Introduction: Extracranial-Intracranial bypass procedures of the posterior circulation are less commonly performed than anterior circulation bypasses, and, typically, are more technically challenging. Indications for posterior circulation bypass may include the treatment of complex posterior circulation aneurysms or vaso-occlusive disease, such as Moyamoya disease, atherosclerotic disease, or acute thrombo-embolic occlusive disease.
Methods: This was a retrospective study of 28 posterior circulation bypass procedures performed by two cerebrovascular surgery fellowship-trained surgeons over an 11 year period, from a total of 163 Neurovascular bypass procedures. Bypasses included 8 Occipital-PCA, 5 STA-PCA, 5 STA-SCA, 2 Occipital-PICA, and 8 vertebral artery bypasses. Bypasses were performed under burst suppression with barbiturates or propofol, and intra-operative bypass patency was confirmed with micro-Doppler ultrasonography. Delayed follow-up angiographic or CTA imaging was available in 23 of the patients.
Results: Posterior circulation bypass procedures were successfully performed in all 28 patients, however 4 patients had indirect, onlay procedures to the PCA due to insufficient size of recipient vessels. There were no mortalities, and one new neurologic deficit was seen following bypass. Two of the 23 patients with follow-up imaging demonstrated occlusion of the bypass, of which one STA-SCA showed the new neurologic deficit. Two patients required re-operation within the 30 day post-op period, one for a delayed wound infection, and the other for evacuation of a subdural fluid collection.
Conclusions: With proper fellowship training and sufficient clinical volume, posterior circulation bypass procedures can be performed, with relative safety in carefully selected cases. This series demonstrated a 10.7% rate of clinically evident complications, with neurologic improvement seen in 82% of the patients on delayed follow-up.
Patient Care: It will further define the indications and benefits of posterior circulation bypasses for patients with compromised cerebral circulation at risk for stroke.
Learning Objectives: Gain knowledge about the indications and techniques for posterior circulation bypasses