Enthusiasm for delivering an alternative blood supply to the brain by surgical means has waxed and waned for over three decades. In situations where a major cerebral vessel is sacrificed for removal of macroscopic pathology (such as a skull base tumour or giant intracranial aneurysm), the need to replace lost cerebral blood flow (CBF) is obvious and often required as part of a staged surgical procedure.^1,2 In such cases, the need and type of surgical bypass graft (high or low flow) is dictated by the presence or absence of adequate collateral vascular pathways, the design of the circle of Willis, and any extracranial to intracranial (EC-IC) vascular connections.³ Detailed cranial angiography and observation of the clinical and physiological responses to temporary test occlusion of parent vessels provide the relevant information. When reliably practised, daunting cervical and cranial pathologies can be approached confidently with acceptable morbidity.⁴ Although simple in principle, techniques for assessing the need for surgical bypass procedures are not always practised resulting in incomplete treatments, and/or high surgical morbidity from cerebral strokes. Centralisation of expertise and adoption of a more appropriate referral of difficult pathology will serve to address the variation in practice for such cases.

CEREBRAL REVASCULARISATION IN CHRONIC VASCULAR OCCLUSION

A far more intense debate surrounds the indications for cerebral revascularisation in the treatment of …