Hi, My name is Michelle. My son, Sam, is 11 years old and has PWS on 1/3 of his left hand and his arm. We were told the same as you when he was small and so consequently left things alone. The advice we received was that the cons of general anaesthetic outweighed the pros of the treatment. They use general anaesthetic on infants because they cannot be sure of them keeping still. When we returned to Great Ormond Street at a later date we were told that it probably was better to start treatment as soon as possible, but at that time Sam was about 7 and too scared.
Sam has since had a few incidents where his hand has become swollen and painful. This can happen when it is cold or when he has a temperature. Some times it may have been as a result of it being knocked (only very slightly tho!). We decided to go back to GOSH and ask for some advice. The surgeon (Dr Samira Syed) said that as the child grows, their PWS can undergo changes. Sam's hand has started to develop minute red spots (which I cannot see!) and these are sign that it is thickening. She suggested we try a test laser session on an area where his PWS is less dense than his hand. In November Sam had this test done on his arm - he had a local anaesthetic cream applied (magic cream!) and I gave him some Calpol. He was very relaxed as the surgeon and nurse explained everything beforehand - even down to describing how the machine looked. He didn't feel a thing! We were told to use iced water to cool the area after treatment and given cream to apply four times a day. It was sore the next few days but healed very quickly - he had to miss football and PE at school for two weeks but that was all.
Sam will be returned to Great Ormond Street Hospital in May for further treatment to the rest of his arm if the surgeon is happy with the results. As yet, I cannot see an improvement but this may happen in time. She is uncertain whether they will actually treat his hand as this area is much darker than the PWS on his arm, but we are hopeful. She also said that the swelling on the hand is more severe and may prove too painful.
I hope this has been of some help. Please feel free to email me should you want to talk more. My email address is firstname.lastname@example.org