Still doing headbutts in 2017 with all the info we know about concussions is stupid as hell anyway. Hopefully he'll stop doing them.Shibata suffered a subdural hematoma and had emergency surgery.
A subdural hematoma is most often the result of a severe head injury. This type of subdural hematoma is among the deadliest of all head injuries. The bleeding fills the brain area very rapidly, compressing brain tissue. This often results in brain injury and may lead to death.
Hopefully this is the end of those headbutts.