What Causes A Tremor In Hand After A Shoulder Surgery?

My husband had surgery in June, 2010 on his right shoulder to repair a partially torn rotator cuff and bicep detachment. A nerve block was inserted in his neck/shoulder area for pain. When the block was removed three days after surgery, there was a tremor in his right hand - sort of a rolling motion between his thumb and first finger. The orthopedic surgeon could not determine the tremor s cause and referred my husband to a neurologist for tests. The neurologist spent five minutes with him and said that it was Parkinson s. He has no other Parkinson s symptoms. He prescribed Mysoline, which had no effect on the tremor and made him feel as though he were on speed. He was referred to a neurologist who specializes in motion disorders who prescribed Sinemet. After beginning with 1/2 tablet 3x a day, my husband is now taking 2 1/2 tablets 4x a day with no reduction in the tremor; in fact, his tremor has increased. We were informed that Sinemet was the go to medication for Parkinson s. However, having been on it for several months with no change, maybe this tremor isn t Parkinson s-related. We would like information as to whether this tremor could be related to the shoulder surgery and/or the nerve block that was used.