A Practical Cadaveric Model for Intracranial Bypass Training

Abstract

Intracranial bypass is technically challenging and difficult to learn owing to its relative rarity and complexity. Although multiple training models for intracranial bypass exist, a detailed depiction of the use and fidelity of cadaveric specimens for bypass training is lacking in the literature. This study describes use of preserved cadaveric specimens as a practical training model for performance of multiple intracranial bypasses and discusses the surgical setup for a cadaveric bypass laboratory. Using a cadaveric specimen and basic microneurosurgical instruments and supplies, 5 intracranial bypasses were performed (superficial temporal artery [STA]-to-middle cerebral artery [MCA], MCA-to-MCA, STA-to-posterior cerebral artery [PCA], anterior cerebral artery-to-anterior cerebral artery, and posterior inferior cerebellar artery-to-posterior inferior cerebellar artery) using pterional, subtemporal, interhemispheric, and suboccipital approach. Bypass integrity was assessed by direct fluid injection into the adjacent vessel segment. All procedures were recorded. Procedural steps mirrored actual bypass surgery and included vessel marking, performance of arteriotomy, and completion of an end-to-end, end-to-side, or side-to-side anastomosis. Simulations included anatomically appropriate exposures of common intracranial (MCA, PCA, posterior inferior cerebellar artery, anterior cerebral artery) and extracranial (STA) vessels encountered during cerebral bypass surgery and high-fidelity recreations of the operative corridors associated with deeper anastomoses, such as STA-to-PCA bypass. Vessel diameters were 1.5-2.1 mm, and anastomosis times were 20-40 minutes. Immediate feedback on anastomotic integrity was achieved via direct fluid injection adjacent to the anastomosis site. The cadaveric specimen trainee model is a relatively simple yet high-fidelity approach for learning intracranial bypass.