Background and purpose The Raymond–Roy grading scale is used for aneurysm coiling with only limited data on its validity. The scale was developed based on the extent of initial aneurysm occlusion from 1 to 3. However, the model usefulness in evaluating recurrence, retreatment, and rebleeding is unknown. Our goal was to perform a meta-analysis to evaluate the predictiveness of the Raymond scale.

Methods We performed a systematic review of the English literature for aneurysm coiling which reported the initial embolization results, based on the Raymond–Roy grading scale, and the respective recurrence rates, retreatment rates, and rebleed rates. This yielded data for 4587 aneurysms. We conducted a Bayesian random effects meta-analysis to evaluate the outcomes with respect to the reported initial embolization results.

Results We found the Raymond scale to be predictive of retreatment, with statistically higher rates of retreatment with higher initial Raymond grade. Furthermore, we found a higher probability of rebleeding for initial grades 2 or 3 versus grade 1, which approached significance. The rebleed rates were probably affected by monitoring and treatment of recurrence. However, although there was a trend towards higher recurrence rates with initial grade, this was not statistically significant.

Conclusions The modified Raymond–Roy scale appears to provide reasonable predictive value for treated aneurysm, especially for the clinically more important aspects of retreatment and rebleed rates.