Hi Sarah,
Welcome to the NeuroTalk Support Groups.
I'm really sorry to read what has happened to you and I hope you find some support and information here.

There are a number of older posts that might be helpful for you if you do a full forum search for
'Eden-Lange Procedure' and also for 'Spinal Accessory Nerve'.

Spinal Disorders and Back Pain Forum

I see you've posted in General Health Conditions. You might also try posting in the
Thoracic Outlet Syndrome/Brachial Plexopathy Forum
Some of the members there might have some information for you as well.

Reflex Sympathetic Dystrophy (RSD and CRPS) Forum