Hi! My first thoughts were that maybe he had his stroke right after surgery..........did they do a CT scan within 24 hrs fo surgery......ours did, I believe. My daughter, now age 10 had 2 surgeries at age 6 and 8....both sides.......no strokes prior, but a stroke after each surgery..........the first within 12 hours after the first surgery, the 2nd approx. 5 days post surgery--hers were the right caudate internal capsule. She has recovered amazingly well, some left side weakness in her fingers..........a little difficult with swallowing thin liiquids, a bit of hypernasal speech.......though they do not know if this was related to moyamoy for sure. She also had a seizure just prior to her first stroke, so is on Tegretol for seizures and aspirin for stroke risk.  I hope your child continues to heal well!
-young children are very resilient........amazes me.....
dawn

Matthew also had a stroke within days of his surgery.  It was actually the most severe one (his strokes being a 2, a 1, and a 3 on a scale of 1-10). 

We were still in Boston at the time.  So we took him straight back to Dr. Scott.  He reminded us that the surgery is not an instant cure.  It takes time.  Matthew has done well since.  No more strokes.   

I hope you son continues to do well as the new blood vessels grow. 

On a side note, Matthew also had renal artery stenosis.  How is it affecting your son's blood pressure?  I have always sworn that was what made Matthew's strokes so light.  When the blood flow was trying to stop, his heart just keep pushing it up there and kept the strokes from being any higher on that scale. 

When you ready to deal with renal stenosis, I can tell you what we tried to do.  It would have been a perfect solution if we had done it earlier (before the doctors tried their stupid first solution).  Whatever you do, do not try angioplasty (the "open the artery with a balloon" thing).

Kim -- mom to Matthew, 19, 3 strokes at 7 and single left kidney due to renal artery stenosis