A Survey of Microsurgical Technique for Extracranial-to-Intracranial Bypass

BACKGROUND: Extracranial-to-intracranial bypass surgery is a well-established technique that has been practiced for over 50 years. Since then, numerous technical variants have developed nationally and internationally. OBJECTIVE: Based on a survey, to collect information on cerebrovascular bypass surgeons and their background, surgical volume, and technical steps of extracranial-to-intracranial bypasses with focus on superficial temporal artery to middle cerebral artery (STA-MCA) bypass. METHODS: An electronic survey was distributed among bypass neurosurgeons. Responses were analyzed for national-international variations of STA-MCA bypass surgery techniques. The survey focused on the technical aspects of the surgery itself rather than patient selection or perioperative management. RESULTS: Survey responses were collected from 51 neurosurgeons performing cerebrovascular bypass, from 11 different countries across North America, Europe, and Asia. The largest age block was early-to mid-career (66.7% aged 36-50 years). Most participating surgeons (80.40%) performed less than 20 bypasses annually, whereas a select few surgeons (3) performed more than 50 annually. The most common bypass was STA-M4MCA bypass with a linear incision (34%) over the parietal branch (44%) and choosing an MCA recipient based on diameter (61.2%). The interrupted anastomosis technique was most common (74%). CONCLUSIONS: The results of this electronic survey will help to identify common patterns in STA-MCA bypass surgery and will serve as a guide to other neurosurgeons to modify and improve their technique. Cerebrovascular bypass is still widely practiced, including by young neurosurgeons, who are actively learning from established masters who share their experience.