Giant Vertebrobasilar Dissection Aneurysm and Dolichoectasia Bypass Treatment

Objective Giant vertebrobasilar artery dissection aneurysm as well as VBD patients (vertebrobasilar dolichoectasia, VBD) have poor prognosis even under interventional therapy and conventional neurosurgical operation. There are two concepts to deal with it: direct basilar tip bypass with vertebral artery and basilar artery occlusion simultaneously or bypass to provide flow to basilar artery tip combined with flow reduction. Retrospectively analyze operative results under different concept for giant basilar artery aneurysm as well as VBD patients.

Methods Total 14 patients with VBD or huge vertebrobasilar artery dissection aneurysms under three kinds of surgical operation from February of 2013 to March of 2017: Group 1: STA-P2 anastomosis with bilateral vertebral artery occlusion, five cases; V3-RA-P2 (radial artery) bypass with vertebral artery occlusion, three cases. More than eight cases accept bypass and supply artery occlusion simultaneously. Group 2: STA-P2 anastomosis with vertebral artery flow reduction, six cases; six cases provide bypass flow to basilar tip with supply artery flow reduction in contrast with occlusion. Supply artery flow reduction provided by direct suture or clip stenosis under hybrid intervention operation theater. Modified Rankin's score (MRs) applied to evaluate operative results.

Results Group 1: eight cases under basilar tip bypass operation with supply artery occlusion simultaneously: two cases of brain stem compression symptom relieved after operation without complication; four cases showed breath restriction and severe neurological deficits after operation, partially recovered after 3 months with MRs 0–3; two cases suffered severe postoperative complications, 3-month follow-up MRs 4–5, left permanent neurological complications. Group 2: six cases accepted basilar tip bypass with vertebral artery flow reduction: all six cases have good postoperative results without complications, one case suffered SAH and died during 3-month follow-up.

Discussion The etiology for huge dissection vertebra-basilar artery and VBD patients is still unclear. However, both fatal diseases have the same poor prognosis if no surgical intervention. Such patients have the unanimous anatomic characteristics: no posterior communicating artery which keep torn vertebra-basilar artery supplying flow to basilar tip resulting in artery elongated and lumen expansion. Bypass operation through cranial base route could offer enough flow to basilar tip to decrease the pressure in vertebrobasilar lumen that has become universally accepted standard procedure. The key-point for the treatment lays in the risk of supply artery occlusion. From group 1 study shows that intraoperative artery occlusion has definite risk compared with group 2 decrease the artery flow after bypass without occlusion. Flow reduction without occlusion couldn't prevent subsequent aneurysm rupture. The study needs further follow-up and recruit more cases in the future.

Conclusion Bypass for basilar tip could supply enough flow to decrease the pressure for vertebra-basilar artery expansion. Ruptured aneurysms need to occlude supply artery simultaneously after bypass in case of fatal bleeding. Vertebral artery stenosis under hybrid intervention equipment decreases flow in vertebral-basilar system which as greatly safer than artery occlusion simultaneously.

No conflict of interest has been declared by the author(s).