Flow-assisted surgical cerebral revascularization

Abstract

<jats:p>✓Extracranial–intracranial bypass surgery has advanced from a mere technical feat to a procedure requiring careful patient selection and a justifiable decision-making paradigm. Currently available technologies for flow measurement in the perioperative and intraoperative setting allow a more structured and analytical approach to decision making. The purpose of this report is to review the use of flow measurement in cerebral revascularization, presenting algorithms for flow-assisted surgical planning, technique, and surveillance.</jats:p>

Vertebro-Basilar Junction Aneurysms: A Single Centre Experience and Meta-Analysis of Endovascular Treatments

“…Moreover, access to the VBJ is difficult and hampered by the petrous bone and the direct proximity of the aneurysm to the brain stem, perforating arteries and lower cranial nerves makes the approach dangerous. Selected cases may benefit from indirect therapies, such as proximal arterial occlusion and aneurysm trapping, with or without flow replacement, but these procedures may increase the operative risk and compromise the post-operative outcome 4,5,10,40,41,46,50 . In some other situations combined endovascular/microsurgiAspirin therapy was stopped four months after endovascular treatment.…”

Intraoperative tools for cerebral bypass surgery

“…Direct intraoperative flow measurements can be made with the use of a microvascular ultrasonic flow probe on donor and recipient vessels [23]. The flow in ml/min appears as a waveform and as a digital display on the detection unit and is indicated as positive or negative depending on the direction of flow relative to the orientation of the probe [23][24][25]. It allows quantification of the flow and indirect information on the patency of the anastomosis (by measuring the donor and the recipient distally and proximally to the anastomosis).…”

“…CFI is defined as the ratio bypass flow/cut flow. A CFI of 1.0 indicates a highly successful flow-augmentation bypass [23][24][25].…”

In Vivo Evaluation of Quantitative MR Angiography in a Canine Carotid Artery Stenosis Model

“…16 The QMRA software has automated the placement of a perpendicular imaging plane and the selection of the appropriate VENC based on the actual flow in the vessel under study. To date, this technique has been used to guide patient management in cerebral revascularization surgery [17][18][19][20] ; assess intracranial and extracranial vessel stenosis pre-and poststent placement 21 ; measure blood flow in cerebral aneurysms 22 ; evaluate subclavian steal syndrome 23 ; assess collateral volume flow in large-vessel cerebrovascular disease 24 ; and predict outcomes of balloon-occlusion testing. 20 Although in vitro validation of QMRA has been performed by using flow phantoms, 16 in vivo evaluation of clinically relevant cerebrovascular flows, in conjunction with progressive arterial stenosis, has not been previously described.…”