ConcernforFriend,
First, as you have noted, the diagnosis must be firm. Is it Thoracic Outlet Syndrome (TOS), or something else. If you are treating the wrong thing, then of course, it won't work.
There are basically two types of TOS. One, unfortunately, is seen mostly in women, and is the type that is not very well understood. In this type, the patient has some of the typical signs of TOS, but no underlying cause, such as a cervical rib or overdeveloped scalene muscles in the neck (body builders/weight lifters). So, this type is very hard to diagnose, and the usual treatments are only somewhat helpful.
In the second type, there is classic symptoms, reproducible on exam, and the patient has an identifiable structural cause, such as the cervical rib, overdeveloped scalene and other muscles in the neck, large first rib, fascial band compressing the neurovascular structures in the lower neck and shoulder, an old clavicle fracture, narrowed space between the clavicle and the first rib, or other structural abnormality. (One rare cause of TOS, especially in smokers, is a Pancoast Tumor in the lung.) This type usually responds to either the discontinuation of body building or the surgical removal of the offending abnormal structure.
But, it is usually the first type that gets most of the attention, because treatments for it are not very successful. This can be due to several things, but probably the biggest thing is, that it is the improper diagnosis in the first place.
So, unless she has an identifiable structural cause, about the only thing that can be done is the physical therapy, weight management, strengthening of the shoulder suspension muscles, proper biomechanics, proper ergonomics in the work place, proper posture, injections of steroids or Botox, relaxation techniques, medications, and the like.
In some cases of recalcitrant TOS, even without an identifiable cause, a resection of the first rib will to tried as a last ditch effort. Again, this will help in some patients. Others are no better off and now have problems from the surgery and well as the continued problems in the arm.
Again, it is very important to make sure that the diagnosis is firm. The nonsurgical treatments are always tried first. If everything fail, and the patient is showing objective signs of nerve compression and obstruction of the vascular structures, then surgical removal of offending structure or the first rib is then tried.
Hope your friend feels better.
Good luck.