Treatment of vertebral artery dissecting aneurysms with flow diverter: A single-center experience

Objective To evaluate the safety and efficacy of flow diverter (FD) in the treatment of vertebral artery dissecting aneurysms (VADA). Methods The clinical and imaging data of perioperative period and follow-up were retrospectively collected and analyzed from 22 patients with VADA treated with FD at Department of Neurosurgery, Changhai Hospital, Navy Medical University from August 2010 to March 2019. Of the 22 aneurysms, 4 were recurrent aneurysms, 1 was acute ruptured aneurysm and 17 were unruptured aneurysms. Modified Rankin scale (mRS) was used to comprehensively evaluate the patients after surgery, and O＇kelly-Marotta (OKM) grading scale was to evaluate aneurysm embolization. Results All 24 FDs were implanted successfully in 22 VADA (with 19 Tubridge FDs and 5 Pipeline FDs). The technical success rate was 100%. Ten aneurysms were treated with FD combined with coil embolization. The immediate results of embolization were classified according to Raymond′s classification, with 2 cases of grade Ⅱ and 8 cases of grade Ⅲ. Twelve aneurysms were treated with only FD and significant intra-aneurysmal contrast hemostasis was retained immediately after operation in all 12 cases. No procedure-related hemorrhagic or ischemic complications occurred during the perioperative period. As for clinical follow-up 13.0(8.3-67.9)months, 22 patients had the mRS score of 0. No novel neurological deficits were reported. The short-term imaging follow-up at 6.0(4.7-7.1)months involved 20 cases and the complete occlusion rate was 13/20. The complete occlusion rates were 17/20 for last follow-up at 7.7(6.0-24.4) months and 8/8 for long-term follow-up at 26.5(23.3-31.4) months, respectively. No recurrence was demonstrated. Eight PICAs covered by FD and 3 PICAs harboring aneurysms were all patent during follow-up. One case developed severe in-stent stenosis at 3.5-month follow-up post FD placement in which balloon dilatation and angioplasty with stenting was performed. Twenty-two months later, the stenosis of the lumen returned to normal and the aneurysm was completely occluded. Conclusion FD treatment of VADA seems to have high surgical safety and satisfactory results. Long-term efficacy needs to be further evaluated in large case series. Key words: Intracranial aneurysm; Aneurysm, dissecting; Vertebral artery; Flow diverter