Multimodal treatments of brain arteriovenous malformations: a comparison of microsurgical timings after endovascular embolization

BACKGROUND: To compare the clinical outcomes of hybrid microsurgery and embolization with multi-staged procedure for patients harboring brain arteriovenous malformations (bAVMs). METHODS: We retrospectively reviewed bAVM patients from a multicenter, prospectively collected database (NCT03774017) between June 2016 and June 2020. Patients were divided into single-staged hybrid operation (HO) group and multi-staged operation (MO) group according to the received treatment, in which microsurgeries were performed with embolization in a single setting or with multi-stage procedure, respectively. Cases were 1:1 matched between the two groups. Outcomes were compared between groups, which included neurological deficits (NDs), perioperative rupture, and proportion of complete resection. Variables associated with NDs were analyzed. RESULTS: In total, 198 out of 544 cases were identified, including 120 in the HO group and 78 in the MO group. Sixty-six cases were matched in each group resulting in a total of 132 patients in this case-controlled study. Mean age was 29.2 years old, with 82 (62.1%) being male. No significant difference was observed in baseline demographics and clinical characteristics between the two groups. There were 7 ruptures occurred in the interval between embolization and microsurgery for MO group while none in the HO group (P=0.023). This yielded a rupture risk of 4.1% per year for the MO group. Duration of surgical resection was significantly reduced in HO group (P=0.001). Compared to MO, HO was more favorable to avoid short-term NDs (3.0% vs. 15.2%, P=0.021), but long-term outcomes were similar. The HO modality (OR, 0.110; 95% CI: 0.017–0.737; P=0.023) was confirmed as the protective factor for short-term NDs. CONCLUSIONS: HO is an effective setup to treat complex bAVMs with avoiding interval hemorrhage risk and reducing surgical risk. We also observed overall similar obliteration rate and resulting clinical outcomes between HO and MO.