Cerebral bypass procedures in the posterior circulation are difficult to perform and are considered to be high-risk surgery. Venous grafts, like that formed using the saphenous vein (SV), are simple to obtain without posing a high risk of morbidity. The main disadvantage of these high-flow grafts is the mismatch in vessel diameter between donor and recipient vessels in the posterior circulation.
The authors performed a retrospective case study based of data from intraoperative video, patient charts, axial images, and cerebral angiograms.
They treated a 66-year-old man who presented with a giant aneurysm of the vertebrobasilar junction and another large aneurysm of the basilar tip. They chose to create a vertebral artery (VA)–superior cerebellar artery anastomosis with a tapered-down SV graft. It was necessary to reengineer the SV graft to include a gentle taper that would allow for this anastomosis. The vein was incised for a distance of 2.5 cm. A triangular section of the vein, 2 mm at the base and 20 mm high, was then excised from the opened end of the SV. The 2.5-cm-long venotomy was then closed with interrupted 9-0 Prolene sutures creating a gentle taper to the vein down to ~ 2.5 mm in diameter. Thereafter, the authors created a standard end-to-side anastomosis of the VA to the SV with 8-0 Prolene. Postoperatively both VAs were obliterated with coils just proximal to the vertebrobasilar aneurysm. The bypass was patent; after a prolonged stay in the intensive care unit, the patient recovered gradually.
This technique of linear venotomy along the distal 2.5 cm of the vein and subsequent tapering down of the diameter diminishes the circumference of the distal end of the graft, facilitating bypass to smaller vessels. This is a novel and feasible technique to eliminate vessel mismatch in cerebral bypass procedures in the difficult accessible vessels of the posterior circulation.