Learning curve and embolisation strategy in single-stage surgery combined embolisation and microsurgery for brain arteriovenous malformations: results from a nationwide multicentre prospective registry study.

[OBJECTIVE] Single-stage surgery combining embolisation and microsurgery has been increasingly used as a stand-alone procedure to cure complex AVMs. This study aimed to investigate the learning curve and embolisation strategy for single-stage surgery for AVMs.

[METHODS] This prospective cohort study used data from the nationwide Multimodality Treatment for Brain Arteriovenous Malformations (MATCH) registry in China, conducted between August 2011 and December 2023. A total of 213 complex AVMs were divided into two groups. Group 1 included the first 25 patients. The 188 cases in group 2 included patients numbered 26-213. A case-crossover design was employed to evaluate the influence of complications, unfavourable outcomes and worsening modified Rankin Scale (mRS) score. Cumulative summation analysis was performed to assess the learning curve.

[RESULTS] The rate of major complications decreased from 52.00% in group 1 to 34.57% in group 2 (p=0.089), while the rate of unfavourable outcomes decreased from 44.00% in group 1 to 18.62% in group 2 (p=0.004). The distribution of the three preoperative embolisation strategies was as follows: curative: 72.00% and 19.15%, palliative: 24.00% and 67.55%, and targeted: 4.00% and 13.30%, respectively (p<0.001). Multivariable regression analysis showed that surgeon experience was associated with a lower rate of unfavourable outcomes (p=0.022, OR=0.333). The mean follow-up duration was 49.90±20.54 months. The follow-up mRS score of 5-6 decreased from 9.09% in group 1 to 0.8% in group 2 (p=0.035).

[CONCLUSIONS] Performing single-stage combined surgery in 25 AVM cases is necessary to achieve reproducibility. Rates of major complications and unfavourable outcomes decreased significantly after the first 50 procedures. Palliative and targeted embolisation strategies are associated with a lower rate of unfavourable outcomes.

[TRIAL REGISTRATION NUMBER] NCT04572568.