Natural history of brainstem cavernous malformations: prospective hemorrhage rate and adverse factors in a consecutive prospective cohort

The study reported an annual hemorrhage rate of 7.0% exclusively for brainstem CMs, which significantly increased if patients presented with both hemorrhagic presentation and focal neurological deficit (9.2%), or any other risk factor. Patients with a risk factor for hemorrhage needed close follow-up regardless of the number of prior hemorrhages. It should be noted that the referral bias in this study could have overestimated the annual hemorrhage rate. This study improved the understanding of the natural history of brainstem CMs, and the results are important for helping patients and physicians choose a suitable treatment option based on the risk factors and stratified annual rates.Clinical trial registration no.: ChiCTR-POC-17011575 (http://www.chictr.org.cn/).