Hirayama disease. Muscle strength?

Hi I am Tuhin from Kolkata. I have been suffering from weakening of left upper limb with very limited movement of the thumb since Jan 2012(4 years now). My left hand is quite thin as compared to right hand. Sometimes i feel strong pain in my weak left hand and back. However there are no symptoms in my lower limbs and right hand with little bit of muscle twitching in my right hand. Early diagnosis showed that it is Hirayama and doctors suggested me cervical collar therapy. Recent diagnosis showed that the disease has reached its non-progressive state. Doctors from kolkata have kept me under supervision and told me to follow up after every 6 months. My question is - Is there any treatment possible for this disease so that i can get back to normal ? Any surgery that can improve muscle strength? Please help. Your suggestions are much appreciated.