A well done interscalene block will nearly completely eliminate your post operative pain for 8-12 hrs. A pain pump in the subacromial space will decrease but not eliminate your pain for 2 to 3 days and is extremely safe. I recommend using both for my shoulder arthroscopy patients. If you are afraid of needles and the interscalene block then just go with the pain pump, it is simple to use and very safe.
Dr.Robert E. Bayless