From what I understand the operation began around 3 hours ago.
Here is a full translation, made by my friend Mieko and with a little cleaned up English by me:
"I'm sorry for being so sudden in revealing this news.
I believe that I am heading in a positive direction.
Hopefully this is the resolution to the problems which have became so since the re-formation of X Japan was decided.
I have been doing my best on stage and at the ten concerts which started at Tokyo Dome in March last year, but unfortunately things have not necessarily been perfect.
But regardless, the time that I spent with everyone during those shows are very wonderful memories carved in my life no matter what lays ahead in the future.
I have consulted with both Japanese and American doctors who are famous and skilled in this area of work in the past few weeks,
The wide spectrum of medical opinion I was given ranged from "playing drums is no longer possible" to "normal life will again be possible in the future if the disk of the neck is replaced and is given sufficient time to rest afterwards".
I told them "Please do anything which can be done so that my body is able to play the drums once more. Please make my body able to play the piano once more. I do not care what needs to be done to achieve this, even if it means replacing the part of my neck which is damaged".
I believe that this operation will succeed, even now several hours before the operation.
And furthermore, I will carry out concerts in other countries which are due to be announced in the future aswell as more performances in Japan and the concert in France which is already confirmed.
Please, everybody pray that the surgery is a success.
Though I'm not very good with words,
My body is shattering, and I will keep playing music until the last second.
~Do towards ruin~ (laughter...)
Love
Yoshiki"