial Aneurysms

Abstract

Introduction Complex intracranial aneurysms (CIAs) comprise a subset of lesions with defiant vascular architecture, difficult access, and prior treatment. Surgical management of CIAs is often challenging and demands an assessment on a case-by-case basis. The generational evolution of bypass surgery has offered a long-standing potential for effective cerebral revascularization. Herein, we aim to illustrate a single-center experience treating CIAs. Methods The authors conducted a retrospective analysis of clinical records of patients treated with cerebral revascularization techniques at Hospital Nacional Dos de Mayo, Lima, Peru during 2018–2022. Relevant data were collected, including patient history, aneurysm features on imaging, preoperative complications, the intraoperative course, aneurysm occlusion rates, bypass patency, neurological function, and postoperative complications. Results Seventeen patients (70.59% female; median age: 53 years) received treatment for 17 CIAs (64.7% saccular; 76.5% ruptured). The most common clinical presentation included loss of consciousness (70.6%) and headaches (58.8%). Microsurgical treatment included first, second, and third-generation bypass techniques. In 47.1% of cases, an anastomosis between the superior temporal artery (STA) and the M3 segment was predominantly used, followed by an A3-A3 bypass (29.4%), STA-M2 bypass (17.6%), and an external carotid artery to M2 bypass (5.9%). Intraoperative aneurysm rupture occurred in 11.8% of cases. Postoperative complications included ischemia (40%), cerebrospinal fluid fistulas (26.7%), and pneumonia (20%). At hospital discharge, the median Glasgow Coma Scale score was 14 (range: 10–15), and 58.2% of patients had a modified Rankin Scale (mRS) score of ≤ 2. At the six-month follow-up, 82.4% of patients had an mRS score ≤ 2, and the morbidity rate was 17.6%. Conclusion CIAs represent a wide spectrum of defiant vascular lesions with a poor natural history. Among the long-standing microsurgical techniques, bypass surgery offers the potential for definitive treatment; however, it merits extensive training and manual dexterity. Our case series illustrated the paramount role of cerebral revascularization for CIAs with a critical approach on a case-by-case basis to provide optimal technical success and neurological outcomes.